Precambrian Geology
Northern Swayze Greenstone Belt
Ontario Geological Survey
Report 297
1995
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Precambrian Geology
Northern Swayze Greenstone Belt
Ontario Geological Survey
Report 297
J. A. Ayer
EDNO
1995
N O DA
•
CANADA
ONTARIO
Northern Ontario
Development Agreement
Entente de développement
du nord de l'Ontario
This publication was funded under the Minerals program of the
Canada-Ontario Northern Ontario Development Agreement (NODA),
a four year joint initiative signed November 4, 1991.
Minerals • Minéraux
i
© Queen’s Printer for Ontario, 1995
ISSN 0704-2582
ISBN 0-7778-3813-3
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Canadian Cataloguing in Publication Data
Ayer, John Albert
Precambrian geology, Northern Swayze Greenstone belt
(Ontario Geological Survey report, ISSN 0704-2582; 297)
Includes bibliographic references.
ISBN 0-7778-3813-3
1. Geology-Ontario-Swayze Region. 2. Geology, Stratigraphic-Precambrian. 3. Greenstone belts-Ontario-Swayze
Region. I. Ontario. Ministry of Northern Development and Mines. II. Ontario Geological Survey. III. Title. IV. Series.
QE191.A93 1995
551.7’1’09713133
C95-964027-4
Every possible effort is made to ensure the accuracy of the information contained in this
report, but the Ministry of Northern Development and Mines does not assume any liability
for errors that may occur. Source references are included in the report and users may wish
to verify critical information.
If you wish to reproduce any of the text, tables or illustrations in this report, please write for
permission to the Director, Ontario Geological Survey, Ministry of Northern Development
and Mines, Willet Green Miller Centre, 933 Ramsey Lake Road, Sudbury, Ontario P3E 6B5.
Cette publication est disponible en anglais seulement.
Parts of this publication may be quoted if credit is given. It is recommended that reference
be made in the following form:
Ayer, J.A. 1995. Precambrian geology, northern Swayze greenstone belt; Ontario Geological
Survey, Report 297, 57p.
Critical Reader: P.C. Thurston
Edited/Produced by: Geomatics International Inc.
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Contents
Introduction ..................................................................................................................
Mineral Exploration ................................................................................
Previous Geological Work ......................................................................
Present Geological Survey......................................................................
Acknowledgments ..................................................................................
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General Geology ..........................................................................................................
Archean ................................................................................................................
Ultramafic Metavolcanic Rocks ....................................................................
Mafic Metavolcanic Rocks ............................................................................
Intermediate Metavolcanic Rocks ................................................................
Felsic Metavolcanic Rocks ............................................................................
Clastic Metasedimentary Rocks ....................................................................
Chemical Metasedimentary Rocks ................................................................
Metamorphosed Ultramafic Cumulate Rocks ..............................................
Metamorphosed Mafic Intrusive Rocks ........................................................
Felsic to Mafic Plutonic Rocks......................................................................
Kapuskasing Structural Zone ................................................................
Nat River Granitoid Complex ................................................................
Kenogamissi Batholith ..........................................................................
Tom Smith Lake Granitic Complex ......................................................
Kukatush Pluton ....................................................................................
Hoodoo Lake Pluton ..............................................................................
Ivanhoe Lake Pluton ..............................................................................
Alkalic Mafic Intrusive Rocks ......................................................................
Proterozoic ............................................................................................................
Mafic Intrusive Rocks ..................................................................................
Phanerozoic ..........................................................................................................
Pleistocene and Recent ..................................................................................
Metamorphism ......................................................................................................
Alteration ..............................................................................................................
Silicification ..................................................................................................
Chloritoid-bearing Volcanic Rocks ..............................................................
Carbonatization ..............................................................................................
Epidotization ..................................................................................................
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Geochemistry................................................................................................................
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Structural Geology ......................................................................................................
Kapuskasing Structural Zone ................................................................................
North Swayze Greenstone Belt Zone ..................................................................
Folding ..........................................................................................................
Faulting ..........................................................................................................
Ductile Faults ........................................................................................
Brittle-Ductile Faults ..............................................................................
Brittle Faults ..........................................................................................
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Economic Geology ......................................................................................................
Gold ......................................................................................................................
Arkell ............................................................................................................
BHP-Utah Mines Limited ..............................................................................
B.P. Resources Limited ..................................................................................
Bromley..........................................................................................................
Card Lake Copper Mines Limited ................................................................
Hoodoo-Patricia ............................................................................................
Joburke Mine ................................................................................................
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Johnson Wright ..............................................................................................
Jonsmith ........................................................................................................
Kalbrook ........................................................................................................
Little Long Lac Gold Mines Limited ............................................................
Mining Corp ..................................................................................................
Nib Yellowknife ............................................................................................
Tremblay ........................................................................................................
Unigold Resources Limited ..........................................................................
Copper and Zinc ....................................................................................................
Dome Exploration ..........................................................................................
Hudbay Mining Limited ................................................................................
Karvinen ........................................................................................................
Keevil Mining Group Limited ......................................................................
Noranda Exploration Company Limited ......................................................
United MacFie Mines Limited ......................................................................
Nickel and Platinum Group Elements ..................................................................
Akweskwa Lake ............................................................................................
Amax Minerals Limited ................................................................................
International Norvalie ....................................................................................
Ireland ............................................................................................................
McIntyre Johnson ..........................................................................................
Norduna..........................................................................................................
Iron ........................................................................................................................
Nat River ........................................................................................................
Radio Hill ......................................................................................................
Asbestos ................................................................................................................
Reeves Mine ..................................................................................................
Talc ........................................................................................................................
Penhorwood Mine ..........................................................................................
Barite ....................................................................................................................
Cryderman Mine ............................................................................................
Silica ....................................................................................................................
Horwood Mine ..............................................................................................
Roseval Mine ................................................................................................
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References ....................................................................................................................
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Metric Conversion Table ..............................................................................................
57
FIGURES
1.
Key map showing the location of the synoptic area. ..........................................
3
2.
General geology of the northern Swayze greenstone belt. ..................................
6
3.
Jensen cation plot of ultramafic volcanic samples. ..............................................
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4.
Chondrite-normalized REE plot of ultramafic volcanic samples. ........................
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5.
Jensen cation plot of mafic volcanic samples.......................................................
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Chondrite-normalized REE plot of mafic volcanic samples. ..............................
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7.
Jensen cation plot of intermediate to felsic volcanic samples. ............................
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8.
Chondrite-normalized REE plot of intermediate to felsic volcanic samples. ......
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9.
Jensen cation plot of ultramafic cumulate and gabbroic samples. ......................
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iv
10. Chondrite-normalized REE plot of samples from the Reeves ultramafic
to gabbroic body. ..................................................................................................
23
11. Chondrite-normalized REE plot of samples from the ultramafic to
gabbroic body hosting the Ireland nickel showing. ..............................................
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12. Jensen cation plot of altered mafic volcanic samples from the Joburke Mine. ..
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13. Chondrite-normalized REE plot of altered mafic volcanic samples
from the Joburke Mine. ........................................................................................
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14. Pearce and Cann plot of volcanic samples from the northern
Swayze greenstone belt. ........................................................................................
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15. Pearce and Cann plot of altered mafic volcanic samples from
the Joburke Mine. ................................................................................................
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TABLES
1.
Lithologic units for the northern Swayze greenstone belt. ..................................
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2.
Lithogeochemical sample descriptions and locations. ........................................
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3.
Whole-rock geochemical data from Foleyet and Ivanhoe townships. ................
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4.
Whole-rock geochemical data from Muskego and Keith townships. ..................
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5.
Whole-rock geochemical data from Reeves, Penhorwood, Sewell and
Kenogaming townships. ......................................................................................
37
GEOLOGICAL MAPS
Map 2627 - Precambrian Geology, Northern Swayze Greenstone Belt ..........back pocket
v
Abstract
This report is a synopsis and compilation of the geology of Foleyet, Ivanhoe, Muskego,
Keith, Reeves, Penhorwood, Sewell and Kenogaming townships at a scale of 1:50 000. It
covers most of the northern Swayze greenstone belt within the southwestern part of the
Abitibi Subprovince and a small part of the eastern margin of the Kapuskasing Structural
Zone.
The oldest rocks in the area consist of northeasterly trending paragneiss and amphibole gneiss, intruded by both the Shawmere anorthosite complex and granitoid gneiss,
within the Kapuskasing Structural Zone, on the western margin of the synoptic area.
Tonalite gneiss associated with the Shawmere complex has been dated at 2765 Ma.
Kapuskasing Structural Zone rocks have been metamorphosed to granulite facies conditions and are interpreted to be a segment of Archean lower crust thrust eastwards over the
Abitibi Subprovince along the Ivanhoe Lake cataclastic zone.
East of the Ivanhoe Lake cataclastic zone, the northern Swayze greenstone belt consists of easterly trending supracrustal rocks subdivided into 3 distinct assemblages. The
Muskego–Reeves assemblage in the northern part of the belt consists of mafic flows intercalated with ultramafic volcanic flows, iron formations, clastic sedimentary rocks and
localized accumulations of intermediate to felsic flows and pyroclastic rocks. Conglomerate,
wacke and mudstone occur in an extensive clastic sedimentary unit in the uppermost
stratigraphic reaches of the Muskego–Reeves assemblage in the northwest part of the belt.
The Horwood assemblage lies to the south. It consists predominantly of tholeiitic mafic
flows with minor intercalations of fine-grained clastic sedimentary rocks, calc-alkalic
pyroclastic rocks and ultramafic flows. The Hanrahan assemblage consists of intermediate
to felsic pyroclastic rocks and flows capped by iron formation, within the Hanrahan antiform in the southeast part of the belt.
Extensive sill-like bodies of massive, medium-grained, cumulate-textured ultramafic
rock occur in all the assemblages. Locally, in the Muskego–Reeves assemblage, the cumulatetextured ultramafic units grade along strike into ultramafic flows and thus may represent
proximal-facies flows or feeder intrusions. Differentiation into an uppermost gabbroic
unit occurs in the northern part of the Reeves ultramafic body.
Granitoid intrusions include both early foliated and late massive rock units. Early
intrusions tend to be more sodic and are predominantly tonalite and granodiorite. They are
most abundant in the large granitic complexes outside the supracrustal sequence, including
the Kenogamissi batholith, the Nat River granitic complex and the Tom Smith Lake
granitic complex. Smaller, early intrusions of foliated porphyry, granodiorite and granite
occur within the supracrustal assemblages. Late intrusions include bodies such as the
Ivanhoe Lake, Hoodoo Lake and Kukatush plutons, within the supracrustal rocks, and
parts of the larger external granitic complexes mentioned above. Late granitic phases consist predominantly of massive to weakly foliated granodiorite, granite and monzonite,
with minor diorite, syenite, gabbro and clinopyroxenite. Late intrusive phases of the Tom
Smith Lake granitic complex and the Hoodoo Lake pluton have been dated at 2680 and
2684 Ma, respectively.
Lithogeochemical data indicate the mafic volcanic rocks are magnesium and iron
tholeiites. The tholeiitic mafic and the komatiitic ultramafic flows are depleted in light
rare earth elements, suggesting derivation from a long-term depleted ensimatic Archean
mantle at a constructive plate margin. These geochemical patterns are most similar to
those of modern basalts formed at mid-oceanic ridges. The intermediate to felsic volcanic
rocks are calc-alkalic with highly enriched light rare earth elements. They were most likely derived from destructive plate margins associated with Archean island arc environments. The cumulate-textured ultramafic bodies have geochemical patterns which suggest
an origin common to that of the ultramafic flows.
vi
Polyphase deformation has resulted in at least 5 separate fabric generations.
Generations D1 to D3 are related to regional folding events, with or without associated
ductile deformation. Generations D4 and D5 are spatially associated with regional shear
zones and are interpreted to be related to late ductile deformation. Three distinct generations
of faulting are distinguished. Faults associated with D4 and D5 are designated as ductile
and brittle-ductile faults. Late northerly trending brittle faults are Proterozoic in age and
may be associated with the Matachewan diabase dikes.
A number of significant gold occurrences and a past-producing gold mine indicate
good potential for gold mineralization in the northern Swayze greenstone belt. The
Joburke mine produced about half a million tons of ore grading approximately 0.11 ounce
Au per ton. All of the gold mineralization is spatially associated with ductile deformation
zones. Typically the mineralization occurs in quartz veins in highly deformed and carbonatized mafic volcanic rocks.
Two types of exhalative copper-zinc mineralization are present in the area: 1) localized
concentrations of sphalerite and chalcopyrite within sulphide-facies iron formations; and
2) lenses of strata-bound, massive to disseminated sulphides with minor sphalerite and
chalcopyrite, in sequences containing calc-alkalic felsic, tholeiitic mafic and komatiitic
ultramafic volcanic rocks. Hydrothermal alteration consisting of chloritoid-bearing volcanic
rocks and silicification is locally associated with the stratabound sulphide mineralization.
Potential may also exist for magmatic nickel-copper-platinum group element
deposits. Documented occurrences are predominantly associated with the ultramafic
cumulate bodies in the Hanrahan assemblage. Asbestos and talc are also associated with
the ultramafic rocks. Two ore bodies occur in the Reeves ultramafic unit. The Reeves
asbestos mine produced about 140 000 tons of asbestos and the Penhorwood talc mine is
currently milling 450 tons per day of talc. Industrial minerals, including barite and silica,
have been produced from veins closely associated with granitic intrusions in the
Hardiman deformation zone, in southwestern Penhorwood Township.
Ayer, J.A. 1995. Precambrian geology, northern Swayze greenstone belt; Ontario Geological Survey,
Report 297, 57p.
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Precambrian Geology
Northern Swayze
Greenstone Belt
J. A. Ayer
Geoscientist, Precambrian Geoscience Section, Ontario Geological Survey.
Report approved for publication by B. Dressler, Section Chief, Precambrian
Geoscience Section, Ontario Geological Survey. This report is published with the
permission of John Wood, Director, Ontario Geological Survey.
1
OGS REPORT 297
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OGS REPORT 297
an estimated 27 million tons of 29% total iron in the Nat
River iron formation in Penhorwood Township. A third
iron formation extends about 10 km with an east-northeast
trend across the north-central part of Keith Township. This
iron formation, identified as the Palomar iron formation,
has been explored by a number of companies but as it is
relatively thin throughout its length, resource tonnage figures
were never calculated.
PREVIOUS GEOLOGICAL WORK
The earliest geological reference to the map area is by
Parks (1900) who produced the first map of the area surrounding Ivanhoe and Horwood lakes. Tanton (1917) outlined the distribution of the “greenstones” in the map area
in a reconnaissance survey along the Canadian National
Railway (CNR) line between Gogama and Oba. A geological map by Harding (1937), at a scale of 1:63 360, included
all of Ivanhoe and Keith townships and the southern third
of Foleyet and Muskego townships. A regional-scale mapping project, published at a scale of 1:250 000 by Thurston
et al. (1977), included all of the map area. The western
half of the map area is also included in a 1:100 000 scale
map by Percival (1981).
Previous detailed mapping, predominantly conducted
at a scale of 1:15 840, covered substantial parts of the map
area and includes 1) the northern half of Keith Township
and the southern part of Muskego Township by Prest
(1951) at a scale of 1:12 000; 2) Reeves, Penhorwood,
Sewell and Kenogaming townships by Milne (1972); 3)
the southern half of Keith Township by Breaks (1978); and
4) the northwestern part of Foleyet Township by Riccio
(1981).
The area was covered by an airborne magnetic survey
at a 400 m line spacing and was published in 1963 at a
scale of 1:63 360 (ODM–GSC 1963a-d). A higher resolution airborne magnetic and electromagnetic survey at a
200 m line spacing includes the parts of the map area
underlain by supracrustal rocks and was published at a
scale of 1:20 000 (OGS 1990)
PRESENT GEOLOGICAL SURVEY
This synoptic report is part of a continuing project to
update the geological database of the northern Swayze
greenstone belt (NSGB). The initial phases of the project
were funded by the Northern Ontario Development
Agreement (NODA) and were focussed on detailed mapping
(1:15 840 scale) of Foleyet and Ivanhoe townships in 1991
(Ayer 1993), and Keith and Muskego townships in 1992
(Ayer and Theriault 1992). Reeves, Penhorwood, Sewell
and Kenogaming townships were investigated in 1993,
with detailed mapping at a scale of 1:20 000 focussed on
specific areas with regard to special geological, structural,
geochemical or metallogenic problems. The accompanying
synoptic geological map (Map 2627, back pocket) is at a
scale of 1:50 000 and represents a compilation of informa4
tion derived from the detailed mapping outlined above,
previous mapping projects and from data contained in
mineral exploration files. Exploration work filed for
assessment credit is on file at the Resident Geologist’s
office in Timmins and is now available in a summarized
format in Geological Data Inventory Folios (GDIF) for all
of the 8 townships across the NSGB.
Diamond-drill core stored at a number of locations in
Timmins, including the Ministry of Northern Development and Mines drill core library, and at Falconbridge
Limited and Placer Dome Canada Limited, was examined
and in some places sampled. Diamond-drill hole locations
were derived from the GDIFs available as open files in the
Resident Geologist’s office, Timmins, and from the relevant
company files for those holes not located on the GDIFs.
The geological coding of rock units which were not directly
observed by the author have been derived from the drill
logs and are prefixed by the letter “D” on Map 2627
(back pocket).
Geological data were recorded in the field on acetate
overlays superimposed on 1:15 840 scale aerial photographs. The data were subsequently transferred to cronaflex
base maps prepared by the cartography section of the
Ontario Ministry of Natural Resources.
Data from airborne total intensity and electromagnetic
surveys (OGS 1990) were utilized to derive colour-contoured
magnetic susceptibility and vertical derivative maps.
These maps enhance subtle geological and structural features
and greatly aided in geological interpretation, particularly
in areas with extensive overburden cover. The geological
coding of units interpreted from the geophysical maps are
prefixed by the letter “G” on Map 2627 (back pocket).
A number of regional-scale geological projects
focussing on the Swayze greenstone belt are also currently in
progress. These are as follows: 1) a mineral deposit study
(Fumerton 1992, 1993); 2) surficial geological mapping
and drift geochemistry (Kaszycki 1992; Bernier and Goff
1993); 3) a regional-scale bedrock mapping and
geochronology study (Heather 1993; Heather and van
Breemen 1994); and 4) computer-assisted compilation and
analysis of a wide range of digital data using Geographic
Information System technology (Harris et al. 1994).
ACKNOWLEDGMENTS
M. Puumala and R. Theriault served as senior assistants in
1991 and 1992, respectively. Their contribution to the mapping and the development of geological concepts applied
to the resulting map is very much appreciated. S. Beauchamp,
C. Lang, T. Searcy, Y. Rappaport, T. Hearty, S. Connell
and S. Morrison are gratefully acknowledged for their
capable assistance as junior assistants during the 3 years of
mapping.
NORTHERN SWAYZE GREENSTONE BELT
Appreciation is also extended to the staff of the Resident
Geologist’s office and drill core library in Timmins for logistical support. Members of the geological staff of Noranda
Exploration Company Limited, Falconbridge Limited, Placer
Dome Canada Limited, Marshall Minerals Corporation and
Cominco Limited are thanked for access to diamond-drill
core and proprietary exploration data, and for many fruitful
discussions about the geology of the synoptic area. I would
also like to thank G. Ross of Foleyet for his time and insight
on a number of property tours in and around the map area.
5
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NORTHERN SWAYZE GREENSTONE BELT
Jackson et al. (1994) define supracrustal assemblages
as regional map units that contain rocks sharing some,
but not all, of the following properties: lithic attributes,
geochemistry, facies association, geophysical signature,
structural style and age. The units contained within an
assemblage need not be stratigraphically related, and an
assemblage may either be in fault or depositional contact
with other assemblages.
The MRA is confined to the northern part of the belt
and is composed of tholeiitic mafic volcanic rocks with
lesser components of komatiitic ultramafic volcanic rocks,
calc-alkalic intermediate and felsic volcanic units, and
clastic and chemical sedimentary units. The HWA extends
south of the synoptic area into the central part of the
Swayze greenstone belt. It consists predominantly of
tholeiitic mafic volcanic rocks, with minor intercalations
of fine-grained clastic and chemical sedimentary rocks,
calc-alkalic felsic pyroclastic rocks and komatiitic ultramafic flows. The HNA is confined to the southeastern part
of the NSGB and consists predominantly of calc-alkalic
intermediate and felsic volcanic rocks that have been
intruded by extensive ultramafic and gabbroic sills. A laterally extensive, but relatively thin, unit of iron formation
caps the HNA and delineates much of the boundary
between the HNA and the MRA.
Table 1 is a presentation of the main rock units within the
synoptic area. These units are discussed in more detail below.
ARCHEAN
Ultramafic Metavolcanic Rocks
Previous mapping in the synoptic area took place prior to
the general recognition of the existence of ultramafic
extrusive rocks and thus all ultramafic rocks were classified as intrusions (e.g., Prest 1951; Milne 1972; Breaks
1978). However, current mapping has shown many of
these ultramafic units to be of extrusive origin. The close
spatial relationship of the komatiite flows (unit 1, Map
2627, back pocket) with massive, medium-grained cumulate-textured serpentinite bodies of more enigmatic origin
(unit 7, Map 2627, back pocket) suggests a cogenetic relationship which is not as yet fully understood.
Komatiitic ultramafic flows (unit 1, Map 2627, back
pocket) represent an estimated 5% of the MRA, 1% of the
HWA and were not observed within the HNA. A number
of these units in the MRA are laterally extensive. The most
extensive unit occurs in Penhorwood and eastern Keith
townships, with dimensions of about 15 km (length) by up
to 1 km (width). In central Keith Township, a number of
lenticular units 1 to 2 km long appear to lie along the same
stratigraphic horizon, suggesting the lenticular morphology
might represent basinal areas of komatiite accumulation
separated by areas of higher paleorelief without komatiite
deposition. This observation is supported by the common
Table 1. Lithologic units for the northern Swayze greenstone belt.
PHANEROZOIC
CENOZOIC
QUATERNARY
PLEISTOCENE AND RECENT
Glacial, glaciofluvial, lacustrine and fluvial
deposits
Metamorphosed Ultramafic Cumulate Rocks
Dunite, peridotite, pyroxenite
Chemical Metasedimentary Rocks
Magnetite iron formation, siderite iron formation, sulphide
iron formation, graphitic mudstone, chert
Unconformity
PRECAMBRIAN
PROTEROZOIC
Mafic Intrusive Rocks
Diabase dikes
ARCHEAN
Alkalic Mafic Intrusive Rocks
Lamprophyre dikes
Late Felsic to Mafic Plutonic Intrusive Rocks
Granodiorite, quartz monzodiorite, granite, tonalite, quartz
diorite, gabbro, clinopyroxenite, pegmatite, porphyry, felsite
Early Felsic to Mafic Plutonic Intrusive Rocks
Tonalite, quartz diorite, granodiorite, quartz monzodiorite,
granite, diorite, gabbro, porphyry, felsite
Metamorphosed Mafic Intrusive Rocks
Gabbro, melagabbro, leucogabbro, diorite, anorthosite,
anorthositic gabbro
Clastic Metasedimentary Rocks
Sandstone, siltstone, mudstone, conglomerate, tuffaceous
wacke, paragneiss
Felsic Metavolcanic Rocks
Tuff, lapilli tuff, tuff breccia, massive flow, brecciated flow
Intermediate Metavolcanic Rocks
Tuff, lapilli tuff, tuff breccia, pillowed flow, massive flow,
amygdaloidal flow, brecciated flow
Mafic Metavolcanic Rocks
Massive flow, pillowed flow, variolitic flow, amygdaloidal
flow, brecciated flow, plagioclase-phyric flow, pyroxenespinifex-textured flow, tuff, lapilli tuff, tuff breccia
Ultramafic Metavolcanic Rocks
Massive flow, spinifex-textured flow, polyhedral-jointed
flow, brecciated flow
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OGS REPORT 297
association of the komatiitic flows with sulphidic iron formation and fine turbidites, which implies relatively deepwater deposition.
The extrusive origin of these ultramafic rocks is
indicated by features such as spinifex textures. In some
well-preserved areas, flow units and top criteria are determinable based on the classic distribution of uppermost
flow-top breccias, fine, random spinifex grading downwards
into coarse oriented spinifex (A zone) and a lowermost
cumulate unit of equigranular ultramafic rock (B zone;
Donaldson 1982). Flow units range from 1 to 10 m thick
in the map area. Many of the flows are massive, fine- to
medium-grained cumulate-textured units commonly displaying well-developed polyhedral jointing, with or without
associated spinifex textures. Massive komatiitic flows
range from equigranular to porphyritic. The rocks typically
feel talcose when powdered and have a wide variety of
weathered surface colours, ranging from green to orangebrown. Where highly strained, the ultramafic volcanic
rocks have been altered to chlorite-talc-carbonate schists,
with or without a bright green fuchsitic mica.
In komatiites with olivine spinifex, the relict olivine
crystals have blade-like morphologies (pseudomorphed by
serpentine, chlorite or amphibole) with an interstitial
groundmass of fine-grained plumose pyroxene (replaced
by amphibole and/or chlorite), with or without intergrown
plagioclase and opaque minerals. The olivine spinifex may
be randomly oriented and fine grained near the tops of
flow units to extremely coarse grained with a preferred
orientation roughly perpendicular to the orientation of the
flow units. In the lowermost parts of the flow units
(B zone), orthocumulate textures predominate. Cumulus
olivine (pseudomorphed by serpentine, chlorite and/or
amphibole) occurs as equant, medium-grained euhedral
crystals with fine-grained intergranular intergrowths of
plumose pyroxene and opaque minerals, very similar in
habit to the interstitial textures within the spinifex parts of
the flow.
Rare komatiitic flow units consisting of pyroxene
spinifex were observed. A good example of this komatiite
type occurs in the ultramafic volcanic unit immediately
north of the Radio Hill iron formation, east of the
Groundhog River. In these units, the uppermost part of the
flow units (A zone) consists of acicular, skeletal amphibolitized pyroxenes in an interstitial groundmass of very
fine-grained amphibolitized pyroxene, plagioclase and
opaque minerals. In the lower part of the flow unit
(B zone), an orthocumulate texture is preserved consisting
of medium-grained, equant, euhedral, skeletal, tremolitized
pyroxenes in a goundmass similar to the spinifex part of
the flow unit.
An unusual heterolithic breccia occurs in ultramafic
volcanic rocks located north of the CNR tracks about 1 km
west of Palomar siding in Keith Township. The breccias
are surrounded to the south, west and north by a large area
of massive, medium-grained, adcumulate-textured ultramafic rocks (unit 7, Map 2627, back pocket). The breccia
8
consists of angular to subrounded clasts of spinifex-textured komatiite, and amygdaloidal mafic and intermediate
volcanic rocks. Clast types vary within the unit from dominantly intermediate flow clasts to dominantly ultramafic
flow clasts. Brecciated clasts are supported in a sparse
matrix of finely comminuted material largely derived from
the clasts. Locally, thin, spinifex-textured to massive
komatiite flows are interbedded with breccia units. This
feature indicates the breccia is synvolcanic, rather than
tectonic as was originally suggested by Prest (1951).
Mafic Metavolcanic Rocks
Mafic volcanic rocks represent about 70% of the MRA,
90% of the HWA and do not occur within the HNA, with
the possible exception of mafic units east of the Mindedo
Creek fault in eastern Kenogaming Township. Amphibolitic remnants represent about 10% of the Kapuskasing
Structural Zone and are probably mafic volcanic units
and/or synvolcanic mafic intrusions metamorphosed to
granulite facies (Riccio 1981).
Amphibolites in the Kapuskasing Structural Zone
occur as isolated rafts intruded by a variety of granitic
gneisses. These rafts occur both as large mappable units
and as outcrop-scale inclusions. The mappable units are
commonly surrounded by granitic gneiss with abundant,
unassimilated amphibolite inclusions. The amphibolites
are fine- to medium-grained, dark grey to black rocks with
strongly foliated to gneissic textures. They are mainly
composed of hornblende and plagioclase. Accessory minerals
include clinopyroxene, garnet, quartz and opaque minerals.
Mafic volcanic rocks in the Swayze greenstone belt
vary from light green, to dark green to black on weathered
surfaces. They range from soft and chloritic to relatively
hard and amphibolitic. Massive flows are the most common
mafic volcanic rock type and vary from fine to medium
grained. Pillowed flows occur in gradational contact with
the massive flows. Pillows average 30 to 50 cm in length
with thick selvages (up to 2 to 3 cm) that are darker green
in colour and more rusty than the pillow interiors. The
mafic volcanic rocks are predominantly aphyric in hand
specimen. Rare exceptions occur in a few outcrops of
plagioclase-megaphyric mafic volcanic rocks adjacent to
the Nat River granitoid complex in southeastern Muskego
Township and northeastern Penhorwood Township.
Vesicles infilled with quartz, carbonate and/or epidote are
widespread in the pillowed flows. They typically range up
to 2 to 3 mm in diameter and are concentrated in the outer
parts of the pillows. Variolitic flows consist of abundant,
light grey, 1 to 5 cm varioles which tend to coalesce in the
interior parts of pillows. In thin section, the varioles consist of radiating to concentric intergrowths of fine-grained,
acicular, amphibolitized pyroxene with very fine-grained,
intergranular anhedral plagioclase. They have slight protuberances on their outer surfaces (visible in thin section),
suggesting an origin as devitrification spherulites rather
than immiscible liquids.
NORTHERN SWAYZE GREENSTONE BELT
Relict subophitic textures are preserved in some mediumgrained massive flows. Massive mafic flows containing
pyroxene spinifex textures occur locally in northern Keith
Township. Lower cumulate-textured bases (B zone) were
not observed in these spinifex-textured basaltic flows.
Rather, the central parts of these flow units exhibit a fine to
extremely coarse spinifex texture, with crystals oriented
roughly perpendicular to the flow direction. Textures in the
spinifex-textured mafic flows are microscopically similar to
the ultramafic pyroxene spinifex-textured flows (described
above), except that the content of fine-grained interstitial
plagioclase is sufficiently high (up to 30%) to suggest a
basaltic composition. Pyroxene spinifex textures also occur
sporadically in the coarser grained massive mafic flows.
They consist of actinolitized pyroxene in large, acicular,
dendritic grains in a groundmass of finer grained plagioclase
and amphibole.
Breccias consisting of brecciated pillows or autoclastic
flow breccias in massive flows are locally present. Mafic
pyroclastic rocks consisting of tuff, lapilli tuff and tuff
breccia are very rare. These units are largely reported in
diamond-drill core logs and could possibly be misidentified
flow breccia.
Mineralogically, the mafic volcanic rocks predominantly
consist of amphibole and plagioclase. Throughout much of
the area, the mineral assemblage of actinolite and albite, with
or without accessory epidote, sericite, carbonate, quartz,
chlorite, leucoxene and opaque minerals, indicates they are
of mid- to upper-greenschist metamorphic facies. Locally,
the presence of garnet, biotite, hornblende and plagioclase of
oligoclase to andesine composition indicate the mafic
volcanic rocks were recrystallized to amphibolite metamorphic facies within 1 to 2 km of the contacts with the large
granitoid bodies, and throughout much of southern Ivanhoe
Township.
Intermediate Metavolcanic Rocks
Intermediate volcanic rocks constitute about 10% of the
MRA with much of these occurring in the northwestern part
of the assemblage. They represent about 5% of the HWA and
75% of the HNA.
The intermediate volcanic rocks are medium to light
green-grey on weathered surfaces. In the northwestern part
of the MRA, the majority of the intermediate volcanic rocks
are flows which are typically plagioclase-phyric and amygdaloidal. Pillowed flows have thin dark grey to dark green
pillow selvages. Amygdules may constitute up to 20% of the
rock and range up to several centimetres in diameter. They
are typically infilled with carbonate, quartz, epidote, biotite
and/or chlorite. Plagioclase and rarely pyroxene (replaced by
amphibole) phenocrysts may constitute up to 20% of the
flows. They occur in a very fine-grained groundmass of
recrystallized amphibole, chlorite, epidote, opaque minerals
and/or biotite, commonly with plagioclase microlites either
in random pilotaxitic or aligned trachytic orientations.
Pillow breccia, autoclastic flow breccia and highly
vesicular flows are abundant east of the Ivanhoe Lake
pluton. This is also an area of extensive hydrothermal
silicification that probably occurred as a consequence of
the original porosity of these rocks. Pillow breccias are
more abundant than pillowed flows in this area and consist
of light grey, irregularly shaped, amygdaloidal pillow fragments in a medium grey, sericitic hyaloclastite matrix.
Intermediate fragmental rocks consisting of tuff, lapilli
tuff and tuff breccia are common within the HNA, but relatively uncommon within the MRA. Clast populations
within the fragmented units range from monolithic to heterolithic. The fragments are composed of various aphyric
to porphyritic, nonvesicular to highly vesicular, intermediate
volcanic clasts (possibly pumiceous in texture). These
fragmental rocks are light to medium grey-green and relatively hard. Fine- to medium-grained plagioclase crystals
(constituting 5 to 30% of the rock) are common and minor
quartz crystals may also be present. Plagioclase, amphibole,
biotite and quartz are essential minerals, while accessory
minerals may include chlorite, sericite, carbonate, epidote
and opaque minerals. With a few exceptions, the fragmental
units of the HNA are poorly sorted without any visible
bedding or grading. Rare interbeds of finely laminated
siltstone and normal grading occur in the northern margin
of the HNA. Massive to laminated, amygdaloidal intermediate flows and flow breccias were also observed in a
number of localities within the HNA.
Felsic Metavolcanic Rocks
Felsic volcanic rocks constitute about 5% of the MRA in a
number of isolated lenticular units scattered throughout
the assemblage. Minor felsic units also occur in the HWA
and HNA.
The felsic volcanic units are light grey on weathered
surfaces and are typically quartz- and/or feldspar- phyric.
Felsic volcanic rocks are massive to fragmented.
Pyroclastic units are subdivided into tuff, lapilli tuff and
tuff breccia. Felsic flows are exposed in a small outcrop on
the southeast side of Highway 101. They are massive and
generally nondescript, but locally contain zones of angular
flow breccia and isolated miarolitic cavities infilled by
very fine-grained quartz. Felsic volcanic rocks commonly
contain up to 25% plagioclase and quartz phenocrysts in a
very fine-grained groundmass of recrystallized quartz,
feldspar, sericite, biotite, chlorite, carbonate and epidote.
Some of the felsic units appear to be complexes of
intrusive and extrusive origin, possibly in an exogenous
dome-like setting. The Groundhog Lake felsic complex is
a large enclave (3 by 5 km) within the Kukatush pluton.
The complex consists, for the most part, of a weakly foliated, homogeneous, porphyritic, very fine-grained, massive
felsic rock. Subordinate felsic to intermediate pyroclastic
rocks and interbedded wackes occur along the southern
margin of the body. The massive felsic rock is typically
9
OGS REPORT 297
composed of 1 to 2% feldspar phenocrysts (1 to 3 mm in
diameter) in a very fine-grained, equigranular groundmass
of anhedral quartz and feldspar with 2 to 10% muscovite,
biotite, chlorite and epidote. Microscopic examination of a
sample from the south-central part of the complex
revealed that muscovite grains are partially replaced by
fibrolitic sillimanite. This feature indicates the complex
has experienced metamorphism to amphibolite facies.
Irregular patches of coarser-grained granitic material were
locally observed, likely produced by the escape of a related,
volatile-rich phase. Minerals within the coarser phase are
similar, but with a higher proportion of biotite to muscovite
(i.e., 8% biotite, 2% muscovite) and about 5 to 10% microcline. The microcline occurs in subhedral crystals in the
groundmass and as rare rapakivi-textured phenocrysts,
consisting of microcline cores surrounded by finer, euhedral,
plagioclase crystal-rich rims. Miarolitic cavities were
observed within the porphyritic rock along the west shore
of Groundhog Lake.
Clastic Metasedimentary Rocks
Clastic sedimentary rocks represent about 10% of the MRA
and are a very minor component of the HWA and HNA.
A wide variety of sedimentary types are present. Clastic
sedimentary rocks of the MRA, consisting of conglomerate,
sandstone, siltstone and mudstone, are poorly exposed in a
unit up to 4 km wide that extends across the northwest and
central part of the map area and terminates against the
cumulate-textured ultramafic to gabbroic unit hosting the
Reeves and Penhorwood mines. The conglomerate units
are heterolithic and composed of well-rounded to subangular
clasts of felsic porphyry, volcanic clasts of varying composition (i.e., ultramafic to felsic) and up to 5% of a fine,
sugary-textured quartzose material which could represent
either recrystallized chert or vein quartz. Conglomerate
beds are up to 1 m thick and are typically in contact with
interbedded, fine- to medium-grained sandstone beds up to
50 cm thick. Normal grading and interbedded siltstone and
mudstone units are locally evident.
A relatively proximal provenance is suggested for this
clastic sedimentary unit. It is most likely that the sediments
were derived from local volcanic edifices and deposited by
turbidity currents in submarine fans. This is indicated by
the proportion and variety of volcanic clasts, and the
changes in dominant clast types in different locations. For
example, conglomerates observed along the Ivanhoe
River, in Foleyet Township, contain clasts of spinifextextured ultramafic volcanic rocks and massive sulphides
where the sedimentary unit overlies a thick ultramafic
volcanic unit in the vicinity of a number of known massivesulphide lenses (Ayer 1993). In contrast, the conglomerates
and wackes south of Slate Rock Lake, in Keith Township,
contain relatively abundant quartz-phyric felsic clasts and
quartz sand immediately east of a 500 m thick unit of
quartz-phyric felsic volcanic rocks.
10
Another clastic unit, up to 1 km wide, lies north of the
main clastic unit in the southwestern part of Muskego
Township. It is not well exposed and lies within the Slate
Rock deformation zone. This unit appears to lack conglomerates and consists of turbiditic sandstone, siltstone
and mudstones with a considerable intermixture of intermediate volcanic rocks. North of Slate Rock Lake, wackes
within this northern unit are thickly bedded and normally
graded. They consist of feldspathic wacke with a framework
of mainly plagioclase grains and subordinate quartz
grains, in a matrix of finer-grained feldspar and quartz
with accessory sericite, chlorite, opaque minerals, biotite,
epidote and zircon.
A third clastic unit lies immediately south of the
Radio Hill iron formation. Its width is somewhat conjectural, as there are only a few outcrops of thickly bedded
wacke occurring sporadically immediately south of the
Radio Hill iron formation.
Less extensive clastic sedimentary units are scattered
throughout the map area. They consist of thinly to thickly
bedded wacke, siltstone, mudstone and minor conglomerate.
In general, these units are intimately intermixed with ultramafic to felsic volcanic units and in some localities with
chemical sedimentary rocks. The coarser parts of the units
are composed of minor conglomerate and feldspathic and
lithic wacke.
Siltstones are light grey to dark grey, and mudstones
are dark grey to dark green on weathered surfaces. Both
are typically schistose and thinly laminated. Silty layers
are composed of very fine-grained recrystallized feldspar,
quartz, chlorite, sericite, carbonate and biotite. Mudstones
have a higher proportion of micaceous minerals.
Tourmaline porphyroblasts occur in turbidites interbedded
with ultramafic to intermediate volcanic rocks northeast of
Palomar Lake, in northeastern Keith Township.
Chemical Metasedimentary Rocks
Chemical sedimentary rocks, consisting of banded magnetite-, sulphide-, graphite-, siderite- and chert-facies iron
formation occur scattered throughout the map area in all
the supracrustal assemblages. Three extensive units of
magnetite iron formation are the Palomar, the Radio Hill
and the Nat River iron formations which are described in
more detail below. Sulphide iron formation consists of
fine-grained, laminated pyrite or beds of concretionary
pyrite nodules interbedded with graphitic mudstones
and/or chert. These sulphide iron formations and graphitic
mudstones occur in units with fine-grained wacke and
siltstone and are interbedded with mafic and ultramafic
volcanic rocks in a number of localities throughout the
map area, many of which have been identified by geophysical surveys and diamond drilling. The sulphides are predominantly pyrite and/ or pyrrhotite and may also include
sphalerite and chalcopyrite (see “Economic Geology”).
NORTHERN SWAYZE GREENSTONE BELT
A banded magnetite-chert iron formation unit, termed
the Palomar iron formation (Ayer, in press), occurs north
of the MacKeith fault in Keith Township. The iron formation is about 10 km long and up to several hundred metres
thick. The unit consists of a number of separate iron
formation units up to 12 m thick, interbedded with massive and pillowed mafic flows. Magnetite-rich beds of
fine-grained euhedral magnetite intergrown with anhedral
quartz are up to several centimetres thick. Chert beds of
similar thickness consist of recrystallized anhedral to
granular quartz and commonly contain radiating sprays of
prismatic tremolite porphyroblasts. Locally, a distinctive
blue magnetite-chert banded iron formation was intersected
in diamond-drill core. This unit is distinguished by the
presence of porphyroblasts of a blue amphibole of possible
sodic composition (riebeckite?).
The Radio Hill iron formation has a strike length of
about 10 km with a maximum thickness of 500 m in the
vicinity of Radio Hill, in Penhorwood Township.
Throughout much of its length it is overlain by komatiite
flows to the north and underlain by thickly bedded wacke.
Milne (1972) indicates 2 seams of iron formation separated
by felsic volcanic rocks on the western margin of
Penhorwood Township. Only the southern seam appears to
continue westward into Keith Township. East of Leadbeater Lake in Penhorwood Township, the 2 units coalesce
and thicken (probably in an isoclinal F1 fold nose) to form
a single zone about 200 m thick. East of this, in the
Radio Hill area, the iron formation is folded into an isoclinal S-shaped fold about 500 m thick (F2 folding?),
plunging north-northwest at about 50° (Milne 1972).
The unit consists of magnetite, siderite, sulphide, silicate
(minnesotaite), hematite (jasper) and graphite iron formation typically interbedded with chert. A number of distinctive
facies changes occur in the Radio Hill iron formation. In
the Radio Hill area in Penhorwood Township, the unit
consists of magnetite, siderite, sulphide, silicate, hematite
and graphite iron formation. West of the Groundhog River
in Keith Township, the magnetite and silicate facies are
absent. Milne (1972) has characterized 4 major vertical
facies transitions in the Radio Hill area. They are, from
south to north (hanging wall to footwall), 1) sulphide, silicate and carbonate facies, 0 to 50 m in thickness; 2) oxide
facies with minor carbonate and silicate facies, 30 to 100 m
in thickness; 3) carbonate and silicate facies, 10 to 80 m in
thickness; and 4) sulphide facies, 0 to 25 m in thickness.
The Nat River iron formation caps the HNA and thus
outlines much of the boundary between the HNA and the
MRA in Penhorwood and Kenogaming townships. It
extends about 20 km and ranges from 30 to 60 m in thickness. The iron formation consists of magnetite, sulphide,
silicate and graphite iron formation interbedded with
chert. Magnetite-chert iron formation is the predominant
facies type and its continuous presence is indicated by a
strong aeromagnetic response along its margins to about
the Nat River. East of the Nat River, the magnetic response
is attenuated along the south margin, but a response continues to the east on airborne geophysical surveys. This
feature suggests a facies change to sulphide and/or
graphite facies. Sporadic lenses of magnetite-facies also
occur further to the east at the HNA-MRA contact, southwest and south of Crawford Lake. The iron formation does
not appear to continue east of Crawford Lake.
Metamorphosed Ultramafic
Cumulate Rocks
Cumulate-textured ultramafic bodies represent about 20%
of the HNA and 2% of the MRA. The units are up to 15
km in length and 500 m in width. The interpreted setting
of these rocks is somewhat enigmatic and the unit may be
composed of both flows and sills. The rocks of this unit
were originally mapped as intrusions (Prest 1951; Milne
1972). Many of these massive cumulate-textured units
within the MRA grade laterally, and rarely vertically, into
spinifex-textured komatiitic flows. Recent research on
rocks with similar textures and chemistry in other Archean
terranes has indicated that some of these cumulate-textured
ultramafic rocks are a proximal facies of komatiitic flows
(Hill et al. 1990). Others, such as the numerous ultramafic
cumulate bodies within the HNA, may be sills. These units
do not grade into spinifex-textured komatiites and may be
subvolcanic intrusions related to the same magmatic
events which resulted in the komatiite flows found in the
MRA.
The ultramafic cumulates are fine- to medium-grained
massive rocks that range in colour from white to dark
green on weathered surfaces. They are strongly magnetic
and where undeformed, are relatively resistant to weathering.
Where they have experienced strong ductile deformation,
they are soft, talcose and may contain green fuchsitic
mica. Ubiquitous irregular joints related to serpentinization
outline polyhedral columns from 10 to 100 cm in diameter.
Primary textures are dominantly net-textured adcumulate
to mesocumulate and rarely orthocumulate. Forsterite
cores within serpentinized rims, surrounded by thin interstitial rinds rich in opaque minerals, have been microscopically observed in some of the adcumulates. Rocks with
mesocumulate textures contain serpentinized, anhedral
olivine crystals with a higher proportion of interstitial
material consisting of talc, serpentine, carbonate and
opaque minerals. Preserved orthocumulates, in which
serpentinized cumulate olivine grains are isolated in a
groundmass of intercumulus material, are rare within this
unit but are commonly observed in the cumulate portions
of spinifex-textured flows. North of the CNR tracks and
west of Palomar siding in Keith Township, rare spherical
structures up to 1 cm in diameter are infilled with serpentine
and sulphides. These features are suggestive of amygdules
and may be further evidence of an extrusive origin for
some of the massive, cumulate-textured ultramafic rocks.
An extensive cumulate-textured body, hosting both
the Reeves asbestos mine and the Penhorwood talc mine,
occurs in northern Penhorwood and southern Reeves
townships. The unit has a northerly trend which is distinctly
11
OGS REPORT 297
variant from the overall easterly trend of most rock units
in the NSGB. The northern part of the unit is folded about
a northerly trending F2 antiformal syncline. Exposure is
best in the northwestern part of the unit in the vicinity of
the Reeves Mine, where based on the differentiation trends
(see “Geochemistry”), the ultramafic body faces to the east.
It is underlain by poorly exposed komatiitic volcanic rocks
on the west and mafic volcanic rocks to the north. The
komatiite unit is up to about 150 m wide. The basal portion
consists of talc-carbonate schists in highly strained contact
with schistose clastic sedimentary rocks to the west. The
schists are succeeded to the east by spinifex-textured
flows grading into brecciated flows. The komatiite unit is
overlain by a thick unit of massive, serpentinized adcumulate dunite capped by about 3 m of pyroxenite grading into
a thick gabbroic unit in the core of the antiformal syncline.
In the Reeves unit there is a gradational contact between
an underlying ultramafic unit and the overlying gabbro,
indicating the gabbros are differentiates. Differentiation
was also observed in the serpentinite unit overlying the
Nat River iron formation in northern Kenogaming
Township. The unit is about 250 m thick at the eastern end,
where it appears to consist of several units grading
upwards from olivine orthocumulates into garbbroic zones
and spinifex-textured pyroxenites. Locally, the gabbroic
portion of these differentiated bodies have random
spinifex textures consisting of elongate branching pyroxenes in a groundmass of fine-grained plagioclase. These
textures are similar to the gabbroic central zones of large
differentiated komatiite flows such as the Boston Creek
flow in the Kirkland Lake area of the Abitibi greenstone
belt (Stone et al. 1987).
Metamorphosed Mafic
Intrusive Rocks
Mafic intrusions include dark green, medium- to
coarse-grained gabbro and minor melagabbro. Light greygreen, medium- to coarse-grained leucogabbro may form
isolated bodies, such as the lenticular intrusion west of
Muskego Lake in northeastern Ivanhoe Township, or
occur more commonly as minor differentiates closely
associated with gabbroic to ultramafic bodies. Inequigranular textures composed of randomly oriented, acicular,
amphibolitized pyroxenes in a finer plagioclase-rich
groundmass are common. Relict subophitic textures were
also observed in thin section.
The most extensive mafic intrusion within the map area is
the Shawmere anorthosite. It is located in the northwestern
portion of the map area within the Kapuskasing Structural
Zone. Within the NSGB, less extensive mafic intrusive
rocks represent about 5% of the HWA and HNA, and less
than 1% of the MRA. Some of these are intrusive units, as
indicated on previous maps (Prest 1951; Milne 1972;
Breaks 1978). Others, however, may be extrusive in origin,
representing large ponded and locally differentiated flows.
The Shawmere anorthosite complex is a deformed
and metamorphosed Archean basement-type anorthosite
within the Kapuskasing Structural Zone. It underlies the
western part of Foleyet Township in a northeast-trending
complex about 50 by 10 km in size (Thurston et al. 1977).
Riccio (1981) subdivided the intrusion into a main zone
and a marginal zone. In the map area, the main zone consists largely of leucogabbro and anorthosite, with smaller
amounts of gabbro, melagabbro and ultramafic rocks. The
marginal zone consists of foliated, garnetiferous amphibolite cut by anorthosite and gabbro dikes. The gabbroic
rocks typically consist of plagioclase megacrysts in a fineto medium-grained recrystallized matrix of plagioclase,
amphibole and pyroxene with or without minor opaque
minerals, quartz and garnet. Anorthositic rocks consist of
a medium-grained granulated mosaic of plagioclase and
only rarely contain plagioclase megacrysts. Mafic minerals
consist largely of hornblende, but may also include garnet,
titanite, epidote, chlorite and biotite. Gneissic textures predominate in the margins and clotty and coronitic textures
in the central parts.
The compositional and textural similarity of the mafic
intrusions in the Swayze belt with the volcanic rocks
strongly suggests that they are synvolcanic and that some
may be thick massive flows that cooled slowly. However,
locally crosscutting contacts indicate that at least some of
these are intrusions. Some of the gabbro bodies are closely
associated with the cumulate-textured ultramafic units.
12
The elliptical Cornice Creek gabbro occurs in the
southwestern part of Keith Township. The intrusion is well
foliated along its margin, and locally contains felsic to
mafic volcanic xenoliths. The rock is characterized by
large clusters (5 to 10 mm) of hornblende crystals set in a
finer grained matrix dominated by plagioclase. Such texture
is typical of many other gabbroic bodies in Keith
Township. Microscopically, the rock displays a subophitic
texture with coarse-grained, subhedral, amphibolitized
pyroxene crystals that partially to totally enclose subhedral
to euhedral plagioclase crystals.
Felsic to Mafic Plutonic Rocks
The relative age of the plutonic rock units indicated on
Map 2627 (back pocket) is based on the absence or presence
of a tectonic fabric and its intensity of development, as
there are only a few precise U-Pb zircon age determinations
on the plutonic bodies within the area. The reader is
advised that these criteria should only be considered as
guidelines to relative age. Previous U-Pb age determinations
(Percival and Krogh 1983; Frarey and Krogh 1986) suggest
that the plutonic rocks of the Kapuskasing Structural Zone
(KSZ), with a minimum crystallization age of 2765 Ma,
are generally older than those of the NSGB. Initial results
of an ongoing U-Pb geochronological study focussed on
the Swayze greenstone belt (SGB) and surrounding granitoids also suggest younger ages for the plutonic suites of
the SGB, but also show a wider range of ages than was
NORTHERN SWAYZE GREENSTONE BELT
previously recognized. For example, results of the study
indicate an age of 2740 Ma for the Chester biotite trondhjemite pluton in the southeastern part of the SGB
(Heather and van Breemen 1994). In addition, the study
reveals that the Kenogamissi batholith is composed of
phases with a wide range of ages, from 2713 to 2665 Ma.
The more extensive granitic complexes and plutons
are described below. Smaller intrusions consist of early to
late granitic stocks and dikes within the supracrustal rocks
of the NSGB and are not described in any detail. Early
foliated porphyritic dikes and intrusions are found
throughout the map area, but they are most abundant in the
predominantly sedimentary rocks of northern Keith and
northwestern Penhorwood townships. The intrusions are
predominantly of plagioclase porphyry with subordinate
amounts of plagioclase-quartz porphyry. Plagioclase porphyry consists of medium- to coarse-grained, oscillatoryzoned, euhedral plagioclase phenocrysts in a very finegrained groundmass of anhedral-granoblastic quartz and
feldspar, with lepidoblastic biotite or chlorite (after
biotite?) and minor amounts of epidote, carbonate and
opaque minerals. The plagioclase phenocrysts have been
moderately altered to sericite, epidote and/or carbonate.
KAPUSKASING STRUCTURAL
ZONE (KSZ)
Located west of the Ivanhoe Lake cataclastic zone, the
granitoid gneisses of the KSZ are compositionally variable, consisting mainly of tonalite and granodiorite. A
tonalite gneiss body within the Shawmere anorthosite
complex on the western margin of Foleyet Township may
be coeval with or intrudes the Shawmere anorthosite. The
tonalite gneiss has a minimum Pb-Pb age of 2765 Ma, thus
providing a lower limit for the age of the complex and the
associated paragneisses and amphibolites of the KSZ
(Percival and Krogh 1983).
In general, tonalite and diorite gneiss occurs adjacent
to, and within, the Shawmere anorthosite complex, whereas
granodiorite intermixed with tonalite gneiss is concentrated
further east in the KSZ. The tonalite gneiss commonly
contains abundant amphibolite xenoliths. Minor quartzsaturated phases consisting of diorite and monzonite
gneiss occur adjacent to the Shawmere anorthosite complex in southwestern Foleyet Township. Tonalite gneiss is
light grey and contains plagioclase (andesine), quartz,
biotite, with or without hornblende and accessory alkali
feldspar, apatite, epidote and opaque minerals. Granodiorite
gneiss is a light pinkish grey with 5 to 15% alkali feldspar
and biotite as the main mafic mineral. Diorite gneiss is
dark grey with plagioclase (andesine), quartz, hornblende,
with or without biotite, and accessory alkali feldspar,
apatite, epidote and opaque minerals.
NAT RIVER GRANITOID COMPLEX
The Nat River granitoid complex marks the northern
boundary of the north Swayze greenstone belt and extends
from the Ivanhoe Lake cataclastic zone eastward across
the map area. The distribution of this complex is largely
based on the interpretation of aeromagnetic patterns. This
interpretation, supported by sparse outcrop, also indicates
that the early felsic to intermediate intrusions have lower
and less variable magnetic susceptibilities. The complex
consists of 1) both early, strongly foliated to gneissic,
hornblende-biotite tonalite to granodiorite and late, massive to weakly foliated, biotite granodiorite; 2) weakly
foliated pegmatite and aplite dikes; and 3) massive granite
dikes.
Early phases are predominantly strongly foliated to
gneissic tonalites and granodiorite. The tonalite is light
grey on weathered surfaces and consists of plagioclase
(oligoclase), quartz and biotite, with accessory epidote and
titanite. In eastern and western Muskego Township, the
dominant rock type is medium-grained, moderately to
weakly foliated pink-weathering hornblende-biotite granodiorite and biotite granodiorite. These early intrusive
phases are cut by diorite, felsite and pegmatite, and locally
contain minor inclusions of tonalite and diorite. Typically
the hornblende-biotite granodiorite consists of 35 to 40%
plagioclase (moderately altered to sericite and epidote),
20 to 25% quartz, 10 to 20% microcline, 15 to 20% hornblende, 1 to 5% chloritized biotite and trace amounts of
titanite, opaque minerals, epidote and zircon. Biotite granodiorite consists of 60 to 70% plagioclase, 20% quartz,
10% biotite and 5% alkali feldspar. The minor hornblende
diorite probably represents a more primitive intrusive
phase, closely associated with the granodiorite in southwestern Muskego Township. Hornblende diorite consists
of 40 to 60% plagioclase (moderately to strongly altered to
sericite and epidote), 20 to 40% hornblende, less than
5% biotite, less than 5% quartz, less than 5% opaque minerals and less than 5% epidote.
Compositions of the late granitic intrusions within the
Nat River granitoid complex are generally more potassic
than the early foliated to gneissic granitoids. They are predominantly granite and granodiorite, with or without coarsegrained, tabular alkali-feldspar phenocrysts. A large late
felsic pluton intrudes the foliated granodiorite and diorite
within the Nat River granitoid complex in Muskego
Township and northeastern Foleyet Township. It consists
of a massive to weakly foliated, equigranular to porphyritic,
medium-grained biotite granite and granodiorite with or
without muscovite. Compositionally, these late-stage
granitic intrusions are distinguished from the surrounding
early granitoids by their higher potassium content, significant differences in mafic mineral composition and common
porphyritic nature. Typically they consist of 35 to 40%
microcline, 30 to 35% quartz, 15 to 25% plagioclase, 5%
biotite, less than 2% muscovite, less than 2% titanite and
trace amounts of epidote, apatite and opaque minerals.
Porphyritic granite is common south of Beatty Lake, where
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OGS REPORT 297
it contains 5 to 10%, zoned alkali-feldspar phenocrysts 1 to
5 cm in size. Large inclusions of massive, coarse-grained,
alkalic melagabbro occur within the granite on the southwest side of Beatty Lake. The melagabbro consists of 60
to 70% hornblende, 15 to 20% plagioclase (moderately
altered to sericite and epidote), 10 to 15% microcline, 2 to
3% titanite and trace amounts of apatite and opaque minerals. The alkalic gabbro probably represents a compositionally primitive early phase of the granitic magma.
Foliated, medium-grained hornblende gabbro with
accessory magnetite is seen in outcrop along the
Groundhog River north of Highway 101. Granitic inclusions
and crosscutting aplite dikes suggest the gabbro is an early
intrusive phase of the complex. Airborne magnetic survey
data indicate the gabbro is about 2 km wide along the
southern margin of the complex. Another unit of perhaps
similar chronology occurs along the southern margin of
the Nat River granitoid complex in western Reeves and
Sewell townships. This unit was not observed in the synoptic mapping and thus has been compiled from Milne
(1972). He describes the unit as a mixture of biotite-hornblende granodiorite and diorite. The diorite is composed of
30 to 40% hornblende with coarse-grained plagioclase and
interstitial quartz, with accessory titanite, magnetite and
apatite, and secondary epidote, chlorite, carbonate, sericite
and pyrite. Because the exposure is very poor in this part
of the map area, the unit has been largely interpreted from
aeromagnetic maps, as it has a markedly higher magnetic
response than the surrounding foliated tonalite and granodiorite.
In northeastern Foleyet and northwestern Muskego
townships, the Nat River granitoid complex consists of
tonalitic gneiss, paragneiss and amphibolite intruded by
biotite-muscovite granite and pegmatite. The granite consists of plagioclase (oligoclase), microcline, quartz, biotite
and muscovite, with trace amounts of epidote, titanite,
opaque minerals and rarely garnet, which is suggestive of
an aluminous “S type” granite. The pegmatite dikes consist of graphic-textured intergrowths of perthite and
quartz, biotite, muscovite, and may also contain minor
fine-grained garnet. Locally, plagioclase within the granite
in the northwestern part of Muskego Township has undergone significant epidotization suggesting propylitic alteration, perhaps as a result of the intrusion of abundant
granitic pegmatite dikes in the area. Similar dikes cut foliated granodiorite along Highway 101 in west-central
Muskego Township. In this locality, however, the pegmatite dikes also contain minor quantities of chalcopyrite
and molybdenite, which are also suggestive of porphyrytype mineralization.
KENOGAMISSI BATHOLITH
Within the synoptic area, the Kenogamissi batholith
occurs in the southern part of Penhorwood Township, the
14
southern and eastern parts of Kenogaming Township and
the southeastern part of Reeves Township. It is a large,
elliptical granitoid complex that separates the Swayze
greenstone belt from the Abitibi greenstone belt. Reconnaissance mapping by Heather (1993) has documented a
complex sequence of at least 6 intrusive phases which range
from early foliated to late massive granitic phases.
Geochronological studies by Heather and van Breemen
(1994) have revealed a large range of ages, including 1)
foliated hornblende tonalites at 2713 Ma; 2) foliated biotite
tonalite to granodiorite at 2697 Ma; 3) massive to foliated,
potassium-feldspar megacrystic, hornblende granodiorite at
2692 Ma; and, 4) massive biotite granite at 2665 Ma.
Only marginal phases were observed in the present
study. These range from biotite tonalite in the southwest to
hornblende-biotite tonalite and biotite granodiorite in the
southeast. These southern marginal phases are strongly foliated, with northerly dips becoming progressively steeper
towards the east. A septum of foliated hornblende monzodiorite, crosscut by biotite tonalite and aplite dikes, joins the
batholith with the Nat River granitoid complex in southcentral Sewell Township. Moderately foliated biotite granite
occurs in the batholith south of a large supracrustal inclusion
in southeastern Sewell Township.
A late granite phase is indicated within the
Kenogamissi batholith south of Montgomery Lake, in
southeastern Penhorwood and southwestern Kenogaming
townships. Milne (1972) indicated this phase is continuous
with a septum of granitic rocks joining the batholith with the
Kukatush pluton. High resolution aeromagnetic maps indicate that this granitic septum is more likely a series of separate intrusions, as is indicated on Map 2627 (back pocket),
that are most likely satellite bodies or apophyses of the
batholith. Milne (1972) described the granite (or rather
quartz monzonite in Milne’s classification scheme) as being
massive and inequigranular with coarse-grained plagioclase
in a medium-to fine-grained groundmass. The mineralogy is
described as mainly oscillatory-zoned oligoclase, microcline and quartz, with minor biotite and muscovite, accessory titanite, magnetite and apatite, and secondary sericite
and epidote.
TOM SMITH LAKE GRANITIC COMPLEX
A complex of early foliated tonalite and granodiorite, late
foliated monzonite and diorite and massive granite and
granodiorite, located east of the Ivanhoe Lake cataclastic zone
in western Ivanhoe Township, is herein identified as the
Tom Smith Lake granitic complex. Compositions are highly
variable and mainly include tonalite, granodiorite, granite
and quartz-saturated, alkalic intrusions. Foliated tonalite is
light grey and consists of plagioclase (oligoclase), quartz and
biotite with minor alkali feldspar, titanite, apatite and epidote.
Foliated granodiorite typically contains up to 10% coarsegrained alkali-feldspar phenocrysts in a finer grained groundmass of plagioclase (oligoclase), microcline, quartz and
biotite, with minor myrmekite, titanite and opaque minerals.
NORTHERN SWAYZE GREENSTONE BELT
Late monzonite, syenite and diorite, with gabbro and
clinopyroxenite xenoliths, occur in 2 separate bodies: 1)
along the Ivanhoe Lake cataclastic zone in southwestern
Foleyet Township; and 2) south of the broad part of
Ivanhoe Lake in west-central Ivanhoe Township.
The phases along the Ivanhoe Lake cataclastic zone
have a strongly developed cataclastic fabric defined by
elongate alkali-feldspar augen. Intrusive phases along
Ivanhoe Lake contain medium-grained alkali-feldspar
phenocrysts and are only moderately to weakly foliated.
Percival (1981) interpreted the alkalic intrusions in these 2
areas as a narrow continuous body. Aeromagnetic data
from these areas indicate isolated magnetic highs separated
by magnetic lows. Thus, a more likely interpretation is
that of 2 isolated alkalic intrusions separated by a large
unexposed area, which is probably underlain by early foliated tonalite and/or granodiorite. Geochronological sampling of a diorite from south of the broad part of Ivanhoe
Lake indicates a U-Pb age of 2680 +3-2 Ma (Percival and
Krogh 1983).
Foliated syenite and monzonite are pinkish-grey, typically with up to 10% coarse-grained alkali-feldspar augen
where the rock is strongly deformed. The phenocrysts
consist of perthitic alkali feldspar surrounded by anhedral,
recrystallized alkali feldspar and plagioclase in the matrix
with clinopyroxene, biotite and accessory apatite and
opaque minerals. Foliated diorite is dark grey, with mediumgrained plagioclase (oligoclase) crystals in a finer groundmass of hornblende, quartz and biotite, with accessory
titanite, opaque minerals, apatite and epidote.
Gabbro and clinopyroxenite occur as inclusions or
large rafts in the monzonite and syenite intrusions. These
mafic intrusions manifest a tectonic foliation but their
mineralogy indicates a relatively unmetamorphosed
nature, in contrast with the mafic and ultramafic intrusive
rocks in the supracrustal sequences discussed above.
Gabbros are dark grey to black and contain 50% normally
zoned plagioclase (oligoclase), 25% augite, 12% hornblende and 12% biotite and trace amounts of titanite,
epidote, carbonate and zircon. Clinopyroxenite is dark grey
and medium grained, with coarse-grained hornblende phenocrysts. A typical clinopyroxenite consists of 70% augite,
20% hornblende and 10% plagioclase, with trace amounts
of titanite and apatite.
In the southwest part of Ivanhoe Township, the main
phase of the complex is a homogeneous biotite granite
consisting of microcline, plagioclase (oligoclase), quartz
and biotite with trace amounts of apatite, epidote and
opaque minerals. Numerous pegmatite dikes, consisting of
graphic-textured intergrowths of perthite and quartz,
intrude the granite.
KUKATUSH PLUTON
The Kukatush pluton is a 5 by 15 km, elongate, easttrending body, located in southeastern Keith and south-
western Penhorwood townships. It is a homogeneous
intrusion consisting of a massive, equigranular, mediumgrained hornblende monzonite. In contrast to the low
magnetic susceptibilities of the Hoodoo Lake pluton and
the Groundhog Lake felsic complex, the Kukatush pluton
exhibits a positive aeromagnetic anomaly which, in conjunction with limited exposure, indicates a more extensive
distribution to the west into Hoodoo Lake than indicated
on previous maps (Thurston et al. 1977; Breaks 1978). The
high-resolution aeromagnetic maps also suggest modification of the interpreted contacts of Milne (1972) in southwestern Penhorwood Township.
The most abundant phase of the pluton consists of a
massive, equigranular, medium-grained hornblende monzonite. As seen in thin section, monzonite typically consists
of 40 to 50% plagioclase (slightly altered to sericite and
epidote), 20 to 30% microcline, 0 to 5% quartz, 10 to 20%
hornblende, less than 5% biotite (chloritized with epidotized rims), less than 3% magnetite, less than 3% titanite
and trace amounts of epidote, apatite and zircon. A more
differentiated hornblende-biotite quartz monzonite, containing 10% alkali-feldspar phenocrysts (1 cm in size) and
10 to 20% quartz, occurs locally as a marginal phase. Both
phases commonly contain a significant proportion of
mafic volcanic xenoliths (5 to 10%). Inclusions of finegrained, felsic volcanic rock were also observed in the
vicinity of the Groundhog Lake felsic complex.
A number of small intrusions with northeast elongation,
located between the Kukatush pluton and the Kenogamissi
batholith, are most likely satellites of the Kenogamissi
batholith. These bodies consist of biotite granodiorite,
muscovite granite and quartz-feldspar porphyry. They are
strongly foliated, dip gently to the northwest, and are in
sheared contact with the supracrustal rocks on their southeastern margins. This suggests that southeasterly directed
thrusting along the northwestern contact of the Kenogamissi batholith may have created the structural site of the
veins hosting the quartz and barite open pit mines in this area.
HOODOO LAKE PLUTON
The Hoodoo Lake pluton is a 5 by 10 km northeast-trending
ovoid, in western Keith and eastern Ivanhoe townships.
Although exposures are restricted to the southeastern margin, intrusive contacts are well defined by a distinct negative aeromagnetic anomaly. The surrounding mafic volcanic rocks are metamorphosed to amphibolite facies, with
foliations paralleling the intrusive contact and dipping in
towards the centre of the pluton. U-Pb zircon geochronology indicates a crystallization age of 2684±3 Ma
(Frarey and Krogh 1986). It is a massive, homogeneous,
porphyritic biotite granodiorite characterized by large
alkali-feldspar phenocrysts (1 to 3 cm in size) set in a
medium-grained groundmass. The granodiorite consists of
50 to 60% subhedral, oscillatory-zoned plagioclase (slightly
altered to sericite and epidote), 15 to 25% quartz, 10 to 15%
microcline, less than 5% biotite and minor amounts of
titanite, epidote, apatite, opaque minerals and zircon.
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OGS REPORT 297
IVANHOE LAKE PLUTON
PROTEROZOIC
The Ivanhoe Lake pluton is a triangular intrusion about 8 km
across. The western part is a massive, pinkish-grey weathering, alkali-feldspar porphyritic, biotite granodiorite consisting of plagioclase (andesine), quartz, microcline and
biotite, with trace amounts of opaque minerals, titanite,
epidote, sericite and carbonate. The eastern part of the pluton
consists of massive, light grey weathering, alkali-feldspar
porphyritic, biotite-quartz monzodiorite composed of
strongly saussuritized plagioclase, microcline, quartz and
biotite with trace amounts of titanite and opaque minerals.
Abundant, grey weathering, equigranular tonalite dikes
intrude the surrounding country rock on the southeast
margin of the pluton.
Mafic Intrusive Rocks
Alkalic Mafic Intrusive Rocks
Alkalic mafic intrusions consist of lamprophyre dikes too
small to be portrayed on Map 2627 and are therefore not
included on the map’s legend (back pocket). The dikes are
most abundant in the 4 western townships in close proximity to the KSZ. They have a consistent northeasterly
trend. The suite is interpreted to be Archean, but may also
include intrusions associated with alkalic magmatism
focussed along the KSZ, which occurred over a protracted
period in the Proterozoic and Paleozoic eras (Sage 1991).
Some of these dikes may be genetically related to a 40 cm
kimberlitic dike reported in core from diamond drilling by
Dome Exploration (Canada) Limited, in Keith Township
west of the Horwood Lake road and north of the Kukatush
pluton. Watson et al. (1978) indicated the dike consists
mainly of olivine (40%), phlogopite (25%) and carbonate
minerals (20%), and lesser amounts of spinel, ilmenite,
clinopyroxene, serpentine, perovskite and apatite.
The dikes range from mafic to ultramafic in composition. They are commonly porphyritic and typically contain
biotite. Massive biotite lamprophyre dikes up to 20 cm
thick occur in foliated monzonite along the west side of
Ivanhoe Lake and in the massive granite pluton in southwestern Ivanhoe Township. The dikes are carbonate-rich,
weather recessively and are rusty brown in colour. They
consist of fine-grained pyroxene and biotite phenocrysts,
extensively replaced by carbonate, in a very fine-grained
groundmass whose original mineralogy is obscured by
extensive carbonate alteration. Phenocrysts (0.5 to 2 cm)
of clinopyroxene (30%; moderately altered to amphibole)
and biotite (20%) in a groundmass of fine-grained orthoclase (30%), carbonate (15%) and opaque minerals (5%)
were identified by thin section examination of a sample
from a 30 cm dike cutting granitoids, along Highway 101
west of Scorch Creek. A 5 m ultramafic lamprophyre dike
observed in core from a diamond-drill hole on the east side
of Muskego Lake, consists of phenocrysts of enstatite 1 to
5 cm in size (40%; partially altered to talc and serpentine)
in a groundmass of phlogopite (20%), tremolite (25%),
serpentine (10%) and opaque minerals (5%).
16
Diabase dikes occur scattered throughout the map area
and are genetically related to 3 Proterozoic magmatic
events: 1) a northwest-trending Matachewan swarm with a
U-Pb age of 2454±2 Ma; 2) a northeast-trending swarm
restricted to the KSZ with an Ar-Ar age of 2043 Ma; and
3) an east-northeast-trending Abitibi swarm with a U-Pb
age of 1140±2 Ma (Osmani 1991).
A large number of tholeiitic diabase dikes (unit 11,
Map 2627, back pocket) occur throughout the map area,
but are most abundant in the 4 eastern townships. All dikes
of this set have a northwesterly to northerly trend, are
slightly to moderately magnetic and are interpreted as
members of the Matachewan swarm. They are most readily
detected on vertical gradient or second derivative magnetic
survey maps and in many places have their location postulated on the basis of magnetic interpretation. The dikes
are dark grey to black on weathered surfaces near their finegrained contact margins and are brown-weathering, mediumgrained and diabasic-textured in their central parts.
Exposed dikes range up to 80 m in width and some are plagioclase-phyric. Thin section examination of a sample of porphyritic diabase indicates it consists of 20% bytownite phenocrysts (An80), 2 to 10 mm in size and strongly altered to
sericite and epidote, in a subophitic groundmass of normally
zoned labradorite (50%), hypersthene (25%; moderately
altered to amphibole and chlorite) and opaque minerals (5%).
Two large east-northeast-trending olivine diabase
dikes (unit 12, Map 2627, back pocket), found in the
southeastern part of the synoptic area, are part of the
Abitibi swarm. The southern dike is up to 130 m wide and
may extend for a total length of over several hundred km
(Milne 1972). The dikes are characterized by very high
magnetic susceptibility and thus their position on Map
2627 (back pocket) is largely based on aeromagnetic interpretation. The diabase is very susceptible to weathering
and thus outcrops typically consist of a veneer of largely
unconsolidated masses of pea-sized sand. The fresh rock is
light grey coloured. The central parts of the dikes are very
coarse grained and subophitic textured, with lathes of
labradorite, interstitial titanaugite and accessory olivine,
biotite, magnetite and apatite.
Within the Kapuskasing Structural Zone the diabase
dikes (not shown on Map 2627, back pocket) are up to 10 m
wide and trend east to northeast. They are interpreted to be
part of the Kapuskasing swarm of diabase dikes (Percival
1990). The dikes are tholeiitic quartz diabase. They are
fine to medium grained, brown weathering, and have a
subophitic texture. They consist of plagioclase (normally
zoned from andesine to oligoclase) and clinopyroxene
with minor opaque minerals and quartz.
The larger Matachewan diabase dikes have envelopes
of epidote alteration and locally have associated sulphide
NORTHERN SWAYZE GREENSTONE BELT
mineralization. Milne (1972) indicates 3 such sulphide
occurrences in the eastern part of the synoptic area: 1) disseminated bornite and chalcopyrite in the serpentinite
adjacent to the diabase dike cutting the Reeves asbestos
deposit; 2) disseminated chalcopyrite and pyrrhotite associated with the diabase in the iron formation outcrop south
of Crawford Lake, in Kenogaming Township; and 3) scattered veinlets containing stibnite in mafic volcanic rocks
associated with the diabase dike in southwestern Sewell
Township.
(Kaszycki 1992). Varved clay and sand deposits are also
visible in the banks of the Ivanhoe River.
PHANEROZOIC
METAMORPHISM
Pleistocene and Recent
Mineral assemblages in paragneiss and amphibolite gneiss
indicate granulite-facies metamorphic conditions prevailed
in the Kapuskasing Structural Zone. Geothermometry and
geobarometry by Percival (1990) indicate metamorphic
conditions increase eastward across the KSZ, representing
the exposure of progressively deeper, lower crustal rocks.
He estimates maximum temperatures in the range of 700
to 800°C and pressures in the 8 to 9 kilobar range in the
easternmost part, adjacent to the Ivanhoe Lake cataclastic
zone.
The map area lies within the Abitibi upland of the James
Bay region which exhibits moderately rolling relief, with elevations averaging between 300 and 400 m (Kaszycki 1992).
All surface drainage is northward into Hudson Bay via the
Groundhog River and its tributaries. The map area is
extensively covered by drift and is characterized by a gently
rolling till plain.
A number of esker systems with a southerly trend
transect the synoptic map area. Extensive deposits of outwash sand, reworked into rolling hills by eolian processes,
are evident in the central parts of Ivanhoe Township and
are closely associated with the main esker meandering in
a southerly trend across central Foleyet and Ivanhoe townships. This esker represents an extensive esker system with
a regional extent of over 75 km (Thurston et al. 1977). The
esker is up to 100 m wide and rises up to 30 m above the
surrounding countryside. Two other significant esker
systems bisect the map area. One extends from the northwestern boundary of Reeves Township to the southeastern
boundary of Keith Township. The esker rises up to about
20 m above the surrounding country where it parallels the
Groundhog River in eastern Keith Township. A third esker
trends from the northwestern boundary of Sewell
Township to the southeastern boundary of Penhorwood
Township. The esker rises to over 60 m above the surrounding terrain in east-central Penhorwood Township.
Associated subaqueous fan and eolian sand and gravel
deposits parallel these esker systems and they have locally
been quarried for their aggregate.
Glacial striae observed throughout the map area indicate the main direction of ice flow was to the southwest at
190° to 200°. This feature is related to the main direction
of ice transport during the Late Wisconsinan between 10 700
and 11 500 years BP (Prest 1970). Other, more obscure,
trends of ice movement have also been identified locally
within the map area (Kaszycki 1992). The older trending
striae may reflect a pre-Wisconsinan glaciation (Bird and
Coker 1987).
Much of the map area is covered by glacial till up to
35 m thick. Laminated silt and clay occurs in topographic
lows in river valleys and along the shore of Horwood Lake
Recent swamp and muskeg deposits occur throughout
the map area. They are extensive in low areas, particularly
in northwestern Keith and southwestern Muskego townships. Investigations of the economic potential for peat in
this area indicated a number of sites with potentially commercial resources, with a depth averaging between 2 and 3 m
(Dendron Resource Surveys Ltd. 1984).
All supracrustal rocks with the NSGB have been subjected to greenschist- or amphibolite-facies metamorphic
conditions. Greenschist-facies mineral assemblages are
evident throughout most of the belt. Mineral assemblages
indicative of amphibolite facies occur throughout southern
Ivanhoe Township, south of the Muskego River fault.
Contact metamorphism of the supracrustal rocks within
1 km of the external granitoid intrusions and 500 m of the
larger internal plutons has also produced amphibolitefacies mineral assemblages. This metamorphic upgrading
is most evident as a colour change from dark green to
black in mafic volcanic rocks. Typical mineral assemblages in greenschist-facies mafic volcanic rocks include
albite, actinolite, chlorite and epidote, while amphibolitefacies rocks contain oligoclase, quartz, hornblende, and
epidote with localized development of medium-grained,
feathery hornblende porphyroblasts or equant garnet porphyroblasts.
Mineral assemblages consisting of biotite, muscovite,
garnet and andalusite in the pelitic sedimentary rocks
south of the Ivanhoe Lake pluton are also indicative of
lower amphibolite-facies metamorphism. Porphyroblastic
growth is locally evident in sedimentary rocks and felsic
volcanic rocks. Hornblende porphyroblasts occur in a
mudstone metamorphosed to amphibolite facies in close
proximity to the contact with the Nat River granitoid complex, in southwestern Muskego Township. Amphibole and
tourmaline porphyroblasts were observed in greenschistfacies chert beds and turbidites, respectively, in Keith
Township. Chloritoid porphyroblasts in schistose felsic
volcanic rocks indicate that upper greenschist-facies
contact-metamorphic conditions occurred about 1 km south
of the Nat River granitoid complex in south-central
Muskego Township. The chloritoid porphyroblasts are
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OGS REPORT 297
randomly oriented and overprint an S1 and S2 tectonic fabric, within the Slate Rock deformation zone, indicating that
the contact metamorphic event came relatively late in the
tectonic history of the area.
occurred prior to deformation and was cut by the posttectonic Ivanhoe Lake pluton. This and the early porosity
control of the moderate silicification strongly suggests that
silicification was synvolcanic.
Contact strain aureoles also appear to have developed
in conjunction with contact metamorphism, as the
supracrustal rocks surrounding the Hoodoo Lake and
Kukatush plutons have a well-developed tectonic foliation
which parallels the plutonic contacts and dips steeply
inwards towards the pluton centres. The latter feature suggests erosion has removed much of the upper part of the
plutons.
Patchy zones of silicification also occur in an outcrop
of quartz- and feldspar-phyric felsic pyroclastic rocks
southeast of Highway 101, in the main felsic unit in southeastern Foleyet Township. A felsic flow in the same unit
on the southeast side of the highway also appears to be
silicified and is cut by abundant quartz veins and cavities
infilled with very fine-grained silica.
ALTERATION
Mineral assemblages indicative of alteration are evident in
a number of localities in the NSGB. Four distinct types are
documented:
1) hydrothermal silicification of volcanic rocks
2) hydrothermal alteration producing chloritoid-bearing
volcanic rocks
3) carbonatization associated with ductile deformation
4) epidotization associated with metamorphism and
hydrothermal alteration
Silicification
Hydrothermal silicification was observed in a number of
localities in the northwestern part of the Muskego–Reeves
assemblage. The most extensive is a northeast-trending
zone of silicification, exposed over an area of 1 by 5 km,
in northeastern Ivanhoe Township (Ayer 1993). It occurs
within intermediate to mafic flows cut by the southeastern
margin of the Ivanhoe Lake pluton. Silicification has only
occurred to a moderate degree in much of the zone and is
most evident in pillow breccia, where the fragments are
light grey in a darker grey schistose matrix. Silicification
in these zones appears to have been controlled by early
porosity, as the most intense bleaching is concentrated
around amygdules. This is also supported by the lack of
silicification evident in the minor non-amygdaloidal or
unbrecciated flows occurring within the silicified zone.
Intense silicification is only exposed in the western part of
the zone. In these areas, the silicification is manifested by
light grey to white rock in which the original volcanic textures have been largely destroyed by multiple generations
of fracturing, pervasive silicification and quartz veining.
Thin section examination of both types of silicification
indicate a considerably higher proportion of very finegrained quartz, feldspar, sericite and biotite than is evident
in the unsilicified mafic flows. Numerous dikes of tonalite
cut the silicified zone and foliated silicified inclusions in
massive quartz monzodiorite locally occur in intrusive
breccias near the southeastern margin of the Ivanhoe Lake
pluton. These relationships indicate the silicification
18
Chloritoid-bearing Volcanic Rocks
Chloritoid porphyroblasts are found in drill core of carbonatized mafic flows associated with a subeconomic
strata-bound sulphide zone and in carbonatized felsic tuffs
along the Ivanhoe River, in southeastern Foleyet Township
(Ayer 1993). An extensive zone of chloritoid alteration, up
to about 500 m wide and with an apparent strike length of
4 km also occurs in Muskego Township (Ayer, in press).
Fine feathery chloritoid is visible on cleavage surfaces in
a plagioclase-phyric felsic schist north of Keith Lake.
Along strike with this unit, to both the east and west,
medium-grained, black tabular porphyroblasts of chloritoid
in felsic carbonatized schists were observed in diamonddrill core. As chloritoid in greenschist-facies metavolcanic
rocks has been documented to be the result of hydrothermal
alteration (Lockwood 1986), it is assumed that this zone
represents a zone of conformable hydrothermal alteration
which could be associated with sulphide mineralization.
Of economic significance, chloritoid-bearing altered volcanic rocks are associated with a number of Archean volcanogenic massive-sulphide deposits (Franklin et al. 1975).
Carbonatization
Extensive carbonatization is characteristic of ductile
deformation zones in the NSGB. The carbonate is commonly a rusty-weathering iron-magnesium carbonate or
light grey weathering calcium carbonate. The most intense
carbonatization appears to be associated with highly schistose rocks with chlorite and/or sericite, and may occur in
broad zones up to 1 km wide in major shear zones such as
the Slate Rock deformation zone.
Epidotization
Rounded, epidote-rich clots occur within amphibolitefacies mafic volcanic rocks in south-central Ivanhoe
Township. Epidotization is also evident within and surrounding large diabase dikes. In addition, epidote was
observed as fine-to coarse-grained euhedral crystals within
quartz-carbonate veins in ultramafic volcanic rocks cut by
granodiorite dikes west of the Hoodoo Lake pluton, in
Ivanhoe Township. The above types of epidotization are
NORTHERN SWAYZE GREENSTONE BELT
probably related to remobilization of alkali elements by
contact metamorphism.
Pervasive epidotization, possibly related to propylitic
hydrothermal alteration, occurs in the foliated granitic
rocks along the southwestern side of the open part of
Ivanhoe Lake. In addition, plagioclase in the granite located
in the northwestern part of Muskego Township has under-
gone significant epidotization, suggesting propylitic alteration, perhaps as a result of the intrusion of abundant
granitic pegmatite dikes in the area.
Epidotization is also locally evident in ductile deformation zones. In the deformation zone on the west side of
Ivanhoe Lake, the evidence suggests it occurred prior to
carbonatization (Ayer 1993).
19
OGS REPORT 297
Geochemistry
20
PK - Peridotitic komatiite
BK - Basaltic komatiite
BK
PK
MgO
Al 2O3
Individual Flow Samples
Paired Flow Samples
93-1014 pyroxene spinifex
91-1010 olivine spinifex
91-119 talc-chlorite schist
91-1215 cumulate base
92-231 polyhedral joints
92-249 pyroxene spinifex
92-248 cumulate base
93-1108 olivine spinifex
93-1109 cumulate base
93-1114 olivine spinifex
93-1115 cumulate base
Figure 3. Jensen (1976) cation plot of ultramafic volcanic samples. Many
of the samples are paired, representing a spinifex top and cumulate base
from the same flow.
20
Basaltic komatiites
10
Peridotitic komatiites
Lu
Yb
Tm
Er
Dy
Ho
Tb
Eu
Gd
Sm
Pr
Nd
La
1
Ce
The ultramafic volcanic rocks of the Muskego–Reeves
assemblage (MRA) range in MgO contents from 17 to 40%.
They all plot in the komatiitic fields on a Jensen cation
plot (Figure 3), and display a wide range in Mg-Fe-Al
major oxide variation from peridotitic komatiites (PK) to
basaltic komatiites (BK). A number of paired samples are
plotted on Figure 3. These represent 2 samples from single
flow units: one representing the spinifex-textured rock in
the chilled upper part of the flow, and the second from the
lower, cumulate-textured part of the same flow. These
paired samples show the cumulate portion to be more
primitive than the chilled spinifex-textured part of the
flow. In general, the olivine spinifex-textured peridotitic
komatiite flows demonstrate a smaller range in Mg-Fe-Al
major oxide variation than do the pyroxene spinifex-textured basaltic komatiite flows. Figure 4 displays the chondrite-normalized rare earth element (REE) values for a
number of the PK and BK samples. The figure demonstrates that all the PK samples show distinct light rare
earth element (LREE) depletion ([La/Lu]N = 0.5), negative
Eu anomalies and flat heavy rare earth element (HREE)
patterns at values 2 to 4 times that of chondrite. On Figure
4, sample 93-1108 is from the spinifex-textured top and
sample 93-1109 is from the cumulate base of the same
flow. The cumulate sample is more primitive, with lower
REE values, but the parallel trend of the REE patterns of
these 2 samples demonstrates that there has been negligible
REE fractionation between the chilled upper margin of the
flow, which presumably closely resembled the original liquid
composition, and the cumulate base. The BK samples are
distinctive from those of the PK, with more fractionated
REE values in the 6 to 10 times chondrite range, slightly
elevated LREE values ([La/Lu]N = 1.5) and no Eu anomalies.
FeO + TiO2
Rock/Chondrite
The lithogeochemical features of the synoptic area are
based on whole-rock analyses of 136 samples. Sample
locations are displayed on Map 2627 (back pocket) and
sample descriptions indexed by township and UTM coordinates are provided in Table 2. Tables 3, 4 and 5 present
analytical results for samples collected in 1991, 1992 and
1993, respectively. Whole-rock sample analyses were performed by the Geoscience Laboratories of the Ontario
Geological Survey, Toronto, for the 1991 samples (Table 3),
X-Ray Assay Laboratories, Toronto, for the 1992 samples
(Table 4), and the Geoscience Laboratories, Geoservices
Branch, Sudbury, for the 1993 samples (Table 5). Major
oxide contents were determined by X-ray fluorescence
(XRF). Loss-on-ignition (LOI) was determined by gravimetric methods; carbon dioxide and sulphur contents were
determined by infrared spectrometry. Trace elements were
determined by atomic adsorption (AA), X-ray fluorescence, inductively coupled plasma optical emission spectrometry (ICP-OES), and inductively coupled plasma mass
spectrometry (ICP-MS).
93JAA-1108
93JAA-1035
91JAA-0039
93JAA-1109
93JAA-1033
93JAA-1014
93JAA-1121
Figure 4. Chondrite-normalized REE plot of ultramafic volcanic samples.
NORTHERN SWAYZE GREENSTONE BELT
20
FeO + TiO2
Rock/Chondrite
HFT - High-iron
tholeiite
HMT - High-magnesium
tholeiite
CB - Calc-alkalic
basalt
10
HFT
Al 2O3
MgO
91JAA-1047
Lu
Yb
Er
Tm
Dy
Ho
Tb
Gd
Eu
Sm
Pr
Iron tholeiite
Nd
La
CB HMT
Ce
4
Magnesium tholeiites
91JAA-0008
93JAA-1112
91JAA-0196
93JAA-1107
Figure 5. Jensen (1976) cation plot of mafic volcanic samples.
Figure 6. Chondrite-normalized REE plot of mafic volcanic samples.
Comparison with the geochemistry of komatiites in
Newton Township (Cattell and Arndt 1987), in the southern Swayze greenstone belt (SSGB) indicates many similarities between the 2 areas. In both areas the olivine
spinifex-textured komatiites show distinctive LREE
depletion, but in the northern Swayze greenstone belt
(NSGB) the REE values range to lower values suggesting
more primitive magmas. This is also indicated by higher
absolute values of MgO and Ni in the NSGB. In addition,
in both areas the komatiitic basalts range to moderately
LREE-enriched values.
The overall depleted LREE patterns in the komatiite
and mafic volcanic samples from the MRA and HWA
suggest derivation from the same source region of depleted
Archean mantle. These same LREE-depleted patterns are
evident in the ultramafic and mafic volcanic rocks of
Newton Township in the SSGB (Cattell and Arndt 1987).
A depleted Archean mantle source is also indicated in a
Sm-Nd isotopic study of the Newton Township ultramafic
and mafic lavas, with epsilon Nd values of +1.6 to +4.2
(Cattell et al. 1984). These features suggest that the extensive
mafic to ultramafic volcanic suites of the NSGB and
SSGB developed in a rift environment, with little or no
involvement of continental crust, and may be an Archeanequivalent tectonic setting to mid-oceanic ridge or back-arc
basin volcanism in modern environments.
The potential for nickel-copper deposits in the MRA
komatiites appears to be favourable, as their geochemistry is similar to that of the host rocks of nickel-copper
deposits in the Abitibi greenstone belt. Barrie et al. (1993)
state that nickel-copper deposits in the Abitibi Subprovince
are hosted exclusively in komatiite flows and hypabyssal
sills, represented by chill compositions (i.e., spinifextextured) with high MgO contents (20 to 35%, anhydrous),
very low incompatible element contents and LREEdepleted signatures ([La/Lu]N = 0.5 to 0.8 and Zr/Y less
than 2.5). In comparison, most barren komatiites have less
primitive compositions, higher absolute values of REE
and flat to elevated LREE patterns.
Mafic volcanic rocks from the MRA and Horwood
assemblage (HWA) dominantly plot in the tholeiitic field
on a Jensen cation plot (Figure 5). Magnesium tholeiites
predominate and consist of pillowed and massive flows,
including some pyroxene spinifex-textured flows. Iron
tholeiites are volumetrically subordinate and consist of
pillowed and massive flows lacking spinifex. Both iron
and magnesium tholeiites are dominantly LREE depleted
([La/Lu]N = 0.6), with or without slight Eu depletion (Figure
6). However, iron tholeiites generally have higher REE
values (e.g., sample 91JAA-1047, Figure 6).
Similarities also exist between mafic volcanic and komatiite REE patterns in the MRA and HWA with those of the
Kidd–Munro assemblage. The tholeiitic mafic volcanic
rocks in the 2 areas also have similar patterns to modern
mid-oceanic ridge basalts with depleted LREE values for
magnesium and iron tholeiites, but with higher absolute
values for the iron tholeiites (Jackson et al. 1994).
Intermediate to felsic volcanic samples from the
Hanrahan assemblage (HNA) and MRA plot within the
calc-alkalic field on the Jensen cation plot and show ratios
which range from calc-alkalic basalts to rhyolites (Figure 7).
All display a high degree of LREE fractionation ([La/Lu]N
= 10), flat to concave-upward HREE patterns, with or
without slight Eu depletion (Figure 8). What appears to be
lacking, in comparison with Abitibi assemblages such as
the Kidd–Munro assemblage, are the tholeiitic felsic differentiates or rhyolites designated as FIII-type by Lesher
et al. (1986). All intermediate to felsic volcanic rocks sampled to date in the NSGB show high degrees of REE fractionation with highly elevated LREE and depleted HREE
21
OGS REPORT 297
FeO + TiO2
100
CB - Calc-alkalic basalt
Rock/Chondrite
CA - Calc-alkalic andesite
CD - Calc-alkalic dacite
CR - Calc-alkalic
rhyolite
10
CR CD
Al 2O3
MgO
Lu
Yb
Er
Tm
Dy
Ho
Tb
Gd
Eu
Sm
Pr
Nd
La
CB
CA
Ce
1
93JAA-1062
91JAA-0170
92JAA-1134
92JAA-0258
92JAA-0194
93JAA-1071
91JAA-0184
Figure 7. Jensen (1976) cation plot of intermediate to felsic volcanic
samples.
Figure 8. Chondrite-normalized REE plot of intermediate to felsic volcanic samples.
patterns typical of calc-alkalic FI-type rhyolites (Lesher et
al.1986). In modern day volcanism these rocks are more
typical of destructive-margin tectonics than the rifting-type
environment suggested by the tholeiitic felsic and intermediate volcanic rocks of the Kidd–Munro assemblage
(Barrie et al. 1993).
REE values of 0.3 to 0.9 times chondrite. Samples from
the overlying gabbroic part of the body (93JAA-1124,
93JAA-1006 and 93JAA-1005) have flat REE patterns at
values 1 to 10 times chondrite with either Eu enrichment
or depletion. These patterns indicate that besides olivine
and pyroxene, plagioclase must have crystallized on the
liquidus at some stage in the magma evolution and was
concentrated in the gabbroic differentiates. The 3 ultramafic samples all have Eu values below detection limits
and thus these rocks would most likely display Eu depletion
anomalies on Figure 10, if their absolute Eu values were
known.
Thus, volcanism in the NSGB can be characterized as
having occurred in 2 distinct tectonic environments. The
ultramafic and mafic suites of the HWA and the MRA
appear to have been derived from a depleted mantle source
with the mafic flows most similar to modern mid-oceanic
ridge basalts. The intermediate to felsic suites of the HNA
and the MRA are clearly calc-alkalic in their affinity and
demonstrate a more evolved magmatic source, most similar
to modern island arcs forming at destructive continental
margins.
FeO + TiO2
HFT - High-iron tholeiite
HMT - High-magnesium
tholeiite
BK - Basaltic komatiite
Samples from the ultramafic cumulates and associated
gabbroic differentiates of the MRA (Figure 9) show a similar range to the ultramafic and mafic volcanic samples on
the Jensen cation plots (see Figures 3 and 5), and are most
probably synvolcanic sills or large ponded flows. Analyses
of samples from the Reeves ultramafic to gabbroic body
are displayed on Figure 10. Two dunite samples are very
primitive, with similar REE patterns at 0.2 to 0.4 times
chondrite values and slightly fractionated LREE values
([La/Lu]N = 1.5 to 2). Sample 93JAA-1119 is the most
primitive and occurs at the base of the unit, while sample
93JAA-1118 occurs about 50 m above the base. Sample
93JAA-1122 is a pyroxenite sample which occurs at the
top of the ultramafic part of the body, an estimated 100 m
above the base of the unit. In contrast to the underlying
dunites, the pyroxenite sample displays moderate LREE
depletion ([La/Lu]N = 0.6) but with relatively primitive
22
PK - Peridotitic
komatiite
HFT
BK
HMT
PK
Al 2O3
MgO
Figure 9. Jensen (1976) cation plot of ultramafic cumulate and gabbroic
samples.
NORTHERN SWAYZE GREENSTONE BELT
10
Rock/Chondrite
Rock/Chondrite
10
1
1
93JAA-1118
93JAA-1122
93JAA-1068
93JAA-1095
93JAA-1006
93JAA-1119
93JAA-1124
93JAA-1069
93JAA-1096
Lu
Yb
Tm
Er
Ho
Tb
93JAA-1005
Dy
Eu
Gd
Nd
Sm
Pr
Ce
La
Lu
Yb
Tm
Er
Ho
Tb
Dy
Eu
Gd
Nd
Sm
Pr
La
Ce
.1
93JAA-1097
Figure 10. Chondrite-normalized REE plot of samples from the Reeves
ultramafic to gabbroic body.
Figure 11. Chondrite-normalized REE plot of samples from the ultramafic
to mafic body hosting the Ireland showing.
Samples collected from the differentiated body hosting the Ireland nickel showing in northeastern Kenogaming Township are shown on Figure 11. Three samples
from the northeastern part of the body represent peridotite (93JAA-1096), pyroxenite (93JAA-1097) and gabbro (93JAA-1095). All 3 samples show similar patterns,
with significant to moderate LREE depletion ([La/Lu]N =
0.35 to 0.85). In contrast, peridotite and gabbro samples
from the western end of the body (93JAA-1068 and
93JAA-1069) display flat to slight LREE enrichment patterns ([La/Lu]N = 0.8 to 1.4). This difference may have
some economic significance, as the western samples were
collected in the immediate vicinity of known concentrations of nickel, copper and platinum group element (PGE)
mineralization. It is possible that the samples enriched in
LREE were contaminated by the assimilation of underlying
units enriched in LREE, such as the felsic rocks of the
HNA (e.g., see sample 93JAA-1071, Figure 8) and/or the
Nat River iron formation. This may have provided a mechanism for sulphur saturation and thus the concentration of
nickel sulphides in this area (see “Economic Geology”).
canic samples from the Joburke Mine plot in the intermediate to basaltic parts of the iron tholeiite field. This is in
contrast to the patterns of the unaltered mafic volcanic
samples collected throughout the NSGB (see Figure 5) in
which only a minor number of the mafic suite samples are
iron tholeiites. This iron enrichment is most probably the
result of hydrothermal alteration and the resultant mobility
of iron and magnesium. Similar shifts (not shown) were
also evident in carbonatized volcanic samples (bearing
chloritoid) from other parts of the synoptic area (i.e., samples 91JAA-0170, 92JAA-0109, and 92JAA-0221, Tables
3 and 4).
Alteration has had a significant effect on whole-rock
geochemical patterns and in particular has affected the
more mobile elements, such as the incompatible elements
iron and magnesium. In sampling for the synoptic project,
the effect of alteration was minimized as much as possible
by collecting only samples without evident alteration, and
by the removal of weathered surfaces and veining prior to
sample submission. Figures 12 and 13 illustrate the effect
of hydrothermal alteration on a suite of highly carbonatized
mafic samples collected in the immediate vicinity of the
Joburke Mine, in Keith Township. The altered samples
were provided by Noranda Exploration Company Limited
and were analyzed at X-Ray Assay Laboratories, in Toronto.
Locations and results of individual samples are provided
by Hall and Plant (1992a, 1992b). Figure 12, a Jensen
cation plot, illustrates that many of the altered mafic vol-
The intense hydrothermal alteration around the
Joburke Mine may also be evident in the REE patterns.
Figure 13 shows that while the LREE values are in the
normal range for MRA mafic volcanic rocks, the middle
rare earth element (MREE) and HREE values are distinctly
depleted, probably as a result of the alteration. Strong
depletion in HREE has been documented in carbonatized
metabasic schists adjacent to auriferous veins at the Dome
Mine in Timmins and has been attributed to leaching by
carbonate- and potassium-rich hydrothermal fluids
(Kerrich and Fryer 1979). In distinct contrast, Schandl and
Gorton (1992) document mobility in the LREE in the
hydrothermally altered host rocks of Superior Province
massive-sulphide deposits. Hall and Plant (1992b), however, suggest that depletion in HREE values could also be
an artifact of the analytical technique if there has been
incomplete digestion of refractory minerals in the ICP
analysis.
Tectonic environment interpretations are illustrated
in Figures 14 and 15, in which the mafic volcanic samples collected from the NSGB plot within the field of
ocean floor basalts. If the field of unaltered mafic volcanic rocks on Figure 14 is compared with those of
altered mafic volcanic samples from the Joburke Mine
23
HMT - High-magnesium
tholeiite
TD - Tholeiitic
dacite
CB - Calc-alkalic basalt
TA - Tholeiitic
andesite
CA - Calc-alkalic
andesite
HFT - High-iron
tholeiite
CD - Calc-alkalic
dacite
HFT
TA
TD
Rock/Chondrite
FeO + TiO2
10
HMT
CA
CB
CD
Lu
Yb
Er
Tm
Dy
Ho
Tb
Gd
Eu
Sm
Pr
Nd
La
Ce
1
MgO
Al 2O3
Figure 12. Jensen (1976) cation plot of altered mafic volcanic samples
from the Joburke Mine.
Figure 13. Chondrite-normalized REE plot of altered mafic volcanic samples from the Joburke Mine. Representative samples from analyses provided by Noranda Exploration Company Limited.
area (Figure 15), the “blurring” to the left and right of the
ocean floor basalt field in the Joburke samples is most
likely an effect of hydrothermal alteration resulting in
mobility of the high field strength elements (HFSE),
which are generally considered to be immobile. In particular, Figure 15 demonstrates that there is considerably
more mobility in yttrium as the deviation is focussed
along a line parallel to the yttrium axis with little deviation towards the zirconium or titanium axes. This confirms the above-observed REE mobility, as yttrium is a
relatively more compatible HFSE and is thus geochemically more similar to the HREE, while zirconium is a relatively incompatible HFSE and is thus geochemically
more similar to the LREE.
Ti/100
Ti/100
WPB - with plate basalts
WPB - with plate basalts
OFB - ocean floor basalts
OFB - ocean floor basalts
LKT - low potassium
tholeiites
LKT - low potassium
tholeiites
CAB - calc-alkalic
basalts
CAB - calc-alkalic
basalts
WPB
LKT
LKT
WPB
CAB
Zr
OFB, LKT, CAB
CAB
Yx3
Figure 14. Pearce and Cann (1973) plot of mafic volcanic samples from
the northern Swayze greenstone belt.
24
Zr
OFB,LKT,
CAB
Yx3
Figure 15. Pearce and Cann (1973) plot of the altered mafic volcanic
samples from the Joburke Mine.
NORTHERN SWAYZE GREENSTONE BELT
Table 2. Lithogeochemical sample descriptions, township and UTM co-ordinates. (All UTM values are within Grid Zone 17.)
Sample No.
Sample description
Township
Easting
Northing
91JAA-0006
pillowed mafic flow
Ivanhoe
390237
5329160
91JAA-0008
pillowed mafic flow
Ivanhoe
389725
5329536
91JAA-0009
massive granodiorite
Ivanhoe
387492
5338216
91JAA-0039
massive komatiite flow
Ivanhoe
384931
5335133
91JAA-0049
foliated tonalite
Ivanhoe
380532
5333195
91JAA-0057
massive granodiorite
Ivanhoe
381876
5330026
91JAA-0066
massive granite
Ivanhoe
381584
5324022
91JAA-0068
pillowed mafic flow
Ivanhoe
392902
5332461
91JAA-0073
polyhedral jointed komatiite flow
Ivanhoe
394003
5332466
91JAA-0077
polyhedral jointed komatiite flow
Ivanhoe
394071
5332272
91JAA-0094
massive quartz monzodiorite
Ivanhoe
391294
5335062
91JAA-0102
intermediate amygdaloidal flow
Ivanhoe
393075
5335410
91JAA-0105
leucogabbro
Ivanhoe
393914
5336075
91JAA-0109
intermediate plagioclase-phyric tuff
Ivanhoe
393914
5336075
91JAA-0113
massive mafic flow
Ivanhoe
393820
5336406
91JAA-0119
altered schistose ultramafic with chloritoid
Foleyet
392034
5339710
91JAA-0124
plagioclase-phyric felsic lapilli tuff
Foleyet
392034
5339710
91JAA-0127
massive mafic flow with medium-grained pyroxene needles
Ivanhoe
393260
5338193
91JAA-0135
pillowed mafic flow
Ivanhoe
395174
5327932
91JAA-0136
pillowed mafic flow
Ivanhoe
394195
5325192
91JAA-0137
massive mafic flow
Ivanhoe
394195
5325078
91JAA-0139
massive mafic flow
Ivanhoe
394836
5325210
91JAA-0149
polyhedral jointed komatiite flow
Foleyet
393906
5340575
91JAA-0155
quartz-phyric felsic tuff
Foleyet
391888
5340270
91JAA-0161
plagioclase-phyric felsic tuff
Ivanhoe
387581
5334572
91JAA-0163
syenite gneiss
Foleyet
385555
5339690
91JAA-0168
massive intermediate flow
Foleyet
391992
5338863
91JAA-0170
altered quartz-phyric felsic tuff with chloritoid
Foleyet
393375
5339814
91JAA-0173
massive mafic flow
Foleyet
391345
5342700
91JAA-0176
massive mafic flow
Foleyet
390235
5341753
91JAA-0184
quartz-phyric brecciated felsic flow
Foleyet
391560
5340715
91JAA-0185
intermediate plagioclase & quartz-phyric tuff
Foleyet
392532
5342797
91JAA-0193
massive mafic flow with medium-grained pyroxene needles
Foleyet
393498
5338502
91JAA-0196
massive mafic flow with medium-grained pyroxene needles
Ivanhoe
391368
5334494
91JAA-0197
silicified amygdaloidal flow
Ivanhoe
391746
5334088
91JAA-0198
massive mafic flow
Foleyet
391803
5340459
91JAA-1010
spinifex-textured komatiite flow
Ivanhoe
390706
5331830
91JAA-1024
polyhedral-jointed komatiite flow
Ivanhoe
391380
5333030
91JAA-1047
amphibolitized mafic flow
Ivanhoe
388549
5324646
91JAA-1060
gabbro
Ivanhoe
391154
5326347
91JAA-1074
gabbro
Ivanhoe
390670
5328525
91JAA-1095
mafic flow
Ivanhoe
392326
5327271
91JAA-1116
gabbro
Ivanhoe
392817
5326524
91JAA-1136
amygdaloidal mafic flow
Ivanhoe
395155
5329397
91JAA-1168
tonalite gneiss
Foleyet
383389
5340869
25
OGS REPORT 297
Table 2. Continued.
Sample No.
Sample description
Township
Easting
Northing
91JAA-1174
91JAA-1215
granodiorite gneiss
Foleyet
384127
5341206
polyhedral-jointed komatiite flow
Ivanhoe
390706
5331830
91JAA-1218
silicified flow
Ivanhoe
391345
5334295
91JAA-2007
paragneiss
Foleyet
395738
5348736
92JAA-0018
adcumulate dunite
Keith
399128
5334137
92JAA-0045
massive mafic flow
Keith
401684
5334388
92JAA-0047
pillowed mafic flow
Keith
400588
5333080
92JAA-0066
amygdaloidal pillowed intermediate flow
Keith
397575
5337317
92JAA-0109
altered felsic schist with chloritoid
Muskego
403836
5338692
92JAA-0141
adcumulate dunite
Keith
405170
5335847
92JAA-0142
amygdaloidal intermediate flow
Keith
405170
5335847
92JAA-0151
spinifex pyroxenite at base of differentiated flow
92JAA-0173
massive mafic flow
92JAA-0194
quartz- and feldspar-phyric felsic schist
92JAA-0198
variolitic pillowed mafic flow
Keith
406359
5331941
92JAA-0199
massive mafic flow
Keith
406359
5331941
92JAA-0221
altered felsic schist with chloritoid
Muskego
402615
5338435
92JAA-0229
massive mafic flow
Keith
407911
5331965
92JAA-0231
polyhedral-jointed komatiite flow
Keith
408401
5332430
92JAA-0237
massive mafic flow
Keith
408234
5335800
92JAA-0248
polyhedral base of pyroxene spinifex ultramafic flow
Keith
409188
5334010
92JAA-0249
pyroxene spinifex top of komatiite flow
Keith
409188
5334010
92JAA-0250
massive mafic flow with medium-grained pyroxene needles
Keith
408765
5333780
92JAA-0252
polyhedral komatiite flow with olivine phenocrysts
92JAA-0253
massive mafic flow
92JAA-0258
Keith
406826
5335432
Muskego
406602
5338400
Keith
403426
5332611
Keith
406549
5335450
Muskego
407247
5339261
intermediate lapilli tuff
Keith
406906
5335697
92JAA-1017
adcumulate dunite
Keith
396859
5336225
92JAA-1030
quartz-phyric felsic flow
Keith
397775
5336805
92JAA-1043
massive mafic flow
Keith
397922
5335232
92JAA-1052
pyroxene spinifex mafic flow
Keith
397882
5334681
92JAA-1053
variolitic pillowed mafic flow
Keith
398400
5334590
92JAA-1073
massive mafic flow
Muskego
397311
5340702
92JAA-1097
plagioclase megaphyric mafic flow
Muskego
409387
5341716
92JAA-1116
massive granite
Muskego
404032
5341240
92JAA-1134
plagioclase-phyric felsic porphyry
Keith
404845
5328884
92JAA-1143
plagioclase-phyric felsic porphyry
Keith
406874
5328984
92JAA-1144
monzonite
Keith
407364
5327536
92JAA-1156
polyhedral-jointed komatiite flow
Keith
404963
5324471
92JAA-1157
massive mafic flow
Keith
404649
5324255
92JAA-1162
felsic schist
Keith
402310
5324715
92JAA-1170
massive intermediate flow
Keith
403425
5325310
92JAA-1180
granodiorite
Keith
400203
5326416
92JAA-1193
quartz-phyric felsic tuff
Keith
395718
5326151
93JAA-1001
massive mafic flow
Reeves
419426
5339535
93JAA-1005
gabbro
Reeves
419622
5338572
93JAA-1006
gabbro
Reeves
419800
5337983
26
NORTHERN SWAYZE GREENSTONE BELT
Table 2. Continued.
Sample No.
Sample description
Township
Easting
Northing
93JAA-1008
pillowed mafic flow
Penhorwood
419952
5337110
93JAA-1014
spinifex-textured komatiite flow
Reeves
419114
5339035
93JAA-1016
pillowed mafic flow
Penhorwood
420479
5335754
93JAA-1020
polyhedral-jointed komatiite flow
Penhorwood
420479
5334444
93JAA-1021
pillowed mafic flow
Penhorwood
421478
5336120
93JAA-1027
pillowed intermediate flow
Reeves
422227
5338688
93JAA-1033
spinifex-textured komatiite flow
Penhorwood
415708
5333601
93JAA-1035
massive komatiite flow
Penhorwood
414827
5332014
93JAA-1041
plagioclase porphyry
Penhorwood
416389
5336332
93JAA-1042
massive mafic flow
Penhorwood
415854
5326847
93JAA-1043
massive orthocumulate ultramafic
Penhorwood
413405
5325923
93JAA-1046
spinifex-textured komatiite flow top
Penhorwood
412158
5326030
93JAA-1055
quartz- and feldspar-phyric felsic tuff
Penhorwood
424430
5331663
93JAA-1059
plagioclase-phyric intermediate flow
Penhorwood
423757
5334659
93JAA-1062
plagioclase-phyric intermediate brecciated flow
Penhorwood
424071
5334218
93JAA-1068
melagabbro
Kenogaming
429624
5335890
93JAA-1069
adcumulate ultramafic
Kenogaming
429624
5335890
93JAA-1071
plagioclase-phyric felsic tuff
Kenogaming
429613
5336024
93JAA-1078
intermediate flow
Kenogaming
430510
5333250
93JAA-1083
intermediate tuff breccia
Kenogaming
428146
5331775
93JAA-1085
massive mafic flow
Kenogaming
427703
5330244
93JAA-1086
intermediate lapilli tuff
Kenogaming
430495
5331525
93JAA-1090
pillowed mafic flow
Sewell
424652
5339400
93JAA-1095
gabbro
Kenogaming
431667
5337092
93JAA-1096
spinifex-textured ultramafic pyroxenite
Kenogaming
431550
5337093
93JAA-1097
orthocumulate ultramafic peridotite
Kenogaming
431550
5337093
93JAA-1100
massive mafic flow
Reeves
411617
5339041
93JAA-1101
mafic flow
Reeves
411582
5339468
93JAA-1102
intermediate
Reeves
411828
5338207
93JAA-1104
massive mafic flow
Reeves
416118
5340807
93JAA-1106
intermediate flow
Reeves
417042
5340935
93JAA-1107
plagioclase-phyric mafic flow
Reeves
420238
5341136
93JAA-1108
spinifex-textured komatiite from flow top
Penhorwood
418116
5332918
93JAA-1109
polyhedral-jointed komatiite from base of flow
Penhorwood
418116
5332918
93JAA-1111
polyhedral-jointed komatiite flow
Penhorwood
417639
5333293
93JAA-1112
pillowed mafic flow
Penhorwood
416433
5333100
93JAA-1113
massive mafic flow
Penhorwood
419749
5333770
93JAA-1114
spinifex-textured komatiite from flow top
Penhorwood
419546
5333942
93JAA-1115
polyhedral-jointed komatite from base of flow
Penhorwood
419546
5333942
93JAA-1117
massive mafic flow
Penhorwood
423328
5335665
93JAA-1118
adcumulate about 50 m above base of ultramafic unit
Reeves
419187
5339845
93JAA-1119
adcumulate at base of ultramafic unit
Reeves
419079
5338894
93JAA-1121
brecciated komatiite flow
Reeves
418878
5338772
93JAA-1122
pyroxenite at top of ultramafic unit
Reeves
419895
5338730
93JAA-1124
gabbro at bottom of gabbroic unit
Reeves
419895
5338730
27
28
SiO2
XRF
51.66
54.46
64.86
44.99
70.47
68.61
72.51
51.80
45.31
43.76
65.41
61.59
49.53
57.67
54.55
34.97
72.15
48.74
57.02
51.27
51.09
51.46
46.50
75.94
73.82
56.87
Sample No.
Method
91JAA-0006
91JAA-0008
91JAA-0009
91JAA-0039
91JAA-0049
91JAA-0057
91JAA-0066
91JAA-0068
91JAA-0073
91JAA-0077
91JAA-0094
91JAA-0102
91JAA-0105
91JAA-0109
91JAA-0113
91JAA-0119
91JAA-0124
91JAA-0127
91JAA-0135
91JAA-0136
91JAA-0137
91JAA-0139
91JAA-0149
91JAA-0155
91JAA-0161
91JAA-0163
0.89
0.18
0.14
0.40
1.17
0.83
0.76
1.28
1.03
0.27
0.31
1.30
0.74
0.64
0.56
0.46
0.35
0.33
0.79
0.17
0.40
0.17
0.35
0.49
0.79
0.87
XRF
TiO2
17.58
14.11
13.26
6.64
15.87
13.87
14.53
14.72
13.64
15.69
6.08
14.32
17.54
11.64
16.36
15.55
6.84
6.59
14.06
14.65
15.89
16.75
6.75
16.32
13.92
15.78
XRF
Al2O3
5.66
1.64
0.51
12.13
12.58
12.79
12.32
11.13
12.69
1.32
10.16
11.50
7.73
8.72
5.95
3.58
11.33
11.39
11.65
1.32
2.35
0.90
10.09
3.67
11.38
11.07
XRF
Fe2O3
0.08
0.03
0.03
0.18
0.21
0.20
0.20
0.27
0.23
0.06
0.17
0.14
0.07
0.16
0.07
0.05
0.18
0.17
0.18
0.02
0.03
0.01
0.19
0.05
0.21
0.17
XRF
MnO
3.07
0.70
0.32
18.34
5.12
6.90
6.72
3.86
8.80
0.97
16.60
5.00
4.64
8.71
3.97
1.59
23.04
21.85
6.37
0.37
0.89
0.51
22.30
1.46
7.83
7.23
XRF
MgO
4.82
0.62
2.98
9.56
7.27
9.88
11.20
7.77
10.09
2.81
15.41
5.83
4.40
14.07
5.72
2.79
7.35
8.22
9.72
1.21
1.62
2.25
7.17
3.05
7.43
8.97
XRF
CaO
5.17
1.78
4.26
0.21
3.72
1.58
1.66
2.97
1.45
2.99
0.13
3.34
1.54
1.32
3.58
4.21
0.51
0.44
2.84
3.98
4.33
5.69
0.14
4.42
3.39
3.32
XRF
Na2O
4.44
5.21
0.86
0.16
0.95
0.86
0.16
0.26
0.14
2.22
0.03
0.19
2.83
0.40
1.36
3.38
0.07
0.04
0.27
4.54
4.44
1.91
0.03
3.21
0.10
0.17
XRF
K2O
Table 3. Whole-rock geochemical data from Foleyet and Ivanhoe townships. Major element oxide values in weight %, trace and rare earth element values in ppm.
0.54
0.05
0.06
0.03
0.07
0.07
0.06
0.11
0.11
0.06
0.04
0.22
0.18
0.05
0.11
0.17
0.03
0.03
0.07
0.05
0.13
0.05
0.03
0.18
0.06
0.08
XRF
P2O5
0.55
1.35
1.04
4.50
1.04
1.20
0.67
0.42
2.92
1.60
11.69
2.59
2.31
4.42
0.77
1.02
5.39
5.02
1.90
0.51
1.08
0.74
5.75
1.96
0.23
0.86
LOI
99.67
99.49
99.40
98.65
99.46
99.27
99.55
99.81
99.84
100.14
95.59
98.98
99.65
99.66
100.04
98.21
98.85
99.39
99.65
99.33
99.77
99.45
97.79
99.67
99.80
100.18
Total
OGS REPORT 297
SiO2
XRF
56.04
49.90
50.86
50.32
75.26
63.99
51.39
49.49
62.74
52.09
44.75
51.35
50.23
50.94
50.23
53.08
50.60
53.96
66.23
67.93
38.99
70.54
70.62
Sample No.
Method
91JAA-0168
91JAA-0170
91JAA-0173
91JAA-0176
91JAA-0184
91JAA-0185
91JAA-0193
91JAA-0196
91JAA-0197
91JAA-0198
91JAA-1010
91JAA-1024
91JAA-1047
91JAA-1060
91JAA-1074
91JAA-1095
91JAA-1116
91JAA-1136
91JAA-1168
91JAA-1174
91JAA-1215
91JAA-1218
91JAA-2007
Table 3. Continued.
0.39
0.44
0.25
0.23
0.54
0.85
0.56
0.71
1.39
1.74
1.39
0.26
0.36
0.97
0.52
0.72
1.10
0.90
0.14
0.87
1.64
0.47
0.78
XRF
TiO2
15.16
14.47
5.06
16.99
16.44
14.96
11.15
13.90
13.42
13.03
13.42
5.35
6.89
15.34
14.87
14.85
14.39
17.44
12.97
15.86
13.09
11.48
16.85
XRF
Al2O3
2.15
2.80
9.29
2.08
3.52
8.76
11.75
10.77
16.42
18.29
16.42
9.93
11.07
9.70
6.39
10.42
10.18
4.44
1.21
12.03
17.35
15.02
8.64
XRF
Fe2O3
0.06
0.04
0.18
0.03
0.05
0.24
0.21
0.19
0.24
0.26
0.24
0.22
0.17
0.22
0.10
0.20
0.18
0.11
0.04
0.36
0.23
0.41
0.12
XRF
MnO
0.87
1.29
23.67
1.03
1.56
6.13
10.61
6.85
4.88
4.38
4.88
17.07
22.52
6.11
4.35
7.16
7.10
1.38
0.58
5.38
4.36
1.97
4.89
XRF
MgO
5.38
3.61
8.91
4.16
3.66
11.46
11.56
11.17
9.21
8.54
9.21
12.20
6.95
9.60
5.80
13.19
10.81
2.62
0.91
11.14
7.38
9.18
4.80
XRF
CaO
3.42
2.69
0.09
5.04
4.71
1.84
1.37
1.99
2.69
2.20
2.69
0.88
0.27
2.56
2.61
1.40
2.26
6.03
0.20
1.27
3.47
0.45
4.52
XRF
Na2O
0.56
1.99
0.03
1.23
1.70
0.27
0.14
0.13
0.33
0.24
0.33
0.10
0.05
1.19
1.24
0.38
0.14
1.07
6.19
0.23
0.28
0.32
1.03
XRF
K2O
0.12
0.09
0.03
0.12
0.38
0.07
0.05
0.07
0.10
0.13
0.10
0.03
0.03
0.07
0.10
0.07
0.11
0.18
0.05
0.09
0.13
0.11
0.16
XRF
P2O5
0.52
1.39
12.78
0.63
0.95
1.16
1.10
0.70
0.34
0.13
0.34
1.96
5.79
1.60
1.32
1.58
1.89
1.12
1.74
2.10
0.86
10.53
1.77
LOI
99.25
99.35
99.28
99.47
99.74
99.70
99.10
99.56
99.25
99.88
99.25
99.35
98.85
99.45
100.04
99.46
99.55
99.28
99.29
99.65
99.65
99.84
99.60
Total
NORTHERN SWAYZE GREENSTONE BELT
29
30
80
73
13
1830
17
19
0
60
1860
2200
32
63
490
187
67
1630
10
276
119
87
83
131
45
30
0
17
91JAA-0008
91JAA-0009
91JAA-0039
91JAA-0049
91JAA-0057
92JAA-0066
91JAA-0068
91JAA-0073
91JAA-0077
91JAA-0094
91JAA-0102
91JAA-0105
91JAA-0109
91JAA-0113
91JAA-0119
91JAA-0124
91JAA-0127
91JAA-0135
91JAA-0136
91JAA-0137
91JAA-0139
91JAA-0149
91JAA-0155
91JAA-0161
91JAA-0163
AA
Method
91JAA-0006
Cr
Sample No.
Table 3. Continued.
1.01
0.99
1.06
0.14
0.38
0.21
0.18
0.31
0.31
0.97
0.32
0.66
0.81
0.29
0.78
1.32
0.36
0.24
0.38
1.70
2.04
2.23
0.20
1.67
0.36
0.35
ICP-OES
Be
Co
Sc
V
15
3
3
543
58
67
71
89
89
6
1190
50
62
182
61
18
974
1149
70
5
8
10
1379
13
67
71
16
2
2
67
34
39
39
44
46
3
78
29
21
52
19
9
77
83
43
4
5
4
88
9
39
40
9
2
1
28
26
44
47
42
36
3
21
24
17
46
16
4
19
22
47
2
3
2
24
5
47
50
93
3
2
161
174
258
254
285
230
5
121
187
116
239
101
47
145
132
267
12
23
9
135
50
270
270
ICP-OES ICP-OES ICP-OES ICP-OES
Ni
69
4
4
11
33
128
110
122
145
136
58
4
22
94
46
12
37
16
136
7
19
5
26
14
61
20
ICP-OES
Cu
74
25
43
66
84
114
86
93
72
43
55
51
87
116
69
73
64
83
135
37
54
40
58
88
89
84
ICP-OES
Zn
1.0
0.0
0.0
6.0
0.0
0.0
0.0
0.0
7.0
0.0
5.0
0.0
0.0
67.0
0.0
0.0
9.0
5.0
0.0
0.0
0.0
0.0
7.0
0.0
1.0
1.0
AA
Pd
2.0
0.0
0.0
8.0
0.0
0.0
0.0
0.0
7.0
0.0
6.0
0.0
0.0
17.0
0.0
0.0
11.0
9.0
0.0
0.0
0.0
0.0
10.0
0.0
2.0
2.0
AA
Pt
2.0
0.0
0.0
0.0
3.0
3.0
4.0
2.0
2.0
2.0
2.0
0.0
0.0
3.0
0.0
0.0
2.0
0.0
3.0
0.0
0.0
2.0
3.0
2.0
4.0
3.0
AA
Au
1280
850
340
45
170
145
60
145
35
490
145
75
3656
145
250
930
115
50
95
890
940
565
50
1040
95
100
AA
Ba
16
11
11
9
19
18
19
27
23
11
6
32
18
13
15
7
6
6
15
4
11
3
7
7
18
20
ICP-MS
Y
79.40
24.42
23.11
0.47
2.79
2.09
2.12
4.12
3.75
26.07
0.55
13.56
14.92
1.51
13.89
56.49
0.46
0.30
2.10
27.27
77.31
4.30
0.36
49.70
1.92
1.39
ICP-MS
La
179.68
51.31
51.94
1.61
7.24
6.15
6.09
11.68
10.42
58.01
1.43
34.10
35.73
4.25
29.07
111.76
1.39
1.03
6.11
52.68
142.51
8.73
1.10
98.61
5.59
4.66
ICP-MS
Ce
OGS REPORT 297
Cr
AA
84
53
45
283
0
0
294
340
58
197
1920
1700
64
14
99
123
210
90
34
26
1600
74
20
Sample No.
Method
91JAA-0168
91JAA-0170
91JAA-0173
91JAA-0176
91JAA-0184
91JAA-0185
91JAA-0193
91JAA-0196
91JAA-0197
91JAA-0198
91JAA-1010
91JAA-1024
91JAA-1047
91JAA-1060
91JAA-1074
91JAA-1095
91JAA-1116
91JAA-1136
91JAA-1168
91JAA-1174
91JAA-1215
91JAA-1218
91JAA-2007
Table 3. Continued.
0.69
0.65
0.10
1.50
1.20
0.22
0.15
0.21
0.30
0.52
0.36
0.14
0.18
0.32
0.57
0.19
0.35
1.12
1.01
0.23
0.33
0.30
0.53
ICP-OES
Be
Co
Sc
V
9
23
961
11
23
69
127
58
67
23
55
1009
737
72
54
100
83
18
3
120
36
32
84
5
8
68
6
9
36
43
37
36
39
41
68
69
34
18
38
40
16
2
40
43
13
25
5
8
18
4
4
44
49
42
40
40
39
18
23
42
16
38
38
10
1
31
44
19
16
32
35
88
21
36
231
220
221
264
322
304
87
129
260
90
209
228
90
2
213
366
90
95
ICP-OES ICP-OES ICP-OES ICP-OES
Ni
7
6
40
38
12
107
105
112
32
7
55
2
113
99
53
137
95
13
4
101
34
14
20
ICP-OES
Cu
39
27
52
40
65
68
72
76
67
92
132
99
66
86
70
67
88
77
36
74
97
137
88
ICP-OES
Zn
0.0
0.0
7.0
0.0
0.0
0.0
1.0
13.0
0.0
0.0
0.0
6.0
10.0
5.0
0.0
18.0
10.0
0.0
0.0
5.0
0.0
0.0
0.0
AA
Pd
0.0
0.0
7.0
0.0
0.0
1.0
1.0
14.0
0.0
0.0
0.0
6.0
8.0
5.0
0.0
18.0
8.0
0.0
0.0
5.0
0.0
0.0
0.0
AA
Pt
0.0
0.0
0.0
0.0
0.0
5.0
8.0
3.0
6.0
5.0
3.0
2.0
2.0
3.0
4.0
2.0
0.0
0.0
0.0
0.0
0.0
6.0
2.0
AA
Au
190
590
45
335
580
200
45
45
125
65
80
60
40
505
195
95
125
335
545
130
60
70
220
AA
Ba
6
11
7
3
6
20
13
17
22
38
27
5
7
20
15
16
22
13
13
15
34
10
16
ICP-MS
Y
12.57
11.07
0.61
13.71
29.56
2.40
1.39
2.62
2.83
3.08
3.60
0.19
0.44
2.47
12.05
1.71
3.88
15.10
27.12
2.82
4.69
11.56
8.38
ICP-MS
La
28.76
24.64
1.74
28.02
63.86
6.80
3.95
7.21
8.20
9.58
10.29
0.75
1.37
7.06
25.76
5.03
10.89
34.73
56.05
7.76
13.01
26.21
21.50
ICP-MS
Ce
NORTHERN SWAYZE GREENSTONE BELT
31
32
0.76
0.90
10.74
0.22
1.01
13.89
4.76
0.95
0.20
0.25
11.26
3.35
0.66
4.23
4.49
0.23
6.18
1.57
1.78
0.97
0.98
1.05
0.29
6.05
5.60
21.73
91JAA-0008
91JAA-0009
91JAA-0039
91JAA-0049
91JAA-0057
91JAA-0066
91JAA-0068
91JAA-0073
91JAA-0077
91JAA-0094
91JAA-0102
91JAA-0105
91JAA-0109
91JAA-0113
91JAA-0119
91JAA-0124
91JAA-0127
91JAA-0135
91JAA-0136
91JAA-0137
91JAA-0139
91JAA-0149
91JAA-0155
91JAA-0161
91JAA-0163
ICP-MS
Pr
91JAA-0006
Method
Sample No.
Table 3. Continued.
91.67
19.50
23.01
1.84
5.59
5.45
5.27
9.58
8.66
22.55
1.34
21.77
17.03
3.82
13.71
42.38
1.45
1.31
4.97
15.18
45.71
4.26
1.35
39.92
5.19
4.78
ICP-MS
Nd
15.79
3.17
5.87
0.81
2.06
1.90
1.86
3.11
2.72
3.62
0.55
5.61
3.83
1.41
2.86
5.76
0.58
1.59
1.71
1.88
6.24
0.84
0.64
6.09
1.80
1.82
ICP-MS
Sm
3.77
0.62
0.83
0.34
0.88
0.68
0.72
1.18
0.92
0.89
0.17
1.46
1.10
0.47
0.84
1.40
0.21
0.14
0.63
0.47
1.02
0.23
0.10
1.38
0.64
0.86
ICP-MS
Eu
10.15
2.06
2.64
1.18
2.98
2.56
2.37
3.82
3.74
2.54
0.81
6.22
3.46
1.88
2.77
3.25
0.92
0.88
2.10
1.13
3.68
0.64
0.94
3.32
2.54
2.77
ICP-MS
Gd
1.10
0.29
0.34
0.20
0.52
0.46
0.43
0.66
0.59
0.34
0.14
0.99
0.55
0.33
0.40
0.34
0.15
0.16
0.37
0.11
0.44
0.07
0.17
0.37
0.44
0.45
ICP-MS
Tb
5.16
1.73
1.93
1.58
3.49
3.27
3.23
4.77
4.30
1.96
1.02
6.16
3.60
2.43
2.74
1.61
1.22
1.21
2.75
0.60
2.36
0.39
1.31
1.69
3.19
3.29
ICP-MS
Dy
5.16
1.73
1.93
1.58
3.49
3.27
0.74
1.07
0.95
0.38
0.22
1.26
0.67
0.51
0.54
0.26
0.26
0.25
0.64
0.09
0.40
0.06
0.28
0.28
0.74
0.80
ICP-MS
Ho
5.16
1.73
1.93
1.58
3.49
3.27
2.16
3.10
2.70
1.09
0.68
3.45
1.91
1.49
1.54
0.59
0.81
0.71
1.87
0.29
1.03
0.19
0.85
0.63
2.16
2.18
ICP-MS
Er
0.22
0.15
0.15
0.12
0.30
0.31
0.31
0.47
0.38
0.15
0.09
0.50
0.25
0.21
0.22
0.07
0.11
0.08
0.30
0.03
0.15
0.02
0.12
0.09
0.33
0.34
ICP-MS
Tm
1.30
1.26
1.10
0.81
2.08
2.18
2.33
3.08
2.41
1.04
0.68
3.21
1.73
1.48
1.53
0.52
0.82
0.60
1.99
0.29
0.96
0.22
0.84
0.52
2.19
2.26
ICP-MS
Yb
0.18
0.19
0.16
0.09
0.30
0.31
0.32
0.43
0.35
0.17
0.10
0.47
0.21
0.22
0.21
0.07
0.12
0.07
0.29
0.04
0.13
0.03
0.12
0.08
0.33
0.35
ICP-MS
Lu
OGS REPORT 297
2.83
2.89
1.96
1.10
6.16
4.12
1.57
0.84
3.02
1.14
0.26
0.17
1.62
1.54
1.28
1.07
0.64
1.02
6.87
3.08
0.28
2.82
2.70
91JAA-0170
91JAA-0173
91JAA-0176
91JAA-0184
91JAA-0185
91JAA-0193
91JAA-0196
91JAA-0197
91JAA-0198
91JAA-1010
91JAA-1024
91JAA-1047
91JAA-1060
91JAA-1074
91JAA-1095
91JAA-1116
91JAA-1136
91JAA-1168
91JAA-1174
91JAA-1215
91JAA-1218
91JAA-2007
ICP-MS
Pr
91JAA-0168
Method
Sample No.
Table 3. Continued.
10.36
11.67
1.61
12.40
26.49
5.77
3.43
5.47
2.83
9.21
8.82
1.07
1.55
6.24
12.47
4.55
8.55
17.02
22.57
5.87
10.37
13.23
13.23
ICP-MS
Nd
1.90
2.43
0.63
2.27
4.30
1.97
1.16
1.76
2.22
3.63
3.05
0.47
0.64
2.13
2.69
1.67
2.67
3.49
3.62
1.89
3.47
2.83
3.33
ICP-MS
Sm
0.60
0.74
0.23
0.83
0.86
0.65
0.45
0.69
0.80
1.32
1.13
0.16
0.21
0.80
0.77
0.63
0.96
1.01
0.83
0.70
1.12
0.72
1.12
ICP-MS
Eu
1.49
2.23
0.92
1.47
2.81
2.57
1.88
2.43
3.04
5.28
4.06
0.74
1.03
2.98
2.64
2.31
3.33
2.76
2.38
2.34
4.60
2.71
3.14
ICP-MS
Gd
0.19
0.30
0.16
0.16
0.29
0.45
0.31
0.41
0.54
0.92
0.70
0.13
0.19
0.51
0.41
0.41
0.57
0.40
0.33
0.38
0.81
0.33
0.49
ICP-MS
Tb
1.07
1.93
1.25
0.72
1.43
3.31
2.27
2.94
3.76
6.28
4.95
0.99
1.32
3.43
2.66
2.85
3.91
2.57
2.00
2.65
5.71
1.80
3.02
ICP-MS
Dy
0.20
0.38
0.26
0.10
0.23
0.72
0.51
0.66
0.83
1.35
1.11
0.21
0.28
0.75
0.56
0.65
0.85
0.50
0.41
0.59
1.29
0.36
0.61
ICP-MS
Ho
0.53
1.13
0.76
0.23
0.53
2.15
1.43
1.83
2.34
3.91
3.03
0.55
0.72
2.05
1.50
1.74
2.33
1.39
1.17
1.71
3.61
1.18
1.59
ICP-MS
Er
0.07
0.15
0.10
0.02
0.06
0.31
0.21
0.29
0.34
0.61
0.47
0.08
0.10
0.31
0.23
0.26
0.33
0.18
0.18
0.25
0.54
0.18
0.22
ICP-MS
Tm
0.47
1.05
0.74
0.18
0.36
2.10
1.47
1.86
2.34
4.08
3.14
0.55
0.73
1.92
1.45
1.71
2.20
1.20
1.33
1.76
3.49
1.61
1.56
ICP-MS
Yb
0.05
0.17
0.10
0.02
0.05
0.29
0.23
0.29
0.36
0.60
0.48
0.08
0.10
0.31
0.24
0.29
0.30
0.16
0.19
0.24
0.53
0.24
0.22
ICP-MS
Lu
NORTHERN SWAYZE GREENSTONE BELT
33
34
SiO2
XRF
36.80
54.00
48.40
55.30
75.90
39.10
64.30
43.70
51.10
75.00
50.80
54.60
39.70
52.10
38.10
51.30
44.50
49.00
50.80
39.00
53.50
67.60
35.40
73.90
46.60
48.80
47.60
53.00
48.00
73.10
74.70
69.80
60.70
42.60
51.60
66.50
56.80
69.10
69.40
Sample No.
Method
92JAA-0018
92JAA-0045
92JAA-0047
92JAA-0066
92JAA-0109
92JAA-0141
92JAA-0142
92JAA-0151
92JAA-0173
92JAA-0194
92JAA-0198
92JAA-0199
92JAA-0221
92JAA-0229
92JAA-0231
92JAA-0237
92JAA-0248
92JAA-0249
92JAA-0250
92JAA-0252
92JAA-0253
92JAA-0258
92JAA-1017
92JAA-1030
92JAA-1043
92JAA-1052
92JAA-1053
92JAA-1073
92JAA-1097
92JAA-1116
92JAA-1134
92JAA-1143
92JAA-1144
92JAA-1156
92JAA-1157
92JAA-1162
92JAA-1170
92JAA-1180
92JAA-1193
0.12
1.13
0.82
0.64
0.20
0.13
0.54
0.42
0.96
0.31
0.69
1.48
0.82
0.75
0.20
0.75
0.42
0.69
0.86
0.10
1.34
0.57
0.12
0.09
0.87
0.84
0.73
0.87
0.75
0.12
0.29
0.34
0.48
0.35
0.74
0.36
1.80
0.25
0.36
XRF
TiO2
1.34
14.90
15.00
17.10
12.60
1.51
16.10
8.35
13.00
14.40
13.30
14.50
11.10
14.10
2.89
13.90
7.74
11.70
13.80
1.35
15.20
14.40
1.50
14.30
13.70
13.80
11.80
14.70
15.60
15.20
12.60
15.80
16.70
5.95
14.30
12.00
16.10
16.60
15.30
XRF
Al2O3
8.07
8.32
11.60
9.36
1.52
8.24
4.03
11.70
13.30
1.57
11.80
11.40
10.30
12.00
8.42
11.50
13.30
11.20
11.90
7.99
12.00
3.95
12.40
1.64
20.70
12.60
12.40
8.44
12.30
1.10
1.83
2.24
3.94
11.30
11.90
4.86
9.11
1.52
2.93
XRF
Fe2O3
0.10
0.18
0.18
0.22
0.04
0.13
0.06
0.23
0.21
0.06
0.27
0.23
0.22
0.20
0.12
0.25
0.21
0.17
0.19
0.15
0.17
0.05
0.17
0.03
0.62
0.18
0.19
0.15
0.20
0.03
0.04
0.04
0.08
0.19
0.21
0.13
0.14
0.04
0.08
XRF
MnO
37.80
6.57
7.63
3.26
0.76
36.80
2.27
20.60
8.03
0.39
7.31
5.02
5.21
6.97
34.00
7.53
19.90
12.30
7.12
40.00
3.49
1.86
35.20
0.46
5.32
7.88
11.80
7.96
7.84
0.36
0.90
0.78
2.59
26.10
7.57
2.43
3.85
0.98
1.59
XRF
MgO
0.23
9.14
11.00
6.94
2.03
1.37
3.80
7.74
7.76
0.37
12.90
8.68
13.30
8.92
1.87
9.18
7.98
6.77
10.30
0.33
5.39
2.20
0.82
1.36
9.35
9.33
6.86
8.06
11.60
2.04
1.38
2.67
4.22
5.65
11.00
6.81
5.83
3.05
2.58
XRF
CaO
0.01
2.66
1.90
2.89
2.84
-0.01
7.05
0.03
0.76
3.88
2.01
2.17
0.76
2.75
0.01
1.36
0.07
3.21
3.31
-0.01
4.53
8.71
-0.01
3.84
1.20
2.42
2.65
3.12
1.40
5.74
2.32
4.90
5.70
0.37
2.17
3.54
3.68
5.75
6.78
XRF
Na2O
-0.01
0.12
0.03
0.83
1.44
-0.01
0.48
0.03
0.02
2.32
0.24
0.70
0.34
0.59
0.02
0.07
0.02
0.05
0.21
0.04
-0.01
0.05
-0.01
2.65
0.23
0.04
0.14
1.57
0.42
1.93
3.22
2.56
3.28
0.03
0.21
1.17
1.45
2.53
0.80
XRF
K2O
Table 4. Whole-rock geochemical data from Muskego and Keith townships. Major element oxide values in weight %, trace and rare earth element values in ppm.
0.02
0.12
0.07
0.17
0.07
0.03
0.12
0.05
0.08
0.08
0.05
0.14
0.07
0.06
0.02
0.06
0.04
0.06
0.08
0.02
0.11
0.13
0.02
0.04
0.09
0.08
0.07
0.36
0.06
0.05
0.07
0.12
0.28
0.03
0.06
0.08
0.16
0.10
0.08
XRF
P2O5
14.70
2.45
2.40
2.00
1.60
12.30
1.10
5.20
5.32
1.45
0.95
1.00
18.40
0.75
12.40
2.45
5.10
3.00
1.85
11.50
3.65
0.60
13.00
1.40
1.20
2.65
3.20
1.10
1.10
0.20
0.90
0.80
0.35
6.75
0.80
2.20
0.75
0.35
0.65
LOI
99.18
99.59
99.03
98.71
99.00
99.59
99.85
98.05
100.54
99.83
100.32
99.92
100.22
99.19
98.05
98.35
99.28
98.14
100.42
100.47
99.37
100.12
98.61
99.71
99.87
98.62
97.43
99.33
99.27
99.87
98.25
100.05
98.32
99.32
100.56
100.08
99.67
100.27
100.55
Total
OGS REPORT 297
92JAA-0018
92JAA-0045
92JAA-0047
92JAA-0066
92JAA-0109
92JAA-0141
92JAA-0142
92JAA-0151
92JAA-0173
92JAA-0194
92JAA-0198
92JAA-0199
92JAA-0221
92JAA-0229
92JAA-0231
92JAA-0237
92JAA-0248
92JAA-0249
92JAA-0250
92JAA-0252
92JAA-0253
92JAA-0258
92JAA-1017
92JAA-1030
92JAA-1043
92JAA-1052
92JAA-1053
92JAA-1073
92JAA-1097
92JAA-1116
92JAA-1134
92JAA-1143
92JAA-1144
92JAA-1156
92JAA-1157
92JAA-1162
92JAA-1170
92JAA-1180
92JAA-1193
Method
Sample No.
Cr
Sc
Cu
Zn
Bi
Mo
0.80
1.10
1.50
1.70
0.90
0.80
1.10
1.40
1.60
1.10
1.40
1.80
1.30
1.50
0.90
1.50
1.40
1.30
1.60
0.80
1.70
1.20
1.30
1.50
2.40
1.60
1.60
2.10
1.40
1.40
1.50
1.20
3.00
1.10
1.50
1.10
1.40
1.70
1.10
6680
497
227
0
47
1710
111
2410
225
17
445
0
158
97
1950
0
2990
1510
214
0
194
64
5430
14
302
260
792
343
297
12
21
20
78
2240
152
18
63
33
30
7
45
40
13
4
9
9
33
42
4
45
61
40
53
13
45
29
39
39
8
43
9
7
1
40
40
38
21
39
1
3
3
6
21
54
6
56
2
5
10
89
104
103
4
20
24
42
76
3
94
10
85
131
29
69
12
371
34
4
119
61
5
2
36
74
76
26
116
2
17
22
37
9
46
12
84
4
4
12
109
90
128
45
25
97
110
89
30
108
121
62
69
44
108
79
69
62
35
98
64
47
31
89
82
84
94
77
34
38
194
75
67
61
76
163
46
26
4.00
-3.00
5.00
-3.00
-3.00
6.00
-3.00
5.00
4.00
-3.00
-3.00
6.00
-3.00
4.00
4.00
4.00
-3.00
-3.00
4.00
4.00
-3.00
-3.00
3.00
-3.00
7.00
9.00
-3.00
5.00
-3.00
-3.00
-3.00
-3.00
-3.00
4.00
-3.00
-3.00
-3.00
-3.00
-3.00
-1.00
-1.00
-1.00
1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
3.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
-1.00
ICP-OES ICP-OES ICP-OES ICP-OES ICP-OES ICP-OES ICP-OES
Be
Table 4. Continued.
Sb
17.00
-3.00
8.00
-3.00
-3.00
-3.00
-3.00
-3.00
30.00
-3.00
-3.00
-3.00
75.00
-3.00
29.00
-3.00
-3.00
-3.00
-3.00
5.00
-3.00
-3.00
18.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
-3.00
7.00
-5.00
-5.00
-5.00
-5.00
-5.00
-5.00
8.00
-5.00
-5.00
-5.00
-5.00
-5.00
-5.00
7.00
-5.00
-5.00
-5.00
-5.00
9.00
-5.00
-5.00
7.00
-5.00
-5.00
-5.00
-5.00
-5.00
-5.00
-5.00
-5.00
-5.00
-5.00
14.00
-5.00
-5.00
-5.00
-5.00
-5.00
ICP-OES ICP-OES
As
8
9
9
42
69
11
14
10
7
61
14
27
19
21
7
7
10
4
10
9
8
4
8
75
14
6
5
49
19
67
76
64
82
4
11
40
40
80
30
XRF
Rb
81
149
47
183
499
80
453
108
55
458
159
320
115
133
98
98
97
99
145
68
40
90
84
686
137
94
193
1002
72
762
724
1048
1483
86
96
324
489
865
317
XRF
Ba
15
213
157
371
167
30
374
31
221
168
155
140
112
141
50
155
14
89
224
15
158
189
12
98
110
178
96
546
110
416
288
398
1410
26
93
340
161
824
390
XRF
Sr
1.00
20.00
10.00
14.00
11.00
1.00
9.00
19.00
22.00
7.00
3.00
10.00
15.00
12.00
2.00
14.00
9.00
8.00
8.00
-1.00
19.00
2.00
1.00
7.00
16.00
12.00
19.00
26.00
18.00
22.00
17.00
14.00
10.00
5.00
8.00
6.00
43.00
27.00
6.00
ICP
Li
2.0
4.0
2.0
4.0
2.0
2.0
7.0
2.0
2.0
6.0
2.0
2.0
3.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
3.0
8.0
2.0
7.0
3.0
2.0
2.0
6.0
2.0
4.0
2.0
3.0
10.0
2.0
2.0
7.0
3.0
6.0
2.0
XRF
Nb
8
80
58
163
153
7
167
239
62
129
35
80
57
46
14
45
31
52
66
5
94
155
7
61
57
57
49
164
40
58
101
145
227
19
46
143
123
119
99
XRF
Zr
0.10
0.80
0.90
1.80
2.20
0.10
2.10
0.00
0.90
4.00
0.00
0.90
0.00
0.20
0.10
0.50
0.00
0.30
1.00
0.20
1.10
2.90
0.10
4.40
0.50
1.40
0.50
5.60
0.70
0.00
2.90
0.00
0.00
0.20
0.00
2.00
1.30
0.00
0.00
XRF
Th
La
0.30
3.80
3.20
15.20
11.30
0.30
17.20
3.40
12.80
4.10
1.90
0.40
1.90
2.50
3.70
0.30
3.90
15.90
0.20
24.00
2.30
3.60
2.70
52.70
2.30
16.20
0.60
12.60
3.80
0.10
0.10
0.07
0.50
0.60
0.10
0.60
0.10
1.30
0.10
0.10
0.10
0.10
0.10
0.13
0.10
0.10
0.80
0.10
1.20
0.05
0.10
0.10
1.10
0.10
0.80
0.10
0.40
0.10
ICP-MS ICP-MS
U
NORTHERN SWAYZE GREENSTONE BELT
35
36
1.30
2.80
1.60
0.80
0.10
0.90
0.80
1.40
0.10
1.60
3.80
0.10
4.90
1.00
1.20
1.00
12.70
0.90
3.40
0.30
2.90
1.70
9.70
28.80
12.30
5.90
1.10
6.00
6.40
10.50
0.80
11.50
38.20
0.80
50.50
6.80
9.90
7.60
120.00
6.70
34.70
1.90
27.60
11.50
11.30
8.90
1.40
11.50
4.00
7.00
0.40
5.00
14.70
0.50
17.10
5.40
6.30
5.00
48.70
4.70
4.50
0.80
4.50
8.00
6.50
10.30
0.50
7.10
6.50
14.70
9.30
0.50
12.80
ICP-MS
Nd
2.50
3.30
0.60
1.90
1.50
2.20
0.20
2.80
3.20
0.20
3.20
1.90
2.00
1.70
8.50
1.70
1.60
0.30
1.60
2.70
2.20
2.00
0.20
2.30
2.10
2.90
1.90
0.20
2.60
ICP-MS
Sm
0.67
1.23
0.21
0.48
0.48
0.77
0.05
0.90
0.87
0.03
0.61
0.68
0.78
0.59
2.24
0.61
0.56
0.12
0.50
1.03
0.75
0.40
-0.05
0.87
0.71
0.97
0.52
0.06
0.94
ICP-MS
Eu
2.40
4.50
0.90
1.40
2.10
2.90
0.30
3.60
3.00
0.20
2.70
2.60
2.60
2.20
7.00
2.20
2.30
0.50
2.30
3.40
2.90
1.60
0.20
3.00
2.90
3.10
1.70
0.30
2.40
ICP-MS
Gd
Negative numbers indicate that the content is below the detection limit of the analytical method used.
0.10
1.40
1.30
3.70
2.50
0.10
3.50
0.90
10.50
9.50
35.20
25.30
0.80
35.50
92JAA-0018
92JAA-0045
92JAA-0047
92JAA-0066
92JAA-0109
92JAA-0141
92JAA-0142
92JAA-0151
92JAA-0173
92JAA-0194
92JAA-0198
92JAA-0199
92JAA-0221
92JAA-0229
92JAA-0231
92JAA-0237
92JAA-0248
92JAA-0249
92JAA-0250
92JAA-0252
92JAA-0253
92JAA-0258
92JAA-1017
92JAA-1030
92JAA-1043
92JAA-1052
92JAA-1053
92JAA-1073
92JAA-1097
92JAA-1116
92JAA-1134
92JAA-1143
92JAA-1144
92JAA-1156
92JAA-1157
92JAA-1162
92JAA-1170
92JAA-1180
92JAA-1193
ICP-MS
Pr
ICP-MS
Ce
Method
Sample No.
Table 4. Continued.
0.30
0.70
0.10
0.10
0.30
0.40
-0.10
0.50
0.40
-0.10
0.30
0.40
0.40
0.30
0.70
0.30
0.30
0.10
0.30
0.50
0.40
0.20
-0.10
0.40
0.40
0.30
0.20
-0.10
0.30
ICP-MS
Tb
2.00
5.00
1.10
0.70
2.40
3.00
0.30
3.90
2.20
0.20
1.30
2.90
2.70
2.30
3.30
2.50
2.60
0.50
2.40
3.60
3.10
1.00
0.20
3.20
3.20
2.20
1.00
0.30
1.70
ICP-MS
Dy
0.36
1.05
0.22
0.10
0.48
0.60
0.05
0.78
0.39
0.05
0.18
0.58
0.53
0.45
0.53
0.51
0.56
0.11
0.49
0.72
0.63
0.17
-0.05
0.63
0.59
0.38
0.17
0.06
0.29
ICP-MS
Ho
1.10
3.10
0.60
0.30
1.40
1.70
0.20
2.30
1.00
0.10
0.50
1.70
1.50
1.20
1.40
1.60
1.70
0.30
1.40
2.20
1.80
0.50
0.10
1.80
1.80
1.10
0.50
0.20
0.80
ICP-MS
Er
0.10
0.50
0.10
-0.10
0.20
0.30
-0.10
0.30
0.20
-0.10
0.10
0.30
0.20
0.20
0.20
0.20
0.30
0.10
0.20
0.30
0.30
0.10
-0.10
0.30
0.30
0.10
0.10
-0.10
0.10
ICP-MS
Tm
1.20
3.50
0.70
0.30
1.60
1.90
0.20
2.40
1.10
0.20
0.80
1.80
1.50
1.30
1.40
1.70
2.00
0.40
1.50
2.50
2.00
0.60
0.10
1.80
1.90
0.90
0.80
0.20
0.80
ICP-MS
Yb
0.17
0.49
0.15
-0.05
0.54
0.36
-0.05
0.39
0.19
-0.05
0.13
0.30
0.20
0.21
0.20
0.26
0.38
-0.05
0.25
0.43
0.31
0.13
-0.05
0.25
0.27
0.27
0.16
0.04
0.11
ICP-MS
Lu
OGS REPORT 297
5.67
5.68
18.91
16.54
16.81
15.38
51.29
52.56
44.87
49.48
50.20
47.82
40.65
56.87
48.94
45.00
45.75
48.69
39.36
42.87
67.10
61.41
68.39
50.94
38.29
67.02
59.38
48.68
93JAA-1006
93JAA-1008
93JAA-1014
93JAA-1016
93JAA-1020
93JAA-1021
93JAA-1027
93JAA-1033
93JAA-1035
93JAA-1041
93JAA-1042
93JAA-1043
93JAA-1046
93JAA-1055
93JAA-1059
93JAA-1062
93JAA-1068
93JAA-1069
93JAA-1071
93JAA-1071D 67.64
59.74
93JAA-1005
93JAA-1035D 45.77
47.76
93JAA-1001
93JAA-1078
93JAA-1083
93JAA-1085
15.26
17.10
4.13
7.93
16.53
15.73
15.10
7.47
4.65
14.15
9.70
14.77
14.07
5.41
14.31
12.14
13.91
20.83
12.53
15.44
XRF
XRF
Method
Al2O3
SiO2
Sample No.
0.19
0.09
0.11
0.03
0.03
0.15
0.20
0.06
0.33
0.05
0.16
0.13
0.22
0.20
0.19
0.19
0.22
0.26
0.14
0.18
0.20
0.17
0.24
0.10
0.17
0.19
XRF
MnO
8.54
4.16
4.20
0.89
0.93
35.15
14.49
1.98
1.96
3.04
22.22
32.72
6.44
4.29
21.30
21.38
11.31
3.68
4.75
25.42
8.10
10.27
7.29
8.92
4.58
6.48
XRF
MgO
11.39
4.43
6.16
2.94
2.93
0.74
10.91
1.99
7.47
1.97
7.85
1.51
10.13
10.54
9.24
9.18
10.01
10.95
6.14
8.45
5.85
6.88
9.53
13.29
6.03
8.59
XRF
CaO
1.64
3.54
4.07
4.67
4.71
-.01
1.13
1.57
0.97
5.66
0.53
-.01
2.95
2.62
0.26
0.26
2.57
1.38
2.77
0.15
3.09
3.92
2.82
1.17
3.24
3.20
XRF
Na2O
0.18
0.44
0.92
1.42
1.43
-.02
0.44
2.53
1.47
0.45
-.02
-.02
0.61
0.81
-.02
-.02
-.02
-.02
-.02
-.02
0.05
-.02
0.13
0.10
0.10
0.09
XRF
K2O
0.69
0.63
0.56
0.32
0.31
0.19
0.36
0.64
0.59
0.55
0.37
0.28
1.17
0.81
0.29
0.29
0.50
0.72
0.75
0.24
1.34
0.63
0.78
0.09
1.52
1.25
XRF
TiO2
0.07
0.21
0.23
0.10
0.10
-.05
0.05
0.30
0.18
0.22
-.05
-.05
0.11
0.08
-.05
-.05
0.06
0.06
0.14
-.05
0.10
0.08
0.07
-.05
0.11
0.14
XRF
P2O5
11.50
6.26
5.79
2.26
2.24
10.75
9.75
3.75
6.22
4.16
11.61
9.78
13.69
7.27
10.12
10.13
12.24
10.32
7.79
7.94
14.41
10.51
11.44
5.62
14.97
9.30
XRF
Fe2O3
0.79
2.64
2.05
2.21
2.25
10.32
1.89
2.79
1.99
1.82
5.47
10.91
1.19
6.12
5.45
5.12
7.16
7.59
5.24
10.13
3.98
4.94
3.27
3.80
3.12
3.20
LOI
98.94
98.88
99.21
99.29
98.50
99.69
98.09
100.53
98.32
100.09
98.60
99.32
99.35
99.40
98.33
98.01
98.78
98.68
98.66
98.59
99.25
99.73
98.95
98.82
98.93
99.16
TOTAL
-0.30
-0.30
-0.30
1.16
1.22
-0.30
0.48
-0.30
0.32
-0.30
-0.30
0.77
0.54
4.26
0.78
0.71
3.75
4.45
2.39
2.87
-0.30
1.74
0.68
-0.30
0.58
-0.30
CO2
0.03
-0.03
0.13
-0.03
-0.03
0.41
-0.03
1.02
0.09
-0.03
-0.03
-0.03
0.09
0.15
0.03
0.03
0.08
0.06
0.04
0.03
-0.03
0.06
-0.03
-0.03
-0.03
0.04
S
76
307
341
515
516
74
181
499
295
106
26
14
103
422
12
12
34
43
52
42
75
56
134
83
77
67
AA
Ba
330
89
114
0
0
4559
2377
70
141
44
2683
3599
226
221
2232
2080
2676
355
177
1960
196
644
179
616
0
205
AA
Cr
0.26
0.76
0.90
0.93
0.92
-0.2
-0.2
0.73
0.70
0.62
-0.2
-0.2
0.42
0.36
-0.2
-0.2
-0.2
0.28
0.60
-0.2
0.43
-0.2
0.33
-0.2
0.36
0.41
AA
Be
43.39
22.65
21.01
5.43
5.50
124.0
51.58
16.45
21.10
15.22
88.30
101.80
42.58
45.16
92.83
93.44
59.22
38.00
27.61
88.38
49.67
48.59
58.77
34.95
43.53
53.80
AA
Co
72.35
48.21
33.45
4.39
4.88
129.8
49.09
19.95
33.05
-5
71.75
5.15
109.6
94.35
33.39
33.13
90.65
105.3
13.10
19.65
167.2
142.7
23.80
44.18
-5
15.54
AA
Cu
Table 5. Whole-rock geochemical data from Reeves, Penhorwood, Sewell and Kenogaming townships. Major element oxide values in weight %, trace and rare earth element values in ppm.
Ni
-6
-6
-6
-6
-6
6.95
-6
-6
-6
-6
-6
6.38
-6
-6
-6
-6
-6
-6
-6
-6
-6
-6
-6
-6
-6
-6
99.82
85.89
79.82
8.09
8.26
450.1
203.2
41.03
51.21
23.10
1024
1779
71.79
157.6
1321
1335
758.6
132.3
134.0
1444
98.12
152.7
117.8
162.6
11.81
80.03
AA ICP-OES
Mo
NORTHERN SWAYZE GREENSTONE BELT
37
38
13.36
13.34
15.27
6.63
6.61
4.51
60.07
47.17
49.05
46.25
42.21
53.08
47.17
48.72
55.77
46.62
40.13
38.44
41.16
46.35
51.32
41.84
49.39
38.62
35.91
48.32
49.36
44.28
93JAA-1095
93JAA-1096
93JAA-1097
93JAA-1100
93JAA-1101
93JAA-1102
93JAA-1104
93JAA-1106
93JAA-1107
93JAA-1108
93JAA-1109
93JAA-1111
93JAA-1112
93JAA-1113
93JAA-1114
93JAA-1114D 41.82
39.73
93JAA-1090
93JAA-1101D 47.21
65.86
93JAA-1086
93JAA-1115
93JAA-1117
93JAA-1118
93JAA-1119
93JAA-1121
93JAA-1122
93JAA-1124
13.53
4.19
4.57
1.60
1.32
15.16
13.83
12.77
5.31
3.67
4.85
15.15
15.71
15.42
15.54
7.51
7.27
13.64
13.88
15.36
XRF
XRF
Method
Al2O3
SiO2
Sample No.
Table 5. Continued.
0.11
0.07
0.15
0.07
0.12
0.25
0.14
0.16
0.16
0.20
0.23
0.11
0.12
0.11
0.17
0.12
0.18
0.07
0.20
0.20
0.15
0.14
0.20
0.18
0.28
0.09
XRF
MnO
14.11
25.72
21.20
41.17
41.29
4.28
32.06
25.77
25.64
6.54
6.45
29.11
35.79
33.28
9.22
4.37
8.28
1.78
8.59
8.46
5.02
23.50
19.25
7.48
5.37
4.84
XRF
MgO
15.28
3.90
9.47
0.34
0.21
10.52
2.75
5.85
5.87
9.79
8.95
3.65
1.64
3.46
10.93
3.88
9.82
5.35
8.10
8.10
5.20
5.18
8.86
9.62
7.86
6.52
XRF
CaO
0.21
-0.01
-0.01
-0.01
-0.01
1.03
0.06
0.34
0.35
1.78
2.15
0.06
0.02
0.15
1.19
4.96
2.06
3.16
1.52
1.52
4.63
0.51
0.34
1.45
1.32
2.72
XRF
Na2O
0.03
-0.02
-0.02
-0.02
-0.02
-0.02
-0.02
0.05
0.05
0.55
-0.02
-0.02
-0.02
-0.02
0.04
0.09
0.13
0.82
-0.02
-0.02
0.30
0.82
0.02
2.13
0.06
1.00
XRF
K2O
0.16
0.09
0.21
0.02
0.04
0.78
0.25
0.36
0.36
0.84
0.71
0.29
0.20
0.24
0.59
1.13
0.78
0.48
1.06
1.06
1.00
0.38
0.37
0.61
1.91
0.52
XRF
TiO2
-0.05
-0.05
-0.05
-0.05
-0.05
0.07
-0.05
-0.05
-0.05
0.09
0.07
-0.05
-0.05
-0.05
0.06
0.23
0.08
0.16
0.10
0.10
0.15
-0.05
-0.05
0.06
0.21
0.13
XRF
P2O5
5.62
8.63
8.61
5.39
7.86
10.39
9.75
10.17
10.16
12.84
10.84
9.37
8.42
9.15
11.06
8.25
11.66
4.29
13.21
13.20
9.45
9.96
11.37
12.74
16.92
5.58
XRF
Fe2O3
5.33
5.90
4.98
15.02
10.33
6.52
10.44
7.61
7.52
1.32
10.53
9.41
12.20
8.96
3.69
5.27
1.76
1.62
5.66
5.65
5.20
8.60
3.95
1.72
3.63
1.79
LOI
98.68
97.85
97.54
99.49
99.75
98.40
99.72
98.78
98.62
99.09
99.03
98.51
100.51
100.36
98.72
99.78
98.88
98.87
99.00
98.81
99.70
98.85
97.91
98.70
98.60
98.61
TOTAL
1.42
-0.30
-0.30
1.80
0.34
2.99
0.55
-0.30
-0.30
-0.30
5.95
-0.30
0.50
-0.30
0.35
2.33
-0.30
-0.30
3.73
3.75
2.14
0.71
-0.30
-0.30
1.12
-0.30
CO2
-0.03
-0.03
-0.03
0.12
0.06
0.10
0.09
0.03
0.03
-0.03
-0.03
0.05
0.03
0.03
0.06
-0.03
0.06
-0.03
0.03
0.03
-0.03
0.03
-0.03
0.03
0.12
-0.03
S
51
14
17
30
42
59
18
22
29
106
76
32
23
43
76
88
109
190
69
61
62
106
30
227
56
305
AA
Ba
1982
2043
1674
733
2488
416
2034
2453
2468
43
124
1551
1706
1891
407
94
178
67
119
114
100
1127
2611
130
148
134
AA
Cr
0.22
-0.2
-0.2
-0.2
-0.2
0.27
-0.2
-0.2
-0.2
0.26
0.23
-0.2
-0.2
-0.2
0.24
0.62
0.26
0.73
0.32
0.32
0.81
-0.2
-0.2
0.22
0.38
0.65
AA
Be
41.07
94.70
78.28
101.6
124.2
56.68
93.07
89.82
90.90
43.40
26.91
90.77
94.36
90.90
48.02
26.76
45.72
13.20
48.89
48.39
33.13
71.40
71.60
43.65
58.11
23.02
AA
Co
3.73
20.35
-5
13.76
8.63
61.09
17.44
7.74
7.50
154.8
99.50
5.05
5.11
9.12
114.9
84.94
146.8
20.56
63.15
63.35
8.40
13.93
4.09
24.98
85.10
53.96
AA
Cu
-6
-6
-6
7.52
14
-6
-6
-6
-6
-6
-6
-6
6.61
6.27
-6
-6
-6
-6
-6
-6
-6
-6
-6
-6
-6
-6
AA
Mo
201.1
582.8
1460
2886
2737
132.9
1744
1252
1272
60.32
77.14
1707
1985
1767
185.7
72.57
121.5
33.14
178.6
179.4
70.22
1255
326.9
31.88
94.24
127.6
ICP-OES
Ni
OGS REPORT 297
41.36
40.82
19.46
38.83
33.36
44.93
17.60
18.42
37.82
30.17
20.33
20.35
28.08
41.34
15.79
23.01
7.32
15.05
12.02
43.30
11.96
3.47
3.49
14.34
14.44
38.74
93JAA-1005
93JAA-1006
93JAA-1008
93JAA-1014
93JAA-1016
93JAA-1020
93JAA-1021
93JAA-1027
93JAA-1033
93JAA-1035
93JAA-1035D
93JAA-1041
93JAA-1042
93JAA-1043
93JAA-1046
93JAA-1055
93JAA-1059
93JAA-1062
93JAA-1068
93JAA-1069
93JAA-1071
93JAA-1071D
93JAA-1078
93JAA-1083
93JAA-1085
ICP-OES
Sc
93JAA-1001
Method
Sample No.
Table 5. Continued.
232.5
114.6
103.9
31.23
31.65
102.8
189.2
88.30
109.5
66.08
167.9
114.7
308.0
177.6
134.5
135.2
199.9
251.5
133.5
118.3
322.4
203.5
257.1
52.60
445.9
269.7
ICP-OES
V
15.31
11.78
11.30
3.51
3.50
3.11
8.92
13.23
12.86
9.97
8.13
3.52
22.66
12.76
6.88
6.90
11.41
14.93
13.79
6.20
22.41
14.44
17.08
2.82
21.66
25.75
ICP-OES
Y
86.82
77.51
85.13
58.34
57.56
85.81
85.31
95.13
145.3
44.72
66.61
77.12
119.8
75.26
59.51
59.72
66.77
81.26
104.4
73.54
136.6
72.38
143.1
40.84
72.11
164.8
ICP-OES
Zn
W
La
126.8
428.2
582.0
269.4
264.9
2.05
47.83
234.4
329.5
203.1
19.67
8.56
158.2
229.2
28.48
29.01
58.32
137.4
182.3
93.01
50.77
31.77
70.49
124.7
59.53
142.8
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
2.62
23.66
29.53
16.15
16.11
0.46
1.99
38.88
17.64
17.29
0.39
0.23
4.12
2.70
0.40
0.42
2.87
2.02
9.99
0.46
3.41
3.46
2.37
0.36
4.05
5.09
ICP-OES ICP-OES ICP-MS
Sr
6.85
53.27
65.06
29.81
29.51
1.15
5.20
85.35
39.65
39.24
1.32
0.73
11.07
7.47
1.31
1.33
6.64
5.90
22.72
1.26
9.81
8.14
6.64
0.87
11.33
14.40
ICP-MS
Ce
1.08
6.80
8.27
3.45
3.45
0.16
0.69
10.57
4.88
4.82
0.24
0.12
1.70
1.22
0.26
0.25
0.91
0.99
2.91
0.20
1.58
1.16
1.03
0.15
1.74
2.27
ICP-MS
Pr
5.07
25.61
30.62
11.66
11.86
0.72
3.05
37.81
18.12
17.01
1.40
0.75
8.16
6.14
1.42
1.39
4.22
4.97
12.30
1.20
8.19
5.36
5.23
0.62
8.32
10.55
ICP-MS
Nd
1.71
4.48
4.92
2.00
2.10
0.26
0.95
5.91
3.47
3.04
0.62
0.33
2.71
1.89
0.65
0.64
1.34
1.68
2.91
0.53
2.70
1.62
1.84
0.25
2.69
3.44
ICP-MS
Sm
0.64
1.30
1.35
0.66
0.65
0.07
0.30
1.54
1.13
0.83
0.33
0.14
0.99
0.83
0.16
0.16
0.48
0.68
0.87
0.20
1.00
0.58
0.61
0.21
0.66
1.05
ICP-MS
Eu
0.40
0.47
0.49
0.19
0.20
0.07
0.22
0.57
0.43
0.35
0.21
0.08
0.58
0.38
0.18
0.18
0.32
0.37
0.46
0.14
0.63
0.38
0.42
0.05
0.58
0.76
ICP-MS
Tb
2.26
3.62
3.70
1.53
1.57
0.39
1.27
4.39
3.06
2.52
1.00
0.46
3.38
2.30
0.93
0.87
1.70
2.22
2.97
0.74
3.60
2.19
2.46
0.32
3.26
4.39
ICP-MS
Gd
2.74
2.39
2.28
0.84
0.81
0.54
1.54
2.77
2.41
1.85
1.47
0.62
4.07
2.50
1.17
1.22
2.14
2.68
2.81
1.02
4.29
2.56
3.01
0.36
4.02
5.15
ICP-MS
Dy
NORTHERN SWAYZE GREENSTONE BELT
39
40
Sc
14.24
34.40
35.15
32.69
21.65
23.11
30.85
31.84
10.06
41.11
22.43
35.37
9.96
7.89
10.37
45.16
45.20
19.15
19.86
13.40
41.23
4.83
3.08
14.53
13.87
28.87
93JAA-1090
93JAA-1095
93JAA-1096
93JAA-1097
93JAA-1100
93JAA-1101
93JAA-1101D
93JAA-1102
93JAA-1104
93JAA-1106
93JAA-1107
93JAA-1108
93JAA-1109
93JAA-1111
93JAA-1112
93JAA-1113
93JAA-1114
93JAA-1114D
93JAA-1115
93JAA-1117
93JAA-1118
93JAA-1119
93JAA-1121
93JAA-1122
93JAA-1124
ICP-OES
93JAA-1086
Method
Sample No.
Table 5. Continued.
V
103.7
79.62
104.5
41.94
49.12
238.8
115.5
159.9
161.8
273.2
262.1
117.0
92.58
111.0
193.5
154.2
252.6
62.62
258.4
263.7
193.4
154.7
185.6
226.7
350.6
102.0
ICP-OES
Y
4.97
-2
6.18
-2
-2
17.15
4.93
8.08
7.85
19.65
16.86
5.03
3.49
4.23
13.55
22.62
17.86
13.28
17.54
17.46
16.18
8.02
7.81
14.77
31.24
10.07
ICP-OES
Zn
40.11
47.65
71.52
33.11
49.01
78.64
77.20
67.16
67.90
97.98
130.1
56.95
67.40
56.70
93.51
110.2
93.64
68.63
110.5
111.3
100.9
89.26
100.1
134.1
160.2
72.35
ICP-OES
Sr
W
La
84.57
-1
20.37
1.50
2.83
104.0
15.17
17.31
17.60
118.1
91.68
9.21
7.96
7.10
125.6
137.7
91.21
204.1
98.67
99.12
494.3
88.24
12.24
193.6
79.40
394.7
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
-35
0.61
0.15
0.53
0.09
0.17
2.33
0.53
0.52
0.53
2.43
1.80
1.35
0.31
0.41
1.98
13.10
2.41
16.13
3.41
3.53
13.36
1.06
0.46
2.01
10.28
16.16
ICP-OES ICP-OES ICP-MS
Ce
1.53
0.28
1.23
0.20
0.37
6.64
1.46
1.65
1.67
7.25
5.22
3.45
0.93
1.16
4.57
31.63
6.74
34.27
9.30
9.55
32.04
2.69
1.42
5.08
26.72
33.97
ICP-MS
Pr
1.15
0.06
0.19
0.03
0.04
1.10
0.24
0.31
0.31
1.22
0.88
0.49
0.15
0.21
0.79
4.28
1.07
4.20
1.49
1.53
4.18
0.41
0.25
0.77
3.89
4.12
ICP-MS
Nd
0.45
0.29
0.97
0.10
0.18
5.48
1.16
1.76
1.73
5.84
4.47
2.33
0.91
1.07
4.08
17.29
5.44
15.95
7.25
7.50
16.95
2.11
1.48
3.86
17.47
15.16
ICP-MS
Sm
0.46
0.15
0.44
-0.07
-0.07
1.87
0.48
0.80
0.76
2.04
1.60
0.71
0.36
0.47
1.37
4.20
1.88
3.26
2.39
2.36
3.48
0.76
0.68
1.39
4.93
2.87
ICP-MS
Eu
0.12
-0.03
0.12
-0.03
-0.03
0.79
0.17
0.32
0.31
0.74
0.64
0.20
0.13
0.17
0.55
1.40
0.68
1.04
0.84
0.83
1.11
0.29
0.24
0.55
1.65
0.87
ICP-MS
Tb
0.60
0.04
0.12
-0.02
-0.02
0.45
0.13
0.21
0.21
0.50
0.40
0.17
0.09
0.13
0.32
0.70
0.45
0.44
0.51
0.51
0.53
0.21
0.20
0.36
0.95
0.36
ICP-MS
Gd
0.79
0.20
0.66
0.04
0.06
2.56
0.71
1.17
1.13
2.72
2.32
0.91
0.52
0.69
1.85
4.30
2.51
2.99
2.90
3.05
3.37
1.16
1.04
1.97
5.94
2.59
ICP-MS
Dy
0.19
0.31
0.99
0.06
0.08
3.14
0.98
1.60
1.51
3.59
2.95
1.12
0.71
0.93
2.30
4.37
3.11
2.55
3.68
3.51
3.18
1.44
1.45
2.55
6.08
1.96
ICP-MS
OGS REPORT 297
Ho
Er
Tm
1.11
0.91
0.09
0.68
0.59
0.97
0.23
0.58
0.61
0.47
0.26
0.28
0.55
0.93
0.15
0.34
0.38
0.50
0.54
0.35
0.12
0.14
0.14
0.44
0.46
0.63
93JAA-1005
93JAA-1006
93JAA-1008
93JAA-1014
93JAA-1016
93JAA-1020
93JAA-1021
93JAA-1027
93JAA-1033
93JAA-1035
93JAA-1035D
93JAA-1041
93JAA-1042
93JAA-1043
93JAA-1046
93JAA-1055
93JAA-1059
93JAA-1062
93JAA-1068
93JAA-1069
93JAA-1071
93JAA-1071D
93JAA-1078
93JAA-1083
93JAA-1085
1.78
1.23
1.10
0.31
0.31
0.35
0.92
1.43
1.32
0.98
0.91
0.42
2.63
1.39
0.75
0.73
1.29
1.75
1.57
0.63
2.74
1.64
1.89
0.24
2.54
3.07
0.26
0.17
0.18
0.05
0.04
0.05
0.15
0.21
0.19
0.15
0.14
0.06
0.39
0.20
0.11
0.11
0.20
0.26
0.22
0.10
0.41
0.25
0.28
0.04
0.38
0.47
ICP-MS ICP-MS ICP-MS
93JAA-1001
Method
Sample No.
Table 5. Continued.
Yb
1.67
0.97
1.06
0.24
0.24
0.32
0.96
1.38
1.23
0.83
0.84
0.38
2.55
1.23
0.66
0.69
1.16
1.63
1.35
0.61
2.61
1.58
1.77
0.22
2.34
2.94
ICP-MS
Lu
0.27
0.14
0.17
0.04
0.04
0.06
0.15
0.23
0.18
0.13
0.13
0.06
0.40
0.19
0.11
0.11
0.18
0.23
0.21
0.10
0.37
0.24
0.26
0.04
0.35
0.43
ICP-MS
Rb
1.98
11.02
27.80
41.05
42.03
0.41
13.65
60.35
35.05
8.30
0.28
1.17
16.49
19.30
0.31
0.31
0.78
0.28
0.29
1.25
1.61
0.24
3.44
4.37
0.66
2.04
XRF
Sr
141.65
460.19
591.70
282.73
285.16
2.00
52.09
239.32
349.62
216.06
21.00
8.63
167.30
246.10
31.29
31.35
64.35
147.93
190.47
101.25
55.77
34.90
78.17
129.55
67.94
150.50
XRF
Nb
1.95
5.84
4.96
3.78
3.79
0.33
0.84
5.85
5.43
6.45
0.42
0.33
3.44
2.02
0.54
0.56
1.52
1.91
5.82
0.35
3.62
2.18
2.14
-0.20
4.35
4.37
XRF
Cs
0.30
0.53
2.85
1.07
1.06
0.20
2.29
0.92
1.41
0.10
0.03
0.45
0.27
2.91
0.08
0.08
0.30
0.04
0.08
0.53
0.25
0.16
0.18
0.08
0.05
0.17
XRF
Hf
0.30
1.05
2.84
2.77
2.67
0.10
0.76
3.91
2.48
2.41
0.37
0.12
1.00
0.54
0.38
0.40
1.11
0.35
1.47
0.40
0.54
1.37
0.67
0.12
1.78
1.08
XRF
Ta
0.13
0.36
0.32
0.28
0.28
-0.08
-0.08
0.38
0.37
0.48
-0.08
-0.08
0.24
0.12
-0.08
-0.08
0.11
0.12
0.36
-0.08
0.22
0.15
0.13
-0.08
0.28
0.28
XRF
Th
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
XRF
Nb
Zr
Y
Sr
Rb
4
5
5
3
4
-3
-3
7
5
6
-3
-3
4
3
-3
-3
3
3
6
-3
5
3
3
-3
5
4
53
129
142
130
127
16
32
165
134
142
22
16
74
53
23
23
43
47
108
18
72
53
54
11
85
88
19
14
13
-5
5
-5
11
17
15
12
12
-5
27
17
8
9
14
19
17
8
28
18
22
-5
25
29
132
420
570
257
257
-5
49
228
319
194
20
9
160
232
29
30
62
137
178
88
52
34
73
118
64
141
-5
12
28
36
38
-5
15
57
33
8
-5
-5
18
18
-5
-5
-5
-5
-5
-5
-5
-5
5
5
-5
6
ICP-MS ICP-MS ICP-MS ICP-MS ICP-MS
NORTHERN SWAYZE GREENSTONE BELT
41
42
Ho
Er
Tm
1.31
0.59
0.33
0.33
0.68
0.87
0.79
0.50
0.72
0.93
0.51
0.21
0.16
0.25
0.67
0.83
0.35
0.35
0.22
0.70
0.02
0.01
0.24
0.06
0.54
93JAA-1090
93JAA-1095
93JAA-1096
93JAA-1097
93JAA-1100
93JAA-1101
93JAA-1101D
93JAA-1102
93JAA-1104
93JAA-1106
93JAA-1107
93JAA-1108
93JAA-1109
93JAA-1111
93JAA-1112
93JAA-1113
93JAA-1114
93JAA-1114D
93JAA-1115
93JAA-1117
93JAA-1118
93JAA-1119
93JAA-1121
93JAA-1122
93JAA-1124
0.08
0.19
0.74
-0.05
0.05
1.93
0.63
0.97
0.98
2.30
1.96
0.66
0.48
0.61
1.43
2.46
1.96
1.34
2.04
2.21
1.78
0.89
0.89
1.67
3.41
1.04
0.47
0.03
0.11
0.01
0.01
0.29
0.10
0.15
0.15
0.37
0.31
0.10
0.07
0.09
0.21
0.35
0.30
0.18
0.32
0.33
0.27
0.14
0.14
0.25
0.51
0.15
Yb
0.07
0.17
0.76
-0.03
0.05
1.79
0.57
0.92
0.92
2.35
1.78
0.66
0.45
0.53
1.38
2.09
1.86
1.11
2.01
1.97
1.71
0.87
0.90
1.56
3.12
0.88
ICP-MS
Lu
0.75
0.03
0.13
-0.02
-0.02
0.27
0.09
0.14
0.15
0.38
0.26
0.10
0.06
0.09
0.21
0.27
0.28
0.14
0.29
0.30
0.26
0.14
0.13
0.23
0.45
0.13
ICP-MS
Rb
91.81
0.10
0.27
-0.09
0.15
0.80
0.94
3.06
3.05
19.96
0.14
1.92
0.68
1.14
0.99
4.42
2.61
28.17
0.73
0.70
13.09
28.13
0.47
64.54
1.38
25.76
XRF
Sr
0.30
-2.00
21.1
-2.00
2.99
111.63
15.8
19.70
19.19
123
96.2
9.87
8.44
7.64
126.60
138.16
96.12
205.67
107.56
108.85
504.77
95.16
12.72
207.88
87.12
408.49
XRF
Negative numbers indicate that the content is below the detection limit of the analytical method used.
0.39
ICP-MS ICP-MS ICP-MS
93JAA-1086
Method
Sample No.
Table 5. Continued.
Nb
0.04
-0.20
0.39
-0.20
-0.20
2.08
0.37
0.55
0.55
2.2
1.65
0.70
0.25
0.35
1.34
4.39
2.05
7.50
3.04
3.11
8.77
0.64
0.44
1.23
6.71
3.26
XRF
Cs
0.24
0.02
0.34
-0.02
-0.02
0.09
0.50
0.71
0.70
0.22
0.03
1.64
0.27
0.39
0.04
0.11
0.19
2.91
0.41
0.41
4.55
0.60
0.11
1.65
0.22
0.73
XRF
Hf
-0.08
-0.1
0.37
-0.1
-0.1
0.41
0.35
0.55
0.52
0.94
0.35
0.46
0.31
0.32
0.32
1.65
0.47
1.22
0.60
0.63
1.46
0.35
0.39
0.52
1.40
1.01
XRF
Ta
-10
-0.08
-0.08
-0.08
-0.08
0.13
-0.08
-0.08
-0.08
0.13
0.12
-0.08
-0.08
-0.08
0.08
0.29
0.18
0.53
0.19
0.19
0.41
-0.08
-0.08
0.08
0.40
0.29
XRF
Th
-3
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
-10
XRF
Nb
Zr
Y
Sr
Rb
18
-3
-3
-3
-3
3
-3
3
-3
3
3
-3
-3
-3
-3
8
-3
7
3
3
8
-3
-3
3
7
5
6
10
18
7
8
50
18
25
23
59
44
24
14
18
36
158
53
144
66
67
90
26
22
45
137
110
84
-5
8
-5
-5
20
8
11
9
24
19
8
6
8
15
28
22
15
24
22
19
10
9
18
38
12
-5
-5
21
-5
-5
104
16
18
19
120
89
11
10
9
120
131
91
193
98
98
467
86
15
198
80
391
-5
-5
-5
-5
-5
-5
5
-5
20
-5
-5
-5
-5
5
-5
5
26
-5
5
12
27
-5
63
-5
26
ICP-MS ICP-MS ICP-MS ICP-MS ICP-MS
OGS REPORT 297
NORTHERN SWAYZE GREENSTONE BELT
Structural Geology
KAPUSKASING STRUCTURAL ZONE
Eight generations of deformation are recognized in the
Kapuskasing Structural Zone (Bursnall 1989), and are
herein designated D1 through D8. They include early D1 to
D4 ductile structures and late D5 to D8 ductile-brittle, faultrelated structures. In the KSZ within the map area, D1
gneissosities mainly strike northeast with moderate dips to
the northwest, but are also locally easterly trending, with
moderate northerly dips suggesting folding. Observed outcrop-scale isoclinal folds have shallow plunges to the
southwest. The map-scale variations in the trend of gneissosity from northeast to east are probably the result of
large-scale D3 folds with shallow westerly or northwesterly
plunges. The variation in the trend of gneissosity may have
been influenced by the uplift of the KSZ accompanied by
some dextral displacement, rotating gneissosities near the
cataclastic zone into Z-shaped asymmetry. Lineations in
the monzonite gneiss of the Ivanhoe Lake cataclastic zone
also suggest dextral offset, as they are oriented obliquely
to the dip of cataclastic foliation, rather than downdip
(i.e., plunging west rather than northwest).
Two northwest-trending late faults are associated with
the KSZ in the map area. The western fault lies along the
eastern margin of the Shawmere anorthosite complex and
was previously recognized by Riccio (1981). It is characterized by numerous “veinlets” of black, aphanitic pseudotachylite and mylonite. These cataclastic zones range up to
several centimetres thick, and are extremely variable in
orientation, crosscutting the earlier gneissosity. The eastern fault has been identified as the Ivanhoe Lake cataclastic
zone and is considered to be the boundary between the
KSZ and the Abitibi Subprovince (Percival 1990). On a
regional scale, it is characterized by a zone of cataclasis up
to 1 km wide, marked by positive aeromagnetic anomalies, paired gravity anomalies with a low centred over the
zone, and a broad zone of subsurface reflectors detected
on seismic surveys that dip at about 35° to the northwest
(Percival 1990). In the map area, the Ivanhoe Lake cataclastic zone is characterized by augen-textured monzonite
gneiss, exposed along Highway 101 and the old channel
of the Ivanhoe River north of Highway 101. The monzonite gneiss has shallow, west-plunging stretching lineations and gently plunging folds in the plane of foliation,
with asymmetry indicating a west-side-up displacement
along the cataclastic zone.
NORTH SWAYZE GREENSTONE
BELT ZONE
Five generations of tectonically induced fabric were
observed within the NSGB, indicating that a number of
distinct episodes of deformation have affected the belt in a
complex interplay of polyphase folding, transposition and
faulting. Those designated S1, S2 and S3 are interpreted to
be associated with early, regional-scale folding; S4 and S5
are interpreted to be related to late ductile deformation.
The 2 earliest generations of penetrative fabric are
roughly parallel to the orientation of the units, and each
other, throughout much of the NSGB. Rarely, early F1 isoclinal folds and a penetrative, axial-planar S1 cleavage
were observed as refolded folds in tight to isoclinal F2
folds. Because the axial planar S2 foliation is subparallel to
S1 (with the rare exception of the fold closures), it is therefore difficult to distinguish the S1 and S2 fabrics without
the presence of overprinting relationships. As the S1 and S2
folds are both isoclinal, it is assumed that the associated
deformation resulted in a large amount of regional shortening and transposition. It is, therefore, difficult to determine what the original orientations of F1 structures may
have been because of large-scale transposition into the
generally easterly trend of F2 structures. The S1 foliation or
cleavage is evident in many outcrops as a penetrative flattening fabric. The S2 fabric is evident as a variably developed,
steeply dipping penetrative foliation to a spaced cleavage,
generally subparallel to the S1 fabric. The S3 fabric is a
steeply dipping, spaced axial-planar cleavage associated
with southeast-trending open folds overprinting S1 and S2,
and is most evident in the southeastern part of the NSGB.
Lineations within the map area range from steep to
shallow in plunge. Lineations which mark the intersections
of cleavages and/or bedding planes predominate. However,
only the stretch lineations which measure the elongation of
clasts or minerals were recorded on Map 2627 (back pocket).
The highly variable orientations of minor fold axes and lineations is attributed to later refolding episodes.
The S4 and S5 fabrics are only observed in highly
schistose rocks proximal to shear zones and are thus interpreted to be associated with late ductile deformation. The
S4 fabric consists of a steep, northeasterly trending spaced
cleavage, axial planar to open Z-folds and northeast-trending
Z-shaped kink bands. The S5 fabric is a gently dipping,
pervasive crenulation or kink cleavage with northwest to
northeast strike orientations that are axial planar to gently
plunging open folds to locally tight chevron folds. As
overprinting relationships are uncommon and difficult to
interpret, it is possible that the chronology of S4 and S5
may be reversed.
Folding
A number of fold axes are indicated on Map 2627 (back
pocket) with their interpreted generation. The locations are
based on reversals of top indicators or systematic changes
in the orientation of primary structures and/or foliations.
In the southern part of the Swayze greenstone belt,
Heather (1993) was able to differentiate 2 early fabrics
43
OGS REPORT 297
into an Sa schistosity, that is tightly to isoclinally folded
about a west- to west-southwest striking foliation, designated Sb. It would seem that a similar manifestation
and orientation of early folding fabrics in the northern
Swayze greenstone belt are likely to have been generated
synchronously with those in the southern part of the belt.
Although sparsely distributed, top indicators uniformly
indicate a southward younging direction in the northern
part of the NSGB, from the Nat River granitoid complex
to the main sedimentary unit. East-plunging minor folds
and a number of reversals in younging direction were
observed in sedimentary bedding in the vicinity of the
southern part of Slate Rock Lake, in Keith Township.
Coaxially refolded, thinly bedded sedimentary rocks in
this area and other parts of the map area indicate that at
least 2 early regional folding episodes have affected the
area. The interpretation of the pattern of reversals suggests an east-trending F2 fold in the southern part of
Slate Rock Lake may have refolded an F1 fold axis,
north and south of the F2 axis. Younging reversals, suggesting anticlinal and synclinal closures, also occur in a
band of predominantly volcanic rocks extending up to
several kilometres south of the main sedimentary unit in
northern Keith Township. From the Kukatush pluton to
the MacKeith Lake fault, the observed younging direction is consistently to the north. These features suggest that
the main sedimentary unit in the northern part of Keith
and Penhorwood townships lies in the keel of a synclinorial fold and thus in the uppermost stratigraphic part
of the Muskego–Reeves assemblage.
Coaxial refolding of F1 by F2 was also observed in
minor folds in the Radio Hill iron formation and is most
likely the reason for the extensive thickening of the iron
formation in the vicinity of Radio Hill, in Penhorwood
Township. Milne (1972) reports a possible synclinal
(F1?) fold that causes the iron formation to bifurcate
west of Leadbeater Lake and end abruptly (close) east of
Radio Hill. He also indicates the iron formation is folded
into an isoclinal S-shaped fold (F2?), plunging 50° to the
northwest in the vicinity of Radio Hill.
The Nat River iron formation lies at the boundary of
the MRA and HNA and delineates a northwest-plunging,
east-trending anticlinal structure (see Figure 2). Both
limbs of the fold dip steeply to the north and thus define
an isocline steeply overturned to the south. Top indicators uniformly indicate north facings on the north limb,
suggesting that the fold is an F1 anticline, but there is
insufficient exposure in the closure area, in the western
part of the structure, to distinguish it from a possible F2
anticlinal antiform. The map pattern of iron formation
repetition on the north limb in the vicinity of the east
branch of the Nat River, and south of Crawford Lake,
suggests “S” and “Z” drag folds, respectively, that may
be genetically related to the main antiformal (F2) fold.
Minor folds in outcrops east of the Crawford River, on
the north limb, indicate that F1 isoclines are refolded by
44
east-trending F2 isoclinal folds and are overprinted by
southeast-trending, open F3 folds. In the same area, the
large-scale “Z” fold in the Nat River iron formation
(Map 2627, back pocket) has the wrong vergence to be
a drag fold associated with the Nat River anticline, and
is thus interpreted to be an F1 isoclinal fold unrelated to
the main structure.
The distribution of the northern ultramafic unit in
the HNA is more continuous and modified by folding
than was interpreted by Milne (1972). This reinterpretation
is based on the field evidence for multiple-folding
events, the outcrop distribution and the high resolution
aeromagnetic patterns in this area. The new interpretation
indicates the unit is isoclinally folded in an easterly
trending F2 (or possibly F1?) antiform and refolded on
the southern limb by southeast-trending F3 folds, north of
Chabot Lake.
In the vicinity of the ultramafic to gabbroic unit hosting
the Reeves and Penhorwood mines the trends of S1 and S2
change from predominantly easterly to northerly. The S1
fabric follows the trend of the basal contact of the ultramafic cumulate unit around the northern nose of the fold,
thus suggesting the ultramafic unit is tightly folded about
a north-trending F2 axis, with the gabbroic unit occupying
the core of the F2 antiformal syncline (Map 2627, back
pocket). Easterly flexures and/or offsets in the F2 fold axis
and rock unit contacts are the result of overprinting by
early ductile deformation zones of the D4 to D5 generation
(discussed below). The presence of talc-chlorite schists
along the northwestern margin of the ultramafic unit suggests
that the contact follows an early (D1 or D2), northeasttrending ductile deformation zone. The presence of this
shear zone may also indicate that the abrupt truncation of
the clastic sedimentary unit along the western margin of
the ultramafic body is the result of early faulting.
A southeast-trending F2 antiform and synform are
interpreted in amphibolitic mafic volcanic rocks in
southeastern Ivanhoe Township, based on changes in the
orientation of S1 foliations (Ayer 1993).
Faulting
Fault locations are commonly based on the interpretation of geophysical patterns or offset of rock units,
because of poor exposure. At least 3 distinct generations
of faulting are evident in the NSGB, but determining the
detailed chronology awaits more detailed structural
work and high-precision geochronology. The earliest
generation of faulting is in the widespread ductile deformation zones. The early faults are locally truncated by
less extensive brittle-ductile faults. Thirdly, the latest
generation are brittle faults which do not appear to have
any significant ductile deformation but are not well
exposed.
NORTHERN SWAYZE GREENSTONE BELT
DUCTILE FAULTS
The early deformation zones are generally easterly trending,
parallel to the contacts of rock units and are gradational
from the moderately foliated and relatively unaltered
country rock into the highly deformed, carbonatized,
sericitized and chloritized schistose rocks whose protolith
is often difficult to determine. Intense deformation and
alteration commonly occur in zones 10 m to 1 km wide,
which anastomose around blocks of less deformed and
altered rock. The most extensive early ductile faulting is
associated with the Slate Rock deformation zone (SRDZ)
and is well exposed in southern Muskego and Reeves
townships. The SRDZ is an extensive zone of ductile
deformation up to 1.5 km wide, extending eastward across
the southern part of Muskego Township. It extends westward into Foleyet Township, but poor exposure in this area
results in a higher degree of uncertainty about its location
and extent. To the east, in Reeves and Sewell townships, it
appears to break up into a larger number of parallel zones
which are, individually, narrower than the broad zone in
southern Muskego Township.
Three separate fabrics are evident in the schistose
rocks throughout much of the SRDZ. The early fabric consists of a subvertical, east-trending pervasive schistosity
(S1 or S2), which is interpreted to have formed during D1 or
D2 deformation. It is overprinted by a northeast-trending,
steeply dipping spaced cleavage (S4) which is axial planar
to upright Z-folds and a spaced cleavage (S5) with subhorizontal dips and variable orientations. Small-amplitude
crenulation and chevron folds associated with S5 are subhorizontal and indicate late north-side-up movement in the
SRDZ.
The Deerfoot deformation zone (DDZ) is another
extensive deformation zone which extends from north of
the Kukatush pluton in Penhorwood Township to north of
the HNA in Kenogaming Township. An abrupt change
from southward younging stratigraphy north of the DDZ
to northward younging south of the zone suggests the possibility that the younging reversal may be the result of
thrusting along the fault rather than a regional syncline.
The Hardiman deformation zone (HDZ) extends into
the map area from the south, and joins with the DDZ along
the north boundary of the HNA. The HDZ develops into
several parallel faults in southwestern Penhorwood
Township that dip moderately to the northwest. These
faults are the locus of a number of commercially developed veins of quartz and barite that occur along the faulted
southeastern margins of thin granitic intrusions. In this
vicinity, shear banding indicates late dip-slip movement,
with a relative southeast-side-up displacement.
Many of the deformation zones are locally auriferous
and have been the focus of gold exploration, such as at
the Joburke Mine in the Joburke deformation zone. Three
separate fabrics are also evident in the shear zones associated
with the Joburke Mine but, in contrast to the SRDZ, the
flat S5 crenulation cleavage is only locally developed,
whereas the steeply dipping S4 fabric is a pervasive axialplanar cleavage to northeast trending Z-folds. It has been
suggested (Milne 1972; Jackson and Fyon 1991) that the
Porcupine–Destor fault may strike southwest into the
NSGB. If this is so, it is probable that these numerous eastnortheasterly trending ductile deformation zones represent
the extension of this major structure into the map area.
BRITTLE-DUCTILE FAULTS
The MacKeith fault represents a later generation of brittleductile faulting. The fault trends east-northeast across
much of Keith Township. Where it is well exposed, in the
vicinity of the Joburke Mine, it consists of schistose, brecciated and hematitized rock in a zone up to 50 m wide
which clearly truncates a number of east-southeast-trending
rock units and the earlier Joburke deformation zone. The
western and eastern extensions of the fault are more speculative, but based on airborne geophysical evidence, the
fault appears to be truncated by the Hoodoo Lake pluton in
the east.
The Muskego fault is an east-trending deformation
zone along strike with the MacKeith fault, on the west side
of the Hoodoo Lake pluton in Ivanhoe Township. It is only
exposed in a few small outcrops where it consists of easttrending, foliated, carbonatized and epidotized rocks that
contain radiating sprays of recrystallized amphibole.
Based on aeromagnetic patterns, the fault abruptly truncates
an ultramafic volcanic unit. It is also the locus of an abrupt
transition from greenschist-facies rocks north of the fault
to amphibolite-facies units south of the fault (Ayer 1993).
This transition indicates that higher metamorphic conditions were experienced in rocks south of the fault and
hence a net south-side-up displacement.
BRITTLE FAULTS
Northerly trending faults are indicated on Map 2627 (back
pocket) where they have been interpreted on the basis of
abrupt truncation or offset of rock units. These structures
are most likely high-crustal-level brittle faults which are
delineated by lineaments but are not commonly manifest
in outcrop. Although most evident in the eastern part of the
map area, they probably occur throughout the region and
were most likely the conduits for the numerous
Matachewan diabase dikes. Thus, they are bracketed in
maximum age by the Matachewan diabase dike crystallization age of 2454 Ma. The minimum age is given by
offsetting of the east-northeast-trending Abitibi swarm
dikes with a crystallization age of 1140 Ma. This suggests
a protracted Proterozoic history.
45
OGS REPORT 297
Economic Geology
There are records of exploration activity in the area that
date back to the end of the 19th century (Milne 1972). The
area has attracted considerable exploration attention
because of its apparent continuity with the economically
prolific Abitibi greenstone belt to the east. Gold, base
metals, iron, and industrial minerals such as asbestos,
talc, silica and barite have been the focus of attention;
mines have been established and undeveloped deposits
have been found containing a number of these commodities.
Significant amounts of asbestos and gold have come from
the Reeves Mine and the Joburke Mine, respectively.
Production has also been recorded at the Cryderman
barite, Horwood silica and Roseval silica deposits. The
Penhorwood talc mine is the only actively producing
deposit at the time of writing.
A significant amount of exploration has been conducted in the area, the details of which are not covered
here. For more detailed information on exploration, the
reader should consult 1) the assessment files in the Resident
Geologist’s office, Timmins; 2) assessment data in the
Earth Resource and Land Information System, in Sudbury
and Toronto; 3) previous geological reports of the area
(e.g., Prest 1951; Milne 1972; Ayer 1993; Ayer, in press);
or a mineral inventory report available in hard copy (Fumerton and Houle 1993) and digital copy (Fumerton et al. 1993).
In the following section, localities in which there has
been mineral production or notable grades and quantities
of mineralization are briefly discussed. They are grouped
by their principal commodities and discussed in alphabetic
order. The numbers in parentheses in the heading for each
locality correspond to those appearing on Map 2627 (back
pocket). Their names are based on geographic location,
name of the discoverer, or the company which conducted
the exploration resulting in the discovery, and are not
meant to reflect current ownership. No formal title searches
have been conducted as a part of this study.
GOLD
Gold mineralization occurs in epigenetic vein systems in
close spatial association with ductile deformation zones.
It occurs in a wide variety of rock types, but is most commonly associated with rusty weathering and schistose,
iron carbonatized and/or sericitized, mafic volcanic rocks.
The mineralization is closely associated with quartzcarbonate veining, commonly with disseminated iron sulphides, and locally with arsenopyrite, stibnite and base
metal sulphides. Tourmaline and green mica may also be
present.
Gold was found in sufficient quantities and grade at
the Joburke Mine, in Keith Township, to have supported
the production of almost 1/2 million tons of ore with an
average grade of 0.11 ounce Au per ton. The gold mineralization at the Joburke Mine occurs in 2 structural settings:
46
1) widespread early mineralization with relatively low
grades, which occurs in thin quartz-carbonate veins that
parallel the S1 foliation in highly schistose and carbonatized
basalts within the Joburke deformation zones; and 2) concentrated in late quartz veins and stringers which crosscut
the S1 foliation. The 4 developed Joburke ore zones occur
where these late vein systems are thickened by folding
into steep, easterly plunging, S-shaped fold noses. The
MacKeith Lake fault apparently truncates the Joburke
deformation zones west of the mine and, despite extensive diamond drilling, appears to host only minor gold
mineralization.
Gold is locally present in other deformation zones,
some of them minor and unnamed. Others are of major
extent, such as the Slate Rock Lake deformation zone in
southern Muskego Township, and the Deerfoot deformation zone, which may be the easterly strike extension of
the Joburke deformation zone.
Arkell (3)
Gold mineralization occurs in a north-trending fault in
mafic metavolcanic rocks infilled by irregular masses of
quartz, in southwestern Sewell Township. Tanton (1917)
reports that the vein material mixed with country rock
locally reaches up to 15 m in width. Three pits were excavated on the vein, which was traced for a strike length of
800 m. Minerals reportedly associated with the quartz are
pyrite, pyrrhotite, chalcopyrite, calcite, tourmaline and
“mariposite” (fuchsite?). Tanton (1917) reported assay
results from grab samples of up to 0.7 ounce Au per ton,
and chip samples of 0.02 ounce Au per ton across the
width of the vein.
BHP-Utah Mines Limited (4)
From 1985 to 1989, BHP-Utah Mines covered the southeastern part of Muskego Township with ground magnetometer, electromagnetic (EM), induced polarization (IP),
and geochemical surveys, stripping, trenching and diamonddrilled 20 holes. Surface samples assayed up to 3700 ppb
Au southeast of Big Boulder Lake. Slightly auriferous
zones were detected in a number of the drill holes, with
assay values up to 1030 ppb Au over 0.3 m. Anomalous
values of zinc in disseminated sulphides within schistose
volcanic rocks were also detected in 2 of the drill holes.
B.P. Resources Limited (5)
B.P. Resources Limited explored for gold on a claim group
in south-central Muskego Township and north-central Keith
Township from 1987 to 1989. Work consisted of airborne
and ground magnetic, EM and IP surveys, a geological
survey and diamond drilling. Two holes were drilled in
Keith Township. One of these drill holes, on the east side
of Slate Rock Lake, encountered a number of auriferous
NORTHERN SWAYZE GREENSTONE BELT
intersections associated with intrusive porphyry phases.
Assay results range from 0.01 to 0.04 ounce Au per ton
over 10 to 15 m sections, with gold associated with minor
pyrite in thin chloritic fractures. In Muskego Township, 9
holes were diamond drilled in the area bounded by Keith
Lake to the east, Slate Rock Lake to the west and Scorch
Creek to the north. One hole, about 1 km west of Keith
Lake, intersected 4.8 m of auriferous quartz veins in intermediate volcanic rocks with assay values of up to 0.011
ounce Au per ton over 1.3 m. A second hole, about 500 m
east of Slate Rock Lake, intersected 12 m of auriferous
carbonatized wacke. The wacke contains up to 5% disseminated pyrite and is cut by quartz-carbonate veins.
Assays from this section are slightly anomalous, with values
of up to 0.027 ounce Au per ton over 1.5 m.
Bromley (6)
The Bromley occurrence is located in northwestern
Penhorwood Township. Radio Hill Mines Company
Limited performed a considerable amount of exploration
in 1967, including an airborne EM survey, mapping,
trenching and diamond drilling. A number of mineralized
quartz veins and stockworks were outlined in pervasively
carbonatized and sheared mafic volcanic rocks cut by
tonalite dikes. Silver-bearing sulphides, including argentite and galena, have been reported. Assay values of
0.13 ounce Au per ton and 3 ounces Ag per ton over 0.6 m
(2 feet) were reported from diamond drilling. Another
showing, known as the RF zone, occurs north of the main
showing on the west side of Primer Lake. Samples from
trenching on this showing returned values of up to 15 ounces
Au per ton and 23 ounces Ag per ton, but typically were
much lower (Fumerton and Houle 1993).
In 1989, American Barrick Limited intersected anomalous gold values in a drill hole testing a geophysical
anomaly about 1 km southeast of the main showing. Assay
results reported up to 0.60 g/t Au over 1 m (Fumerton and
Houle 1993).
Card Lake Copper Mines Limited (7)
In 1971 and 1972, Card Lake Copper Mines Limited carried
out a magnetic and EM survey and diamond drilling
focussed on a stibnite showing in southwestern Sewell
Township. The mineralization occurs in a 2 m wide, southeast-trending shear zone within moderately strained, mafic
pillow lavas immediately east of a northwest-trending
diabase dike. Quartz veinlets and the schistose mafic rock
of the shear zone have variable concentrations of disseminated stibnite, arsenopyrite, pyrrhotite, pyrite and chalcopyrite. Assay values indicated up to 1.8 ounces Au per ton,
7.4% Sb and 2.1% As.
Hoodoo-Patricia (10)
From 1946 to 1947, Dunvegan Mines Limited (formerly
Hoodoo Lake Mines Limited) explored a claim group
southeast of the Joburke Mine in Keith Township.
Mineralization similar to that at the Joburke Mine was discovered. From 1985 to 1989, G.K. Sanford, Gail
Resources Limited and finally Marshall Minerals
Corporation conducted airborne and ground magnetometer
and EM surveys, an IP survey, geological mapping, stripping,
trenching and diamond drilling. A program of extensive
overburden removal and limited surface mining for bulk
sampling was undertaken in the vicinity of the Hoodoo
and Patricia showings. The stripping uncovered a large
area of outcrop around the showing which was mapped in
detail by Siragusa (1990).
Results of work on this claim group by Marshall
Minerals Corporation, as summarized from Medd (1990),
indicate the gold mineralization occurs in a south-southeast-trending shear zone within carbonatized mafic volcanic rocks cut by abundant intermediate porphyry dikes.
The Patricia zone occurs at the northeast end of the outcrop area exposed by the stripping program. Gold values
have been intersected in a mineralized zone which pinches
and swells from 3 to 49 m over a strike length of 158 m
and to a depth of 184 m. The mineralized zone consists of
quartz-carbonate veining with disseminated pyrite and
rarely chalcopyrite and galena. Erratic gold values as high
as 0.528 ounce Au per ton over 1.2 m occur over narrow
lenses of pyritic quartz-carbonate vein, separated by nonauriferous, less-altered host rock. The Hoodoo west showing
is a 0.15 to 1.5 m wide vein extending for a distance of
about 61 m in the north-central part of the stripped area.
The vein system has been sampled every 4.6 m and carries
an average grade of 0.15 ounce Au per ton over a width of
1.2 m. The Hoodoo east showing is a quartz-carbonatepyrite vein hosted in a north-northeasterly trending crossfracture in the eastern part of the stripped area. This vein
returned values of 0.072 ounce Au per ton over 0.7 m,
0.152 ounce Au per ton over 0.6 m and up to 4.03 ounces
Au per ton in grab sample. The drilling in this area only
intersected low-grade material (0.03 ounce Au per ton over
7 m with values of up to 0.18 ounce Au per ton over 0.6 m).
A second area of gold mineralization was outlined by
stripping, trenching and diamond drilling, about 1 km
northeast of the Hoodoo–Patricia prospect. The mineralized zones consist of quartz-carbonate veinlets and lenses
0.3 to 1.5 m (1 to 5 feet) wide, with pyrite and minor chalcopyrite and galena. The host rocks are felsic volcanic
rocks with a pervasive east-northeast-trending high-strain
zone consisting of narrow anastomosing zones of sericitic
schist surrounding lenticular blocks of more massive felsic
rock. Drilling indicated values of up to 0.161 ounce Au per
ton over 1.8 m (Medd 1990).
Joburke Mine (15)
The Joburke Mine property consists of a block of 20
patented claims in Keith Township. The property is currently held by Noranda Exploration Company Limited in
a joint venture negotiated with Tarzan Gold Incorporated
in 1988. Gold was discovered in 1946 by Joe Burke and
Maynard Bromby. Underground work by Joburke Mines
Limited was started in July 1947 and continued until
47
OGS REPORT 297
August 1948. Approximately 132 diamond-drill holes
totalling 39 000 feet were drilled (Neelands 1988). A
three-compartment shaft was sunk on the Main Zone to a
depth of 408 feet. Levels were established at the 250- and
375-foot levels and 2714 feet of lateral work was completed. This work showed the existence of 2 gold-bearing
zones: the Main Zone, on which all the underground work
was focussed at this time, and the North Zone, located
about 400 feet northwest of the Main Zone. From this
work, possible ore reserves in the Main Zone were estimated at 130 464 tons averaging 0.268 ounce Au per ton
(Neelands 1988).
In 1964, Denison Mines Limited diamond-drilled 6
holes totalling about 5000 feet, searching for downdip
extensions to the east and west parts of the Main Zone
mineralization.
Noranda Exploration Company Limited optioned the
property in 1973. Mining operations were restricted to the east
and west parts of the Main Zone via a decline extending to
the 250-foot level. From 1973 to 1975, a total of 180 300 tons
grading 0.105 ounce Au per ton was trucked to the Pamour
Mill in Timmins. Prior to these mining operations,
Noranda had estimated a possible reserve of 381400 tons
of 0.21 ounce Au per ton. The resulting low grades may
have been caused by the erratic nature of the gold mineralization within a wide alteration zone of quartz-ankerite.
In 1979, the decline was extended to its ultimate depth
of 489 feet. Total production from 1979 to 1981 was
291 795 tons grading 0.106 ounce Au per ton. The bulk of
this was derived from the Main Zone. Near-surface mineralization was also mined at the North Zone and the
Northwest Pit, a small zone about 1300 feet west of the
shaft area. A total of 21374 tons grading 0.082 ounce Au
per ton was derived from North Zone and 1209 tons grading
0.063 ounce Au per ton from the Northwest Pit.
Exploration on the property was reactivated from 1988 to
1989 with geological, magnetic, EM and IP surveys, stripping, trenching, sampling and diamond drilling.
The property is underlain by compositionally diverse
volcanic rocks which include mafic volcanic flows, porphyritic felsic pyroclastic rocks, flows and/or synvolcanic
intrusions and ultramafic flows. Interbedded sedimentary
rocks include magnetite-chert and siderite-chert iron
formation, turbidites normally graded from conglomerate
or sandstone to siltstone, and graphitic mudstones. Rock
units dip steeply to the north, and strike northeast north of
the MacKeith Lake fault and southeast south of the fault.
All observed top indicators indicate that the stratigraphy
faces consistently to the north. The MacKeith Lake fault
(or Joburke fault, Prest 1951) strikes 075° and dips 60° to
75° to the north. The fault zone contains brecciated fragments of chert, iron formation, lamprophyre dike and talcchlorite schist. Rocks south of the MacKeith Lake fault
generally appear to have experienced greater amounts of
ductile strain than those north of the fault. A significant
amount of dislocation along the fault is suggested by the
change in strike orientation and the abrupt truncation of a
number of rock units. A net sinistral displacement of
48
greater than 915 m was suggested by Prest (1951) based
on the interpreted dislocation of units. He also suggested
however, that this represented the horizontal vector of a
larger, but unmeasurable, vertical displacement.
Gold mineralization is mainly confined to zones up to
about 30 m thick, consisting of intense ductile deformation
with accompanying pervasive iron-carbonate alteration
and localized quartz veining, within the north and south
arms of the Joburke deformation zones. Mineralization
within these deformation zones is of 2 distinct styles. The
first consists of widespread mineralization with relatively
low grades and occurs in thin quartz-carbonate veins
which parallel the S1 foliation. These early veins are commonly folded in conjunction with the S1 foliation into
westerly plunging Z folds with a steeply dipping, northeast-trending axial-planar S2 cleavage. The second consists of thicker and higher grade extensional quartz veins
or intricate networks of quartz stringers and veins which
are found in variously silicified, albitized and carbonatized
mafic volcanic rocks. The vein material is largely quartz,
albite and carbonate with a minor amount of chalcopyrite
and rarely visible gold (Prest 1951). The mined ore zones
are typically confined to locations where these higher grade
veins are thickened by steeply east-plunging S-shaped
folds (Prest 1951).
Johnson Wright (16)
The Johnson Wright occurrence is located in southwestern
Sewell Township. It has undergone exploration including
geophysical surveys, stripping, trenching and diamond
drilling. The mineralization occurs in quartz-carbonate
veins, with pyrite, tourmaline, and minor chalcopyrite and
galena, in sheared and carbonatized mafic volcanic rocks.
The best reported assays of 15 g/t Au and 3.7 g/t Au were
from trench samples collected by Glen Auden Resources
Limited in 1987. The mineralization occurs in parallel 2 to
25 cm quartz veins spaced 2 to 3 m apart in iron-carbonatized,
schistose mafic volcanic rocks exhibiting a southeasttrending schistosity. Individual veins are up to 10 m long
and alteration zones are up to 100 m long.
Jonsmith (17)
Mineralization at the Jonsmith occurrence in central
Kenogaming Township occurs within schistose felsic volcanic rocks of the HNA. It consists of pyritic, sericitized
and silicified fragmental rocks with thin sphalerite
stringers locally cut by quartz veins containing pyrite and
chalcopyrite. Diamond drilling by Falconbridge Mines
Limited in 1966 returned assay values of up to 1.21% Zn,
0.51 ounce Ag per ton and 0.03 ounce Au per ton over 1.1 m,
and 1.03% Zn, 0.55 ounce Ag per ton and 0.01 ounce Au
per ton over 4.3 m. It is interesting to conjecture as to the
origin and significance of the mineralization at this occurrence and it is probably worthy of further study. The disseminated nature, associated rock types and alteration
NORTHERN SWAYZE GREENSTONE BELT
might indicate that the mineralization is of a volcanogenic
massive sulphide type modified by later deformation, or
alternatively, the mineralization could be epigenetic and
related to the deformation.
Kalbrook (18)
This gold occurrence in southeastern Reeves Township
has undergone a considerable amount of exploration
including geophysical and soil geochemical surveys, stripping, trenching and diamond drilling, dating back to
Kalbrook Mining in 1946. Late quartz veins with visible
gold and disseminated pyrite crosscut sheared mafic volcanic rocks with minor interbedded clastic sedimentary
rocks. A number of bands of intense east-trending shearing
are separated by relatively undeformed zones. In one
locality, isoclinally folded schistose and altered units are
cut by an auriferous quartz vein which is discordant to the
early foliation and is only slightly folded (Fumerton and
Houle 1993). The auriferous veins (2 to 20 cm wide) are
zoned, with between 2 and 5 cm of grey, coarse-grained
quartz along the walls, and white, very coarse-grained
quartz in the central part of the vein. Pyrite is erratically
disseminated within the veins and locally is concentrated
in the wallrock. Rare chalcopyrite has also been observed.
Gold occurs as fine specks along fracture surfaces within
the white quartz. Chip samples of a quartz vein in a trench
returned up to 38.89 g/t Au from sampling by Glen Auden
Resources Limited in 1987. Parallel chip sampling by
Fumerton and Houle (1993) returned up to 7.68 g/t Au.
Little Long Lac Gold
Mines Limited (21)
The mineralization at this location in northern Kenogaming Township was explored by Little Long Lac Gold
Mines Limited in 1946, by mapping and 6 diamond-drill
holes. The area is underlain by the Nat River iron formation, intermediate to felsic volcanic rocks of the HNA and
cumulate ultramafic to mafic complexes. Lenses of massive pyrite and pyrrhotite occur up to 1.4 m wide along the
iron formation contacts. The sulphides and small quartz
veins carry low gold values of up to 0.04 ounce Au per ton.
is parallel in trend, and may be a subsidiary structure to the
more extensive Deerfoot deformation zone located several
hundred metres to the south. The main vein consists of
milky quartz and minor calcite cut by fractures infilled
with pyrite and minor chalcopyrite. Reported assay values
from diamond drilling range up to 0.48 ounce Au per ton
over 2.2 m and 0.28 ounce Au per ton over 2.3 m, in 2 separate holes.
Nib Yellowknife (25)
The Nib Yellowknife occurrence, located in north-central
Penhorwood Township, has been explored since the mid
1940s. Work done includes stripping, trenching, geophysical
surveys, and a limited diamond-drilling program by
Steetley Industries Limited in 1987. The mineralization
occurs in quartz veins with disseminated pyrite and
arsenopyrite within a gabbroic unit on the western margin
of the ultramafic body hosting the Reeves and
Penhorwood mines. Reported grab sample assay values
are up to 0.2 ounce Au per ton.
Tremblay (32)
This showing, in southwestern Sewell Township, has been
explored by geophysical surveys, a lithogeochemical survey, geological mapping, trenching and diamond drilling
since 1972. American Barrick Resources Limited carried
out a surface sampling program which returned values of
up to 3.14 g/t Au. Fumerton and Houle (1993) indicate that
the mineralization occurs in a banded altered zone with an
axial quartz vein in schistose mafic volcanic rocks cut by
lamprophyre and granitic dikes. The zone strikes westnorthwest and is exposed for a length of 50 m. The banding
occurs on a millimetre to centimetre scale and consists of
iron carbonate-, tourmaline-, sericite- and chlorite-rich
bands over a width of 1 to 2 m. The axial vein has a highly
irregular shape, is discontinuous and varies between 10
and 20 cm thick. The vein is composed of quartz, albite
and tourmaline, pyrite and arsenopyrite.
Unigold Resources Limited (33)
Mining Corp (23)
Stripping, trenching and diamond drilling by Noranda
Exploration Company Limited and Storimin Exploration
Limited have outlined significant gold mineralization at
the Mining Corp deposit in southeastern Sewell Township.
At least 2 mineralized quartz veins have been identified in
diorite on the western margin of the Kenogamissi
batholith, in Sewell Township. The main vein is exposed
at the surface for a length of 120 m and is from 0.3 to 2 m
thick. The vein occurs in an east-northeast-trending deformation zone consisting of highly schistose and carbonatized diorite up to about 10 m wide. The deformation zone
In 1986 and 1987, Unigold Resources Limited explored
the southeastern part of Muskego Township. Work consisted of ground magnetometer, IP and geological surveys,
stripping, trenching and 9 diamond-drill holes. One of
these holes (DDH # UM-2), located about 1 km east of
Highway 101, encountered a 24 m long auriferous intersection with assay values ranging from 0.01 to 0.1 ounce
Au per ton. The intersection is contained within a unit of
quartz-feldspar porphyry with zones of sericitic alteration
and 1 to 10% pyrite and arsenopyrite. The highest assay
results of up to 0.1 ounce Au per ton over 1.8 m are correlated with the higher sulphide content.
49
OGS REPORT 297
COPPER AND ZINC
The Muskego–Reeves assemblage (MRA) is considered to
have the greatest potential for economic concentrations of
copper and zinc sulphides in the map area. Two distinct
types are observed, both of which are considered to be
related to exhalative synvolcanic processes: 1) iron formation type and 2) volcanogenic massive sulphide (VMS)
type.
The iron formation type of deposits, hosting zinc mineralization with or without copper, are found scattered
throughout the map area. These occurrences appear to be
similar to the Shunsby zinc deposit in the southern part of
the Swayze greenstone belt. The most significant assay
results are from diamond drilling of banded chert-sulphidefacies iron formation and graphitic mudstones, some of
which contain highly anomalous base metal values. For
example, the sulphide iron formation west of the
Groundhog River in Keith Township was diamond drilled
by Dome Exploration (Canada) Limited. Over a strike
length of about 800 m, 3 diamond-drill holes intersected
chert and graphitic argillite with sulphide-rich sections
containing up to 0.74% Zn and 0.03% Cu over 21 m
(described in more detail below).
The potential for VMS type deposits appears to be
greatest in the northwestern part of the MRA. In this
region, diamond drilling has indicated the presence of
stratabound massive to disseminated sulphides with minor
amounts of sphalerite and chalcopyrite, and associated
zones of volcanogenic hydrothermal alteration including
silicification and chloritoid-bearing volcanic rocks.
Massive sulphides were also observed as clasts in a conglomerate in Foleyet Township and as inclusions in the
Ivanhoe Lake pluton, in Ivanhoe Township (Ayer 1993).
The sulphides are closely associated with felsic, mafic and
ultramafic volcanic rocks (Ayer 1993). In the Abitibi
Subprovince, VMS deposits are commonly associated
with this type of compositional diversity (Jackson and
Fyon 1991).
Hydrothermal alteration is evident in Foleyet
Township by the presence of chloritoid porphyroblasts in
carbonatized mafic volcanic rocks that underlie a subeconomic, strata-bound massive-sulphide horizon located by
a diamond-drill hole in southeastern Foleyet Township.
Chloritoid porphyroblasts were also observed in outcrops
of carbonatized felsic volcanic rocks along the Ivanhoe
River, about 1.5 km east of the above-mentioned drill hole.
It is worthy of note that chloritoid-bearing altered volcanic
rocks are associated with a number of Archean volcanogenic massive-sulphide deposits (Franklin et al. 1975).
Another extensive zone of chloritoid alteration occurs in
mafic and felsic volcanic rocks within the Slate Rock
deformation zone in south-central Muskego Township. As
chloritoid in greenschist-facies metavolcanic rocks has
been documented to be the result of hydrothermal alteration (Lockwood 1986) it is assumed that this zone represents conformable hydrothermal alteration, which could
be associated with sulphide mineralization.
50
In addition, an extensive zone of volcanogenic silicification in northeastern Foleyet Township bears resemblance to similar alteration associated with a number of
Archean VMS deposits, including the silicification underlying the Mine Series deposits at Noranda, Quebec
(Gibson et al. 1983).
Dome Exploration (9)
From 1972 to 1983, Dome Exploration (Canada) Limited
conducted a number of exploration programs in Keith
Township. The work included an airborne geophysical
survey with detailed follow-up work in the northeastern
part of the township. It also including ground magnetic
and EM surveys and diamond drilling. Anomalous base
metal values were detected in a number of diamond-drill
holes, with the most significant results from a hole about
1 km south of Slate Rock Lake. This hole intersected a unit
of sulphide iron formation within mafic to intermediate
fragmental rocks. The iron formation consists of black
graphitic argillite with alternating bands and disseminations
of pyrite, pyrrhotite, minor sphalerite and chalcopyrite.
Reported assay values averaged about 0.6% Zn and 0.05%
Cu over 22 m.
Sulphide iron formations were also explored in the
northeastern part of Keith Township. From 1972 to 1973,
Dome Exploration (Canada) Limited conducted ground
magnetometer and EM surveys and completed 6 diamonddrill holes. The highest grade of mineralization was
encountered within a base metal-enriched sulphide iron
formation striking east-northeast, west of the Groundhog
River. It was intersected by 3 holes over a strike length of
about 800 m. The iron formation is intercalated with mafic
and ultramafic volcanic rocks and consists of banded
recrystallized chert and graphitic argillite with sulphiderich sections containing layers of massive to disseminated
sulphides. The sulphides consist mainly of pyrite with
minor sphalerite and chalcopyrite. The sulphide iron
formation in the easternmost hole is relatively zinc-rich,
with an intersection assaying 0.74% Zn and 0.03% Cu
over 21 m (including assay values of up to 1.4% Zn over
5 m), while the westernmost hole is relatively copper-rich,
with assay values of up to 0.3% Cu and 0.25% Zn over 8 m.
From 1972 to 1977, Dome Exploration (Canada)
Limited conducted an airborne magnetometer survey with
follow-up ground magnetometer and EM surveys and
completed 9 diamond-drill holes north of Hoodoo Lake.
Two of the holes intersected sulphide-bearing iron formation intercalated with mafic, felsic and ultramafic volcanic
rocks. The iron formation reportedly consists of a finegrained, grey siliceous rock with layers of up to 20%
pyrrhotite, minor chalcopyrite and sphalerite. Assay
results from this rock returned values of up to 0.35% Zn
over 3 m.
From 1972 to 1973, Dome Exploration (Canada)
Limited conducted ground magnetometer and EM surveys
NORTHERN SWAYZE GREENSTONE BELT
and diamond-drilled 9 holes on a claim group northwest of
Groundhog Lake. The drilling indicated a wide variety of
volcanic rocks including ultramafic, mafic, intermediate
and felsic volcanic rocks with intercalated iron formation.
The iron formation consists of a very fine-grained cherty
rock with variable amounts of chlorite-, graphite- and
sulphide-rich layers. Sulphides included pyrrhotite, pyrite,
chalcopyrite and sphalerite with assay values of up to
0.37% Cu over 2 m and 0.25% Zn over 5 m.
10% Zn and may average about 4% Zn over the width of
the mineralized zone (Fumerton and Houle 1993).
Hudbay Mining Limited (12)
A bore hole was drilled west of Highway 101, on the
east side of the old channel of the Ivanhoe River. The hole
intersected mainly mafic volcanic rocks with an interbedded
unit of graphitic mudstone with disseminated pyrrhotite,
pyrite, sphalerite and chalcopyrite. Assays from this zone
returned values of up to 0.35% Zn and 0.07% Cu over 3.5 m.
From 1980 to 1982, Hudbay Mining Limited conducted an
airborne geophysical survey and diamond-drilled 8 holes
to follow up on geophysical anomalies in southeastern
Foleyet and northeastern Ivanhoe townships. One of the
holes in southeastern Foleyet Township intersected a zone
of subeconomic stratabound sulphides. Talc-chlorite
schists, assumed to represent deformed ultramafic flows,
are found in the uppermost part of the hole. This unit is
succeeded by a unit of locally amygdaloidal chlorite-carbonate schist which represents altered and deformed mafic
flows containing up to 10% fine- to medium-grained, randomly oriented chloritoid porphyroblasts. The schist is
abruptly overlain by 8 m of disseminated to massive sulphides including pyrite, sphalerite and chalcopyrite in
graphitic felsic pyroclastic rock. The highest reported zinc
assay value from this section was 0.6% Zn over 0.9 m.
This mineralized section grades down the hole into unmineralized and unaltered felsic pyroclastic rocks that continue
to the end of the hole.
Karvinen (19)
From 1982 to 1986, W. Karvinen, Quinterra Resources
and Utah Mines explored for base metals and gold in
northeastern Penhorwood Township by magnetic, EM and
IP surveys, geological mapping, trenching and diamonddrilling 1 hole. Sphalerite and chalcopyrite mineralization
are associated with the Nat River iron formation. Values of
up to 0.9% Zn, 0.1% Cu and 11 g/t Ag were reported in
selected grab samples. There appears to be some degree of
structural control to the mineralization, as the iron formation is isoclinally folded and locally brecciated. Highly
schistose and carbonatized mafic and ultramafic volcanic
rocks within the Deerfoot deformation zone lie immediately
to the north of the iron formation.
In 1986, zinc mineralization was identified by stripping
and trenching in another showing about 500 m to the
northeast (also known as the Nat River zinc showing).
Here, the sulphide mineralization occurs in pillowed to
massive intermediate volcanic rocks of the HNA that
immediately underlie the Nat River iron formation.
Sphalerite mineralization occurs with quartz veins and
minor chalcopyrite and pyrite in a narrow (100 cm) anastomosing zone with an exposed strike length of about 100 m.
Results from grab sampling along the zone indicate up to
Keevil Mining Group Limited (20)
In 1964 and 1965, Keevil Mining Group Limited conducted
ground EM and magnetic surveys, geological mapping
and diamond drilling in southeastern Foleyet Township
and northeastern Ivanhoe Township.
Three diamond-drill holes (65-18, 65-19, 65-20) were
also drilled in northeastern Foleyet Township, about 700
to 1100 m east of the southeastern margin of the Ivanhoe
Lake pluton. The drill holes intersected mafic flow units
with interbedded sedimentary units consisting of wacke,
siliceous siltstone and graphitic mudstone. Sulphide mineralization has been reported in all 3 holes associated with
the mudstone units. In 1 hole, disseminated to semi-massive
pyrite and pyrrhotite with minor sphalerite and chalcopyrite constitute up to 30 to 70% of the rock over short sections.
Assays from this section returned anomalous values of up
to a maximum of 0.28% Zn and 0.05% Cu over 3 m.
Noranda Exploration Company
Limited (26)
Noranda conducted an exploration program on a claim
group in the northwestern part of Keith Township from
1970 to 1972. The work consisted of ground magnetometer
and EM surveys and 2 diamond-drill holes. A unit of brecciated intermediate volcanic rocks with thin stringer veins
of pyrrhotite, pyrite and minor chalcopyrite and sphalerite
was intersected in the western hole (DDH K-72-3).
Reported assay results range up to 0.12% Zn and 0.02% Cu
over 1.7 m.
United MacFie Mines Limited (34)
Exploration at this occurrence has been concentrated on a
copper showing in an enclave of sulphide iron formation
within the Nat River granitic complex, in Muskego
Township. From 1970 to 1972, United MacFie Mines
Limited conducted ground magnetometer and EM surveys, and diamond-drilled 3 holes. Sampling of trenches
on the mineralized zone returned a weighted average of
0.30% Cu over a width of 8.2 m. The diamond-drill holes
encountered disseminated sulphides and stringers over
varying widths, consisting of pyrite, pyrrhotite and minor
chalcopyrite and sphalerite. Assay results reported in the
drill logs indicate trace amounts of gold and silver, but
51
OGS REPORT 297
copper and zinc were not reported. Detailed surface examination of the occurrence reported in Thurston et al. (1977)
indicates that the iron formation consists of alternating
layers of quartz, sulphides, magnetite and amphibole.
Locally they contain minor intercalations of what may be
fine-grained, metamorphosed lithic sandstone. The unit
has been intruded by pink, medium-grained porphyritic
granite and blue-grey quartz diorite.
Another hole, located further to the north, intersected an
18 m zone with copper mineralization in a unit identified
as a grey banded tuff. The mineralization consists of chalcopyrite stringers which returned anomalous values of up
to 0.32% Cu.
NICKEL AND PLATINUM
GROUP ELEMENTS
The Ireland occurrence is located in northern Kenogaming
Township. It was discovered by Timmins Nickel
Incorporated in 1989 and explored in 1990 by stripping,
trenching and diamond drilling. The showing consists of
cumulate-textured dunites differentiating into melagabbro,
isoclinally interfolded with magnetite-chert iron formation
and felsic tuffs of the underlying HNA. Mineralization
consists of 1 to 2% disseminated sulphides which locally
form a poorly developed net texture containing up to 10%
sulphides. The sulphides consist of pyrrhotite and minor
amounts of pentlandite. Late fractures are also mineralized
with pentlandite. Grab samples returned assay values of up
to 0.94% Ni, 0.10% Cu, 0.27 g/t Pt and 0.2 g/t Pd.
Geochemical analyses of the ultramafic rocks in the vicinity of the mineralization show REE patterns that are distinctively different than those of similar, but unmineralized, ultramafic rocks in the same unit to the northeast.
The slightly elevated LREE patterns in the rock hosting
the mineralization suggest that contamination of the ultramafic magmas may be the mechanism responsible for
localizing the sulphides and platinum group element mineralization (see “Geochemistry”).
Nickel occurrences are closely associated with the cumulatetextured ultramafic rocks, mostly within the Hanrahan
assemblage (HNA). The presence of large ultramafic bodies,
some of which have documented nickel mineralization, is
an indication that there may be good potential for komatiitehosted nickel deposits similar to those found in the
Timmins area and the Kambalda area of Australia (Lesher
1989). In addition, locally elevated platinum group element levels in assay results are also of exploration interest.
Akweskwa Lake (1)
There may be some confusion about the location of this
showing in Kenogaming Township, as the area is underlain by numerous ultramafic bodies, a number of which
have associated nickel mineralization. A grab sample taken
at this location is reported to have assay values of 1% Cu
and 0.9% Ni (Milne 1972). In 1973, Hanna Mining conducted a regional survey and sampled ultramafic rocks
over much of Kenogaming Township. The highest returned
assay value in this immediate area was only 0.30% Ni.
Fumerton and Houle (1993) report a massive, fine- to
medium-grained, highly serpentinized peridotite with
about 2% disseminated sulphides at the indicated area of
mineralization, but could not find any evidence of channel
sampling. Grab samples collected by Fumerton and Houle
(1993) returned values of up to 0.28% Ni and 0.13% Cu.
Amax Minerals Limited (2)
Amax minerals conducted a magnetic and EM survey in
1978 that was followed up by a diamond-drill hole in
1979, in northeastern Kenogaming Township. Drill logs
report assay values of up to 0.25% Ni over 3 m within a
carbonatized and serpentinized ultramafic unit containing
talc and chlorite bands.
International Norvalie (13)
In 1971, Norvalie Mines Limited optioned the Jonsmith
property in east-central Kenogaming Township and diamond drilled a number of holes in this area, east of the
occurrence. One of the holes returned a value of 0.26% Ni
over 3 m of serpentinized ultramafic rock containing 1 to 2%
disseminated and fracture-filled pyrrhotite and pyrite.
52
Ireland (14)
McIntyre Johnson (22)
The McIntyre Johnson occurrence lies in poorly exposed,
amphibolite-facies mafic metavolcanic rocks in the eastcentral part of Sewell Township. McIntyre Porcupine
Mines Limited carried out geophysical surveys followed
by diamond drilling in 1971. The mineralization is reported
as millerite which occurs in aggregates and along joint
surfaces within a differentiated mafic intrusion. Reported
assay values are up to 0.2% Ni over 2.3 m within peridotite.
Norduna (27)
The Norduna occurrence is located within a cumulatetextured ultramafic body within the HNA, in central
Kenogaming Township. There has been considerable
exploration work on this occurrence since its discovery in
1947. This work has included geophysical surveys, stripping, trenching and diamond drilling, with the most recent
work by Falconbridge Limited. The mineralization consists of up to 5% disseminated sulphides in serpentinized
ultramafic rocks that are in close proximity to the sheared
contact with intermediate fragmental rocks to the south.
The best reported intersection was 0.88% Ni and 0.156%
Cu over 7.6 m, including a 1.5 m section with 1.25% Ni
and 0.24% Cu.
NORTHERN SWAYZE GREENSTONE BELT
IRON
There are 2 economically important iron formations in the
map area: 1) the Radio Hill iron formation and 2) the Nat
River iron formation. The iron deposits in both of these
iron formations occur where the iron formation appears to
thicken by folding and/or faulting.
Nat River (24)
Geophysical surveys and 14 diamond-drill holes by
Kukatush Mining Corporation Limited, from 1959 to
1965, outlined a potential iron deposit containing an estimated 27 million tons of 29% total iron in northeastern
Penhorwood Township. The deposit occurs within the Nat
River iron formation on the northern limb of the Hanrahan
Lake anticline. The continuity of the Nat River iron formation has been largely inferred from magnetic surveys
and details have not been established. The diamond
drilling clearly indicates the deposit area is underlain by a
number of iron formation intersections (Milne 1972). A
possible interpretation shown on Map 2627 (back pocket)
is that of a Z-shaped, isoclinal drag fold on the north limb
of an F1 anticline. Alternative interpretations are repetition
by faulting or a number of separate iron formation horizons.
The iron formation consists predominantly of lean,
finely banded magnetite- and chert-facies iron formation.
In addition, sulphide-, silicate-, carbonate-, and graphitefacies portions are locally present in lesser amounts. The
oxide-facies portions typically consist of thin, lean beds of
black chert containing magnetite interbedded with white
nonmagnetic chert on a centimetre scale. The sulphidefacies portions occur as beds of disseminated to massive
pyrite and minor pyrrhotite up to 20 cm thick interbedded
with chert and/or graphitic argillite.
Radio Hill (29)
Exploration work by Kukatush Mining Corporation
Limited from 1958 to 1965, including geophysical surveys, mapping, trenching and diamond drilling, has indicated an iron deposit with approximately 158 million tons
of magnetic iron ore grading 27.8% acid-soluble iron. The
deposit occurs near the eastern end of the Radio Hill iron
formation in northwestern Penhorwood Township. The
iron deposit has a strike length of 5000 m and a thickness
of up to 500 m. This abnormal thickness is probably the
result of structural modification by at least 2 episodes of
folding. It is overlain by komatiite flows to the north and
underlain to the south by thickly bedded wacke. The iron
formation is folded into an isoclinal S-shape fold (F2 folding)
plunging north-northwest at about 50° (Milne 1972). The
unit consists of magnetite, siderite, sulphide, silicate
(minnesotaite), hematite (jasper) and graphite iron formation
typically interbedded with chert.
Milne (1972) has characterized 4 major vertical facies
transitions in the Radio Hill area. They are, from south to
north (hanging wall to footwall) 1) sulphide, silicate and
carbonate facies (0 to 50 m in thickness); 2) oxide facies
with minor carbonate and silicate facies (30 to 100 m in
thickness); 3) carbonate and silicate facies (10 to 80 m in
thickness); and 4) sulphide facies (0 to 25 m in thickness).
ASBESTOS
There are numerous asbestos occurrences within the ultramafic rocks scattered throughout the map area. However,
the only economically significant deposit is that of the
Reeves Mine, which produced about 146 000 tons of
asbestos. Milne (1972) concluded 1) asbestos mineralization is always associated with faulting and ductile deformation; 2) the formation of the asbestos veins was a separate
event from the general serpentinization of the ultramafic
rocks; and 3) the asbestos veins are later than the main
metamorphic events affecting the ultramafic rocks.
Reeves Mine (30)
The Reeves asbestos mine is located in southeastern
Reeves Township. Exploration continued over a period
of about 20 years and production was started in 1968
by Johns Manville Limited. It produced a total of about
146 000 tonnes of asbestos from about 6 million tons of
ore. Production was divided between a large western pit
and a smaller eastern pit by a north-trending diabase dike.
The ore body is situated within the northern part of a
differentiated ultramafic to gabbroic body 120 to 300 m
thick, which also hosts the Penhorwood talc mine to the south.
The ore zones occur in serpentinized dunite in the northern
closure of an antiformal structure which plunges about 50°
to the northeast. An easterly facing direction, based on the
differentiation from dunite to gabbro (see “Geochemistry”),
and an S1 fabric which wraps around the nose of the fold,
indicates that the fold is an F2 antiformal syncline. This
north-trending fold has been cut by northeast-trending
shears. A major northeast-trending shear crosses the northern apex of the antiformal syncline. The dip of this fault is
approximately 55° to the northwest at the surface but flattens
with depth. Drag folding suggests that it is a reverse fault
in which the north side has moved upwards (Milne 1972).
The orebody is enclosed to the west, north and east by
about 30 m of barren serpentinite in contact with mafic
volcanic rocks. Thus, the ore zone appears to conform
with the general trend of the antiform and has 3 dominant
structural controls: 1) the apex of a tight fold; 2) drag folds
caused by a steep reverse fault; and 3) major asbestos fibre
development is confined to the serpentinized dunitic part
of a differentiated ultramafic to gabbroic body (Milne 1972).
The asbestos in the ore zone occurs in a complex network of veins of various ages. The average grade of the
ore ranges from 2.5 to 4%, with fibres ranging in length
from less than 5 mm up to 15 mm. Many of the asbestos
fibres are composite in nature, with magnetite occurring
either as a sandwich between 2 parallel veins of asbestos
or as a selvage on one wall of the asbestos vein. Ribbon
veins, consisting of a central magnetite-asbestos vein bor53
OGS REPORT 297
dered on both sides by several parallel asbestos veins, also
occur. Where the diabase dike cuts the orebody, the
asbestos fibres have been recrystallized and destroyed for
up to 3 m on either side of the dike (Milne 1972).
TALC
A number of talc occurrences are associated with the
ultramafic rocks of the area. The Penhorwood Mine is the
only currently producing deposit in the map area. It is situated near the sheared western margin of a large differentiated ultramafic to gabbroic body which also hosts the
Reeves asbestos mine. The talc mineralization appears to be
associated with early ductile deformation overprinted by
localized fracturing and pervasive talc-carbonate alteration.
Penhorwood Mine (28)
The Penhorwood Mine is currently operated by Luzenac
Incorporated, with a milling rate of 450 tons to produce
170 to 200 tons of concentrate per day. There is very little
data available on the reserves or dimensions of the deposit.
The open pit deposit is located near the western margin of
an extensive north-trending, cumulate-textured serpentinite body cut by east-trending deformation zones, in northeastern Penhorwood Township. The ultramafic unit also
hosts the Reeves asbestos mine further to the north. The
western margin of the ultramafic unit is highly deformed
and may be the locus of a sheared contact with a unit of
clastic sedimentary rocks to the west.
Fumerton and Houle (1993) indicate that a number of
intense zones of talc-carbonate alteration occur along a
northeast line just east of a parallel shear inferred from
geophysical data. There are several generations of fractures that cut the deposit, all of which have varying
amounts of recrystallized magnesite and talc along the
fracture plane. The ore consists of about 50% talc. It is a
massive, medium-grained, light grey rock consisting of
vitreous talc and translucent carbonate grains together
with disseminated grains of ilmenite and/or magnetite.
Based on chemical analyses, the CaO content varies
between 0.3% and 4.5% and FeO varies between 5% and
8.5%. The massive rock is cut by a number of recrystallized talc and magnesite veins in a number of different
fracture orientations.
BARITE
The Cryderman Mine is the only recorded barite occurrence in the map area.
Cryderman Mine (8)
The Cryderman barite deposit is located in southwestern
Penhorwood Township. It was discovered in 1917 and since
that time has been the focus of a considerable amount of
exploration, including a 450 m decline in 1984 by
Extender Minerals Limited. A total of 673 tonnes of barite
54
were produced from small operations prior to 1940. Reserve
calculations indicate a probable reserve of 90 000 tonnes
grading 95% barite. Milne (1972) indicated that the
deposit occurs along the southeastern margin of the
Kukatush pluton. However, this investigation and highresolution aeromagnetic patterns suggest the deposit
occurs near the southern margin of an elongate body of
foliated granodiorite and granite intruded between the
Kukatush pluton and Kenogamissi batholith. Intense ductile deformation associated with the Hardiman deformation
zone is focussed along the southeastern margin of this
intrusion and it is in this setting that the Cryderman,
Horwood (11) and Roseval (31) veins are situated.
The barite occurs in a northeast-trending vein structure which has been traced over a strike length of 500 m.
Individual veins pinch and swell, from stringers to up to 5 m
thick, and have been traced for 30 m. The veins are typically
zoned from quartz and fluorite at the wall rock contact to
laminated barite and calcite in the walls and massive barite
in the centre.
SILICA
Silica, used for decorative stone and smelter flux, has been
sporadically produced from a number of open pits on large
quartz veins, in the southwestern part of Penhorwood
Township.
Horwood Mine (11)
In 1964, Horwood Mines Limited produced a total of
800 tonnes of silica from a quartz vein in southwestern
Penhorwood Township. The quartz veins occur along the
southeastern margins of elongate, foliated granodiorite
and granite bodies intruded between the Kukatush pluton
and Kenogamissi batholith. The veins occur in highly
strained wall rock within the Hardiman deformation zone.
The Horwood deposit is located in the southwestern part
of a quartz vein which has been traced for a length of
about 550 m and is up to 20 m thick. One of the Roseval
quartz deposits is situated on the northeastern part of the
same vein system.
Roseval Mine (31)
In 1987 and 1988, Roseval Silica Incorporated produced
about 110 000 tonnes of silica from their number 2 and 3
zones. The veins making up these zones occur within parallel shears of the Hardiman deformation zone, situated at the
highly deformed southeast margins of elongate foliated granodiorite to granite bodies that have intruded between the
Kukatush pluton and the Kenogamissi batholith. The number 2 zone is at the north end of the vein system which hosts
the Horwood Mine. The number 3 zone, which occurs on a
different quartz vein several hundred metres to the north, is
located at the highly strained contact of a granite intrusion
with ultramafic talc-chlorite schists. This vein has been
traced along strike for about 200 m and is up to 50 m thick.
NORTHERN SWAYZE GREENSTONE BELT
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OGS REPORT 297
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NORTHERN SWAYZE GREENSTONE BELT
Metric Conversion Table
CONVERSION FACTORS FOR MEASUREMENTS IN ONTARIO
GEOLOGICAL SURVEY PUBLICATIONS
Conversion from SI to Imperial
SI Unit
Multiplied by
1 mm
1 cm
1m
1m
1 km
0.039 37
0.393 70
3.280 84
0.049 709 7
0.621 371
Conversion from Imperial to SI
Gives
inches
inches
feet
chains
miles (statute)
Imperial Unit
Multiplied by
LENGTH
1 inch
1 inch
1 foot
1 chain
1 mile (statute)
25.4
2.54
0.304 8
20.116 8
1.609 344
Gives
mm
cm
m
m
km
AREA
1 cm2
1 m2
1 km2
1 ha
0.155
10.763 9
0.386 10
2.471 054
square inches
square feet
square miles
acres
1 cm3
1 m3
1 m3
0.061 02
35.134 7
1.308 0
cubic inches
cubic feet
cubic yards
1L
1L
1L
1.759 755
0.879 877
0.219 969
pints
quarts
gallons
1g
1g
1 kg
1 kg
1t
1 kg
1t
0.035 273 96
0.032 150 75
2.204 62
0.001 102 3
1.102 311
0.000 984 21
0.984 206 5
ounces (avdp)
ounces (troy)
pounds (avdp)
tons (short)
tons (short)
tons (long)
tons (long)
1 g/t
0.029 166 6
1 g/t
0.583 333 33
1 square inch
1 square foot
1 square mile
1 acre
VOLUME
1 cubic inch
1 cubic foot
1 cubic yard
CAPACITY
1 pint
1 quart
1 gallon
6.451 6
0.092 903 04
2.589 988
0.404 658 6
cm2
m2
km2
ha
16.387 064
0.028 316 85
0.764 555
cm3
m3
m3
0.568 261
1.136 552
4.546 090
L
L
L
MASS
1 ounce (advp)
1 ounce (troy)
1 pound (avdp)
1 ton (short)
1 ton (short)
1 ton (long)
1 ton (long)
CONCENTRATION
ounce(troy)/
1 ounce(troy)/
ton(short)
ton(short)
pennyweights/
1 pennyweight/
ton(short)
ton(short)
28.349 523
31.103 476 8
0.453 592 37
907.184 74
0.907 184 74
1016.046 908 8
1.016 046 908 8
g
g
kg
kg
t
kg
t
34.285 714 2
g/t
1.714 285 7
g/t
OTHER USEFUL CONVERSION FACTORS
1 ounce(troy) per ton (short)
1 pennyweight per ton (short)
Multiplied by
20.0
0.05
pennyweights per ton (short)
ounces (troy) per ton (short)
Note: Conversion factors which are in bold type are exact. The converion factors have been taken from or have been derived from factors given in the
Metric Practice Guide for the Canadian Mining and Metallurgical Industries, published by the Mining Association of Canada in co-operation with the
Coal Association of Canada.
57
OGS Report 300
2
OGS REPORT 297
58
NORTHERN SWAYZE GREENSTONE BELT
ISSN 0704-2582
ISBN 0-7778-3813-3
59