Caledonian and Baikalian tectonic structures on Varanger
Peninsula, Finnmark, Norway, and coastal areas of Kola
Peninsula, NW Russia
DAVID ROBERT5
Roberts, D. 1996: Caledo nian and Baikalian tectoni c st ruct ures on Varange r Peninsula, Finn mark, Norw ay, and coastal areas of Kola Peninsula, NW Russia. Nor. geol. unders. Bull . 431,59-65.
Based on data com piled from biostratig raphy, rad iom etri c dating and palaeomagn et ic st ud ies, contrac t iona l deformat io n and low-grade metamorphism in t he Neop rot erozoic to earliest Palaeozoic successions of coasta l areas of
NE Norway and NW Russia have been constra ined to two main stages. (1) Late Vendian to Early Camb rian Baikalian
defo rmat ion, w ith mainly NW-5Etr endin g folds, affected Upper Riphean seq uences on Rybachi and 5redni in Russia.
These str uct ures can be followed into t he eastern part of Varange r Peninsula. (2) Late 5ilurian t o Early Devonian,
Scandian deforma tion and metamo rphism, wit h fold s and t hrust s of mainly NE-5W tr end , are recorded pri ncipally in
western parts of Varang er, in th e Caledon ian parautoc ht hon and allochthon. Cross-fo lds and second cleavages in
parts of NEVaranger may also be of Caledo nian age.
Within the succession of t he Tanafj orden-Varangerfj orden Region of 5W Varanger Peninsula, palaeoc urren t data
indicate t hat in th e post-glacial Mid Vendia n to Early Cam brian period an uplifting land mass in th e nort heast was
t he major source area fo r detritu s. This is in harmony wit h th e not ion of a rising Baikalian oroge nic and topogr aph ic
hig h during thi s same period, in and beyond th e reg ion now occupied by t he Ryb achi Penin sula. Com bining all t he
evidence, th e Varanger Penin sula thu s appears t o be in the somew hat unique situa t ion of exposing vest iges of both
Caledonia n and Baikalian st ruct ures and low -g rade met amorphic fabrics. Mut ually inte rferi ng fo ld s and cleavages
occur in t he easte rn half of the Barents 5ea Region , not heast of th e Trollfj orde n-Ko magelva Fault Zone.
Oavid Roberts, Norges geolog iske undersekelse, p.a. Box 3006 i.ade, N-7002 Trondheim, Norway.
Introduction
In recent years, research with in the Norweg ian-Russian
collaboration progr amme 'Nort h Area' in Northeast
Finnmark, Norway, and the Kola Peninsula, NW Russia,
has led to several imp ortant advances in ou r know ledge
of the Neoproterozoic sed imentary successions occurr ing
on th e Varanger, Rybachi and Sredni Peninsulas and
Kildin Island (Fig.1) along the coastal fringes of the
Barents Sea (several pape rs in Robert s & Nordgule n
1995). Although investigati o ns of Iit host rat ig raphy and
sedim entary facies have formed the backbone of the
Neoproterozo ic project , research st udies have included
topics such as structu re, low-g rade metamorphism, isot opic dat ing and palaeomag netic investigations, some of
wh ich are st ill in pro g ress.
An important facto r in th e tectonothermal history of
most geological te rranes is the t im ing of the principal
pha se of tectonic deformation . In the case of Varanger
Peninsula, it has been assumed almost wi t hout que stion
that we are dealing exclusively w ith Caledonian deforma tion, and by and large a st ruct ural architecture ascribed
to the Late Silurian-Early Devon ian Scandian event.
Almost a century ago, howeve r, Russian and Finn ish geologists had considered th at Varange r may well form a
western extension of the so-called 'Timanian mountain
chain' stretching from the Timan s (Fig.2), along the northern coast of th e Kola Penin sula and immedi ate ly offshore (Ramsay 1899, Tschernyschev 1901). Schatsky
(1935) later ascribed thi s Tima nide deformation to the
Baikalian oroge ny.
Since that time, little attention has been d irected
Fig. 1. Location map showing th e Varange r,
Rybachi and Sredni Peninsulas and Kildi n
Island, NE Norway-NW Russia. The pericr ato nic (TVR,Sredni,Kildin) and basinal (BSR,
Ryba chi) do ma ins are ind icated by different
do tted orn ame nts. TVR - Tan afjordenVarangerfjorden Region; BSR - Barents Sea
Region; TKFZ - Trollfjo rden-Kom age/va Fault
Zone; SRFZ - Sredni-Rybachi Fault Zone;
GNC - Gaissa Nappe Comp lex; TN Tanah orn Nappe. The area wi tho ut ornament is underlain by Archaean to Early
Proterozoic crystalline rocks.
60
David Raberts
NGU-BULL 431 . 1996
60·E
P e c hora
\---
68· .,
"
---------- \
»>:
\
o
100
I
\
\
200 km
I
~--_--'!WrF
Fig. 2. Location map showing the Timans, Kola Penin sula an d th e no rth ern Urals. The boxed area is that shown in more detail in Fig s. 1 and 3. The shad ed areas in Tim an and th e Urals indicate th e areas of m ain outcrop of Neop roterazaic rocks. Principal fau lts in the Timans: WTF - West Timan Fault; UF - Central
Tima n Fault; ETF- East Timan Fault. The NW-SE trend ing belt delimited by th e WTF and CTFcorresponds to the pericrat on ic domain ofVaranger, Sredni and
Kildin. Likewise, th e basina l do ma in (eq uivalent to Rybachi and the 8SR of Varang er) is that between th e CTF and the ETF. VP - Varanger Peninsula ; RP Rybachi Peninsula; KP - Kanin Peninsula. The structural subdivision of Tim an is mo di fied from m ap versions pr esent ed by Getsen (1987), Olovyanishnikov
(1995) and Siedlecka & Roberts (1995).
towards t hese early ideas, altho ugh they were mentioned
by Siedlecka & Siedlecki (1967) and discussed by
Siedlecka (1975) in her comprehensive review of Russian
and other early literature of the Finnmark-Timan regi on.
At that t ime the issue could not be resolved. Specific studies w it hi n part of the 'Nort h Area' programme, how ever,
have helped to refine our constraints on the t ime of the
main tectonothermal event. Comparison with st ruct ural
t rends prevailing on Varanger Peninsula has thus allowed
reasoned conclus ions to be made concerning the likely
regional distr ibution of Ba ikalian and Caledonian structures. The purpose of t his short cont rib ut ion is to present
relevant data whi ch suggest that Baikalian st ructures
almost certainly occur in the eastern parts of Varanger
Peninsula.
ness. This pericratonic realm (Siedlecka & Roberts 1995)
also characterises t he fluvial, delta ic and coastal marin e
successio ns on Sredni Peninsula and Kildin Island, southwest of t he SRFZ, alth ough in this case t here are no glacial depo sits present and the microfau nal evide nce favours
on ly Late Ri phean depo sition (Samuelsson 1995 and in
press). In Northea st Varanger Peninsula (t he Barents Sea
Region - BSR) and on Ryb achi, submar ine turbid ite systems c.3-4 km thick rep resent a distinctive basinal
domain, termed th e Rybachi-Vara nger Basin by
Drin kwater et al.(1996). Microfauna s here also denote a
Late Riphean age. Thus, Vendian and younger deposit s
are app arent ly lacking on both the Sredni and t he
Rybach i Peninsulas.
Geological framework
Structure and metamorphism
Detai ls of the formal lit hostr ati g raphies of the Neop roterozoic successions of the Varanger, Rybachi and Sredni
Peninsulas and Kildin Island (Fig.1) can be fo und in
Siedlecka & Ro berts (1992) and Sied lecka et al. (1995a, b).
On Varanger, the polyphase NW-SE-trend ing Troll fjo rden-Komagelva Fault Zone (TKFZ) effectively divides the
peninsu la int o two region s, and can be followed sout heastwards on to the Rybachi and Sred ni Peninsulas, whe re it has been termed the Sredni-Rybach i Fault Zone (SRFZ)
(Roberts 1995) (Fig.1).
The sout hw estern Varanger Peninsula (t he Tanafjorden-Varangerfjorden Region - TVR) exposes an Upper
Riphean to Cambrian record up to 3.5 km t hick, including
t he Early Vendian Varangerian glaci al deposits. The
Upper Riphean succession alone is some 2.3 km in thi ck-
Tecto nic stru ctures and metamorphic feat ures of t he suecession s on Varanger Peninsula have been described in a
number of pub lications , to w hich t he reader is referred
for details (e.g. Roberts 1972, Bevins et al. 1986, Rice et al.
1989, Sied lecka & Roberts 1992, Karpuz et al. 1993). In the
case of th e Rybac hi and Sredni Peninsulas, the most relevant contributions on these part icular topi cs are t hose by
Negrutsa (1971), Roberts (1995) and Rice & Roberts
(1995).
The struc tural deformat ion and meta mo rph ism of the se various successions changes app reciab ly in crossing
the majo r NW-SE fault zone (TKFZ and SRFZ). Successions
in most of th e pericratonic doma in of SW Varanger (TVR),
Sredni and Kild in in general display only low er diagenesis-grade compactiona l fab rics. Folds, w here present at
David Roberts
NGU-BULL431 , 1996
61
Kild in
Island __
Ryba chi Peninsula
/'
/'
/'
/' ~
--­
/
/'
RUSSIA
FINLAND
all, are gentle upright structures, trend broadly E-W to
NW-SE and lack any pervasive axial surface cleavage; and
their precise age is uncertain. Towards the west in the
TVR on Varanger Peninsula, however, one is passing into
the Caledonian parautochthon and ultimately into the
Lower Allochthon (Gaissa Nappe Complex - Fig.1 ), where
folds become quite common, trend c.NE-SW (Fig.3), face
southeast, and carry a penetrative axial-planar cleavage.
In contrast, in the basinal domain on Rybachi, northeast of the SRFZ, the turbiditic rocks show abundant NWSE trending and SW-facing, open to tight folds (Fig.3) and
an associated, penetrative, tightly spaced or slaty cleavage. Illite crystallinity data (illite 002 peak) record a lower
anchizone grade of metamorphism in the northeast, but
only upper diagenesis grade moving closer to the SRFZ
(Rice et aI.1995). The age of this tectonothermal cycle on
Rybachi has not yet been determined w ith any precision ;
however, several Russian workers have assumed that it
equates with the Baikalian of Timan . More information is
provided below.
Some 60 km to the northwest, in the easternmost part
of the Barents Sea Region of Varanger Peninsula, much
the same NW-SE (t o N-S) fold-and-c1eavage trend is
encountered (Fig.3), although cross-folds cause local
structural complexities (Roberts 1972, Herrevold 1993).
This low-grade metamorph ic phase has not yet been
dated. Moving toward s the northwest within the BSR, the
fold -axial trend gradaually sw ings through N-S to NE-SW
and ultimately ENE-WSW (Fig.3), w ith ubiquitous SEfacing tight folds , local thrusts and the Tanahorn Nappe
(Fig.1) signifying their association with the Caledonian
orogenic cycle.
Timing of deformation and
metamorphism
In considering the currently known constraints on the
age, or ages of th e fold ing and very low-grade metamorphism outlined above, the map of principal structural
trend s (Fig.3) pro vides a useful backcloth; and one which
SO Km
Fig. 3. Simpli fied map of the varanqerRybachi-Sredni- Kildin tract showing th e
principa l structu ral trend s, mostly the axial
surface traces of folds but par tly th e strike of
N- to NE-dipping stra ta in Kild in, Sredni and
southern mo st Varang er.
holds mo re significance than might at first meet the eye.
Since the situation on the Varanger Peninsula is evidently
unclear , except, as mentioned, in the far west where
Caledonian structures prevail , it is more appropriate to
consider first the relevant data from the Russian areas. As
well as structural (fold axial) trend, biostratigraphic and
isotopic constraints are clearly important, but interesting
information can also be gained from palaeocurrent data
and from field and laboratory studies on mafic dykes.
Rybachi, Sredni and Kildin
Biostratigraphic evidence from these three areas shows
that the success ions are wholly Upper Riphean
(Samuelsson 1995). Earlier, the stratigraphically highest
un it on Sredni Peninsula, the Volokovaya Group
(Siedlecka et al. 1995a), had been assigned a Vendian age
by Russian workers, but this is now rejected on the basis
of recent microfossil studies (Samuelsson 1995 and in
press).This also accords better w ith the fact that there are
no Varangerian tillites on Sredni.
The diagenetic compactional fabric present in the pelites on Sredni and Kildin has been dated using the Rb-Sr
method on illite subfractions (Gorokhov et aI.1995). Early
authigenic illite subfraction s from two separate formations from the Sredni Peninsula yielded an age of 610-620
Ma. Close to the SRFZ, on Sredni, a widely spaced NW-SE
trending cleavage is quite well developed. From one part icular formation in this subarea, within the fault zone,
Gorokhov et al.(1995) separated a second, even finer, illite
subfraction and obta ined a Rb-Sr maximum age for thi s
of 570 Ma. This was considered to relate to an influx of
non -marine, subsurface water arising from an episode of
fault movement along the SRFZ.
On Rybachi, the common NW-SE trending, open to
tight, SW-facing folds are believed to represent a stage of
basin inversion (Robert s 1995) - termed epikinegenesis
(Raznit syn 1972) in Russian literature - the folds and cleavage gradually dying out towards, and just across, the
SRFZ. Accepting that the 570 Ma maximum age noted
62
Dovid Roberts
above tr uly relates to fault mot ion, t hen t his presumab ly
reflect s th e inv ersion and widespread SW-directed compressional defo rmation represent ed by t he st ruct ures on
RybachL Alternatively, t he 'maximum-s70' age may indicate t he end stage of th e inversion, such th at th e peak
metamorphic age, reflected in the pervasive cleavage on
Rybachi, cou ld be somewhere between 610 (Sredni diagenesis) and 570 Ma.
In contrast, the minimum age for the main deform ation on Rybachi Peninsula is poo rly constra ined. In northwestern areas of th e peninsula, a few do lerite dykes up to
6.5 m in th ickness cut th rough th e NW-SE-trendin g folds
and cleavage at high ang les; i.e., the y trend c.NE-SW. An
4°Ar_39Ar laser microprobe study gave no defi nit ive
emp lacemen t age, suggesting only that the dykes are
older t han 450-400 mode l ages (Roberts & Onstott 1995),
while palaeomagnetic data favoured a Late Vendian to
Cambrian age (Torsvik et al. 1995). The fold ing and met amo rph ism of the Rybachi succession, which preceded the
dyke intrusion, would therefo re seem to fall with in the
t ime inte rval Late Vendian to Early Cambrian, w ith the
Vendian period taken to extend from 650 to 545 Ma.
Turning briefly to the situ ation in Timan, whi ch has
simil ar pericraton ic and basinal palaeoenviron mental
zones as in the Rybachi-Sredni-Varanger region (Fig.2),
radiometric dat ing t here, mo stly by th e K-Ar meth od, has
indicated t hat t he Late Riphean succession was deform ed
and metamorphosed in two stages; (1) a main 'Baikalian'
tectonothe rmal event dat ing to th e period c.600-575 Ma
(Malkov 1992, recalculated ages); (2) a less prom inent stage of deforma t ion in t he period c.505-470 Ma. The age
constraint s so far available from Rybachi and Sredn i t hus
supp ort the long -standing noti on that the prin cipal
Baikalian deformat ion also affect ed the se part icular coastal Kola, Neoproterozoic successions.
Varanger Peninsula
Barents Sea Region: varde district
As noted earlie r, this easternmost part of the BSR is characteri sed by a princ ipal cleavage and fold axial t rend
w hich is roug hly NNW-SSE, t houg h w it h local variati ons
due t o c. EN E-W SW cr o ss-f oldin g (Ro b e rt s 19 72 , He r rev ol d
et al., in prep.). It was initi ally assumed by Roberts (1972)
th at all foldi ng in this area develop ed during Late Silurian,
Caledonian (Scandian) orog enesis. An explanation for t he
anoma lous, c.NW-SE struct ural trend and facing reversal
was sou gh t in the likely bufferin g effect of a basement
'ridge' concealed beneath t he sea area south east of
Varanger Peninsula. Rice et al.(1989) interpreted t he
same, WSW-facing stru ctu res as t ip fo lds associated wi th
a late-stage, backthrus t sense of movement alon g an
inferred sole t hrust beneat h t he BSR, thu s appealing to a
late Scandian phase of deformation.
Mafic dykes are rare in t his particular part of t he BSR
and have, as yet , offered meagre const raints on the minimum age fo r the cleavage and fo ld deve lop men t. The
NGU-BULL 431. 1996
c.NE-SW-trend ing dykes are comparat ively unal tered and
post-date the early, NNW-SSE-trend ing spaced cleavage.
As yet, t he only isotopic dating available on t hese dykes is
t hat of K-Ar data w hich have provided ages of c.350 Ma
(Beckinsale et al. 1975). Comb ining t he biost ratigraph ic
and pub lished K-Ar dat a, we t herefore have a meaningless time interval of at least 300 million years (latest
Riphean to earliest Carboniferous) in which to place the
tectonometa mo rphic t ransfo rmat ion of the host rocks to
these dykes.
Despite t he lack of precise radiome t ric dat ing , sign ificant clues as to the likely age of t hese NNW-SSE-trend ing,
syn-c1eavage fo lds can be sou gh t in a consideration of
the structural trend (Fig.3) and t he character of the cleavage, aided by an exam inat ion of satelli te images (Karpuz
et al. 1993) and comparative fiel d stud ies both on
Rybachi and in th is part ofth e BSR on Varanger Peninsula.
To th e present author, t he structures and fabrics encountered in th e Varde district are very much reminiscent of
t hose seen on t he Rybachi Peninsula, th e inference being
th at again we are con ceivably dealing w ith stru ct ures of
Baikalian age (Robert s 1993, 1995). If anyt hing, th e cleavage in the eastern BSR is slig ht ly mo re doma inal in character t han that on Rybachi, but t his is part ly because of
Iithological differences and the fact that t he Ba ikalian
deformat ion and metamorphism was probab ly dying out
lat erally, northwestwards.
Cross-fo lds of ENE-WSW to NE-SW, or even E-W trend
are common in th is area, as reflected in the dome-andbasin map pattern (Roberts 1972, Siedlecki 1980, Rice et
al. 1989, Aamodt et al. 1996). As such t ransverse stru ctures are absent on Rybachi (Robert s 1995), it is reasonable
to argue that the cross-fo lds in th e eastern BSR are
Caledo nian folds whi ch have develop ed as a result of
op en, SSE-directed macro-b uckling of pre-existing
Baikalian st ruct ures. As well as t hese mutu ally interfering
fo lds of disparate age, two cleavages are also present
locally (Robert s 1995), but no systemat ic work has yet
been done to assess th e regio nal exten t of t hese cleavages. In such a scenario one would expect the NW-SE,
assumed 'Baikalian' cleavage to die out gradua lly westwa rds; and th e NE-SW 'Caledonian' cleavage to appear
and inte nsify in the same direct ion.
There has been only one attempt to date a cleavage
directly, that of Tay lo r & Pic kering (19 8 1). Th e se au tho rs
produced an imprec ise Rb-Sr wh ole-rock date of 520 ± 47
Ma from cleaved pelites in the Kongsfjord Format ion near
Hamningberg (Fig.3). Although no details were given, t he
cleavage near the sampling sites is know n to strike c.NESW. The sign ificance and interpretat ion of th is dat e has
been que stioned by Rice et al. (1989) w ho argu ed t hat
th e first Ca ledon ian deformation in this part icular area
was of Scand ian age.
Eastern part of the Tan afjorden-Varangerfjorden
Regio n
Tecton ic deformat ion in th is part icular part of the TVR
NGU-BULL 431 , 1996
was clearly less intense than in the BSR directly northeast
of the TKFZ. That the TKFZalso represents a metamorphic
break is seen in the fact that the rocks in this area have
yielded illite crystallinity values indicative only of diagenesis g rade (Bevins et al. 1986). There is also no trace of
any regionally penetrative, steeply dipping cleavage in
this southeastern part of the Tanafjorden-Varangerfjorden Region.
A maximum age both for the diagenetic compactional
fabr ic and for the oldest folds is set by the fact that the
youngest formation here, the Stappogiedde, is of assumed Late Vendian age. Work is in progress (Rb-Sr on illite
subfract ions) in an attempt to date the diagenesis . Here,
it can be noted that from the southwestern TVG,
Dallmeyer & Reuter (1989) have recorded what they describe as a «d iagenet ically related disturbance at c.635
Ma».
In general, the stratig raph ic succession in the eastern
TVR dips at a few degrees to the north w ith large-scale,
gentle, upright folding on c.E-W axes appearing with in 10
km of the TKFZ (Fig.3). The axial trend of these folds is
thus oblique to the main fault zone. In their trend and en
echelon pattern these folds are comparable to post-cleavage folds occurring close to the SRFZ on Sredni
Peninsula (Ro bert s 1995), which are indicators of dextral
strike-slip movement. Mesoscopic shear zones trending
ENE-WSW and ESE-WNW, with a generally right-lateral
shear sense, have also been recorded in the eastern TVR
(Herrevold et al., in prep .). Closer to the TKFZ, small-scale
NW-SE-trending, SW-facing folds and minor thrusts indicate a phase of SW-directed compression (Karpuz et al.
1993) or possibly transpression . Although the relationship of these SW-facing structures to the E-W folds is unknown, as is the actual age of the folds, it is reasonable to
assume that the former are older and quite likely
Baikalian.
The precise age of uncommon, c.N-S trending mafic
dyke s occurring in two places along the southeastern
coast of the TVR remains unknown. K-Ar data have yielded a figure of c.350 Ma (Beckinsale et al. 1975) while
4°Ar_39Ar pyro xene data are inconclusive (Roberts et al.
1995). One of these dykes has yielded palaeomagnetic
data suggesting that its age may be Late Vendian to Early
Cambrian (Torsvik et al. 1995). For the t ime being, at least,
we therefore have no reliable upper constraint in this
area for the timing of diagenesis or fold deformation.
The importance of hiatuses and angular unconformities in provid ing records of distant orogenic events is well
known, and thei r potential significance in this FinnmarkKola region has been noted by Schatsky (1960) and
Siedlecka (1975). Accepting that the rocks on Rybachi
Peninsula and in the Vardo district of the Barents Sea
Region have been affected by a Late Vendian-Early
Cambrian Baikalian tectonothermal event associated
Oavid Roberts
63
in the TVR are highly relevant. These authors, and also
Edwards (1984), have pointed to an important change in
sediment dispersal patterns which occurred shortly after
the end of the Varangerian glacial epoch. During this
period, Le. broadly Mid Vendian to Early Cambr ian, palaeocurrent data indicate that the major source area for
Vestertana Group sedimentation lay somewhere to the
present-day northeast. Banks et al.(1971 ) suggested that
this uplifted northeasterly situated «land mass» was probably located somewhere to the northeast of the
Trollfjorden-Komagelva Fault Zone, or a related parallel
fault.
Although not mentioned in name, the land mass referred to by Banks et al. (1971) as supplying the major volume of detritus to the Vestertana Group was almost certainly the rising topographic high which resulted from
the Baikalian basinal inversion, tectonic deformation and
metamorphism of the Upper Riphean succession , parts of
wh ich are now exposed on the Rybachi Peninsula.
Vendian deposits are absent on Rybachi and Sredni, and
on Kildin Island, and it is mo re likely than not that they
were never deposited in these part icular 'eastern' areas
during this period of inversion and diastrophism.
Western VarangerPeninsula; BSR and TVR
The structural deformation and metamorphism of the
northwestern halves of both the Barents Sea Region and
the Tanafjorden-Varangerfjorden Region have been
documented in many papers (full bibliography in
Siedlecka & Roberts 1992). In this present contribution, it
will suffice to note that the widespread folding and thrusting - SE-facing in the western TVR and SSE-facing in the
western BSR - and related metamorphism were acquired as a result of Caledonian orogenesis. In the parautochthon of the western TVR, the youngest formation
affected by this deformation is of Early Cambrian age,
whereas on the nearby Digermul Peninsula Oust west of
southwestern Varanger Peninsula) the deformed succession, part of the Gaissa Nappe Complex, extends up into
the Tremadoc.
Constraints on the precise timing of this pervasive foldand -thrust event, however, remain poor. Radiometric
data from the Gaissa Nappe Complex are not definitive,
an age of c.440 Ma (K-Ar) having been suggested by
Dallmeyer et al. (1989) as a maximum for slaty cleavage
development. Earlier, a Rb-Sr whole-rock isochron age of
c.504 Ma had been obta ined on cleaved pelites from the
western TVR (Sturt et aI.1975), but the reliability of this
date has been contested (Dallmeyer & Reuter 1989).
Bylund (1994) has reported palaeomagnetic data from
two sites in the western most TVR, also in the Gaissa
Nappe, which provide evidence of an Early Ordovician
remagnetisation event in those rocks. Clearly, we are in
with b a s in invers ion and upl ift , then th e n orthwestern
dire n eed o f reliable, precise d ating from these area s. For
'tail end ' of the Baikalian may conceivably be reflected in
breaks in the Iith ostratigraphy of the TVR. In this regard,
the sedimentological invest igations of Banks et al.(1971 )
the present, the general consensus is that the principal
tectonometamorphic event is Scandian, in the time interval Late Silurian to Early Devonian .
64
NGU-BULL431,1996
David Roberts
Conclusions
Based partly on constraints provided by biostratigraphic,
radiometric and palaeomagnetic invest igat ions, the
timing of deformation and very low-grade metamorphism of the Neoproterozoic to earliest Palaeozoic suecessions on the Varanger, Rybachi and Sredni Peninsulas
can be deduced. A significant element which also has a
bearing on the topic is that of fold axial trend and the
character of t he associated, pervasive, axial planar cleavage. Pala eocurrent data are also shown to provide crucial
information bearing on the question of timing of orogenesis.
A principal conclusion is that the Varanger Peninsula is
in the somewhat unique situation of exposing the vestiges of both Caledoni an and Baikalian tectonic structures
and low -grade metamorphic fabrics. In the RybachiSredni-Kildin area in Russia, t he t ectonothermal event
marking the basinal inversion or epi kinegen ic stage
appears to fall in the period Late Vendian to Early
Cambrian, correspond ing to th e Baikalian orogeny of earlier Russian worke rs. The prominent, Baikalian, NW-SE
fold -and-c1 eavage t rend seen on Rybachi Peninsula can
be traced without difficulty into the Varde district of the
eastern Barents Sea Region of Varanger Peninsula, where
it is affected by common cross-folds of Caledon ian, probably Scandian trend . Two cleavages occur locally.
Further northwest in the Barents Sea Region, Caledonian
structures and metamorphic fabr ics gradually become
predominant.
The situation regarding timing of deformation in the
TVR ofVaranger Peninsula is lessclear, except of course in
the Caledonian parautochthon and Lower Allochthon in
the west where Scandian defo rmat ion and metamorph ism is dominant. In the eastern TVR, where the strat igraphy extends up into the Late Vendian, a reliable upper
(mi nimum) constra int for the deformation is so far lacking, but unconformities may inst ead be providing reflections of distant Baikalian movements. Sedimentological
work in this part of southern Va ra ng e r Pe ninsu la ha s
show n t hat in t he post-glacial Mid Vend ian t o Early
Cambrian peri od th e majo r source for th e detr itu s accumulatin g in t he Vestertana Group was a land mass situated somewhere to the northeast. This is in good accordance w ith the concept of a rising Baikalian orogenic welt
and topograph ic high in and beyond the region of present-day Rybachi Peninsula.
Ackno wledgements
The author is g rateful to Roy Gabr ielsen, 5tephen Lippa rd and Brian
5turt for thei r helpful review s of th e manu scrip t; to Anna 5iedlecka for
com men ts at a later stage; and to Valery Mo ralev and Vsevolod
Olovya nishnikov fo r d iscussion s on aspects of the geo logy ofTiman.
References
Aamodt, L., Alam, A., Clausen, J.A., Gaabrielsen, R.H., Gjeel svik,T.,
Haaland, HJ., Haug an, M., Kahn, M.5., l.othe , A., Rahman, B. &
5ygnabere, T.O. 1996: Double folding of Eocamb rian siliciclastic
sediments in t he Varanger Peninsula, north ernmos t Norw ay.
(Abst ract). 22nd. Nordic Geolog ical Winter Meeting, Abo, Finland,
Janua ry 1996, Abstract vol um e.
Banks, N.L., Edw ard s, M.B., Geddes, W.P., Hobda y, D.A. & Reading, H.G.
1971: Late Precambrian and Cambro-Ordovician sed imen tation in
East Finnmark. Nor. geo l. unders. 269, 197-236.
Beckin sale, R.D, Reading, H.G & Rex, D.e. 1975: Pota ssium-argon ages for
basic dykes from East Finnmark: stra tigrap hical and struct ural
im plications . Scott. Jour. Geol. 12, 51-55.
Bevins, R.E., Robinson, D., Gayer, RA & Allma n, 5. 1986: Low-gr ade
metamor phism and its relat ionship to thrust tectonics in t he
Caledo nides of Finnmark, North Norway. Nor. geol. unders . Buff. 404,
33-44.
Dallmeyer, R.D. & Reuter, A. 1989: "' Ar-"Ar whol e-rock dat ing and the
age of cleavage in t he Finnm ark autoch thon , northeastern most
Scandi navian Caledon ides. Lithos 22,213-21 7.
Dallmeyer, RD., Reuter, A., C1auer, N. & Leiwi g, N. 1989: Chronology of
tectonot hermal activ ity wi t hin t he Gaissa and Laksefjord Nappe
Complexes, Finnmark, Nort h Norway: evidence fro m K-Ar and ,oAr19Ar ages. In Gayer, RA (ed.) The Caledonian geology of Scandina via,
Graham & Trotma n, London , 9-26.
Drinkw at er, NJ., Pickering, K.T. & Siedlecka, A. 1996: Deep-water, faultcontrolled sedi men tation , Arctic Norway and Russia: response to
Late Proterozoic riflin g and t he open ing of the lapet us Ocean. Jour .
Geol. Soc. London 153, 427-436.
Edward s, M.B. 1984: Sedimentology of the Uppe r Prote rozo ic glacial
record , Vestertana Group , Finnmark, Nort h Norway. Nor. geo l.
unders. 394, 1-76.
Getsen, V.G. 1987: Tecton ics of Timan . Nauka, Leningrad, 170 pp. (in
Russian)
Gorokhov, I.M, Turchenko, T.M., Baskarov, AV ., Kutyavin, E.P., Melnikov,
N.N. & Sochava, AV. 1995: A Rb-Sr st udy of mu lt istage illi te generatio n in shales of t he Pumanskaya and Poropelonskaya For mat ions,
Sredni Peninsula, NW Kola Peninsula. (extended abstract). Nor.
geo l. unders. Specia l Publ. 7, 330.
Herrevold , T. 1993: Struk eurgeologi sk analyse av den aust leqaste delen av
Trofffjorden-Komagelvaforkastn inga, Varanger. Unpubl. Cand.
Scient. thesis, Univ. of Bergen.
Karpuz, M.R., Roberts, D., Olesen, 0 ., Gabrielsen, R.H. & Herrevold , T.
1993: Applica tion of mu ltiple data sets to structu ral stu dies on
Varanger Peninsula, northern Norway. Int. Jour. Remote Sensing 14,
979-1003.
Malkov, BA 1992: Timan Baikalide s: myth or reality? Ukhta branch. USSR
Min eralogical Society, Syktyv kar , 21-29. (in Russian) Negrut sa, V.Z.
1971: St rat igr aphy of hyperborean de posit s in the Sred ni and
Rybachi Peninsula and in Kild in Island. VSEGEI 175, 153 -1 8 6 .(in
Russian).
Olovy anishn ikov, V.G. 1995: Guide for stu dy of stra tot ypi c section of
Vym skaya Series of Upper Precambrian of Timan . (Unpubl. field
guide). Inst. of Geolog y, Russian Acad . Sci., Syktyvkar, Kom i Republic,
Russia 20 pp .
Ramsay, W. 1899: Neue Beit raqe zur Geologi e der Halbin sel Kola. Fennia
15.4. 1-15.
Raznitsyn, V.A. 1972: Caledon ian and Variscan cycles in stabili zat ion of
struc tures in northeast of European USSR. Int. Geol. Rev. 15,8,883890.
Rice, A.H.N., Gayer. RA, Robinson, D. & Bevin s, R.E. 1989: Strik e-slip
restora tion of t he Barents Sea Caledonides terrane, Finnmark,
Nort h Norway . Tectonics 8,247-264.
Rice, A.H.N. & Roberts, D. 1995: Very low- grade metamor phism of Upper
Proterozoic sedimen tary rocks of t he Rybac hi and Sredni
Peninsulas and Kildin Island, NW Kola region , Russia. Nor. geol.
unders. Specia l Pub l. 7, 259-270.
Roberts, D. 1972: Tecton ic deformation in t he Barent s Sea Region of
Varanger Peninsula, Finnmark. Nor . geol . unders. 282, 1-39.
Roberts, D. 1993: Aspects of the struct ural geo log y of Rybachi and
Sredni Peninsulas, and some compa rison s wi th Varanger
Peninsula. (Abst ract). t st. Inte rnational Barents Symposium ,
David Roberts
NGU-BULL431, 1996
Kirkenes, Nor wa y, Octo ber 7993. Abstr act Volum e, Norge s
Geologiske Und ersekelse.
Rob erts. D. 1995: Princi pal feat ures of th e st ruct ural ge ology of Ryb achi
an d Sredni Peninsu las, Northw est Russia, an d so me compa risons
wi th Varange r Peni nsula, Nort h Norway . Nor . geol. unders. Special
Publ. 7, 247-258.
Roberts , D. & Sun dvoll, B. 1990: Rb-Sr w ho le-ro ck and th in-slab da ting of
myl onites from the Kaiak Thrust Zo ne, nea r Borselv, Finnmark. No r.
Geol. Tidsskr. 70, 25 9-266.
Roberts , D. & Nordgulen, 0. (ed itors) 1995: Geolog y of th e eastern
Finnmark -w estern Kola Penin sula regi on. Nor . geol. unders. Specia l
Publ. 7, 378 p p.
Roberts, D. & Onstot t, T.e. 1995: 4°Ar/ J9Ar laser microprobe analyses and
geochemis t ry of do lerite d ykes from th e Rybachi and Sredn i
Penin sulas. NW Kola, Russia. Nor. geo l. unders. Special Publ . 7, 307314.
Robe rt s, D., Rex, D.e. & Guise, P.G. 1995: 40A r-39Ar ana lyses o f pyro xenes fr om dol erit e dyke s from sout heastern Varan ger Peninsula,
Finnmark . Nor . geol. unders. Report 95. 158, 14 pp .
Sam ue lsson, J. 1995: Bio strat igraphy of Kild in Island and th e Sredn i an d
Ryb achi Peninsu las, Ko la, Northw est Russia - pr elim inar y resu lts.
(Extend ed ab strac t). Nor. geol. un ders. Special Publ . 7, 327-329.
Samuel sson, J. in pr ess: Biostratigraphy and palaeobiology of Early
Neop rot erozoic st rata of t he Kola Penin sula, North w est Russia. Nor .
Geol. Tidsskr.
Schatsky, N.5. 1935: On tect on ics of th e Arct ic. Geology and econom ic
deposit s of north ern USSR 1, 149-16S. (in Russian). Schatsky , N.5.
1960: Princi p les of Lat e Precambrian st rati grap hy and t he scope of
th e Rip hean Group . 2 1st. ln t. Geol. Congress, 8, 7- 17.
Siedlecka , A. 1975: Lat e Precam brian st ratig rap hy and struct ure of the
northeastern margin of the Fenn o scand ian Shield (East FinnmarkTiman reg ion ). Nor. geol. unders. 376, 313-348.
65
Sied lecka, A. & Roberts, D. 1992: The bed roc k ge ol og y of Varanger
Peninsula, North Nor w ay: an excur sio n guid e. Nor . geol. und ers.
Special Publ. 5, 4S pp .
Sied lecka. A. & Roberts, D. 1995: Report from a vi sit to t he Komi b ranch
of t he Russian Acad emy of Scie nce s in Syktyvkar, Russia, and f rom
fiel dwo rk in the central Tim ans, Aug ust 1995. Nor . geo l. unders.
Report 95.149, 30 p p.
Sied lecka, A., Lyu btsov . V.v. & Negru tsa, vZ. 1995a: Correlat ion betwe en
Upper Prot erozoic successions in t he Tanafjo rden -Varang erfjord en
region of Varan g er penin sula, northern Nor w ay, and on Sredn i
Penin sula and Kildin Island in t he northern coast al area of Kola
Peninsula in Russia. Nor . g eol. unders. Special Publ. 7, 217-23 2.
Sied lecka, A.• Negr ut sa, V.Z. & Pickerin g, K.T. 1995b: Upper Proterozoic
tu rb idite syst em of th e Rybachi Pen insul a of t he Kongsfjo rd
Sub ma ri ne Fan of the Varanger Pen insula, no rt he rn No rwa y. Nor .
geol. und ers. Special PubI 7.•20 1-216 .
Sied leck i, S. 1980: Geol ogi sk kart over Norg e, berggr u nnskart Vadse - M
1:2S0 000. Nor . geol . unders.
St urt, BA, Pringle, I.R. & Roberts, D. 1975: Caledo n ian nappe seq uence
of Finnmark, northern Norwa y, and t he ti mi ng of th e orogen ic
d efo rmat ion an d metamorp hi sm. Bull. Geol. Soc. Am er. 86, 710-7 18.
Tay lor, P.N. & Picker in g, K.T. 1981: Rb-Sr isot opic age de term inatio n on
t he Late Precambrian Kongs fjord Forma tion, and t he timing of
co m pressio nal deformation in th e Barent s Sea g ro up , East
Fin n mark. Nor. geo l. unders. 367, 105- 110.
Torsvik , T.H., Robert s, D. & Siedlecka, A. 1995 : Palaeomagnet ic da ta from
sedim entary roc ks and dolerite dykes, Kildin Island , Rybac hi, Sredni
and Varang er Penin sula s, NW Russia an d NE Nor wa y: a revi ew . Nor.
geo l. unders. Special Publ . 7, 315-326 .
Tsche rnyschew, T. 1901: On ge olog ical str uct u re of t he Timans and on
relation of the Tim an Fault to other regions of Northern Euro pe.
Zapiski M in.Obstwa 34, 29-33. (in Russian).
Manuscript received April-May 7996; fina l ma nuscrip t ready July 7996.