Nd Isotope Geochemistry of Igneous Rocks in the Glennie Domain
and its Immediate Sub-Phanerozoic Extension: Evidence for
Interactions with the Sask Craton?
Tim C. Prokopiuk I and Kevin M Ansdell
I
Prokopiuk. T.C. and Ansdell, K.M. (2000): Nd isotope geochemistry of igneous rocks in the Glennie Domain and its immediate
Sub-Phanerozoic extension: Evidence for interactions with the Sask Craton?: in Summary of Investigations 2000, Volume 2,
Saskatchewan Geological Survey. Sask. Energy Mines. Misc. Rep. 2000-4.2
Abstract
1. Introduction
The Nd isotopic composition of mafic and granitoid
igneous rocks/ram the Glennie Domain, andfram
drillcore immediately to the south of the PhanerozoicPrecambrian unconformity were used to provide:
(I) constraints on the isotopic composition ofthe
Paleoproterozoic mantle, (2) evidence for the initial
interaction between the Archean Sask Craton and the
juvenile rocks ofthe Trans-Hudwn Orogen, and
(3) the present extent of the Sask Craton. The age of
the mafic volcanic rocks from the southern Glennie
Domain and the Sub-Phanerozoic are not known, but
are assumed to be ca. 1880 to 1850 Ma. The ENi1
{1850 Ma) values range from +3.8 to+ 1.3, which
suggests tha t these mafic magmas were likely derived
from a similar heterogeneous mantle to that which
yielded the ocean floor rocks of the Flin Flon Domain.
The lower values may provide evidence for a small
amount of interaction of this magma with older crustal
materials. Three granitoids in the southern Glennie
Domain have U-Pb ages ofca. 1832 Ma and are thus
broadly coeval with the collision between the Sask
Craton and the Flin Flan-Glennie complex, whereas
the Wapawekka lake pluton is ca. 1850 Ma. The latter
has an E,w (1850 Ma) value of +3.2, whereas the
former have ENi1 ( 1832 Ma) values of +O. 9 to + l . 7. The
Wapawekka lake pluton was probably derived/ram a
similar source as the mafic volcanic roch or by
melting ofrelatively young arc crust, whereas the
younger plutons may have crystallized from magmas
that had undergone up to 20% contamination by
Archean crustal material. The nature of this older crust
is unknown, but may represent the Sask Craton itself.
These granitic magmas may thus be recording the
arrival of the Sask Craton in the Trans-Hudson
Orogen. The granitoid rocks from the Sub-Phanerozoic
have significantly lower ENi1 (1850 Ma) values ranging
from -3.8 to -8.6, and thus have undergone significant
interaction with older crust or are actually Archean in
age. The lowest f.,~.i value obtained in this study is.from
a ca. 1780 Ma pegmatite from the northern Glennie
Domain. The ENi1 (1780 Ma) of-10.6 indicates that the
pegmatitic melt was probably derived by melting ofthe
northern buried extension of the Sask Craton, as
imaged on LITHOPROBE seismic line S2h.
The Trans-Hudson Orogen (THO) is a
Paleoproterozoic zone of orogenesis extending from
Greenland, through central Canada, and into the
northern United States (Hoffman, 1988). The THO
comprises a collage of accreted intraoceanic terranes
(Reindeer Zone) and reworked continental margins
(Lewry and Collerson, 1990), and formed in response
to the collision of the Archean Hearne and Superior
cratons (Bickford et al., 1990), and a third Archean
craton, the Sask Craton, which drifted northwards
between the Superior and Hearne cratons from about
1.83 to 1.80 Ga (Ansdell el al., 1995).
The Sask Craton outcrops in structural windows
located in the Flin Flon- Glennie complex (Figure I ;
Chiarenzelli e t al., 1998; Ashton et al., 1999), but
extends into the subsurface as a crustal-scale
anticlinorium which is separated from the bounding
Superior and Hearne cratons by Paleoproterozoic crust.
The geometry of this craton has been estimated from
LITHOPROBE and COCORP seismic sections (Lucas
et al. , 1993; Nelson et al., 1993; Lewry et al., 1994;
Baird et al., 1996), whereas its extent has been
estimated from Nd and Pb isotope analyses ofpostcollisional pegmatites in the exposed THO (Steinhart et
al. , 1997; Ansdell and Stem, 1997), and Precambrian
rocks intersected in drill holes through the Phanerozoic
cover (Collerson et al., 1988). Together, these methods
have shown that the Sask Craton extends over I 000 km
under the Phanerozoic cover and tapers northwards
towards the northern end of the Glennie Domain.
Although geophysical anomalies have been used to
extrapolate the Paleoproterozoic clements of the THO
southwards (e.g. Green et al., 1985), geochronological
and isotopic data suggest that the volume of juvenile
Paleoproterozoic crust is probably insignificant below
the Phanerozoic cover (Collerson et al. , 1988). The
character of this southward change in age and isotopic
composition of the Precambrian rocks is, however,
unknown.
One of the problems is that the Nd isotopic
composition of magmatic rocks in the Glennie
Domain, other than post-collisional pegmatites
(Bickford et al., 1992), are poorly known, and thus it is
unclear whether the older igneous rocks may record
'Department uf Geological Sciences. University of Saskatchewan, 114 Science Place. Saskatoon, SK S7N 5E2.
Saskatche wan Geological Survey
79
56°30'
ROTTENSTONE
DOMAIN
Wathaman
Ball!olilh
., ,.
;
;
;
dec ided to analyze magmatic
rocks fro m d rill holes closest to
the Phanerozoic unconformity to
provide the most reasonable bas is
for the southward extrapolation
of data from the exposed T HO.
;
/
;
/
,l'(ISSEY}IEW
DOMMN ,,,/
., .,
., .,
/
., .,
;
,.
/
;
.,
.,
/
;
/
2. Sampling and
Analytical Techniques
./LARONGE
/ ;' DOMAIN
b
O
'lg
/
/
!
:
I
Nemeiben
Zone
M.36
., .,
.M38
"fLON
COVER
Flin Fk>n
DOMAIN
• M28
•
Samples (Figure I) were chosen
from the rock collections at
Saskatc hewan Energy and Mines,
~ and consisted of either powders.
u:! outcrop samples, or drillcore. The
absol ute age o f the samples was
either known , or assumed from
well-understood geological
re lationships. The only samp le
located at a significant distance
from th e contact w ith the
Phanerozoic rocks is 9811-3004,
a ca. 1780 Ma post-collisio na l
pegmatite, wh ich was used to
he lp del ineate the northern extent
of the Sask Craton.
N d isoto pe a nalyses were
performed at the Univers ity of
0
50
Saskatchewan,
and the results
- ,
...
I
Kilometres
repo rted in Tab le 1. Rock and
drillcore sam ples were jawFigure I - Simplified geological map of the Gle1111ie Domain, a11d surro1111di11g
crushed and ground in a tungsten
Paleoproterow ic terra11es ofthe Reindeer Zo11e of the Tra11s-Hudson Oroge11 (after
Ashton, 1999; Delaney, 1992). The Flin Flon-Gle11nie Complex comprises the Gle11nie carbide sw ing mi ll. Powdered
and Flin Flon domains. The grey-shaded regions in the Glennie Domain are
samples were completely spiked
greenstone belts. The location ofsamples are indicated by tl,e collar of the ,!rill hole
w ith the appropriate amount of a
f or the Sub-Phanerowic samples, and the location of outcrops in the exposed shield.
mixed 1' ''Sm-"r'N d tracer so lu tion
The complete sample numbers are sh own in Table I.
prior to digestion in HF-HN0 1 in
screwtop Te flon containers. Sm
and Nd were se parated using
interaction with Archean crust. Thus, th ese rocks may
standard cation-exchange procedures. prior to loading
have a significantly di fferent Nd isotopic composition
on outgassed rhenium filamen ts with I 11 PO, and 2.0N
HC I. Isotop ic analyses were performed in static mode
from litho logically similar arc and ocean floor rocks in
the Flin Flon Domain (Stern et al., I 995a, I 995b;
on a Finnigan M AT 261 mass spectro meter. Spike
Wha len et al , 1999). In addition, extrapolation of
unmix ing, and mass fractio nation corrections were
geophysical anoma lies over long dista nces is difficult,
perfonned offline, and used the following
normalization ratios: 14 ~Ndl 44 Nd-"- 0.72 l 9 and
and in fac t Green et al. ( 1985) indicate that the
14
southward extension of the Glennie Domain is
MSm/ 1~4 Sm=0.49419. Ana lyses of standards during the
particularly inconclusive. Thus, it is difficult to relate
course o f this project yielde d the fo llow ing values: La
Jolla Nd standard yielded a 143 Nd/ 144Nd value of
the isotopic data obtained from drill ho les across the
0.5 I 183 5 ±9; Ames Nd standard y ie lded an a verage
whole of southern Saskatche wan with specific regions
144
4
within the exposed THO . In order to address some of
' ' Nd/
Nd value of0.512 102 ±11 (n ~3); and Ames
these problems, it was decided to determ ine the Nd
Sm standard 14"Smr 4 Sm a value of 0.6075 1 ±3. The
isotopic composition of pre- and post- colli sional
epsilon Nd (£-;d) values at th e present or at the age of
the rock were calculated using the fo llow in g reference
igneous rocks in the Glennie Domain. The fonner
values: 14 'Nd/ 144Nd C HU R (prcsent)=0.5 12638 and
included mafic volcanic rocks, which are as sum ed to
147
provide an indication of the Nd isotopic compositio n o f
Sm/ 144 Nd CH U R (present)=0. 1966 (Go ldste in et al. ,
the Paleo proterozo ic mantle, The latter included ca,
1984). The T DM values were calculated using the
fo llowing re ference va lues: 14·'Ndf '4 '1Nd Depicted
1.83 Ga granitoid rocks. interpreted to have been
intruded synchronous with the deve lopment of reg iona l
Mantle (present}=0 .5 I 3 16 and 14"Sm/ 144 Nd Depleted
Mantle (present)=0.2 141 (Goldstein et al.. 1984).
scale thrust fa ults related to the first interactions
between the Reindeer Zone and the Sask Craton
Proced ural blan ks are about I 00 pg Nd and 30 pg Sm ,
but are insignificant for these samples.
(Ansdell et al., 1995; Ashto n et al. , 1999). It was a lso
54°30'
80
Summary of Investigations]{)()(). I·"o /rr111e 2
Table I - A11aly tical data.
To'.\1
Sample
UTM
Su b- Phanerozoic
601,207 1
Ml l
M2XA
605.l5X5
M28F
6053585
M36B
609674 1
M.,8A
608.1 570
lJTM
l..ocation
589 147
Sclco Ba ll,1n1ync
Bay: 207'
532178 A nglo-American
Wapa \\'·ekJ..:.a #J:
100 1'
5]2278 Ang.lo-Americ.:an
W tlp3V•··t:kka #J:
1052'
4467 16 DMR Morin
Lake: 289'
4668(,4 DMR La Rongc:
Rock Type
Sm (ppm)
Nd (ppm)
11
~
Sml"uNd
IHN<L''~·Nd·
eNd (0) (Ga)
Age
(Ma)
E,o
(Age)
granite pegma1itc
8.88
]6. 1?
0. 14829
0.5 1 185] ±20 · 15.3
3.0 1
1850
-3.8
malic volcanic
4.54
22 .71
0. 1207)
0.5 11908 ±2 1 -14.2
2.[)4
185()
·'-8
mafic volcanic
478
20.59
0 14025
0.512018 ±07 -1 2. 1
2.35
1850
,u
granite
0 .6 1
3 .76
0.09716
0 .511 195 ± 16
·28.2
2.55
1850
-4.6
grani1ic gneiss
7 53
50.85
0 08'144
0 .5 10894 ± 12 -34.0
2.75
1850
· 8.6
matic vok an ic
malic vo lcamc
.5J6
0.513076 ±.21
8.6
0 .5 12286 ±.08
·6.9
0 .512293 :1-20
-6.7
0 .511 591 ±44 -20.4
2.1 ?
7.70
20.85
0 21956
0 . 15.•63
0.1~737
0. 10287
2 .14
I XSO
1850
1850
1833t
13. 1
+3.4
·2.6
- 1.7
52.1"
Southt'rn C lcnn ie Domain
8822-11
6091500
~61350
5~74XO
8922-12 1 6088740
6087112()
8922-250
537 150
8822-}75 609'1590
5iU560
malic volcanic
µranodiorlrc
1.95
3A<>
2.0 1
.1.55
11:rtmitc
5 .10
D .'14
O 090 79
0 .5 11420 ± 19 -B .8
2.14
183 1t
+ I.I
grnnodioritc
3.64
25 .59
0.08594
0 .5 11346 ± 10 -25.2
2 .1 5
J8J2t
- 0.9
l,!rano<liorite
2 23
12.83
0 10509
0.5 11 684 ±1)9 -18.6
2.or,
1850
, .1.2
~rnnile pcgmatile
5.67
19.02
0. 18002
0 .51 1900 ±.19 - 14.4
1780
- IOJ,
8822- ,77
6092%0
8822-.l i S
60<J57 5(1
8922-1 9
60'>2075
Brow nell Lake
Wapawckka l.akc
Wapa,\.·ekk,l l ..(1k.c
Carroll ( .akc
Block
58 1760 l.lrownell Lake
r1 u1on
570.160 Maynard Creek
l'luro11
542400 Wapawckka Lake
~ o r lhern (;Jennie Domain
'18 1 1-.>004 598 1880
624092 Gloe ckkr Lake
u .n
2 32
i\otes: f rK>tagc reprcscn1s depths measured d1) wn rhe length of the core.
• e1Tnrs reported to :?a x 1O"" _
.
. . ·,
.
t lJ-Pb zircon c1g:cs (from M cN1coll 111 t1/. 1992): all oth er a!!t::) assumed for compar,tt1 \e purpo~cs.
3. Discussion of Results
A na lyti ca l results a re prov ided in Table I and include
i;~d val ues at present (i:~iO)) and at the assumed or UPb aoe of the rock ( i:;'ld (Age )). T hese values are an
ind itato r of the N d isoto pic compositio n o f the sa~~le
re lat ive to that o f the bulk earth, or C HU R (chondnt1c
uni fonn reservoir) (De Pao lo and Wasserbu r~, 1976), at
the present and at the age of the ~ock_. Negat,_ve v~lues
fo r an igneous rock at its crystall1zat1o n age implies
tha t the magma resu lted fro m partia l mel ting of, or
interact io n 'w ith a long-te nn LREE-e nric he d source ,
such as o lder crust, whereas posit ive values suggest
de rivat ion d irect fro m a LR EE-de pleted source, such as
the depleted mant le. T he depleted ma ntle mode l age
(T ) represents the amount of time th at has e lapsed
D\1
'
since
the samp le had the same 14) Ndj l44N d ratw
as t}le
depicte d ma nt le source region, and gives an
.
approximate idea as to the age of the crust from which
the magma was gene rated . T \1e Nd isotopic
_
compos itio n of rocks are typically preserved d uring
weathering. sed imentation, and metarnorph1 sm. .
a lth ough McCulloch a nd Black ( 1984 ) a nd Baro v1ch
and Pa tchett ( 199 1) indicate d that Sm and Nd can be
redistributed d uring upper amphibolite to granulit~
facics metamo rph ism . and myloniti zati on, respectiv e ly.
None of the sa mples ana lyzed exceed upper .
amphibo lite fac ies conditions, nor arc they h1g h_ly
deformed, and so it is assumed th at the Sm-Nd isotope
syste mat ics are represen tat \ve o! their in itia l va l_ues . _
The Nd isotope evo lutio n Imes to r the samples m this
study are shown in Fig ure 2.
Saskatchewan ( ieolo1<ical .':,'urvey
a) Mafic Rocks
Southern Glen nie Domain
Samples 8822- 11, 8922- 12 1, and 8922-250 are
tholeiitic arc or ocean floor basalts from the BrownellWapaw ekka lakes greenstone be lt in the southern part
of the Glennie Domain ( De laney, 1992). The age of
these rocks is unknown, althoug h they predate the ca.
1850 Ma granito ids and may be as o ld_as ca. 188~ Ma
(McN icoll el al. 1992). The age used in Table I 1s
1850 Ma, and thu s the i:Nd (Age) value of the mafic
rocks can be used to determine whether the mafic
maornas may have resu lted from melting of the
rec~ntly formed volcan ic pile. Extrapolat ion of the i:._d
va lues to 1880 Ma does not affect the interpretations
made here .
At 1850 Ma, the mafic rocks have
i:"d
values between
-".!.6 and + 3.4, wh ic h ind icate that the mafic me lts
could not be derived by melting of the depleted mantle
of Go ldstein et al. (1984) (F igure 2). However, Stern et
al. ( I 995a) argued, from combined geoc he mical and
isotopic data of m id-ocean ridge and ocean island
.
basalts, that the Nd isotopic com pos itio n of the
Paleoproterozo ic mant le be low the Flin Flon Doma m
was hetcro"eneous and ranged from +S.4 to +2.1 . T he
three samples from the southern G lennie f?omain are
within this range. and thus could be expla ined by
derivation from s imilar mantle sources. The extent of
interactio n with newly fonned and thus slightly o lder
Paleoproterozo ic crust, o r even s_ma ll ar~ounts ?f
Archean crust, cannot be determ ined using Nd isotopes
onlv and must await more deta iled trace clemen t
ana-lyses. In add ition, a better underst andi ng of the
petroge nes is of these rocks req uires trace element
analyses.
XI
10
. StJb..Ph¥*'ozoic
M11
Depleted Mantle
5
.
'1J
z
c
0
_, .---
- --- ___
-"". :...-:" .:... : ··
--
M2 BE
~
~ --t-,---,-.--,
· _-_---:' --- - - - - - - - - ~ . . . , . : . . ; ; _ __
a.
w
-s
-10
-15
I
I
_...,_ _ _ _ _ _ _ _ _ _ _ _ __ ,
Archean
Crust
-. ·
ss22- 11
•
eg22. 121
I
I
8922-250
+
8822-375
•
"822-377
8822-378
•
I
l
8922-19
j Northern Glenn ie Domain
I
1600
SouthemGlennit Domilin
I
...
M368
·~
+
0
(/)
.. M28A
•
1800
2000
2400
2200
2600
2800
9811-300<
3000
3200
Age (Ma)
Figure 2 - Epsilon Nd-age plot showing i:N, value at assumed or known age of rock, and extrapolation towards Depleted
Mantle. The field for Archean crust is after Collerson et al. ( 1988) and Ansdell and Bleeker (199 7), and Depleted Mantle is
after Goldstein et al. (1984).
Sub-Phanerozoic
M28A and M28E a re sam ples of amphibo lite grade
mafic volcanic rocks from a drill ho le located to the
south of the G lennie Domain. They have E,._d values at
1850 Ma of +3. 8 and+ 1.3, respectively. The best
interpretation for M28A is that the mafic magma was
derived from a similar source as the mafic volcanic
rocks in the southern Glennie Domain, and is probably
Paleoproterozoic in age. The ENd va lue of + 1.3 obtained
from M2 8E is similar to the lower values obtained
from arc rocks in the Flin Flon Domain (Ste m et al. ,
1995b), and may provide evidence for the interaction
of this magma with older crustal materials. However,
this material may have been Paleoproterozoic sediment
which contained minor amounts of recycled Archean
or earlier Proterozoic elastic detritus.
Overall, the E:-id values of the mafic volcan ic rocks are
similar to other juvenile Paleoproterozoic mafic
volcanic rocks in the THO. The mafic rocks from the
Sub-Phanerozoic drillcore do not provide evidence for
large-scale interaction w ith o lder crust, although t hey
probably fonned in an oceanic environment prior to the
arrival of the Sask Craton.
b) Granitoid Rocks
Southern G lennie Domain
Four granitoid rocks that intrude the supracrustal rocks
of the southern Glennie Doma in were analyzed. Three
of these y ie lded simi lar U-Pb zircon ages of ca.
1832 Ma (Table I; McN icoll et al., 1992). These
granitoids were em p laced broadly synchronous with
the initiation of southwest-directed thrusting, which
82
was re lated to the collision between the Sask Craton
and the Flin Flon-Glennie complex ( Ansdell et al..
1995; Ashton et al. , 1999). Thus. these rocks may
record some interaction with th e newly a rr ived Sask
Craton. The fourth, the Wapawekka Lake granodiori te,
formed during the earlie r phase of g ra nito id
magmatism , and is thu s assumed to be 1850 Ma.
The ca. 1832 Ma plu ton ic rocks have very sim ilar Nd
isotopic compositions at time of formation ( E'4d values
between +0.9 and + 1.7 ; Table I). In contrast, the
Wapawekka Lake granodiorite, w hich is assumed to be
older, has an e~d value of +3 .2 at 1850 Ma. The latter
value lies within th e range exhibited by the middle
successor arc granito ids in the Fli n Flon Domain,
whereas the younger granitoids have sign ificant ly
lower E:-,J values than rocks of the same age in the Flin
Flo n Domain (Wh alen et al., 1999). However, these
va lues arc sim ilar to those exhibi ted by older gran itoid
rocks ( 1860 to 1880 Ma) in the Flin Flon Domain,
which are thought to have been generated by mel ting
of mant le wedge or juveni le arc crust w ith subsequent
small amounts of contam ination by ass imi lation o f
older crust.
The best in terpretation of the data from the southern
G lennie Domain is that the Wapawekka La ke
granodioritic magma was derived from a sim ilar source
as the mafic volcanic rocks, or by mel ting of relat ive ly
young mantle-derived crust. The 1832 Ma plutons have
cons isten t calculated T 0 M ages, wh ich suggests that
these magmas cou ld have fonned by part ial me lting o f
2. 14 Ga crust ( Figure 2). There is no known crust of
this age w ithin the THO , and so these magmas could
have formed by either: ( I) me lting of sli ght ly o lder
basaltic crust. similar in isotopic composition to sample
M28E, o r (2) contamination of + 3 .0 magmas with
Summa r ,:
cl Investigations ]()()(),
1·0 ! 11me l
older Archean crust with an £Nd value of about -10.0 or
less. A simple two-component mixing calculation
using the following end-member components (granitic
magma Nd=30 ppm and ENd=+ 3 .O; Archean crust
Nd=30 ppm and ENd=-1 0.0) indicates that the EM value
of the 1832 Ma plutons could result fro m 20%
contamination by Archean crust. If the Archean crust
has a lower £Nd va lue or higher concentration of Nd
then the weight fraction of older c rust requ ired would
decrease accordingly. In addition, it is not known
whether this Archean component would consist of
Archean crysta lline rocks, or Archean crust that had
been recycled and deposited into Paleoproterozo ic
sedimentary basins and subsequently incorporated into
the 1832 Ma magmas.
Northern Glennie Domain
An undeformed ca. 1780 Ma granitic pegmatite which
intrudes my loniti zed granitoid g neisses a long the
northern boundary of the G lennie Domain (Harper,
1998; Harper et al., 2000) was a nalyzed to determine
whether its Nd isotopic compos ition suggested
interaction with significantly older crust. The £Nd value
at the assumed age of intrusion is - I 0.6 (Table 1),
which suggests extensiv e contamination by or direct
derivation from Archean crust ( Figure 2). This
Archean crust is probably the northern extension of the
Sask Craton, which is imaged on LITHOPROBE
seismic line S2b ( Hajnal et al. , 1996), and indicates
that the Sask Craton had underthrust the
Paleoproterozoic rocks of the THO at least as far north
as thi s point by ca. 1780 Ma.
southern La Ronge Domain is necessary before the Nd
isotopic compositions of the granitoids in this study
can be fully interpreted.
Sample M 11 is a coarse-grained granito id with a E:,.,d
value of -3.8 at an assumed age of 1850 Ma. This value
is significantly lower than the values obtained from the
ca. 1832 Ma granito ids in the Glennie Domain.
Therefore, even though the crystallization age of th is
rock is not known, the init ial magma interacted with a
s ub,stantial amount of older, possib ly Archean, crust
prior to crystallization.
4. Summary
I)
The Nd isoto pic composition of mafic volcanic
roc ks from the southern Glennie Do main and two
samples from the Sub-Phanerozoic indicate
deriv ation from a sim ilar mant le to that from
which the Flin Flon arc and ocean floor rocks were
generated.
2)
The ca. 1850 Ma Wapawekka Lake granodiorite
has an e'ld value of + 3.2, wh ich is similar to the
successor arc p lutons of the Flin Flon Domai n, and
is thu s probab ly derived by remelting of juveni le
arc crust.
3)
In contrast, the ca. 1832 Ma granitoids have lower
e]';d values, which suggest up to approximately
20% contamination by older crustal material. The
nature of this contaminant is unknown , but may be
Paleoproterozoic sedimentary rocks containing
Archean detritus, or actual Archean crust. If it is
th e latter, then these gran ito ids may be samp ling a
small component of the Sask Crato n, which thus
provides fu rther constraints on the arrival of this
craton in the THO.
4)
The age of the granitoids from the SubPhanerozoic drillcore are unknown, although all
three samp les have negative i;"'d values. These data
suggest significant interaction w ith Archean
crustal mate ria l, although the lack of age control
makes inte,pretation diffi cult.
5)
The ca. 1780 Ma pegmatite from the northern
Glennie Domain has an Ei-;d value of -10.6, which
suggests that the pegmatitic melt was probab ly
generated from Archean crust. The location of th is
sample, and the interpretatio n of the
LITHOPRO BE seismic signature lends support to
the theory that this Archean crust is the Sask
Craton. T hi s sample thus marks the northernmost
limit of the Sask Craton.
Sub-Phanerozoic
Three granitic samples were taken from drill holes that
inte rsected the basement below the Phanerozoic
sedimentary cover. The ages of these samples are not
known, but are presumed to be Paleoproterozoic,
because they are taken from drill holes that are as close
as possible to the exposed THO. Drill holes M36 and
M38 are situated with in the extension o f the La Ronge
Domain, whereas MI I li es immediately to the south of
the G lennie Domain in the Deschambault Lake area.
The samples from M36 and M38 have Ei-;d values of
-4 .6 and -8.6 at an assumed age of 1850 Ma, and T DM
ages of 2.55 and 2. 75 Ga, respectively (Table I , Figure
2 ). These magmas have thus interacted significantly
with older crust, or are actually Archean in age.
However, no geochrono logical data is available for
th ese rocks. Simi lar E:-Jd values have been o btained
from the Wathaman Batholith and the TonaliteMig matite Complex on Reindeer Lake (Kyser and
Stauffer, 1992). These authors s uggested that low £~d
values in the gneisses of the Tonalite-M igmatite
Complex resulted from metamorphism of supracrusta ls
containing detritu s shed from the Hearne craton. The
Watham an Rath olith formed fro m magmas that
incorporated sign ificant quantities of this older
supracru sta l material. A better understanding of the
geological, age, and petrogenet ic relationships in the
Saskatchewan (ieoloRical S11rvey
More detailed and integrated geochronolog ical,
geochemic al, and isoto pic ana lys is is req uired to fu ll y
understand the development of the southern G lennie
Do main and the southern extensio ns of the La Ronge
Domain. in order to be able to extrapo late to the Su-bPha nerozo ic basement. These new data, however, do
suggest that the ca. 1832 Ma granitoids may be
providing e vidence for th e arr iva l of the Sask Craton,
which then undc rthru st as far no rth as the northern
G le nni e Do ma in.
83
5. Acknowledgments
This study was initiated while Tim Prokopiuk was a
recipient of an NSERC Underg raduate Research
Scholarship. The supplement to the scholarship, and
sampling and analytical costs were borne by an
NSERC Research Grant lo Kevin Ansdell. Samples
were collected in Regina with the assistance and advice
of Gary Delaney, Ken Ashton, Charlie Harper, and
Lynn Kell ey. Technical support in the Isotope
Laboratory at the University of Saskatchewan was
provided by Diane Fox, Chris Holmden, and Kerrie
Fanion. Tim Prokopiuk appreciated the midsummer
break from lab work provided by Don Wright and Ralf
Maxeiner. Bill Slimmon and Ken Ashton are thanked
for a digital copy of a Glennie Domain map on which
Figure I is based, and Gary Delaney is thanked for his
comments on the manuscript. LITHOPROB E
Publication # I I 03 .
6. References
Ansdell, K.M. and Bleeker, W. ( 1997): The margin of
the Superior Craton : Neodymium isotope
constraints on the evolution of the Thompson
Nickel Belt, Manitoba; Geol. Assoc. Can./Miner.
Assoc. Can., Abst. Vo l., v22, pA-4-5.
Ansdell, K.M., Lucas, S.B., Connors, K., and Stern,
R.A. (1 995): Kisseynew melasedimentary gneiss
belt, Trans-Hudson Orogen (Canada): Bac k-arc
orig in and collisional inversion; Geo!., v23,
p I 039-1043.
Ansdell, K.M. and Stern, R.A. ( 1997): The Scimitar
Complex: Initial SHRIMP U-Pb and Nd isotope
data from granitoid rocks; in Summary of
Investigat ions 1997, Saskatchewan Geo logical
Survey, Sask. Energy Mines, Misc. Rep. 97-4,
pl 45-149.
Ashton, K.E. ( 1999): A proposed lithotectonic
domainal reclassification of the southeastern
Reindeer Zone in Saskatchewan; in Summary of
In vestigations 1999, Volume 1, Saskatchewan
Geological Survey, Sask. Energy Mines, Misc.
Rep. 99-4. 1, p92-100.
Ashton, K.E., Heaman, L.M., Lewry, J.F., Harllaub,
R.P., and Shi, R. ( 1999): Age and origin of the Jan
Lake Complex: A g limpse of the buried Archean
craton of the Trans-Hudson Orogen; Can. J. Earth
Sci., v36, p 185-208.
Baird, D., Nelson, K., Knapp, J., Walters, J., and
Brown, L. ( 1996): Crustal structure and evolution
of the Trans-Hudson Orogen: Results from se ismic
reflection profiling; Tectonics, v 15, p4 I 6 -426.
Barov ich, K.M. and Patchett, P.J . ( 199 1): Behavior of
isotopic systematics during defonn ation and
metamorphism: A Hf, Nd and Sr isotopic study of
mylonitized granite; Contrib. Mineral. Petrol.,
v l09, p386-393 .
8-1
Bickford, M .E., Collerson, K.D., Lewry, J.F., and
Orrell, S.E. ( 1992): Pegmatites and leucogranites
as probes of crust beneath allochthonous orogenic
rocks in the Glennie and La Ronge domains; in
Summary of Investigations 1992, Saskatchewan
Geological Survey, Sask. Energy Mines, Mis<:.
Rep. 92-4, p 124-1 29.
Bickford, M., Collerson. K., Lewry, J., Van Schmus,
R., and Chiarenzelli, J. ( 1990): Proterozoic
collisional tectonism in the Trans-Hudson Orogen
in Saskatchewan; Geol., v 18, p 14- 18.
Chiarenzell i, J., Aspler, L., Villeneuve. M., and Lewry,
J. ( 199 8): Early Proterozoic evol ution of the
Saskatchewan Craton and its allochthonous cover,
Trans-Hudson Orogen; J. Geol., vl06. p247-267.
Collerson, K.D., Van Schmus, R.W., Lewry, J.F., and
Bickfo rd, M.E. ( 1988): Buried Precambrian
basement in south-central Saskatchewan:
Provisional results from Sm-Nd mode l ages and
U-Pb z ircon geochronology; in Sum mary of
Investigations 1988, Saskatchewan Geological
Survey. Sask . Energy Mines, Misc. Rep. 88-4,
pl42- 150.
Delaney, G. D. (1992): Gold in the Glennie Doma in;
Sask. Energy Mines, Misc. Rep. 92-5, 7 1p.
DePaolo, O.J. and Wasserburg, G.J. ( 1976): Nd
isotopic variations and petroge netic mode ls;
Geophys. Resear. Lett., v3 , p743-746.
Goldstein, S.L., O' Nio ns, R.K., and Hamilto n, P.J .
( 1984): A Sm-Nd isotopic study of atmospheric
dusts and particulates from maj or river systems;
Earth Planet. Sci. Lett., v70, p22 l-236.
Green, A.G., Weber, W. , and Hajnal, Z. (1 985):
Evolution of Proterozoic terrains beneath the
Williston Basin ; Geo!. , vl3 , p624-628 .
Hajna l. Z., Stauffer, M.R., White, D.J., Lucas, S.B.,
Lew ry, J., Clowes, M.R .. and Ashton, K.E. ( 1996):
Three-d imensional seismic crustal signature of the
western Trans-Hudson Orogen, Saskatchewan; in
LITHO PROBE Trans-Hudso n Orogcn Transect
Meeti ng, Rep. 55, p l 13-1 24.
Harper, C.T. (1 998): The La Ronge Doma in-Glennie
Domain transition: Street Lake area (parts of NTS
640-3 and -6); in Summary of Investigation s
1998, Saskatchewan Geological Survey, Sask.
Energy Mines, Misc. Rep. 98-4. p66-80.
Harper, C.T., Heaman, L.M .. and Prokopiuk, T.C.
(2000 ): Glassy pseudotachylite in
Paleoproterozo ic G loeckler Lake Mylonite Zone at
the Kisseynew Domain- Glennie Domain
boundary, Street Lake area, northern
Saskatchewan: GeoCanada 2000, Calgary, May
2000, Conference CD, ext. abstr. # 124.
Sumnwry of /nr esligarions ]()()()_ 1·olr1m e 2
Hoffman, P.F. ( 1988): United Plates of America, the
birth of a craton: Early Proterozoic asse mbly and
growth of Laurentia; Ann. Rev . Earth Planet. Sci.,
v 16, p543-603.
Kyser, T.K. and Stauffer, M. ( 1992): Petrogenesis of
the Wathaman Batholith ; in LITHOPROBE TransI ludson Orogen Transect Meeting, Rep. 26, p I 26128.
Lewry, J.F. and Co llerson, K .E. ( 1990): The TransHudson Orogen: Extent, su bdivision, and
problems; in~Lewry, J.F. and Stauffer, M.R. (eds.),
The Early Proterozoic Trans-Hudson Orogen of
North America, Geo!. Assoc. Can., Spec. Pap. No.
37, pl-14.
Stem, R.A., Syrne, E.C., Bailes, A.H., and Lucas, S.B.
(I 995b): Paleoproterozoic (1.90-1.86 Ga) arc
volcanism in the Flin Flon belt, Trans-Hudson
Orogen, Canada; Contrib. Mineral. Petrol., vi 19,
pll7-141.
Whalen, J.B .. Syme, E.C., and Stem, R.A. (1999):
Geochemical and N d isotopic evolution of
Paleoproterozo ic arc-type granitoid magmatism in
the Flin Flon belt, Trans-Hudson Orogen, Canada;
Can. J. Earth Sci., v36, p227-250.
Lewry, J. , Hajnal, Z., Green, A., Lucas, S .. White, 0. ,
Stauffer, M., Ashton , K., Weber. W. , and Clowes.
R . ( 1994): Structure of a Paleoproterozoic
continent-continent collision zone: A
LITHOPROBE seis mic reflection profile across
the Trans-Hudson Orogen. Canada;
Tectonophysics, v232, p 143-160.
Lucas, S. B., G reen, A. , Hajnal, Z ., White. 0., Lewry,
J., Ashton , K .. Weber, W. , and C lowes, R. ( 1993):
Deep seismic profile across a Proterozoic coll is ion
zone: Surprises at depth; Nature, v363, p339-342.
McCulloch, M.T. and Black. L.P. (1984): Sm-Nd
isotop ic systematics of Enderby Land g ranu lites
and ev idence for the redistribution of Sm and Nd
dur ing metamorphism; Earth Planet. Sci. Lett.,
v7 L p46-58.
McNicoll, Y.J., Delaney, G.D. , Parrish, R.R. , and
Heaman. L.M. (1992): U-Pb age determinations
from the Gle nnie Lake Domain. Trans-Hudson
Orogen, Saskatchewan; in Radiogenic Age and
Is otopic Studies: Report 6 , Geo!. Surv. Can., Pap.
92-2, p57-72.
Nelson, K., Ba ird, D. , Walters, J., Hauck, M., Brown,
L., Oliver, J.. Ahem. J., Hajna l, Z., Jones, A., and
S loss, L. ( 1993): Trans-Hudson Orogen and
Williston Bas in in Montana a nd North Dakota:
New COCO RP deep profiling results: Geo!., v2 I ,
p447-450.
Steinhart. W.E. , Bickford, M.E. , Lewry, J.F., and
Mock, T.D. ( 1997): C ommon Pb and Sm-Nd study
of the Glennie, Hanson Lake , and La Ronge
domains, and the Hearne province, Trans-Hudson
Orogen: Implication s for tectonic evolution; Geo!.
Assoc. C an./Mineral. Assoc. Can., Abst. Vol. , v22,
pA-142.
S tern, R.A ., Sym e, E.C., and Lucas, J.B. ( 1995a):
Geochemistry of 1.9 Ga MORB- and 018-like
basalts from the Amisk co ll ag e, Flin Flon be lt,
Canada: Evidence for an intra-oceanic o rigin,
Geochim . Cosmochim. Acta, v59, p3 I 3 l-3154.
Saskatchewan GeuloRica/ Survey
85