The Archean of the Baltic Shield: Geology, Geochronology, and Geodynamic settings

409

ISSN 0016-8521, Geotectonics, 2006, Vol. 40, No. 6, pp. 409–433. © Pleiades Publishing, Inc., 2006.Original Russian Text © A.I. Slabunov, S.B. Lobach-Zhuchenko, E.V. Bibikova, V.V. Balagansky, P. Sorjonen-Ward, O.I. Volodichev, A.A. Shchipansky, S.A. Svetov, V.P. Chekulaev,N.A. Arestova, V.S. Stepanov, 2006, published in Geotektonika, 2006, No. 6, pp. 3–32.

INTRODUCTION

The problems of the Early Precambrian geodynam-ics are hotly debated, and their solutions primarilydepend on obtainment of new data on the geology, geo-chronology, and deep structure of the Archean com-plexes [57, 88]. This paper is focused on description ofthe Archean geology of the Baltic (Fennoscandian)Shield—one of the largest Precambrian terranes inEurope. The necessity to integrate and consider theavailable data is dictated by the substantial progress inthe geological, isotopic and geochemical, geochrono-logical, petrologic, and geophysical studies of theArchean complexes achieved in the last decade. As aresult, the extensive and qualitatively new data obtainedlargely from Russia and Finland have provided newinsights into the tectonic evolution of the Baltic Shieldin the Archean as a whole and during particular timeintervals, thus continuing the previous investigations in

this field [72, 132]. Furthermore, the unique fragmentsof the Archean ophiolitic complexes and crustal eclog-ites have been found recently in the Baltic Shield; thesefragments have very significant implications for under-standing the Archean geodynamics [57, 88].

Archean rocks occupy most parts of the Karelian,Murmansk, Belomorian, and Kola provinces (Fig. 1A).The first two provinces are regarded as Neoarchean cra-tons, as opposed to the Belomorian Mobile Belt.

1

The Karelian Province

is a nucleus of the BalticShield (Fig. 1B) and is composed of the Archean gran-ite–greenstone domain [32, 105] that consists of eightterranes—the Vodlozero, Central Karelian, Ilomantsi–

1

The geologic time scale recommended by the International Commis-sion on Stratigraphy [107] is used in this paper (Ma): Eoarchean(>3600), Paleoarchean (3600–3200), Mesoarchean (3200–2800),Neoarchean (2800–2500), Paleoproterozoic (2500–1600), Mesopro-terozoic (1600–1000), and Neoproterozoic (1000–542).

The Archean of the Baltic Shield: Geology, Geochronology, and Geodynamic Settings

A. I. Slabunov

a

, S. B. Lobach-Zhuchenko

b

, E. V. Bibikova

c

, V. V. Balagansky

d

, P. Sorjonen-Ward

e

, O. I. Volodichev

a

, A. A. Shchipansky

f

, S. A. Svetov

a

, V. P. Chekulaev

b

, N. A. Arestova

b

, and V. S. Stepanov

a

a

Institute of Geology, Karelian Scientific Center, Russian Academy of Sciences, Pushkinskaya ul. 11, Petrozavodsk, 185910 Karelia, Russia

b

Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, St. Petersburg, 199034 Russia

c

Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, ul. Kosygina 19, Moscow, 117975 Russia

d

Geological Institute, Kola Scientific Center, Russian Academy of Sciences, ul. Fersmana 14, Apatity, Murmansk oblast, 184200 Russia

e

Geological Survey of Finland, PO Box 1237, 70211 Kuopio, Finland

f

Geological Institute, Russian Academy of Sciences, Pyzhevskii per. 7, Moscow, 119017 Russiae-mail: [email protected]

Received August 16, 2004

Abstract

—The Archean provinces and lithotectonic complexes of the Baltic (Fennoscandian) Shield are con-sidered. The supracrustal complexes are classified by age: <3.2, 3.10–2.90, 2.90–2.82, 2.82–2.75, and 2.75–2.65 Ga. The data on Archean granitoid complexes and metamorphic events are mentioned briefly, whereas therecently found fragments of the Archean ophiolitic and eclogite-bearing associations are discussed in moredetail. The Paleoarchean rocks and sporadic detrital grains of Paleoarchean zircons have been found in the Bal-tic Shield; however, the relatively large fragments of the continental crust likely began to form only in theMesoarchean (3.2–3.1 Ga ago), when the first microcontinents, e.g., Vodlozero and Iisalmi, were created. Themain body of the continental crust was formed 2.90–2.65 Ga ago. The available information on the Pale-oarchean complexes of the Baltic Shield is thus far too scanty for judgment on their formation conditions. Thegeologic, petrologic, isotopic, and geochronological data on the Meso- and Neoarchean lithotectonic com-plexes testify to their formation in the geodynamic settings comparable with those known in Phanerozoic: sub-duction-related (ensialic and ensimatic), collisional, spreading-related, continental rifting, and the settingrelated to mantle plumes.

DOI:

10.1134/S001685210606001X

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Fig. 1.

(A) Tectonic scheme of the Baltic Shield and (B) main tectonic units of its eastern part, compiled after the data published in[4, 49, 64, 70, 115, 116, 133]. (

1

) Neoproterozoic and Phanerozoic sedimentary cover; (

2

) Caledonian Orogen; (

3, 4

) Paleoprotero-zoic Svecofennian Orogen (2.0–1.75 Ga): (

3

) orogenic complexes (

a

) that are thrust over the Archean basement and (

b

) withoutindications of the Archean basement, (

4

) late tectonic juvenile granitoids (1.85–1.75 Ga); (

5

) Archean complexes in zones of Paleo-proterozoic rifting: (

a

) overlain with volcanosedimentary sequences and (

b

) exposed Archean complexes of the Karelian Craton;(

6–8

) Kola Province (KP): (

6

) collisional suture of the Paleoproterozoic (2.30–1.91 Ga) Lapland–Kola collisional orogen includingthe Lapland (

Lb

) and the Umba (

Ub

) granulite belts, (

7

) collage of tectonic sheets composed of Paleoproterozoic and Archean com-plexes including the Inari (

In

) and composite Tersky–Strelna (

TS

) terranes and the Tanaelv (

Ta

) and Kolvitsa (

Ko

) collisionalmelange belts, (

8

) terranes composed of Archean complexes that were nonuniformly transformed in the Paleoproterozoic; (

9

) Belo-morian Mobile Belt (BMB), the Neoarchean collisional orogen that was reworked by Paleoproterozoic rifting and orogenesis(boundaries are shown with a dashed line); (

10

) Neoarchean Karelian (KC) and Murmansk (MC) cratons.

100 km

äC

BMB

KP

MC

In

Lb

Ta

39° E

33° E

21° E

69° N

66° N

33° E

39° E

WHITE SEA

TSKo

Ub

1

2

3

4

5

6

7

8

9

10

a

b

b

‡

B

A

20° E

60° N

1

2

3 4

5

6

BALTICSE

A

WHITE SEA

BARENTS SEA

Framework of the shield

Platform cover

Caledonian Orogen

Crust of the Baltic Shield

Paleo- and Mesoproterozoic(1.75–1.50 Ga), juvenile

Paleoproterozoic(2.50–1.75 Ga), juvenile

Archean (3.5–2.5 Ga) crust that was partly reworkedin the Paleoproterozoic, locally withfragments of Paleoproterozoiccrust

Provinces: 1 — Karelian2 — Belomorian3 — Kola4 — Murmansk5 — Svecofennian6 — Sveconorwegian

200 km

NORWEGIA

N SEA

20

°

E

60

°

N

27° E

64° N

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THE ARCHEAN OF THE BALTIC SHIELD 411

Voknavolok (West Karelian [49]), Kianta, Iisalmi,Ranua, Pomokaira, and Ropi [49, 72, 133] (see Fig. 2)—that differ in the composition and age of rocks. Accord-ing to recent data, the Nordbottnen Craton and the RopiTerrane therein, as well as the Archean rocks in north-ern Finland (Muonio) and Sweden [119], are notincluded into the Karelian Province but are considereda self-dependent structural unit.

The Murmansk Province

(Figs. 1B, 2) is com-posed of diverse granite gneisses and granitoids thatcontain xenoliths of Archean supracrustal rocks [64].

The Belomorian Province

(Figs. 1B, 2) is made uplargely of Meso- and Neoarchean granite gneisses,greenstone rocks, and paragneiss complexes. The prov-ince is distinguished by intense repeated deformationsand high- and moderate-pressure metamorphic eventsthat occurred in both the Neoarchean and Paleoprotero-zoic [20, 26, 53, 72].

The Kola Province

(Figs. 1B, 2) is the Archean tec-tonic collage of the Kola–Norwegian, Keivy, Sos-novsky, and Kolmozero–Voron’ya terranes [4]. Thecollage structure is accentuated by exotic rocks withinthe Keivy Terrane [58]. The terranes consist of theArchean greenstone, schist, paragneiss, granulite, andgranite-gneiss complexes that underwent structuraltransformation and metamorphism in the Archean andPaleoproterozoic. For example, the Keivy Terraneexperienced significant Paleoproterozoic reworking,whereas the Kola–Norwegian Terrane almost escapedthis process [4]. The Kola and Belomorian provincesevolved in the Paleoproterozoic similarly, being ele-ments of the Paleoproterozoic Lapland–Kola colli-sional orogen [103]. The Svecofennian (1.95–1.75 Ga)Pechenga–Imandra–Varzuga and Lapland–Kola colli-sional sutures are localized in the central part of thisorogen [56, 103]. The Lapland–Kola Suture is markedby the Lapland and Umba granulites and the rocks ofthe composite Tersky–Strelna Terrane that served as thejuvenile crustal protolith of granulites [4, 103]. Thesame protolith is predominant in the Inari Terrane.

The thickness of the Earth’s crust in the eastern Bal-tic Shield averages ~40 km and reaches a minimum of30 km in the northern Vodlozero Terrane and a maxi-mum of 62 km at the boundary between the KarelianCraton and Svecofennian Orogen [28]. According tothe seismic data, the crustal structure in the Karelianand Murmansk provinces is more homogeneous than inthe Belomorian and Kola provinces

SUPRACRUSTAL (GREENSTONE AND PARAGNEISS) COMPLEXES

The metamorphosed supracrustal complexesoccupy the much smaller area of the exposed Archeanrocks (~18% in the Belomorian Province and <10% inthe Karelian and Kola provinces; in the MurmanskProvince they are virtually absent). Nevertheless, pre-cisely these rocks serve as the basis for our geodynamicconcept [32, 108]. The supracrustal rocks make upmainly greenstone and paragneiss belts: the complexly

built and, as a rule, collage-type structural units [36, 51,55, 56, 128, 129] that consist of one to a few greenstonecomplexes, often of different age (Fig. 1B). The schistbelts are characterized by predominance of the volca-nosedimentary and sedimentary rocks associated withfelsic volcanics.

In the Karelian Province (Fig. 2), the Vodlozero Ter-rane comprises the Vedlozero–Segozero, Sumozero–Kenozero, South Vygozero, and Matkalahti greenstonebelts. The first two belts consist of two greenstone com-plexes of different ages. The fragments of Paleoarcheansupracrustal rocks are known as well [72].

The Central Karelian Terrane combines the Khedoz-ero–Bolsheozero and Gimoly greenstone belts. The Ilo-mantsi–Voknavolok Terrane includes the Ilomantsigreenstone (schist) belt and the Nurmes paragneiss belt.The Kianta Terrane embraces the Kuhmo–Suomus-salmi–Tipasjärvi and Kostomuksha greenstone belts.The first belt consists of two greenstone complexes ofdifferent ages, while the second belt consists of onecomplex. In addition, paragneisses are abundant in theterrane (Fig. 2); however, their structural settingremains unclear. The West Puolanka paragneiss belt istraceable in the Iisalmi Terrane [110, 116]. The poorlyexposed Ranua Terrane includes the insufficiently stud-ied Oijärvi greenstone belt. The Pomokaira Terrane iscomposed of granitoids.

In the Belomorian Province, the North Kareliangreenstone belt combines three greenstone complexesof different ages. Each of the Yena, Tulppio, Pebozero,Central Belomorian, and Voche-Lambina belts consistsof one complex. The Chupa paragneiss belt is an impor-tant structural unit.

In the Kola Province, the Kola–Norwegian Terranecontains the Olenegorsk greenstone belt composed ofone greenstone complex and the Kola paragneiss belt.The Kolmozero–Voron’ya Terrane consists largely of thegreenstone complex of the same name; presumably oldergabbroids are noted as well. The Sosnovsky Terrane isdevoid of the reliably identified greenstone belts.

To trace lateral inhomogeneities of the Archeansupracrustal rocks important for geodynamic interpre-tation, the complexes related to the specific time inter-vals are considered separately.

The Paleoarchean greenstone belts are severely lim-ited in occurrence (Fig. 2). They have been describedonly in the southeastern Karelian Province in the coreof the Vodlozero Terrane, where they are composed ofkomatiites and pillow metabasalts of the VolotskSequence [42]. Their Paleoarchean age is determinedfrom the Sm–Nd isochron for whole-rock samples ofkomatiites and basalts that yielded

3391

±

16

Ma [71].It cannot be ruled out that some gneisses and amphibo-lites (amphibolite I) of the Vodlozero gneiss complexare highly metamorphosed calc-alkaline volcanic rockswith an age of 3.30–3.55 Ga

2

[48, 81].

2

Unless otherwise specified, the age estimates given here andhereinafter were obtained with the U–Pb method for zircon.

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SLABUNOV et al.

The overwhelming majority of supracrustal rocksare related to the Meso- and Neoarchean greenstoneand schist complexes dated at 3.10–2.90, 2.90–2.82,2.82–2.75, and 2.75–2.65 Ga. The ages of paragneisscomplexes are 2.90–2.82 and 2.75–2.65 Ga.

Supracrustal Complexes Formed 3.1–2.9 Ga Ago

The greenstone complexes of this age are known inthe Vedlozero–Segozero, South Vygozero, Sumozero–Kenozero, and Kuhmo–Suomussalmi–Tipasjärvi green-stone belts of the Karelian Province (Fig. 2). Their con-

100 km

R

In

P

BMB

T

Kl

Ol

Ko

KVo

Kv

KN

Ke

TSSo

CK

Ra

Ki

Ii

IV CK

BMB

Vo

Ye

Sa

Vch

Chu

Nt

33°

E

66°

N

33° E

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

a b c

a

b

c

a b c d

TaNK CB

Pd

KT

Kst

äí

Tl KhB

Il

VS

On M

SV

SK

LakeLadoga

WHITE SEA

Gd

66° N

Vk

N

Vp

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tacts with younger greenstone complexes are, as a rule,tectonic. The Kolmozero–Voron’ya greenstone belt ofthe Kola Province is composed largely of the greenstonecomplex that formed 2.90–2.82 Ga ago. The tectonizeddifferentiated gabbro–anorthosite massifs (Patchem-varek, etc.) that occur nearby within granitoid domainsof the Murmansk Province are also related to this belt[56]. These gabbroic rocks are the oldest basic intru-sions known in the Kola Peninsula (

2925

±

6

Ma) [41].

The Vedlozero–Segozero greenstone belt

islocated at the western margin of the Vodlozero Terraneand consists of two complexes of different ages (Fig. 3).The older complex, in turn, comprises two rock associ-ations dated at 3.05–2.95 Ga [77].

(1) The basalt–andesite–dacite association is repre-sented in full in the Chalka Zone (northern Hautavaarastructural unit) and comprises pillow and amygdaloidlavas, fragmental intermediate and felsic lavas, tuffs ofthe same composition, necks, and dikes. Their visiblethickness is estimated at 2.5 km. The age of subvolca-nic dacitic andesite is

2995

±

20

Ma [79]; andesitic lavais dated at

2945

±

19

Ma [65]. The rocks belong to thedifferentiated calc-alkaline series of normal alkalinitywith geochemical characteristics typical of the Phaner-ozoic island-arc volcanics: Sr/Y < 12, Ce/Nb < 4.5,Th/Nb < 0.72,

(La/Sm)

N

= 1.7,

and

(Gd/Yb)

N

= 1.3. Thesubvolcanic rocks are close in geochemistry to adak-ites. This association is a relict of the oldest volcanicisland arc known in the Baltic Shield [77].

(2) The komatiite–basalt association (Fig. 3) up to2.7 km in thickness occurs in the Hautavaara, Koikary,Palaselga (Palalamba), and Sovdozero structural units[76]. The Sm–Ns isochron age of this association is

2921

±

55

Ma;

ε

Nd

(

t

)

= +1.5 [134]. The upper age limitwas determined by U–Pb dating of dacite dikes, whichyielded

2935

±

15

Ma [13] and

2860

±

15

Ma [75], aswell as by U–Pb dating of gabbrodiorite intrusion,which yielded

2890

±

40

Ma [80]. The sequence iscomposed of diverse lavas, including pillow, variolitic,

and spinifex varieties; pyroclastic interlayers occupy nomore that 5% of the sequence’s volume [78, 134]. TheAl-undepleted pyroxenite and basaltic komatiites andtholeiitic basalts are dominant; their intrusive equiva-lents consist of magnesian gabbro and serpentinizedultramafic rocks. This association is interpreted asderivatives of a mantle plume beneath a backarc basinin the subduction-related geodynamic setting [77].

The South Vygozero greenstone belt.

The ShilosZone is composed largely of metabasalts with sporadicinterlayers of basaltic komatiite and agglomeratic tuff[45, 72]. The basalt–komatiite association is character-ized by the Sm–Nd isochron that yield an age of

2913

±

30

Ma [85, 45]. Basalts are cut through by gabbroic andtonalitic intrusive bodies and metarhyolite dikes.Basalts belong to the tholeiitic series with elevated Cr(250–500 ppm) and Ni (100–150 ppm) contents. Twogroups of rocks are distinguished by their REE con-tents. One group is depleted in LREE ((La/Sm)N = 0.5)and characterized by a low total sum of REE; the othergroup reveals a slightly differentiated pattern((La/Sm)N = 0.65–0.90) and has total REE contents thatare 10–16 times greater than the chondritic level. TheεNd(t) of metabasalt is 1.6 ± 0.5 [45], thereby suggest-ing that the depleted mantle is a source and that crustalcontamination is absent. The association is interpretedas a derivative of the mantle plume [3, 45, 96].

The Sumozero–Kenozero greenstone belt. Twospatially juxtaposed heterogeneous complexes of dif-ferent ages are recognized [74]. The older complex iskomatiite–basalt in composition. Its Sm–Nd whole-rock isochron yields 2916 ± 117 Ma in the LakeKamennoe structural unit [128] and 2960 ± 150 Ma inthe Kenozero structural unit [85]. The komatiite–basaltcomplex consists mainly of pillow lavas of tholeiiticbasalts and metakomatiitic lavas, including those withspinifex texture. Interlayers of felsic volcanics, tuffs, andgraphite-bearing schists, as well as crosscutting basicand felsic dikes and plagiogranite bodies, are noted.

Fig. 2. Geologic scheme of the Archean in the Baltic Shield, compiled after the data published in [1, 4, 15, 36, 37, 49, 51, 64, 67,70, 104, 109, 112, 113, 115, 116, 132, 133]. (1) Phanerozoic complexes; (2) Neo- and Mesoproterozoic complexes; (3–7) Paleopro-terozoic complexes: (3) rapakivi granite (1.65–1.62 Ga), (4) granitoids (1.85–1.75 Ga), (5) volcanosedimentary complexes (2.06–1.85 Ga), (6) complexes of the Lapland and Umba granulite belts (2.0–1.91 Ga), (7) volcanosedimentary complexes (2.50–2.06 Ga);(8) tectonic collages composed of Paleoproterozoic and Neoarchean complexes (In and TS are the Inari and Tersky–Strelna terranes,respectively); (9–22) Archean complexes: (9) gabbroids; (10) sanukitoids (2.74–2.72 Ga), including the Tavajärvi Massif (Ta);(11) granulite complexes (2.74–2.72 Ga for the main phase) including the Varpaisjärvi (Vp), Voknavolok (Vk), Tulos (Tl), Onega(On), Notozero (Nt), Kola (Kl), and Pudasjärvi (Pd) complexes; (12) eclogite-bearing Gridino (Gd) and Salmi (Sa) complexes;(13) paragneiss complexes (2.70–2.78 Ga), including the Nurmes Complex (N); (14–17) greenstone complexes (letters in boxes arethe main greenstone and schist belts of the Baltic Shield, including the Vedlozero–Segozero (VS), Voche-Lambina (Vch), Yena (Ye),Ilomantsi (Il), Keivy schist belt (Kv), Kolmozero–Voron’ya (KVo), Kostomuksha (Kst), Kuhmo–Suomussalmi–Tipasjärvi (KT),Matkalahti (M), Olenegorsk (Ol), North Karelian (NK), Sumozero–Kenozero (SK), Tulppio (T), Khedozero–Bolsheozero (KhB),Central Belomorian (CB), and South Vygozero (SV): (14) 2.75–2.65 Ga; (15) 2.82–2.75 Ga; (16) 2.90–2.82 Ga; including(a) greenstone belts, (b) Kv schist belt, (c) CB belt with fragments of oceanic crust; (17) 3.10–2.92 Ga, including the Chupa (Chu)and Kola (Ko) belts; (18) paragneiss complexes, 2.90–2.82 Ga; (19–22) granite-gneiss complexes: (19) 2.90–2.70 Ga, including(a) the Central Karelian (CK), Kola–Norwegian (KN), and Sosnovsky (So) terranes; (b) the Belomorian Mobile Belt (BMB), Kianta(Ki) and Ropi (R) terranes and the Murmansk Craton; (c) the Keivy Terrane (Ke) with alkali granites; (20) 3.10–2.70 Ga, includingthe Ilomantsi–Voknavolok Terrane (IV) and the margin of the Vodlozero Terrane; (21) 3.60–2.90 Ga in the Iisalmi (Ii), Pomokaira (P),Ranua (Ra), and Vodlozero (Vo) terranes; (22) metavolcanics of the Volotsk Sequence (3.39 Ga); (23) faults: (a) main thrust,(b) normal and reverse, (c) strike-slip, and (d) inferred.

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SLABUNOV et al.

Komatiites (~30 wt % MgO in the spinifex zone)belong to the group of Al-undepleted rocks; the REEpatterns of komatiites and tholeiitic basalts are close tothe MORB-type. Weak positive Nb anomalies arerecorded in spidergrams. The εNd(2875) value is closeto +2.7, thus indicating that the depleted mantle was asource [128]. The Cu–Ni ore occurrences are related tokomatiites. In terms of isotopic and geochemical signa-tures, the komatiite–basalt association is comparablewith complexes of oceanic plateaus [128] geneticallyrelated to the mantle plumes.

The Kuhmo–Suomussalmi–Tipasjärvi green-stone belt. The Luoma and Saarijärvi groups dividedby a tectonic zone [133] are recognized in the northern-most part of the Suomussalmi Belt (Fig. 2). The olderLuoma Group is composed of basic, intermediate, andfelsic lavas and tuffs; the tuffaceous facies locally hoststhe stratiform Ag–Zn–Pb ore mineralization [133, 137].Nearly concordant bodies of metagabbro and uraliteporphyrites probably are the intrusive equivalents of theSaarijärvi basalts. There is a considerable amount ofmetaandesites in the Luoma Group. Their zircon agewas estimated at 2966 ± 9 Ma; however, it cannot beruled out that zircons are xenogenic, and metaandesitesare much younger [133, 137]. The intermediate and fel-sic volcanics of the Luoma Group are characterized by astrongly fractionated REE pattern [135] and probablybelong to subduction-related adakite-like igneous rocks.


These complexes are widespread in the frameworkof the Vodlozero Terrane in the Karelian Province aswell as in the Belomorian and Kola provinces.

In the Vedlozero–Segozero greenstone belt, thegreenstone complex of this age is composed of felsicvolcanics and various sedimentary rocks. The mostcomplete section has been described in the Koikarystructural unit (Fig. 3). Here, the Janis paleovolcanoconsists of lava breccias, lavas, and block agglomeratetuffs; a feeder is filled with subvolcanic dacite. Thechemogenic silicites were deposited in the crater lake.Tuffs, tuffites, tuffstones, tuffaceous conglomerates,and silicites occur at the periphery of paleovolcano.The subvolcanic intrusions are composed of dacite andrhyolite. The dacitic andesites erupted in the subaerialenvironment [78]. Lavas were inferior in abundance tothe products of volcanic explosions. The age of felsicvolcanics related to the Janis paleovolcano is 2860 ±15 Ma [75]; dikes in the Hautavaara structural unit aredated at 2862 ± 45 Ma [65].

The intermediate and felsic volcanics belong to thesodic series [77]. The silica content ranges from 52 to76 wt %; (La/Sm)N = 3.0, (Gd/Yb)N = 2.3, and(Ce/Yb)N = 5.8. The tuffaceous rocks are characterizedby more fractionated REE patterns: (La/Sm)N = 3.5–4.1and (Ce/Yb)N = 22–26. The dacitic andesite (lava) con-tains 5.2–6.2 ppm Th, 13–29 ppm La, 2.6–5.4 ppm Hf,

Fig. 3. Geological sketch-map of the Vedlozero–Segoz-ero greenstone belt, after [77, 78]. (1, 2) Proterozoic:(1) rapakivi granite, (2) volcanosedimentary complexes;(3–6) Neoarchean: (3) sanukitoid-type diorite and grano-diorite (2.74 Ga), (4) gabbrodiorite, (5) gabbronorite,(6) mafic–ultramafic complexes; (7–13) Mesoarchean:(7) two-feldspar granite (2.85–2.87 Ga), (8) adakite-typeandesitic–dacitic metavolcanics and related metasedimen-tary rocks (2.86–2.85 Ga), (9) high-Mg gabbro, (10) komati-ite–basalt association (2.95–3.00 Ga), (11) calc-alkaline andadakite-type metavolcanics (2.95–3.0 Ga), (12) amphibo-lite, (13) granite gneiss (3.15–3.0 Ga); (14) paleovolcanoesof the (1–5) Hautovaara and (6–9) Semch–Koikary green-stone structural units; (15) faults. Paleovolcanoes (numeralsin the figure): (1) Nyalmozero, (2) Ignoila, (3) Hautavaara,(4) Maselga, (5) Chalka, (6) Janis, (7) Korbozero,(8) Elmus, (9) Semch.

10 km

L. Syamozero

L. Segozero

N

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

7

1

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34

5

67

98



and <10 ppm Nb; La/Yb = 7–9, Ti/V = 60–70, Hf/Yb =3–4, and Ti/Zr = 16–37.

This complex was formed in the suprasubductionsetting of the Andean type (active continental margin)[77].

The Sumozero–Kenozero greenstone belt. Thesecond, younger greenstone complex of the LakeKamennoe structural unit consists of metavolcanicrocks that belong to the basalt–andesite–dacite–rhyo-lite (BADR) series with interlayers of carbonaceousand carbonate schists and quartzite accompanied bysubvolcanic intrusions of the adakite series [39, 74,128]. The ages of the BADR and adakite series are2875 ± 2 and 2876 ± 5 Ma, respectively [128].

The rocks of the BADR series are low-Mg andenriched in LREE ((La/Sm)N = 1.4 in basalt and andes-ite and 3.3 in rhyolite) and depleted in Nb and Ti; theadakitic rhyolite has a fractionated REE pattern((La/Sm)N = 3.8–5.1 and (Gd/Yb)N = 2.8–4.5) [128].Such differentiated series are formed in subductionzones as products of melting of the mantle wedge andplunging slab, respectively [128].

The North Karelian system of greenstone belts inthe Belomorian Province comprises the Tikshozero andKeret belts (Fig. 2). In these belts, three greenstonecomplexes are distinguished: Keretozero (2.88–2.82 Ga),Hisovaara (2.80–2.78 Ga) [72] (from which we havedisregarded a younger lithotectonic association [37]),and Chelozero (~2.75 Ga) [2].

The Keretozero Complex that occupies most of theKeret Belt consists of three lithotectonic associations:(1) komatiite–tholeiite, (2) intermediate and felsicmetavolcanics, and (3) basaltic andesites and andesites[16, 82, 83, 86]. Metabasalts of the komatiite–tholeiiteassociation are referred to the sodic tholeiitic series,while the high-Mg rocks are classed with komatiites ofthe Al-undepleted type (10–37 wt % MgO, 0.19–0.90 wt % TiO2, Al2O3/TiO2 ≈ 20, CaO/Al2O3 = 0.64–0.90, Zr/Y = 2–3) enriched in LREE.

The intermediate and felsic metatuffs (from basalticandesite to rhyolite, with predominance of andesite anddacite), metalavas (2877 ± 45 Ma), and subvolcanicintrusions (2829 ± 30 Ma) make up most of the com-

plex. The Sm–Nd model age of andesite ( = 2.80 Ga)is close to the U–Pb age of zircons from this rock,thereby indicating the absence of significant crustalcontamination (εNd(2.8) = +2.8) [16]. The metasedi-mentary interbeds in the basaltic andesite–andesiteassociation are distinguished by high Cr and Ni con-tents (up to 570 and 130 ppm, respectively) and, thus,are products of erosion of volcanic rocks, includingbasalts and komatiites [83]. Graywackes of this compo-sition are typical of ensimatic island arcs [60].

In terms of geochemistry, basaltic andesites andmore felsic rocks are comparable with volcanics of themature island arcs. The volcanic complex marks theearly (2.9–2.8 Ga) subduction-related stage of the evo-

TDMNd

lution of the Neoarchean Belomorian collisional oro-gen [16, 83, 132].

The Central Belomorian greenstone belt in theBelomorian Province [83] was initially regarded as amafic zone [16, 50, 72]. This is a narrow (0.5–3.0 km)belt, which is traced along the axis of the province for150–160 km from NW to SE and probably extends far-ther to the southeast (Fig. 2). The belt is subdivided intofour segments composed of amphibolites and subordi-nate ultramafic rocks [16, 86].

The Seryak fragment is the best preserved wellexposed element of the belt, which is traceable for morethan 70 km. The largest (up to 300 m thick) ultramaficbody is located precisely in this segment. This serpen-tinite body with relict olivine (Fo84–86), orthopyroxene(En85–86), and spinel (ferrialumochromite with >29%Cr2O3) is metamorphosed harzburgite; dunite andorthopyroxenite have been identified in this complex aswell. The ultramafic rocks are commonly depleted inLREE ((La/Yb)N = 0.52); varieties with U-shaped REEpatterns are known as well. Metabasalts (amphibolites)correspond to tholeiites in chemical composition andare comparable with MORB; some varieties may becorrelated with OIB [16, 50, 52, 72, 83]. The mafic–ultramafic sequence is cut through by diorite dated at2.85 ± 0.01 Ga [101].

The trondhjemitic gneiss with an elevated Fe molefraction, which indicates that this gneiss belongs to thetholeiitic series, was found in the mafic–ultramaficcomplex of the Lake Louhi–Pizemsky fragment. Mag-matic zircon from this gneiss dated at 2878 ± 13 Madetermines the upper limit of the belt’s age [16]. Themodel Nd age of the gneiss is 2840 Ma and εNd(2.88) is+2.7; these parameters testify to the juvenile nature ofgranitoids.

Thus, the available geological, isotopic, andgeochemical data allow us to regard the mafic–ultrama-fic rocks of the greenstone complex as a tectonicallydisintegrated and metamorphosed fragment of theMesoarchean ophiolitic association [16, 50, 72, 83].

The Chupa paragneiss belt of the BelomorianProvince consists of migmatized kyanite–garnet–biotite and biotite gneisses with small lenses of fine-grained garnet–biotite gneiss that are commonlyregarded as relicts of the least altered sedimentary pro-tolith [11, 60, 72]. However, some authors suggest thatthe contribution of volcanic rocks was substantial [20].The elevated Ni, V, Co, and Cr contents indicate thatparagneisses originally were graywackes, i.e., the prod-ucts of destruction of mafic and ultramafic rocks andrelated felsic volcanics in a forearc basin [60, 72]. Thethin interlayers of calc-alkaline intermediate-to-felsicvolcanic rocks (mainly dacite) comparable with island-arc volcanics and sporadic tholeiitic bodies [60, 72] areadditional evidence for the formation of this sequencein a forearc basin.

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The Nd model age of 3.01–2.83 Ga [60, 99, 136]and the U–Pb age of 3.2–2.9 Ga for detrital zircons [11]define the maximum age of the sedimentary protolith.The earliest metamorphic zircons are dated at 2.85–2.80 Ga [11]. The age of metadacite incorporated intothe Chupa graywackes is 2870 ± 20 Ma [11]. Thus, thesedimentary rocks subsequently transformed intoparagneisses were deposited 2.87–2.85 Ga ago.

The graywackes were deposited in a forearc basinlocated in front of the volcanic arc marked by andesite,dacite, and basaltic andesite of the Keretozero Complex[60, 83].

The Kolmozero–Voron’ya greenstone belt is anarrow linear structural feature that delineates theboundary between the Kola and Murmansk provinces.The komatiite–tholeiite and basalt–andesite–daciteassociations, together with two terrigenous rock associ-ations, make up these belts [24, 64, 72]. They all arebounded by faults and were juxtaposed with oneanother in the course of Neoarchean collision [56]; i.e.,the section comprises a series of tectonic sheets.

The spinifex texture is observable in komatiitesfrom the komatiite–tholeiite association; lava brecciasare noted as well [24, 84]. Komatiites and komatiiticbasalts, as well as high-Mg and high-Fe metabasalts,are distinguished [73]. All these rocks are characterizedby depletion in REE and by unfractionated REE pat-terns ((Ce/Sm)N = 0.87–1.5 and (Gd/Yb)N = 1.02–1.55)[24, 25].

The age of komatiite formation is estimated at2826 ± 60 Ma (Sm–Nd whole-rock isochron) [73]. TheNd systematics of rocks belonging to this association(εNd(2879) = +2.5 ± 0.3) and their geochemical signa-tures allow us to assume that a mantle plume was thesource of komatiitic and basaltic melts. In particular,komatiites could have been generated in a transitionalzone between the upper and lower mantle [23, 24, 72].

The basalt–andesite–dacite association is composedof calc-alkaline subduction-related volcanics [63]. Theage of quartz porphyry from the Voron’ya Tundra is2828 ± 8 Ma [118].

The terrigenous associations consist of poorly dif-ferentiated metasediments (garnet–biotite gneiss) andcontrasting series varying from metagraywacke (alu-mina gneiss) to polymictic conglomerate [24].

The formation of mafic associations is related tomantle plumes [25], while calc-alkaline volcanics areattributed to the subduction-related melting of the oce-anic crust that divided the Murmansk and Kola prov-inces. These rock associations have been juxtaposed asa result of collision [56, 63].

The Kola paragneiss complex of the Kola–Norwe-gian Terrane is composed of garnet–biotite (often withsillimanite and cordierite and rarely with kyanite andstaurolite) gneiss with sporadic interlayers of (i) two-mica, biotite, amphibole, and biotite–amphibolegneisses; (ii) amphibolite; (iii) amphibole–pyroxene,

amphibole–magnetite, and pyroxene–magnetite schists;and (iv) jaspilite [1, 64, 68]. Some varieties of high-Algneisses reveal relicts of graded bedding and thus areinterpreted as metasedimentary rocks (paragneisses).

The high-Al gneiss corresponds to graywacke incomposition; high Cr (85–165 ppm) and Ni (42 ppm)contents provide additional evidence in favor of theirsedimentary, rather than volcanic, origin, as suggestedin [61]. These paragneisses (comparable in chemicalcomposition with intermediate-to-felsic calc-alkalinevolcanics) are depleted in Nb and Ti and characterizedby strongly fractionated REE patterns [61] probably asa result of the predominance of island-arc volcanics inthe provenance. The isotopic data suggest that the pro-tolith consisted largely of the Meso- and Neoarchean

juvenile materials: does not exceed 3.0 Ga [118,136]. These data are consistent with zircon ages: theage of the best preserved detrital zircon grains of origi-nally magmatic origin is 2910 ± 21 Ma in age, whereasthe ages of most numerous metamorphic zircons are2788 ± 16 and 2743 ± 18 Ma [62]. The findings of zir-con grains dated at 3606 ± 16 Ma [62] show that a Paleo-archean component occurs in the protolith. This com-ponent is identical to that in the Umba paragranulites(3.6 Ma) [102]. The sedimentary rocks likely wereformed 2.9–2.8 Ga ago.

Thus, the Kola paragneiss complex could have beenformed in a backarc basin almost contemporaneouslywith island-arc volcanics of the Kolmozero–Voron’yagreenstone complex.

The Keivy schist belt in the Kola Province consistsof biotite (occasionally with garnet and often with hast-ingsite and microcline) gneiss of the LebyazhinoSequence and biotite–amphibole gneisses and amphib-olites of the Kolovai and Patchervtundra sequences,which are overlain with unconformity by kyanite, stau-rolite–kyanite, sillimanite (with garnet) and carbon-aceous schists, metasandstones, and quartzites of theChervurt, Vykhchurt, and Pestsovotundra sequences[64] combined into the Keivy Sequence. The section ofthe belt is commonly regarded as a stratified sequence.However, it cannot be ruled out that the section is actu-ally composed of imbricate tectonic sheets that werejuxtaposed in the course of Neoarchean collision [56].

The Lebyazhino Gneiss is interpreted as felsicmetavolcanics of normal and elevated alkalinity,depleted in Ti, and with a pronounced Nb minimum inspidergram. The hastingsite-bearing varieties are con-sidered products of alkaline metasomatism [56, 64].The age of volcanism is estimated at 2871 ± 15 Ma [6, 7].The biotite–amphibole gneiss and amphibolite of theschist complex are interpreted as metabasalts andmetaandesites of the calc-alkaline series.

The igneous rocks are comparable in terms ofgeochemistry with volcanics of the active continentalmargins [56].

TDMNd




The complexes of this age make up the Kostomuk-sha greenstone belt and the majority of the Kuhmo–Suomussalmi–Tipasjärvi Belt in the Karelian Province.These complexes are widespread in the North Kareliansystem of greenstone belts, the Yena and Pebozerogreenstone belts of the Belomorian Province, and theOlenegorsk Belt of the Kola Province.

The Kuhmo–Suomussalmi–Tipasjärvi green-stone belt consists of komatiite–basalt, (andesite)–dac-ite–rhyolite, high-Fe basalt, and sedimentary associa-tions. The first two associations are predominant. As arule, metabasalts are banded amphibolites. However,the massive and pillow varieties, as well as interlayersof jaspilite and carbonaceous and mica schists, arenoted as well. Komatiites comprise both spinifex-tex-tured and cumulative facies. A komatiitic lava riverwith granodiorite inclusions incorporated into the lavais known in the Pahakangas district [133]. Cumulativegabbro is associated with komatiites. Basalts are relatedto the tholeiitic series; komatiitic basalts are alsoknown, including a variety with a high Cr content thatreaches 2000 ppm. The LREE and HREE contents inbasalts are 2–10 and 8–10 times higher, respectively,than in chondrite. The REE patterns are low fraction-ated: (La/Sm)N = 0.4–1.5 [126, 135]. The varietiesenriched in LREE occur sporadically. The LREE-depleted komatiites with (La/Sm)N = 0.4–1.5 [126] arepredominant. The age of cumulative gabbro from thekomatiite–basalt association is estimated at 2757 ±20 Ma [133].

The (andesite)–dacite–rhyolite association com-posed of lavas, breccias, tuffs, and tuffites (2798 ± 15,2810 ± 48, and 2791 ± 8 Ma in age) occurs in severalisolated structural units [112, 123, 133]. The age of theMoisiovaara gabbroic sill that intruded into the felsicvolcanic rocks is 2790 ± 18 Ma [123]. The sedimentaryassociation is composed of polymictic conglomerate,graywacke, and quartzite. Sporadic grains with an agereaching 3 Ga were detected among detrital zircons inquartzite [112].

It is suggested that this greenstone belt was formedunder conditions of continental rifting [108, 123, 133].

The Kostomuksha greenstone belt hosts the eco-nomic iron deposit of the same name. The belt consistsof basalt–komatiite, rhyolite–dacite, and sedimentary(ferruginous–siliceous) associations [36, 44, 74, 87].

The Sm–Nd isochron ages of basalt and komatiiteare estimated at 2843 ± 39 [129] and 2808 ± 95 Ma[44], respectively. Sporadic interlayers of jaspilite, car-bonaceous schist, and tuff are intercalated into massive,pillow, and variolitic basaltic lavas. The zircon age(SHRIMP-II) of the sodic tuff coeval with the oldestNiemijärvi Basalt is estimated at 2791.7 ± 6.1 Ma [37].

In geochemical signatures, basalts and komatiitesare comparable with similar rocks of oceanic plateaus.They are depleted in Th and LREE ((La/Sm)N = 0.66),

characterized by a flat HREE pattern ((Gd/Yb)N = 1), achondritic Ti/Zr ratio, a slight positive Nb anomaly, and anaverage εNd(t) of +2.8 [129]. Negative εNd(t) values downto –3.44 were calculated for two basaltic samples [44].

The evolved and unfractionated komatiitic lavashost rare tuffaceous units; peridotitic sills are wide-spread [39]. The Al-depleted komatiites are depleted inLREE ((La/Sm)N = 0.48; (Gd/Yb)N = 1.2) [129]. TheRe–Os isotopic data suggest that they were derivedfrom a plume that arose at the core/mantle boundary:γ187Os = +3.6 ± 1.0 [127].

The rhyolite–dacite association (Shurlovaara For-mation, after [87]) consists of various lavas, tuffs, andtuffites with interlayers of carbonaceous schist and jas-pilite; dikes and subvolcanic intrusions are known. Ageestimates of 2790 ± 21 Ma [14], 2791 ± 24 Ma (ionmicroprobe) [75], and 2795 ± 10 Ma [44] have beenobtained. Gor’kovets and Raevskaya [87] classified thevolcanic rocks as calc-alkaline rhyolite and dacite (spo-radic andesite) with a distinct negative Nb anomaly[130]. Two geochemically different groups of rocks aredistinguished: (1) high-K rocks with highly fraction-ated REE patterns ((La/Sm)N = 4.9–6.2; (Gd/Yb)N =2.5–3.7) and low Al2O3, Sr, and Y and (2) an adakiticgroup with fractionated REE patterns ((La/Sm)N = 2.9–5.3; (Gd/Yb)N = 1.4–2.1) and high Y and Sr [130]. Theplutonic analogues of these rocks are known. The εNd(t)varies from –6.21 to +1.59 [14]. These geochemical sig-natures indicate that the volcanic rocks were related to atleast two mantle and ancient crustal sources [75, 130].

The sedimentary association consists of conglomer-ate; jaspilite, including the orebody; and graywackewith thin interlayers of andesite–dacite–rhyolite tuffs[75] and komatiite bodies [44]. The basal conglomeratecontains pebbles of metarhyodacite (60%), amphiboleschist, and amphibolite (30–40%) [87]. The terrigenoussedimentary rocks are poorly differentiated, immature,and comparable with graywackes from the Neoarcheangreenstone belts. The provenance was composed ofapproximately the same amounts of basic and felsicrocks [54]. The age of dacitic tuffite from this associationis estimated at 2787 ± 8 Ma [14]. This estimate probablyindicates the time of the formation of this rock.

Thus, all three rock associations in this greenstonebelt were formed at approximately the same time 2.80–2.79 Ga ago but in different geodynamic settings.

Two models of the formation of the Kostomukshagreenstone belt are the most popular. According to[44, 87], all associations were formed in a continentalrift. The mafic rocks made up a volcanic plateau, asindicated by the occurrence of komatiitic sills in thesedimentary sequence and negative εNd(t) values ofsome komatiites from borehole cores. Another modelassumes that the greenstone belt is a tectonic collagethat arose as a result of accretion of almost coeval man-tle-plume volcanic plateau and subduction-relatedigneous and sedimentary rocks [36, 37, 75, 128].

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The Matkalahti greenstone belt is situated in thecentral, very poorly exposed part of the Vodlozero Ter-rane in the Karelian Province (Fig. 2). The belt is com-posed of alternating metasedimentary rocks (quartz aren-ite, graywacke, carbonaceous schist) and mylonitizedmetavolcanic rocks of the basalt–komatiite associationwith rare interlayers of foliated felsic metavolcanics[37]. The age of detrital zircons from quartz arenite andgraywacke varies from 3.33 to 2.82 Ga. Thus, this con-trasting complex is younger than 2.82 Ga. The complex

probably formed under conditions of intracratonic rift-ing [37].

The North Karelian system of greenstone belts.The entire Tikshozero greenstone belt and the northernsegment of the Keret Belt are composed of supracrustalrocks of the Hisovaara Complex (2.80–2.77 Ga) thatmarks the late, subduction-related and accretionary set-ting in the evolution of the Belomorian Province. Thiscomplex has been studied most thoroughly in the His-ovaara and Iringora structural units (Figs. 4A, 4B)

Fig. 4. Geological maps of the (A) Hisovaara and (B) Iringora structural units of the North Karelian system of greenstone belts,compiled after the data published in [15, 36, 93, 95, 131].

1 km

B

N

A

2778 ± 21

2783 ± 10

Lake 50

70

60

L. Verkhnee

60

80

50

452804 ± 27

32°30′

32°05′

66°24′

L. Notozero

65°57′

2782 ± 9

2826 ± 18

1 km

Not exposed

75

85

40 40

60

40

30

40

50 70 Lake

80

50

60

4530

30

40

40

75

40

5060 80

70

60

70

50

50

60

50

65

Location ofsamples andU–Pb zircon age,Ma

60°

Quartz arenite

Lower mafic rocks

Metavolcanicsof boninite series

Fe--Ti metabasalt

Northern metaandesite

Island-arc BADRand adakite-type

Potassium granite

Northern tonalite

Southern tonalite

Southern metatholeiite

Tectonic melange

Metaturbidite

Geological boundary

Structural trend

Strike and dip symbols

Main faults

Main thrust faults

Older thrust faults

L. Irinozer

o

metavolcanics



[15, 36, 37, 93, 95]. No less than four lithotectonicunits are recognized in the Hisovaara structural unit: thelower mafic, metaandesitic, volcanosedimentary, andbasic [37].

The mafic association comprises four geochemicaltypes formed under different conditions (from bottomto top): (1) island-arc tholeiitic metavolcanics,(2) metavolcanics of the boninite series that consists oflow-Ti primitive metabasalt and metaboninite proper,(3) OIB-type high-Ti metabasalts, and (4) metabasaltsclose to MORB in composition [131]. The ultramaficrocks and high-Mg basic rocks are additional constitu-ents of this association.

The andesitic sequence consists of amygdaloid,massive, and glomeroporphyritic high-Na andesites,which mainly exhibit a tholeiitic fractionation trend[36]. The age of metamorphic zircon from andesite is2777 ± 5 Ma [15].

The andesite–dacite–rhyolite metavolcanics arecharacterized by the calc-alkaline fractionation trend.Their age is estimated at 2778 ± 21 Ma; zircons fromthe related sedimentary rocks yield 2728 ± 82 Ma[15, 131]. The pillow lavas from the upper associationlocally overlap the underlying rocks with angular uncon-formity, and komatiite sills occur at its base [36, 37].

In general, the Hisovaara greenstone complex is atectonic collage of the aforementioned rock associa-tions, the formation of which was related to the origina-tion and subsequent evolution of the ensimatic island-arc system and its forearc zone about 2.8 Ga ago [36].The occurrence of metavolcanics of the boninite series(Fig. 4A) serves as direct evidence for the formation ofthe North Karelian Belt in such a setting [95].

The geochemistry of the mafic association in theHisovaara structural unit indicates its ensimatic (ophio-lite-like [36]) nature, but the degree of the subsequentdeformation was so significant that the primary featuresof the inferred ophiolitic section have been obliteratedcompletely.

The Iringora structural unit is a less deformed por-tion of the Tikshozero Belt (Figs. 2, 4B). This unit com-prises similar lithotectonic associations but contains thewell-preserved fragments of ophiolites, a unique phe-nomenon as concerns the Archean [93, 131].

The Iringora ophiolites (Fig. 4B) are components ofthe complexly built thrust packets that gently plunge tothe NNE. These packets consist of mafic metavolca-nics, analogues of the upper tholeiites and boniniteseries of Hisovaara. These rocks are thrust over theisland-arc complex of the intermediate and felsic calc-alkaline metavolcanics and related volcanosedimentaryrocks, which may be regarded as a paraautochthon forthe ophiolitic thrust schists (Fig. 4B). In addition,supracrustal rocks of the Iringora structural unit weresubjected to intense deformation and metamorphism,but their primary volcanic and sedimentary structuresare occasionally retained.

The best preserved fragment of ophiolites was foundon the northern coast of Lake Irinozero [93, 131],where the lava and gabbroic complexes crop out alongwith fragments of the sheeted dike complex grading inthe overlying lavas and the melange complex at thebase of the ophiolitic nappe.

The boninite series of the North Karelian Belt isidentical in its geochemical and isotopic characteristicsto the upper pillow lavas of the Troodos ophiolites,which are regarded as a reference high-Ca boniniteseries [92, 131]. The similarity of the Neoarchean andLate Mesozoic boninite series suggests a similarity intheir petrogenetic formation conditions.

The structure of the Iringora Unit indicates that theophiolitic complex was thrust over a mature island arcand related volcanosedimentary wedge. This circum-stance, in turn, implies that ophiolites were formed inthe setting of forearc spreading, as assumed for theirmodern counterparts [131]. Thus, the formation mech-anism and evolution of suprasubduction ophiolites inthe Neoarchean did not differ principally from thoseknown in the following geological history [92].

The Olenegorsk greenstone belt in the Kola–Nor-wegian Terrane is composed of metavolcanic rocks thatvary in composition from basalt to rhyodacite togetherwith metasedimentary rocks, including garnet–biotitegneiss (occasionally with staurolite or sillimanite) andjaspilite that make up economic iron deposits [64, 70].The age of metavolcanics (leptites) is 2760 ± 7 Ma[118]. The deformation and metamorphism of the beltoccurred soon after the deposition of sedimentary andvolcanic rocks, as follows from the age of postdeforma-tion gabbronorite dikes dated at 2738 ± 6 Ma [118].


In the Karelian Province, the rocks of this age areknown from the Voknavolok–Ilomantsi Terrane of theIlomantsi system of greenstone belts, where they arewell studied as hosts of gold deposits; from the CentralKarelian Terrane (Khedozero–Bolsheozero greenstonebelt), where the age of rhyolite is 2730 ± 6 Ma [14]; andfrom the Iisalmi Terrane, where the West Puolankaparagneiss complex is recognized. In the BelomorianProvince, the metasedimentary rocks and metabasaltsof the Suomujärvi Complex, the maximum age ofwhich is estimated at 2731 ± 8 Ma, belongs to thisgroup. However, a zircon grain dated at 3413 ± 5 Mawas detected in quartzite [104]. The same chronologi-cal position is occupied by the volcanosedimentaryassociation with a quartzite unit in the Hisovaara struc-tural unit of the Keret Belt [37], the Chelozero green-stone complex of the Tikshozero Belt [2], and theVoche-Lambina greenstone complex in the structuralunit of the same name. In the Kola Province, the KeivyComplex (Sequence) in the Keivy schist belt has thesame age.

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The Hattu schist belt of the Ilomantsi system con-sists of volcanosedimentary rocks; volcanics are rare[106]. The sedimentary rocks are largely composed offeldspathic graywacke that fits intermediate and felsicvolcanics in composition but is enriched in Cr, Ni, andV. These rocks could have been a result of scouring andredeposition of andesites and dacites (these rocks occurin this complex) and, to a lesser extent, of basalts andgranitic rocks. Beds of polymictic conglomerate, cross-bedded arkose sandstone, and jaspilite are known. Thesedimentary rocks contain detrital zircons dated at2.86 Ga. The εNd (2.75 Ga) value varies from –0.6 to+1.2, thus indicating that the clastic material was sup-plied from the basement rocks [106].

The intermediate and felsic tuffs that occur at thebase of the section have an age of 2754 ± 6 Ma. Thefragments of felsic rocks from the overlying conglom-erate are dated at 2727 ± 14 Ma, while the age of syn-tectonic granitoids varies from 2748 ± 6 to 2724 ± 5 Ma[106]. The calc-alkaline basalt, andesite, and dacite areenriched in LREE and depleted in Ta, Nb, and Ti, as ischaracteristic of island-arc volcanic rocks [106]. Basaltand komatiite occur sporadically except in the Pampalobasalt–komatiite association in the upper part of thesection, where the rocks of basaltic composition com-prise lava, breccia, and tuff, while the komatiitesinclude tuffs and lavas with cumulative and brecciatedzones; intrusive facies are noted. Komatiites areenriched in LREE. The low-Ti tholeiites enriched inLREE ((La/Sm)N ~ 1.1–1.9) and tholeiitic basalts witha flat REE pattern are recognized.

The Nurmes paragneiss complex (Fig. 2) is com-posed of migmatized biotite gneiss with garnet–biotiteinterlayers bearing graphite and sulfides [114]. On thebasis of their chemistry, they are interpreted as parag-neisses, which may be regarded as products of erosionof mafic and felsic rocks that contained 67–68 wt %SiO2 and were enriched in Cr, Ni, and V. These rockshave some features in common with metasedimentaryrocks of the Hattu Belt and were formed probably2720–2680 Ma ago [133].

The West Puolanka paragneiss complex that con-sists of metasedimentary rocks with tuff interlayers andbasic and felsic dikes is close in age (2.70–2.73 Ma) tothe Nurmes paragneiss complex. The age of felsic igne-ous rocks is estimated at 2721 ± 12 Ma (tuff) and2699 ± 7 Ma (dike) [110]. The age of detrital zirconsfrom metasedimentary rocks varies from 3.50 to2.73 Ga, while the Nd model age ranges from 3.23 to2.83 Ga [110].

The Voche-Lambina greenstone belt is located atthe boundary between the Belomorian and Kola provincesand composed of the greenstone complex of the samename that consists of four sequences divided by tectonizedcontacts. The strongly foliated and mylonitized lowersequence tectonically separates the supracrustal rocksfrom the underlying granite gneiss [23]. Thesupracrustal rocks include gneiss and amphibolite with

locally retained relict structures of lava and tuff. Therocks correspond to rhyodacite, dacite, andesite, basal-tic andesite, and basalt in composition. The intermedi-ate and felsic rocks of normal alkalinity dominate; sub-alkaline varieties occur as well [23]. Metasedimentaryrocks (arkose, graywacke, and subgraywacke togetherwith lenses of polymictic conglomerate, tuffaceousconglomerate, and sedimentary conglobreccia) areimportant constituents of the upper three sequences.Granitic rocks, including microcline varieties; gneisses(intermediate and felsic metavolcanics); metagabbro;hornblendite; and less abundant silexites, which arepointed out as pebbles and fragments, indicate the het-erogenous sialic provenances. It is suggested that thesediments were deposited in fans synchronously withmagmatic activity [23].

The lower chronological boundary of the greenstonecomplex is determined by the age (2.81–2.76 Ga) oftonalitic basement rocks and migmatites [35, 97] andthe upper boundary corresponds to the age of magmaticzircon from the metamorphosed andesitic tuff (2663 ±1 Ma) [35]. The most probable age of the complex isestimated at 2.7 Ga. The model Nd age of felsic

metavolcanics ( = 2.76 Ga) and tonalitic gneisses of

the basement ( = 2.81–2.87 Ga) are close to eachother, thus indicating the absence of long-term crustalprehistory of their sources [136].

The specific features of sedimentation and volcan-ism during the formation of the Voche-Lambina green-stone complex testify to its ensialic nature and the for-mation related to the final episodes of the collisionalstage of the evolution of the Neoarchean BelomorianOrogen [83].

In the North Karelian system of greenstone belts,two complexes were formed at that time. The first, Che-lozero Complex is localized in the Tikshozero green-stone belt. This complex consists largely of intermedi-ate metavolcanics, including varieties with relicts ofamygdaloidal and pillow textures, and volcanosedi-mentary rocks; metabasalts and high-Mg basic rocksare less abundant [31]. The age of porphyritic basalticandesite is estimated at 2753 ± 13 Ma [2]; hence, thiscomplex should be referred to as the youngest genera-tion of volcanic rocks in this greenstone system.

Another complex is recognized in the Hisovaarastructural unit, where the volcanosedimentary lithotec-tonic association contains quartz arenites. As has beenestablished through dating of separate zircon grains[37], the deposition of quartz arenites was limited bychronological boundaries of 2.71 and 2.69 Ga (theyoungest age of the detrital zircons of magmatic originand the oldest age of metamorphic zircon, respec-tively). This complex consists of the youngestsupracrustal rocks in the North Karelian system ofgreenstone belts.

In the Keivy schist belt, the rocks of the KeivySequence are regarded as highly differentiated metater-

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rigenous rocks (including redeposited products ofweathering) formed in a quiet sedimentary basin [10].

The model Nd age ( ) of the quartz–muscovite schistfrom the Pestsovotundra Sequence is 2.81 Ma; the207Pb/206Pb ages of detrital zircons cluster are ~2.75 Ga[102]. These data indicate that the metasedimentaryrocks are products of erosion of Meso- and Neoarcheanjuvenile materials.

GRANITOID COMPLEXES

Like greenstone and paragneiss belts, the granitoidcomplexes were formed during several stages that aredistinguished from one another in scale and conditionsof granite formation.

Currently, the Paleoarchean granitoids in the BalticShield are known only in the Ranua Terrane in Finland(Fig. 2), where the zircon age of the Siuruatrondhjemitic gneiss is estimated at 3.5 Ga and the coreof one zircon grain is dated at 3.73 Ga [125]. The modelNd age (tDM) is 3.48 Ga. The composition of this gneissis broadly comparable with the mean composition ofthe Archean TTG associations. However, the SiuruaGneiss is slightly depleted in ê2é5, markedly enrichedin LREE and Th, and characterized by more fraction-ated REE patterns ((La/Yb)N = 151) relative to themean TTG composition.

Granitoids Formed 3.2–3.0 Ga Ago

Mesoarchean granitoids (3.2–3.0 Ga) are known inthree districts of the Karelian Province, where theybelong to the TTG association. In the Pomokaira Ter-rane (Fig. 2), the age of their magmatic crystallizationis estimated at 3.11 Ga; the inherited zircons are 3.16–3.25 Ga in age. The average εNd(t) = –3.7 indicates thatthe age of the source is at least Mesoarchean [117]. TheTTG association of the Iisalmi Terrane has an age of3.1 Ga and εNd(t) = –1.3 [111]. The ancient granitoidsare most widespread in the Vodlozero Terrane (Fig. 2).The U–Pb age of zircons (SHRIMP) from the oldestgneissic tonalite varies from 3210 ± 12 to 3151 ± 18 Ma[12].

The rocks of the TTG association reveal low Rb, Y,Zr, Nb, and Ba contents; negative Ti, Nb, and Ta anom-alies; and fractionated REE distribution ((La/Yb)N =30–50). A Eu anomaly has been detected only intonalite from northern Finland. The εNd(t) varies from

+1.0 to –4.3, while ranges from 3.2 to 3.5 Ga [49, 72].


The granite formation coeval with formation ofgreenstone complexes of the Vedlozero–Segozero Beltwas widespread in the Vodlozero Terrane. Trondhjemiteof the Chebino pluton (2985 ± 10 Ma), tonalite from theLake Chernoe area (2957 ± 23 Ma), and diorite and gra-

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nodiorite of the Kalya River area (2971 ± 11 and 2908 ±12 Ma) were formed here 3.0–2.9 Ga ago [45]. They arecharacterized by positive εNd(t) ranging from 2.3 to 4.2.

The values of are ~3.0 Ga [45, 49, 91]. Theseolder greenstone complexes and granite gneisses arecut through by younger TTG granitoids (Lizhma Riverpluton, >2884 Ma; Shilos pluton, 2859 ± 24 Ma) [45].The same rocks were found in the Kianta Terrane(2843 ± 18 Ma) [123].

The oldest two-feldspar granites known in the BalticShield (2876 ± 21 Ma) [72] are located also in the Vod-lozero Terrane. These granites are close to the I-typeand distinguished by only slight REE fractionation((La/Sm)N = 3.5–5.0; (Gd/Lu)N = 1.6–2.0) and a nega-tive Eu anomaly (Eu/Eu* = 0.35–0.60). The εNd(t) variesfrom –1.5 to +1.8 as a response to the heterogeneity of thesource [49].

Quartz diorite and trondhjemite in the Lake Keretarea (2803 Ma [16]) and diorite–granodiorite of theHisovaara structural unit (2826 ± 18 Ma [15]) belong tothis group in the Belomorian Province. Tonalitic gneisswith an age of 2.81 Ga was established at the northernboundary of this province as pebbles of the basal con-glomerate of the Voche-Lambina greenstone belt [35]and as its basement [97]. In the Tulppio greenstone beltin Finland (Fig. 2), granite (2896 ± 8 Ma), tonalite(2805 ± 4 Ma), and syenite (2.8 Ga) are known [113];tonalite and granodiorite dated at 2823–2810 Ma arepredominant in the Suomujärvi Complex [104].

In the Murmansk Province and the Kola–NorwegianTerrane of the Kola Province the widespread granitoidsof this group are composed of enderbites varying fromquartz diorite to tonalite and trondhjemite in composi-tion [64]. Enderbites and complementary rocks arecharacterized by low and normal alkalinity with theprevalence of Na over K. The age of these granitoids isestimated approximately at 2.83 Ga [64]. The Sm–Ndisotopic data show that their source was virtuallydevoid of the Mesoarchean material [136]. The oldesttonalitic gneiss in the Kola–Norwegian Terrane(2.93 Ga) was established in the section of the KolaSuperdeep Borehole, where the rocks of the TTG seriesdated at 2.83 Ga (tDM = 2.85–2.95 Ga; εNd(t) = 0.5–2.5)are known [12, 139]. The rocks of the TTG associationfrom the northwestern Kola–Norwegian Terrane havezircon ages of 2902 ± 9, 2813 ± 6, and 2803 ± 15 Ma[120]. Two compositional types of TTG rocks are rec-ognized here: (1) tonalites and trondhjemites with anelevated Al2O3 content (17–22 wt %); elevated Sr, Rb,Ba contents; and fractionated REE patterns ((La/Yb)N =44–112 for tonalite and 48–62 for trondhjemite) and(2) the same rocks with lower Al2O3 contents;increased Fe, Ti, Mg, Mn, P, Zr, Y, Co contents and REEtotal; (La/Yb)N = 7–25 in tonalite and 13–41 introndhjemite). Trondhjemite is characterized by a posi-tive Eu anomaly (Eu/Eu* = 1.1–1.4). It is suggested thatthis granitoid complex was formed as a result of a var-

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ious degree of partial melting of the basic crust in awide range of pressure [138, 139].


Granitoids of this period occur everywhere and aresubdivided into three groups: (1) TTG rocks, diorites,and enderbites; (2) subalkali and alkali rocks; and(3) two-feldspar rocks.

(1) TTG rocks, diorites, and enderbites. In theKarelian Province, this group largely comprises latetectonic intrusions. The Tavajärvi (North Karelian)diorite–granodiorite batholith is the largest intrusivebody and bears geochemical attributes of sanukitoids.Its age is estimated at 2724 ± 7.8 Ma [17].

In the Belomorian Province, most granitoids(largely, tonalite and trondhjemite and, less frequently,leucogranite) were formed and underwent migmatiza-tion 2.78–2.70 Ga ago [16, 33, 99, 100]. The hyper-sthene diorite near the village of Pongoma (2728 ±21 Ma) [43] and the settlement of Chupa (2728 ± 4 Ma)[27], as well as migmatite fields and enderbite and char-nockite intrusions of tholeiitic and calc-alkaline seriesnear Lake Notozero [47] and Lake Kovdozero [46],were formed 2.73–2.66 Ga ago. Tonalites (2744 ± 5 and2702 ± 5 Ma) and granites (2721 ± 15 Ma) [113] areknown in the Tulppio Belt, while veined tonalite, gran-ite, and diorite formed 2.68–2.64 Ga ago are located inthe northwestern portion of the province [40, 100].Metatonalite in the Kolvitsa Belt has an age of 2708 ±10 Ma ( = 2.82–2.83 Ga and εNd(t) = 0.1–0.7) [4].

In the Kola–Norwegian Terrane of the Kola Prov-ince, the rocks under consideration are composed ofmonzodiorite (2720 ± 3 Ma), quartz diorite (2679 ±18 Ma) [97], and enderbite (2656 ± 14 Ma) [69]. In thecomposite Tersky–Strelna Terrane, tonalitic gneissesare dated at 2722 ± 18 and 2692 ± 19 Ma [103].

The values of all granitoids in the Belomorianand Kola Provinces fall within the range 2.93–2.72 Ga[16, 49, 60, 99, 103, 136] and almost coincide with theage of magma crystallization. This circumstanceimplies that the source of these rocks does not containa material with a crustal history older than 2.9 Ga.Trondhjemites with an age of 2717–2771 Ma have beenestablished in the Murmansk Province. Their sourcecould have contained Mesoarchean material, as followsfrom the negative values of εNd(t) varying from –0.17 to–0.49 [38].

(2) Subalkaline and alkaline rocks: sanukitoids(high-Mg granitoids), syenite, alkali granite, andnepheline syenite. Sanukitoids in the western KarelianProvince make up a posttectonic pluton dated at~2700 Ma, whereas in the east of the province their ageis 2740 Ma [75, 89, 91, 98, 109, 122]. The sanukitoidintrusions are known in the Central Karelian, Vodloz-ero, Ilomantsi– Voknavolok, and Iisalmi terranes of theKarelian Province (Fig. 2). Their occurrence is very

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probable in the Kianta Terrane [J. Halla, personal com-munication]. Composition of multiphase intrusions,e.g., the Panozero pluton, varies from pyroxenite–monzogabbro to quartz monzonite. Lamprophyre dikesare related to these plutons. Sanukitoids are distin-guished by elevated Cr and Ni contents and high Mg #(0.5–0.7) and are enriched in Sr, Ba, and LREE; theREE pattern is fractionated ((La/Yb)N > 20), and a Euanomaly is not developed. The εNd(t) ranges from –1.3to 2.1 (positive values are prevalent) [122], thus indicat-ing a contribution of mantle matter to the initial melts.In the Karelian Province, syenitic rocks occur largely asposttectonic plutons, e.g., the Khizhjärvi pluton, andvary from pyroxene monzodiorite to leucosyenite. TheKhizhjärvi pluton is coeval to the Panozero pluton, andboth are situated in the same tectonic zone. Syenites aredistinguished from sanukitoids by lesser Mg contentsand enrichment in lithophile elements.

As has been exemplified in the intrusions [75, 122],the initial sanukitoid and syenitic melts were formed asa result of the direct partial melting of the metasomati-cally enriched lithospheric mantle. The mantle metaso-matism and its subsequent melting were separated by atime interval of 60 to 100 Ma [122].

Subalkali granitic plutons (2.67 Ma) and relateddikes are known in the southern Belomorian Province[89–91]. In the Kola Province, this group likely com-prises quartz monzonite, quartz syenite, and latite in thesoutheastern Kola–Norwegian Terrane dated at 2657 ±9 Ma [97] (εNd(t) = –0.8) [136] and the Porosozero mul-tiphase monzodiorite–granite pluton (2733 ± 6 Ma)[70] that cuts through the rocks of the Kolmozero–Voron’ya greenstone belt.

Alkaline rocks of the Keivy Terrane are composedof aegirine–arfvedsonite and lepidomelane–hastingsitegranites and nepheline syenite [5]. Granites occur assills and dikes. The ages of alkali granite are estimatedat 2630 ± 31 and 2654 ± 5 Ma (Belye Tundry pluton)and 2751 ± 41 Ma (Ponoi pluton) [6, 19]. Granosyeniteof the West Keivy pluton is dated at 2674 ± 6 Ma [6].The Ponoi alkali granite is a high-Fe rock with low Pand Sr; extremely low Cu, Ni, V, Cr, and Co; and ele-vated Li (up to 1000 ppm), Zr, Nb, Y, U, Th, and REE

[19]. The εNd(t) is 0.1–2.9 ( = 2.64–2.91 Ga). Gran-ites are classified as anorogenic [59]. Essexite andnepheline syenite of the Sakharjok pluton were formed2682–2613 Ma ago [6].

(3) Two-feldspar granites are ubiquitous; they areposttectonic and referred to as I- and A-types. In theKarelian Province, these granites are 2680–2710 Ma inage. The εNd(t) value depends on the age of the terrane.In plutons of the older Vodlozero Terrane, this valueranges from –0.4 to –4.9, and in the Ilomantsi–Voknavolok Terrane, from –0.1 to –1.2. However, in theyounger Central Karelian Terrane, values of 0.8–2.2predominate [49, 72]. In the Kola Province, monazitegranites (2634 ± 12 Ma) are known [97]. In the Belo-

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morian Province, an age of 2674 ± 4 Ma was estab-lished for plagioclase–microcline granite that occursnear Lake Kichany [30].

METAMORPHISMAs a rule, all Archean complexes of the Baltic

Shield were repeatedly deformed and metamorphosed.The main Archean structural units (Fig. 1B) are charac-terized by specific regimes of Archean metamorphism,which are crucial for both the geodynamic reconstruc-tions and the tectonic demarcation.

The Karelian Province

The Paleo- and Mesoarchean metamorphic eventshave been documented in the lower crustal granulitedated at 3.5 Ga from xenolith in kimberlite of the Iis-almi Terrane [66] and in amphibolite of the VodlozeroTerrane that metamorphosed 3.2–3.1 Ga ago under con-ditions of amphibolite to granulite facies [48].

The PT trends of Neoarchean metamorphismembraces two main events irrespective of the Archeanprotolith age. The first episode, commonly older than2.75 Ga, developed autonomously in each structuralunit at a low pressure (andalusite–sillimanite type) withvariation of temperature from greenschist facies (theSouth Vygozero and Sumozero–Kenozero greenstonebelts) to high-temperature amphibolite facies (the Ved-lozero–Segozero, Kostomuksha, Kuhmo–Suomus-salmi–Tipasjärvi belts). The second metamorphic epi-sode (2.72–2.63 Ma) occurred at elevated pressure(kyanite–sillimanite type) over the entire territory butdiscretely, having been related to the transpressionalzones. The temperature conditions of this episode cor-responded mainly to amphibolite facies in a wide rangeof pressure from 5–7 to 10 kbar even within the samezone [126]. However, examples of greenschist faciesare known in the Koikary and Pedrolampi structuralunits of the Vedlozero–Segozero Belt.

Most of the granulite (granulite–enderbite–charnoc-kite) complexes of the Karelian Province (Varpaisjärvi,Tulos, Pudasjärvi, Voknavolok, and Onega; see Fig. 2)were formed 2.72–2.63 Ga ago [21, 36, 72, 111, 124].They all have much in common and largely consist ofdioritic–tonalitic enderbites that contain inclusions ofmetasedimentary rocks and basic, intermediate, andless abundant felsic and ultramafic granulites. The basicgranulites of the Varpaisjärvi Complex contain zirconwith Mesoarchean ages of 3.20–3.05 Ga [111].

On the basis of geologic and petrologic data,V.M. Shemyakin, V.N. Kozhevnikov, and O.I. Volod-ichev independently arrived at a conclusion on the two-fold granulite-facies metamorphism separated by anamphibolite-facies episode [21, 36]. Similar conclu-sions have been drawn from isotopic geochronologicaldata for the Varpaisjärvi Complex [111, 124]. The ageof 2723 ± 4 Ma for charnockite of the Tulos Complexprobably corresponds to the late episode [21], whose

PT conditions were 750–800°ë and 5 kbar pressure.The occurrences of the superimposed granulite-faciesmetamorphism (T = 750–800°ë; P = 6–7 kbar) arerelated to the shear zones and dated at ~2681 Ma. After-ward, granulites were affected by retrograde metamor-phism under conditions of amphibolite facies (first at680–700°C and P = 6.0–6.5 kbar and then at T = 600°ëand P = 4 kbar).

The first episode of granulite-facies metamorphismin the Karelian Province apparently accompanied theaccretion stage in the evolution of geodynamic systems,whereas the second episode of amphibolite- and granu-lite-facies metamorphism was related to the Neoarcheancollision.

The Belomorian Province

The multifold development of high-pressure meta-morphism, including eclogitic, is the most characteris-tic feature of the Belomorian Province [20, 26].

In terms of the character of Neoproterozoic meta-morphism, the Belomorian Province is subdivided intoeastern and western domains. The P–T–t clockwisetrend that includes a prograde branch of eclogitic meta-morphism (T = 740–865°ë; P = 14.0–17.5 kbar) and aretrograde branch is typical of the eastern domain,especially the Gridino Zone and the Pongoma Bay area.The retrograde branch corresponds to the conditions ofa multistage near-isothermal decompression from 14 to6.5 kbar and a temperature fall from 770 to 650°C(older than 2.72 Ga ago) with a transition from eclogiticfacies to high-pressure granulite facies and further toamphibolite facies of high and moderate pressures. Theconditions of prograde development of eclogites mostlikely corresponded to the setting of “warm” subduc-tion, while the decompression trend of retrograde meta-morphism is related to the exhumation of eclogites.Granulite-facies metamorphism is recorded at thisstage (T = 700–750°ë; P = 6–7 kbar) and marked bymigmatitic and intrusive enderbites as well as byamphibolite-facies metamorphism of moderate pres-sure that occurred about 2.72 Ga ago [43]. At the nextstage (2691 ± 5 Ma), the rocks were metamorphosedagain in a high-pressure regime with a peak at T = 650–700°ë and P = 12–13 kbar as an apparent response tothe transpressional stage of the collisional BelomorianOrogeny.

The counterclockwise trend is typical of the westerndomain, e.g., near lakes Notozero and Kovdozero. Theoldest (2855 ± 5 Ma) [46] moderate-pressure granulite-facies metamorphism (T > 700°ë; P = 5.5–6.5 kbar)was established in garnet–biotite gneisses, which partlyserved as a protolith for kyanite gneisses, and in basiccrystalline schists. The granulite complex of crystallineschists, enderbites, and charnockites of calc-alkalineand high-Fe tholeiitic series [20, 47] was formed lateron (~2.72 Ga [47, 72]). High-pressure metamorphismof kyanite–orthoclase subfacies (T = 650–700°ë; P =

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SLABUNOV et al.

12–13 kbar) and intense migmatization developed fur-ther (~2.70 Ga) [20, 26, 27]. In the northern Belomo-rian Province (Yena segment), the PT parameters of thefirst stage of Neoarchean metamorphism were 620–680°ë and 7.6–8.8 kbar; the second stage was charac-

terized by 665–695°ë and 9.7–10.6 kbar [9]; i.e., as inthe central part of the province, the subsequent meta-morphic event was distinguished by a higher pressure.

The last metamorphic event is known from alldomains and apparently related to Neoarchean collision.

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The Archean eclogites in the Belomorian Provinceare the world’s oldest crustal eclogites. They have beenfound near the settlement of Gridino (White Sea)[22, 83] and the straits of the Narrow and Wide Salma(Lake Ekostrovsky Imandra, Kola Peninsula) [34, 94].

In the first locality, the eclogite-bearing complexoccurs as the Gridino tectonic sheet (Fig. 5A) that istraced for ~50 km from NW to SE and reaches 10 kmin width. This complex is an intensely migmatizedmelange (Fig. 5B), the leucosome of which was trans-formed into granite gneiss of tonalitic–trondhjemiticcomposition that contains enderbite relicts that indicatean event of granulite-facies metamorphism. The alloch-thonous mixture of the clastic component is composedof eclogite; amphibolite, including garnet and garnet–clinopyroxene varieties; metaultramafic and metagab-broic rocks; zoisite metaanorthosite; aluminous andamphibole-bearing gneisses; and marble.

The Neoarchean eclogites (Fig. 5C) consist ofomphacite (28–40 mol % jadeite end member) and gar-net (22–30 mol % pyrope and 22–30 mol % grossular).Their relicts are retained in the symplectitic eclogiteand garnet–clinopyroxene amphibolite that formed as aresult of retrograde decompression. Eclogite wasformed at T = 740–865°ë, P = 14.0–17.5 kbar, and adepth of 60–65 km. The age of zircons (NORDSIM)from eclogite and symplectitic eclogite is 2720.7 ±8 Ma [22]. The morphology of the zircon crystals istypical of high-pressure granulites and eclogites;paragenetic relations between zircon and other miner-als of eclogite are confirmed by depletion of zircon inHREE [18]. The melange zone is crosscut by posttec-tonic trondhjemite veins dated at 2701.3 ± 8.1 Ma [22]and by Paleoproterozoic gabbronorite dikes.

In terms of chemical composition, eclogites fit basicrocks (47–51 wt % SiO2, 1.38–4.3 wt % Na2O + K2O)of the tholeiitic series (FeO*/MgO = 0.5–2.5). The REEcontent is 2–12 times higher than in chondrite; the REEpattern is flat or slightly fractionated ((La/Sm)N = 0.99–1.80; (Ga/Yb)N = 0.77–1.17). Eclogites are correlatedwith MORB, basalts from ophiolites, and metabasalts(amphibolites) of the Central Belomorian greenstonebelt [83].

Eclogites are considered the most importantattributes of subduction. This mechanism explainstransportation of the crustal rocks in zones of high pres-

sure at a relatively low temperature [29], and preciselythis model is suggested for the Neoarchean eclogites ofthe Belomorian Province [22, 83, 92]. Other mecha-nisms of high-pressure mineral formation under crustalconditions are discussed in the literature [29], and thisdiscussion is topical for the Belomorian Province,where not only Neoproterozoic but also Paleoprotero-zoic eclogites are known [20, 22]. The nature of eclog-ites from Belomorye remains a matter of debate, andstudies in this field are currently ongoing [22, 34, 94].

The evolution of metamorphic regimes in the Belo-morian Province reflects the change of subduction-related processes by collision.

The Kola and Murmansk Provinces

In contrast to the Karelian Province, the mineralassemblages of only amphibolite and granulite faciesare established in the Archean complexes of the Kolaand Murmansk provinces; assemblages of greenschistfacies are unknown. The gradual transition betweengranulite and high-temperature amphibolite facies ischaracteristic of the andalusite–sillimanite type of lat-eral metamorphic zoning [67].

As in the case of other granulite complexes of theBaltic Shield, the granulite complex of the Kola–Nor-wegian Terrane (Fig. 2) consists of metasedimentaryand metaigneous rocks; the latter comprise felsic, inter-mediate, mafic, and ultramafic granulites with a preva-lence of enderbites [1, 64]. The maximum pressure esti-mated for cordierite-free mineral assemblages of silli-manite paragneisses amounts to 6.2 ± 1.2 kbar atT = 700°ë; in the zone transitional to amphibolitefacies, this value is P = 5.2 ± 0.9 kbar. Cordierite-bear-ing assemblages were formed at a lower pressure of4.5 ± 0.6 kbar at 700°ë [1, 8]. Kyanite–sillimaniteassemblages from the transitional zone are character-ized by P = 5.3 kbar and T = 580 ± 20°ë. The repeatedmetamorphism in the granulite zone proceeded at P =3.5 ± 0.5 kbar and T = 590°ë.

It is suggested that the first thermal reworking ofparagneisses in the Kola–Norwegian Terrane that pre-dated granulite-facies metamorphism took place2880 ± 45 Ma ago (Rb–Sr age of whole-rock samples,ISr = 0.7005 ± 0.0004) [1]. The age of the oldest granu-lite-facies metamorphism is estimated at 2.83 Ga,

Fig. 5. The Neoarchean Gridino eclogite-bearing complex, after [22, 83]. Geological sketch-maps of (A) North Karelia with thelocation of the eclogite-bearing complex near the settlement of Gridino, close to the White Sea, and (B) southeastern StolbikhaIsland, after A.I. Slabunov, O.S. Sibilev, and O.I. Volodichev. Legend for Panel A. (1) Paleoproterozoic; (2–7) Archean: (2) green-stone complex, (3) paragneiss complex, (4) mafic and ultramafic rocks of the Central Belomorian greenstone belt, (5) eclogite-bear-ing melange of the Gridino tectonic sheet, (6) granite gneisses and migmatites of the Belomorian Mobile Belt, (7) granitoids of theKarelian Craton; (8) inferred thrust faults. Legend for Panel B. (1) Quaternary sediments, (2) pegmatite vein, (3) trondhjemite (2701 ±8 Ma), (4) granite gneiss and orientation of gneissic banding therein, (5) eclogite and plagioclase–clinopyroxene symplectitic rockafter eclogite dated at 2721 ± 8 Ma, (6) amphibolite, (7) leucoamphibolite, (8) zoisite rock, (9) ultramafic rock, (10) orientation ofgneissic banding and schistosity. (C) Photomicrograph of eclogite from the vicinity of Gridino; the garnet–omphacite mineralassemblage is visible: (Prp26) content of the pyrope end member in garnet; (Omp32) content of the jadeite end member in omphacite.The secondary metamorphic mineral assemblages consist of plagioclase (Pl22 is the content of anorthite end member), diopside (Di16 isthe content of jadeite end member), and pargasitic hornblende (Prg-Hbl).

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whereas the age of metamorphic zircon from the lateshear zones that formed also under conditions of gran-ulite facies is 2648 ± 18 Ma [97]. The metamorphic zir-cons from paragneiss near Lake Pulozero mark onemore granulite-facies metamorphic event 2724 ± 49 Maago and retrograde metamorphism of amphibolitefacies 2640 ± 20 Ma ago [69]. The garnet–biotite gneissfrom the Pervomaisky area underwent granulite-faciesmetamorphism 2788 ± 16 Ma ago and amphibolite-facies metamorphism 2743 ± 18 Ma ago [62]. The ter-mination of the Archean structural rearrangement andmetamorphic reworking are determined from the age ofpostdeformational pegmatite, 2556 ± 27 Ma [97].

At least three metamorphic events are recorded inthe rocks from the Kolmozero–Voron’ya greenstonebelt of the Kola–Norwegian Terrane [8]. The first event(2.83–2.76 Ga) proceeded under conditions of epidote–amphibolite and low-temperature amphibolite facies oflow pressure (T = 460–560°ë; P = 2.5–4.3 kbar). Thesecond episode (2.76–2.68 Ga) developed at the sametemperature but at a higher pressure (T = 470–530°ë;P = 3.9–5.8 kbar). The third event (2.68–2.52 Ga) wasrelated to the late shear zones and characterized by thehighest parameters: T = 530–640°ë and P = 6.0–8.5 kbar. A certain analogy of this P–T–t path with theevolution trend of metamorphism in the greenstonebelts of the Karelian Province that is related to accre-tionary and collisional stages attracts attention.

The Archean metamorphism of rocks in the KeivyTerrane generally corresponds to the staurolite–two-mica subfacies [67]. The rocks that experiencedregional metamorphism were markedly affected by theNeoarchean alkali-granitic and basic magmas (the lat-ter are responsible for andalusite metamorphism) andby the Neoarchean and Paleoproterozoic reverse andthrust faulting.

In general, the Archean rocks of the Kola–Norwe-gian Terrane are characterized by wide superposition ofPaleoproterozoic metamorphism that developed atmoderate and elevated pressure (kyanite–sillimanitetype). Furthermore, Paleoproterozoic metamorphismvarying from greenschist to high-pressure granulitefacies is known, e.g., in the Chudjärvi Zone, where theArchean and Proterozoic granulites are juxtaposed [67].

In the Murmansk Province, the oldest metamorphicevents proceeded under conditions of granulite facies ata temperature reaching 750°ë and at 4–6 kbar pressure[68]. The subsequent reworking and migmatization wascharacterized by conditions of amphibolite facies.More specific data are not available.

GEODYNAMIC SETTINGS AND MAIN STAGES OF CRUST FORMATION

The first sialic islands arose 3.5–3.1 Ga ago (Fig. 6).Their largest fragments are known in the VodlozeroTerrane, while the smaller ones are known in the Iis-almi, Ranua, and Pomokaira terranes of the Karelian

Province [72, 121, 133]. The findings of Paleoarcheandetrital zircons in metasedimentary rocks of the Kola[62, 102, 111] and Belomorian [37] provinces allow usto suggest that such fragments were greater in number.It cannot be ruled out that they made up a common con-tinent that broke down in the Mesoarchean [83].

A new stage of crust formation began 3.10–2.95 Gaago. Its history is recorded most fully in greenstone andintrusive complexes of the Vodlozero Terrane. A sub-duction-related system was formed at its western (in thepresent-day coordinates) margin 3.05–3.00 Ga ago.This system comprised an ensialic volcanic arc and aconjugated backarc deepwater basin; indicative com-plexes of these settings have been established in theVedlozero–Segozero system of greenstone belts [77].Having been initiated by a mantle plume, the basalt–komatiite complexes that made up an oceanic plateau inthe Sumozero–Kenozero greenstone belt were formedat that time at the eastern and northeastern margins ofthe Vodlozero Terrane [128]. Afterward these com-plexes were obducted upon the continent. The mul-tiphase mafic intrusions and trondhjemites wereemplaced at that stage into the inner zone of the sialiccore [72].

Furthermore, the subduction system marked by theolder greenstone complex of the Kuhmo–Suomus-salmi–Tipasjärvi Belt in the Kianta Terrane was formedduring this period; the growth of continental crust isfixed in the Ilomantsi–Voknavolok Terrane as well.

In the interval 2.95–2.82 Ga ago, the growth of thecontinental crust was confined to the southeasternKarelian Province, the adjacent territory of the Belo-morian Province, and the Kola Province. Subduction inthe west of the Vodlozero Terrane resulted in the gener-ation of calc-alkaline volcanics of the Vedlozero–Segoz-ero greenstone belt. The volcanosedimentary sequencesderived from the Vodlozero microcontinent weredeposited in the forearc basin of this active margin. Thesubaerial felsic volcanism in the backarc zone wasaccompanied by accumulation of volcaniclastic andterrigenous sediments [77]. Accretion of the Vedloz-ero–Segozero volcanic arc to the Vodlozero microcon-tinent ended with emplacement of the oldest two-feld-spar granites [72]. The first island-arc systems arose atthat time in the Belomorian Province, as reflected in thelateral series of the Keretozero, Chupa, and CentralBelomorian complexes and in the formation of theTulppio greenstone belt [83]. The subduction-relatedconvergent boundary arose at that time in the KolaProvince; the Keivy active continental margin and theKolmozero–Voron’ya island-arc system were formedas well [56].

The active formation of crust continued 2.82–2.75 Ga ago in the newly formed subduction-relatedsystems in the Sumozero–Kenozero Belt at the marginof the Vodlozero Terrane of the Karelian Province; inthe Olenegorsk greenstone belt of the Kola Province;and in the system of North Karelian greenstone belts of



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the Belomorian Province, where a new convergentboundary was formed in the ensimatic setting. The Tik-shozero island-arc system arose along this boundary.The formation of the Iringora suprasubduction ophio-lites was related to the early stage of evolution of thissystem [130]; intermediate and felsic calc-alkaline andadakitic volcanic rocks were formed at the mature stage[15, 36]. The basalt–komatiite associations of theKuhmo–Suomussalmi–Tipasjärvi and Kostomukshabelts were formed at that time in the west of the Kare-lian Province under the influence of the mantle plume.These associations may be interpreted either as prod-ucts of intracontinental rifting [44, 49, 123] or as anoceanic plateau [37, 129]. The rocks of the Matkalahtigreenstone belt were probably formed at the same timeas a result of continental rifting in the Vodlozero micro-continent [37]. The continental crust of the Kianta andCentral Karelian terranes of the Karelian and Kola prov-inces, respectively, and of the Murmansk Province wasformed contemporaneously. Thus, most Archean sialiccrust of the Baltic Shield had been formed by 2.75 Ga ago.

Geologic processes related to the stage of 2.75–2.65 Ga developed throughout the Baltic Shield asactive magmatism, including dikes and large intrusionsof gabbronorite and gabbro [72] that immediately pre-dated the last episode of the Archean granulite-faciesmetamorphism, sanukitoids and syenites, tonalites andgranites, alkali granites, nepheline syenites, and car-bonatites. This magmatic activity demonstrates that themelts formed synchronously in both depleted andenriched lithospheric mantle and at various depthswithin the continental crust and may testify to the activ-ity of mantle plumes [122]. Some authors [20, 26, 83]regard the stage of 2.70–2.65 Ga as collisional. It issuggested that the collision was the most spectacular inthe Belomorian Province, which was a core of thegrowing orogen. The granitoid complexes (sanukitoids)2.73–2.70 Ga in age were emplaced in the zone transi-tional to the Karelian Province [98, 122]; the basinsfilled with intermediate and felsic volcanics and sedi-mentary rocks arose in the central part of the province.Their fragments are retained in the Ilomantsi, Khedoz-ero–Bolsheozero, and Gimoly belts [75, 133]. Accre-tion and collision at the boundaries of terranes in theKarelian Province probably led to the formation of theVarpaisjärvi, Tulos, Voknavolok, and Onega local gran-ulite zones. The granulite complexes of the BelomorianProvince, e.g., Notozero, were formed simultaneously,and the Gridino and Salmi eclogites began to beexhumed. The collapse of orogen started just after itsformation, as follows from the deposition of volcanicand coarse clastic complexes (Voche-Lambina struc-tural unit) and the emplacement of gabbroids (Fig. 2).

The distinct heterogeneity of the Archean crust inthe Kola Province [4, 58] has attracted attention. Thejuxtaposition of the extremely distinct Kola–Norwe-gian and Keivy terranes and their principal differencefrom the Murmansk and Belomorian provinces allow

us to classify these terranes as exotic and the Kola Prov-ince itself as a Neoarchean collage of terranes.

Thus, the generation of the Archean continentalcrust of the Baltic Shield was related largely to subduc-tion of lithospheric plates [32, 36, 55, 75, 83, 99, 105]together with an appreciable contribution of mantleplumes [3, 25, 72, 89, 92, 127, 128]. The eventual for-mation of the Archean continental domain was a resultof collision [26, 36, 83].

The following main conclusions may be drawn fromthe performed study:

(1) The Archean greenstone (schist) and paragneisscomplexes of the Baltic Shield are composed of differ-ent lithotectonic associations, which were formed invarious geodynamic settings related to subduction(ensialic and ensimatic), spreading, continental rifting,mantle plumes, and collision. A wide range of Archeangranitoids and metamorphic regimes is consistent withthis diversity of geodynamic settings.

(2) The Archean core of the shield was formed 3.1–2.5 Ga ago in the process of accretionary and subduc-tion-related events (no less than four episodes) and col-lisional events (no less than two episodes) against thebackground of continuous and intense mantle-plumeactivity. The general sequence and direction of events dur-ing the formation of the continental crust have much incommon with the evolution of Phanerozoic orogenic belts.

ACKNOWLEDGMENTS

We thank V.N. Kozhevnikov for providing us accessto his paper that was being prepared for publication andthe reviewers for their critical comments and helpfulrecommendations. This study was carried out under theSVEKALAPKO Project of the EUROPROBE Program1996–2002. At the final stage, this investigation wassupported by the Academy of Finland; the GeologicalSurvey of Finland; the Russian Foundation for BasicResearch (project nos. 03-05-64010, 03-05-65051,06-05-64876, and 06-05-65237); and program nos. 6and 8 of the Division of Earth Sciences, Russian Acad-emy of Sciences.

REFERENCES1. K. Kh. Avakyan, Geology and Petrology of the Central

Kola Archean Granulite–Gneiss Region (Nauka, Mos-cow, 1992) [in Russian].

2. N. L. Alekseev, V. V. Balagansky, T. F. Zinger, et al.,“Late Archean History of the Belomorian Mobile Beltand the Karelia Craton Junction Zone, Baltic Shield,”Dokl. Akad. Nauk 397 (3), 369–373 (2004) [Dokl.Earth Sci. 397A (6), 743–746 (2004)].

3. N. A. Arestova, “Evolution of Mafic–Ultramafic Mag-matism of the Baltic Shield in the Interval of 3.4–2.4 Ga,” Doctoral Dissertation in Geology and Mineral-ogy (St. Petersburg, 2004).

4. V. V. Balagansky, “Main Stages of the PaleoproterozoicTectonic Evolution of the Northeastern Baltic Shield,”



Doctoral Dissertation in Geology and Mineralogy(St. Petersburg, 2002).

5. I. D. Batieva, Petrology of Alkali Granitoids of the KolaPeninsula (Nauka, Leningrad, 1976) [in Russian].

6. T. B. Bayanova, Ages of Reference Geological Com-plexes of the Kola Region and Duration of MagmaticEvents (Nauka, St. Petersburg, 2004) [in Russian].

7. O. A. Belyaev, F. P. Mitrofanov, T. B. Bayanova, et al.,“The Late Archean Age of Acid Metavolcanic Rocks inthe Malye Keivy Region, Kola Peninsula),” Dokl. Akad.Nauk 379 (5), 651–654 (2001) [Dokl. Earth Sci. 379A(6), 705–708 (2001)].

8. O. A. Belyaev and V. P. Petrov, “New Data on the Pre-cambrian Structural–Metamorphic History of theNortheastern Baltic Shield,” in Geology and MineralResources of the Kola Peninsula (Kola Sci. Center, Rus-sian Acad. Sci., Apatity, 2002), Vol. 2, pp. 195–207 [inRussian].

9. O. A. Belyaev and V. I. Pozhilenko, “Structural-Meta-morphic Evolution of the Belomorian Mobile Belt(Yena Segment),” in The Belomorian Mobile Belt:Geology, Geodynamics, and Geochronology (Karel.Sci. Center, Russian Acad. Sci., Petrozavodsk, 1997),p. 17 [in Russian].

10. I. V. Bel’kov, Kyanite Schists of the Keivy Formation(Akad. Nauk SSSR, Moscow, 1963) [in Russian].

11. E. V. Bibikova, S. V. Bogdanova, V. A. Glebovitsky,et al., “Evolution Stages of the Belomorian Mobile Beltfrom U–Pb Zircon Geochronology (NORDSIM IonMicroprobe),” Petrologiya 12 (3), 227–244 (2004)[Petrology 12 (3), 195–210 (2004)].

12. E. V. Bibikova, V. R. Vetrin, T. I. Kirnozova, et al.,“Geochronology and Correlation of Rocks from theLower Part of the Kola Superdeep Well Section,” Dokl.Akad. Nauk 332 (3), 360–363 (1993).

13. E. V. Bibikova and I. N. Krylov, “Isotopic Dating ofAcid Volcanics in Karelia,” Dokl. Akad. Nauk SSSR268 (5), 189–191 (1983).

14. E. V. Bibikova, A. V. Samsonov, A. Yu. Petrova, andT. I. Kirnozova, “Archean Geochronology of WesternKarelia,” Stratigr. Geol. Korrelyatsiya 13 (5), 3–20(2005) [Stratigr. Geol. Correlation 13 (5), 459–475(2005)].

15. E. V. Bibikova, A. V. Samsonov, A. A. Shchipansky,et al., “The Hisovaara Structure of the North KareliaGreenstone Belt as a Late Archean Accretion IslandArc: Isotopic–Geochronologic and Petrologic Data,”Petrologiya 11 (3), 289–320 (2003) [Petrology 11 (3),261–290 (2003)].

16. E. V. Bibikova, A. I. Slabunov, S. V. Bogdanova, et al.,“Early Magmatism of the Belomorian Mobile Belt, Bal-tic Shield: Lateral Zoning and Isotopic Age,”Petrologiya 7 (2), 115–140 (1999) [Petrology 7 (2),123–146 (1999)].

17. E. V. Bibikova, A. I. Slabunov, T. I. Kirnozova, et al.,“U–Rb Geochronology and Major-Element Chemistryof a Diorite–Plagiogranite Batholith in Northern Kare-lia,” Geokhimiya 35 (11), 1154–1160 (1997) [Geochem.Int. 35 (11), 1021–1027 (1997)].

18. E. V. Bibikova, A. I. Slabunov, T. I. Kirnozova, et al.,“Isotopic–Geochronologic and Geochemical Signatureof Rocks from Late Archean Eclogite-Bearing Melange

in the Gridino Settlement Area (Belomorian MobileBelt, Baltic Shield),” in Proceedings of XVII Vinogra-dov Symposium on Isotopic Geochemistry (GEOKhI,Moscow, 2004), pp. 31–32 [in Russian].

19. V. R. Vetrin, I. L. Kamensky, T. B. Bayanova, et al.,“Melanocratic Nodules in Alkali Granites of the PonoiMassif, Kola Peninsula: A Clue to Petrogenesis,”Geokhimiya 37 (11), 1178–1191 (1999) [Geochem.Intern. 37 (11), 1061–1072 (1999)].

20. O. I. Volodichev, Belomorian Complex in Karelia:Geology and Petrology (Nauka, Leningrad, 1990) [inRussian].

21. O. I. Volodichev, T. B. Bayanova, and N. V. Levkovich,“U–Rb Isotopic Dating of Charnockites in the South-eastern Tulosozero Structural Unit of Western Karelia,”in Implications of Isotopic Geochronology for the Solu-tion of Geodynamic and Ore Formation Problems(Tsentr Inform. Kul’tury, St. Petersburg, 2003),pp. 110–113 [in Russian].

22. O. I. Volodichev, A. I. Slabunov, E. V. Bibikova, et al.,“Archean Eclogites of the Belomorian Mobile Belt,”Petrologiya 12 (6), 609–631 (2004) [Petrology 12 (6),540–560 (2004)].

23. The Voche-Lambina Archean Geodynamic Testing Sitein the Kola Peninsula, Ed. by F. P. Mitrofanov andV. I. Pozhilenko (Kola Sci. Center, Acad. Sci. USSR,Apatity, 1991) [in Russian].

24. A. B. Vrevsky, Petrology and Geodynamic Evolution ofthe Archean Lithosphere (Nauka, Leningrad, 1989) [inRussian].

25. A. B. Vrevsky, V. A. Matrenichev, and M. S. Ruzh’ev,“Komatiite Petrology of Baltic Shield and Isotopic–Geochemical Evolution of Their Mantle Sources,”Petrologiya 11 (6), 587–617 (2003) [Petrology 11 (6),532–561 (2003)].

26. V. A. Glebovitsky, Yu. V. Miller, G. M. Drugova, et al.,“The Structure and Metamorphism of the Belomoride–Lapland Collision Zone,” Geotektonika, No. 1, 53–63(1996) [Geotectonics 30 (1), 53–63 (1996)].

27. V. A. Glebovitsky, T. F. Zinger, and B. V. Belyatsky,“The Age of Granulites and Nappe Formation in theWestern Belomorian Belt,” Dokl. Akad. Nauk 371 (1),63–64 (2000) [Dokl. Earth Sci. 371 (2), 255–258(2000)].

28. Deep Structure and Seismicity of the Karelian Regionand Its Framework, Ed. by N. V. Sharov (Karel. Sci.Center, Russian Acad. Sci., Petrozavodsk, 2004) [inRussian].

29. N. L. Dobretsov, A. G. Kirdyashkin, and A. A. Kir-dyashkin, Deep Geodynamics (Siberian Division, Rus-sian Acad. Sci., Novosibirsk, 2001) [in Russian].

30. G. M. Drugova, O. A. Levchenkov, and T. E. Savel’eva,“Early Precambrian Granitoids of Northwestern Belo-morian Region,” Zap. Vseross. Mineral. O–va 124 (1),35–51 (1995).

31. M. A. Eliseev, “Lopian Structure in the ChelozeroRegion,” in Geology of the Northern and Eastern Kare-lian Structural Zones (Karel. Sci. Center, Acad. Sci.USSR, Petrozavodsk, 1987), pp. 13–36 [in Russian].

32. Greenstone Belts in the Basement of the East EuropeanPlatform: Geology and Petrology, Ed. by S. B. Lobach-Zhuchenko (Nauka, Leningrad, 1988) [in Russian].

430


SLABUNOV et al.

33. T. V. Kaulina and M. N. Bogdanova, “New U–Pb Dataon Magmatism and Metamorphism in the NorthwesternBelomorian Region,” Dokl. Akad. Nauk 366 (5), 677–679 (1999) [Dokl. Earth Sci. 367 (5), 667–669 (1999)].

34. T. V. Kaulina and E. A. Apanasevich, “Archean Eclog-ites in the Shirokaya Salma Area (Kola Peninsula):U−Rb and Sm–Nd Data,” in Proceedings of ScientificConference on the Belomorian Mobile Belt and Its Ana-logues: Geology, Geochronology, Geodynamics, andMineralogy (Karel. Sci. Center, Russian Acad. Sci.,Petrozavodsk, 2005), pp. 174–175 [in Russian].

35. R. V. Kislitsyn, V. V. Balagansky, and I. Mänttäri, “TheAge of the Voche-Lambina Testing Site Supracomplex,Kola Peninsula: U–Pb Zircon Dating,” in General Prob-lems of the Subdivision of the Precambrian (Poligraf,Apatity, 2000), pp. 103–106 [in Russian].

36. V. N. Kozhevnikov, Archean Greenstone Belts of theKarelian Craton as Accretionary Orogens (Karel. Sci.Center, Russian Acad. Sci., Petrozavodsk, 2000) [inRussian].

37. V. N. Kozhevnikov, N. G. Berezhnaya, S. L. Presnya-kov, et al., “Geochronology (SHRIMR-II) of Zirconfrom Archean Lithotectonic Associations in the Green-stone Belts of the Karelia Craton: Implications forStratigraphic and Geodynamic Reconstructions,”Stratigr. Geol. Korrelyatsiya 14 (3), 19–41 (2006)[Stratigr. Geol. Correlation 14 (3), 240–259 (2006)].

38. N. E. Kozlov, A. A. Ivanov, E. V. Martynov, et al.,“Compositional Evolution of the Oldest Archean Meta-morphic Complexes in the Northeastern Baltic Shield,Canada, and Greenland,” in Proceedings of the FirstRussian Conference on Geology and Geodynamics ofPrecambrian (Tsentr Inform. Kul’tury, St. Petersburg,2005), pp. 172–177 [in Russian].

39. Early Precambrian Komatiites and High-MagnesianVolcanics of the Baltic Shield, Ed. by O. A. Bogatikov(Nauka, Leningrad, 1988) [in Russian].

40. N. M. Kudryashov, “Geochronology of Paragneisses,Granite Gneisses, and Metarhyolites in the Lake SennoeArea,” Candidate’s Dissertation in Geology and Miner-alogy (St. Petersburg, 1996).

41. N. M. Kudryashov, B. V. Gavrilenko, and E. A. Apa-nasevich, “Age of Rocks of the Archean Kolmozero–Voron’ya Greenstone Belt: New U–Pb Data,” in Geol-ogy and Mineral Resources of Northwestern Russia(Kola Sci. Center, Russian Acad. Sci., Apatity, 1999),pp. 66–70 [in Russian].

42. V. V. Kulikova, The Volotsk Formation: a Stratotype ofthe Lower Archean in the Baltic Shield (Karel. Sci. Cen-ter, Russian Acad. Sci., Petrozavodsk, 1993) [in Rus-sian].

43. O. A. Levchenkov, T. F. Zinger, V. L. Duk, et al., “U–PbZircon Age of the Hypersthene Diorites and Granitoidsfrom the Pongoma-Navolok Island, the Baltic Shield,Belomorian Tectonic Zone,” Dokl. Akad. Nauk 349 (2),852–854 (1996) [Dokl. Earth Sci. 349 (5), 852–854(1996)].

44. S. B. Lobach-Zhuchenko, N. A. Arestova, R. I. Mil’kevich,et al., “Stratigraphy of the Kostomuksha Belt in Karelia(Upper Archean) as Inferred from Geochronological,Geochemical, and Isotopic Data,” Stratigr. Geol. Korre-lyatsiya 8 (4), 319–326 (2000) [Stratigr. Geol. Correla-tion 8 (4), 319–326 (2000)].

45. S. B. Lobach-Zhuchenko, N. A. Arestova, V. P. Cheku-laev, et al., “Evolution of the South Vygozero Green-stone Belt, Karelia,” Petrologiya 7 (2), 160–176 (1999)[Petrology 7 (2), 160–176 (1999)].

46. S. B. Lobach-Zhuchenko, E. V. Bibikova, G. M. Drugova,et al., “Geochronology and Petrology of the TupayaGuba Igneous Complex in the Northwestern Belomo-rian Region,” Petrologiya 1 (6), 657–677 (1993).

47. S. B. Lobach-Zhuchenko, E. V. Bibikova, G. M. Drugova,et al., “Archean Magmatism in the Notozero Region ofthe Northwestern Belomorian Region: Isotopic Geo-chronology and Petrology,” Petrologiya 3 (6), 593–621(1995).

48. S. B. Lobach-Zhuchenko, S. A. Sergeev, O. A. Levchen-kov, et al., “The Early Archean Vodlozero Gneiss Com-plex and Its Structural and Metamorphic Evolution,”Precambrian Isotopic Geochronology (Nauka, Lenin-grad, 1989), pp. 14–45 [in Russian].

49. S. B. Lobach-Zhuchenko, V. P. Chekulaev, N. A. Are-stova, et al., “Archean Terranes in Karelia: Geological andIsotopic–Geochemical Evidence,” Geotektonika, No. 6,26–42 (2000) [Geotectonics 34 (6), 452–466 (2000)].

50. S. B. Lobach-Zhuchenko, V. P. Chekulaev, V. S. Stepanov,et al., “The Belomorian Foldbelt—the Late ArcheanAccretionary and Collisional Zone of the Baltic Shield,”Dokl. Akad. Nauk 358 (2), 226–229 (1998) [Dokl.Earth Sci. 358 (1), 34–37 (1998)].

51. Yu. V. Miller, Structure of Archean Greenstone Belts(Nauka, Leningrad, 1988) [in Russian].

52. Yu. V. Miller, V. S. Baikova, N. A. Arestova, andI. K. Shuleshko, “Role of the Khetolambina Terrane inEvolution of the Belomorian Mobile Belt,” Geotekto-nika, No. 2, 17–32 (2005) [Geotectonics 39 (2), 112–125(2005)].

53. Yu. V. Miller and R. I. Mil’kevich, “The Fold-and-Nappe Structure of the Belomorian Zone and Its Rela-tionship with the Karelian Granite–Greenstone Domain,”Geotektonika, No. 6, 80–93 (1995).

54. R. I. Mil’kevich and G. A. Myskova, “The Late ArcheanMetaterrigenous Rocks of the Western Karelia: Lithol-ogy, Geochemistry, and Provenances,” Litol. Polezn.Iskop. 33 (2), 177–194 (1998) [Lithol. Miner. Resour.33 (2), 155–171 (1998)].

55. M. V. Mints, “Archean Miniplate Tectonics,” Geotek-tonika, No. 6, 2–22 (1998) [Geotectonics 32 (6), 427–443 (1998)].

56. M. V. Mints, V. N. Glaznev, A. N. Konilov, et al., TheEarly Precambrian in the Northeastern Baltic Shield:Paleogeodynamics, Structure, and Evolution of Conti-nental Crust (Nauchnyi Mir, Moscow, 1996) [in Rus-sian].

57. F. P. Mitrofanov, “Current Problems and Some Solu-tions of the Precambrian Geology of Cratons,” Lito-sfera, No. 1, 5–14 (2001).

58. F. P. Mitrofanov and T. B. Bayanova, “The ArcheanKeivy Terrane of the Kola Collisional Belt: A SpecialStructure Evolving for a Long Time from Protoplatformto Orogen” in Regions of Active Tectogenesis in theRecent and Ancient History of the Earth (GEOS, Mos-cow, 2006), Vol. 2, pp. 41–44 [in Russian].

59. F. P. Mitrofanov, D. R. Zozulya, T. B. Bayanova, andN. V. Levkovich, “The World’s Oldest Anorogenic



Alkali Granitic Magmatism in the Keivy Structural Unitof the Baltic Shield,” Dokl. Akad. Nauk 374 (2), 238–241 (2000) [Dokl. Earth Sci. 374 (7), 1145–1148(2000)].

60. T. A. Myskova, V. A. Glebovitsky, Yu. V. Miller, et al.,“Supracrustal Sequences of the Belomorian MobileBelt: Primary Composition, Age, and Origin,” Stratigr.Geol. Korrelyatsiya 11 (6), 3–19 (2003) [Stratigr. Geol.Correlation 11 (6), 535–549 (2003)].

61. T. A. Myskova, R. I. Mil’kevich, E. S. Bogomolova, andV. F. Guseva, “New Data on the Composition and Ageof a Protolith for Aluminous Gneisses of the Kola andthe Tyndrovaya Groups in the Central Kola Block of theBaltic Shield,” in Proceedings of the First Russia Con-ference on Precambrian Geology and Geodynamics(Tsentr Inform. Kul’tury, St. Petersburg, 2005),pp. 272–275 [in Russian].

62. T. A. Myskova, N. G. Berezhnaya, V. A. Glebovitsky,et al., “Finds of the oldest Zircon 3600 Ma in Age fromGneiss of the Kola Group in the Central Kola Block ofthe Baltic Shield (U–Pb, SHRIMR-II),” Dokl. Akad.Nauk 402 (1), 82–85 (2005) [Dokl. Earth Sci. 402 (4),547–550 (2005)].

63. I. V. Nikitin, “Tectonics of the Kolmozero–Voron’yaZone in the Light of Horizontal Movements,” inRegional Early Precambrian Tectonics of the USSR(Nauka, Leningrad, 1980), pp. 104–111 [in Russian].

64. A. T. Radchenko, V. V. Balagansky, A. A. Basalaev,et al., Explanatory Notes to the Geologic Map of theNortheastern Baltic Shield, Scale 1 : 500000 (Kola Sci.Center, Russian Acad. Sci., Apatity, 1994) [in Russian].

65. G. V. Ovchinnikova, V. A. Matrenichev, O. A. Levchen-kov, et al., “U–Pb and Pb–Pb Isotopic Studies of AcidVolcanics of the Hautovaara Greenstone Belt, CentralKarelia,” Petrologiya 2 (3), 266–281 (1994).

66. P. Peltonen, I. Mänttäri, H. Huhma, and M. J. White-house, “Origin and Transformation of the Lower Crustat the Western Margin of the Karelian Craton, Finland,”in Belomorian Mobile Belt and Its Analogues: Geology,Geochronology, Geodynamics, and Mineralogy (Karel.Sci. Center, Russian Acad. Sci., Petrozavodsk, 2005),pp. 247–248 [in Russian].

67. V. P. Petrov, Early Proterozoic Metamorphism in theBaltic Shield (Kola Sci. Center, Russian Acad. Sci.,Apatity, 1999) [in Russian].

68. V. P. Petrov, O. A. Belyaev, Z. M. Voloshina, et al.,Endogenic Regimes of Metamorphism in the Early Pre-cambrian (Nauka, Leningrad, 1990) [in Russian].

69. L. S. Petrovskaya and T. B. Bayanova, “The Successionof Endogenic Processes in the Archean Rocks of thePulozero Region (Central Kola Block),” in IsotopicDating of Geological Processes: New Methods andResults (GEOS, Moscow, 2000), pp. 264–266 [in Rus-sian].

70. V. I. Pozhilenko, B. V. Gavrilenko, D. V. Zhirov, andS. V. Zhabin, Geology of Ore Districts in the MurmanskOblast (Kola Sci. Center, Russian Acad. Sci., Apatity,2002) [in Russian].

71. I. S. Puchtel, D. Z. Zhuravlev, V. V. Kulikova, et al.,“Komatiites of the Vodlozero Block in the Baltic Shield:A Window into the Early Archean Mantle?,” Dokl.Akad. Nauk SSSR 317 (1), 197–202 (1991).

72. Early Precambrian of the Baltic Shield, Ed. by V. A. Gle-bovitsky (Nauka, St. Petersburg, 2005) [in Russian].

73. M. S. Ruzh’eva, “Komatiitic–Basaltic Magmatism ofthe Kolmozero–Voron’ya Greenstone Belt (Kola Penin-sula) as Evidence for Plume-Tectonic Mechanism2.82 Ga Ago,” in Mantle Plumes and Metallogeny (Prob-lel-2000, Petrozavodsk, 2002), pp. 191–193 [in Russian].

74. S. I. Rybakov, A. I. Svetova, V. S. Kulikov, V. I. Robonen,et al., Volcanism of Archean Greenstone Belts in Karelia(Nauka, Leningrad, 1981) [in Russian].

75. A. V. Samsonov, “Evolution of Magmatism in the Gran-ite–Greenstone Domains of the East European Craton,”Doctoral Dissertation in Geology and Mineralogy(Moscow, 2004).

76. S. A. Svetov, Komatiite–Tholeiite Associations of theVedlozero–Segozero Greenstone Belt in Central Karelia(Karel. Sci. Center, Russian Acad. Sci., Petrozavodsk,1997) [in Russian].

77. S. A. Svetov, Archean Magmatic Systems of Ocean–Continent Transition Zone in the Eastern Fennoscan-dian Shield (Karel. Sci. Center, Russian Acad. Sci.,Petrozavodsk, 2005) [in Russian].

78. A. I. Svetova, Archean Volcanism of the Vedlozero–Seg-ozero Greenstone Belt in Karelia (Karel. Branch, Acad.Sci. USSR, Petrozavodsk, 1988) [in Russian].

79. S. A. Sergeev, “Geology and Isotopic Geology of theArchean Granite–Greenstone Complexes in Central andSoutheastern Karelia,” Candidate’s Dissertation inGeology and Mineralogy (Leningrad, 1989).

80. S. A. Sergeev, N. A. Arestova, O. A. Levchenkov, andS. Z. Yakovleva, “Isotopic U–Pb Dating of the Sem-chensky Gabbrodiorite Intrusion,” Izv. Akad. NaukSSSR, Ser. Geol., No. 4, 15–21 (1983).

81. S. A. Sergeev, E. V. Bibikova, O. A. Levchenkov, et al.,“Isotopic Geochronology of the Vodlozero GneissComplex,” Geokhimiya, 28 (1), 73–83 (1990).

82. A. I. Slabunov, “Upper Archean Keret Granite–Green-stone System in Karelia,” Geotektonika, 28 (5), 61–74(1993).

83. A. I. Slabunov, “Geology and Geodynamics of theBelomorian Mobile Belt of the Fennoscandian Shield,”Doctoral Dissertation in Geology and Mineralogy(Moscow, 2005).

84. V. F. Smolkin, Early Precambrian Komatiitic andPicritic Magmatism in the Baltic Shield (Nauka,St. Petersburg, 1992) [in Russian].

85. N. N. Sochevanov, N. A. Arestova, V. A. Matrenichev,et al., “First Data on the Sm–Nd Age of Archean Basaltsin Karelia Granite–Greenstone Region,” Dokl. Akad.Nauk SSSR 318 (1), 175–180 (1991).

86. V. S. Stepanov and A. I. Slabunov, PrecambrianAmphibolites and Early Mafic–Ultramafic Rocks inNorthern Karelia (Nauka, Leningrad, 1989) [in Russian].

87. Precambrian Stratigraphy of Karelia. Reference Sec-tions of the Upper Archean Rocks, Ed. by S. I. Rybakovand M. M. Stenar (Karel. Sci. Center, Russian Acad.Sci., Petrozavodsk, 1992) [in Russian].

88. V. E. Khain, Main Problems of Modern Geology(Nauchnyi Mir, Moscow, 2003) [in Russian].

89. V. P. Chekulaev, O. A. Levchenkov, S. B. Lobach-Zhuchenko, and S. A. Sergeev, “New Data on Determi-

432


SLABUNOV et al.

nation of Age Boundaries in the Formation of ArcheanComplexes in Karelia,” in Global Problems and Princi-ples of Precambrian Stratigraphic Subdivision (Nauka,St. Petersburg, 1994), pp. 69–86 [in Russian].

90. V. P. Chekulaev, S. B. Lobach-Zhuchenko, andN. A. Arestova, “Archean Magmatism at the North-western Margin of the Ancient Vodlozero Domain nearLake Oster, Karelia: Geology, Geochemistry, andPetrology,” Petrologiya 10 (2), 138–167 (2002) [Petrol-ogy 10 (2), 119–145 (2002)].

91. V. P. Chekulaev, S. B. Lobach-Zhuchenko, andL. K. Levsky, “Archean Granites in Karelia as Indica-tors of the Composition and Age of the ContinentalCrust,” Geokhimiya 35 (8), 805–816 (1997) [Geochem.Intern. 35 (8), 704–715 (1997)].

92. A. A. Shchipansky, “Subduction and Mantle Plume Pro-cesses in Geodynamics of the Formation of ArcheanGreenstone Belts,” Doctoral Dissertation in Geologyand Mineralogy (Moscow, 2005).

93. A. A. Shchipansky, I. I. Babarina, K. A. Krylov, et al.,“The Oldest Terrestrial Ophiolites: The Late ArcheanSuprasubduction Complex of the Iringora Structure,Northern Karelian Greenstone Belt,” Dokl. Akad. Nauk377 (3), 376–380 (2001) [Dokl. Earth Sci. 377A (3),283–287 (2001)].

94. A. A. Shchipansky, A. N. Konilov, M. V. Mints, et al.,“The Late Archean Salmi Eclogites, BelomorianMobile Belt, Kola Peninsula, Russia: Petrogenesis,Age, and Implications for the Geodynamic Interpreta-tion of the Setting of the Early Continental Crust For-mation,” in Proceedings of Scientific Conference onBelomorian Mobile Belt and Its Analogues: Geology,Geochronology, Geodynamics, and Mineralization.Guidebook (Karel. Sci. Center, Russian Acad. Sci.,Petrozavodsk, 2005), pp. 324–327 [in Russian].

95. A. A. Shchipansky, A. V. Samsonov, M. M. Bogina,et al., “High-Mg, Low-Ti Quartz Amphibolites of theHisovaara Greenstone Belt, Northern Karelia: Meta-morphosed Archean Boninites?,” Dokl. Akad. Nauk365 (6), 817–820 (1999) [Dokl. Earth Sci. 365A (3),422–425 (1999)].

96. N. A. Arestova, S. B. Lobach-Zhuchenko, V. P. Cheku-laev, and E. G. Gus’kova, “Early Precambrian MaficRocks of the Fennoscandian Shield as a Reflection ofPlume Magmatism: Geochemical Types and FormationStages,” Russ. J. Earth Sci. 5, 145–163 (2003).

97. Yu. A. Balashov, F. P. Mitrofanov, and V. V. Balagansky,“New Geochronological Data on Archaean Rocks of theKola Peninsula,” in Correlation of Precambrian For-mations in the Kola–Karelian region and Finland (KolaSci. Center, Russian Acad. Sci., Apatity, 1992), pp. 13–34.

98. E. V. Bibikova, A. Petrova, and S. Claesson, “The Tem-poral Evolution of Sanukitoids in the Karelian Craton,Baltic Shield: An Ion Microprobe U–Th–Pb IsotopicStudy of Zircons,” Lithos 79, 129–145 (2005).

99. E. V. Bibikova, T. Skiöld, and S. V. Bogdanova, “Ageand Geodynamic Aspects of the Oldest Rocks in thePrecambrian Belomorian Belt of the Baltic (Fennoscan-dian) Shield,” in Precambrian Crustal Evolution in theNorth Atlantic Region (Geol. Soc. Spec. Publ., London,1996), Vol. 112, pp. 55–67.

100. S. V. Bogdanova and E. V. Bibikova, “The ‘Saamian’ ofthe Belomorian Mobile Belt: New GeochronologicalConstraints,” Precambrian Res. 64, 131–152 (1993).

101. E. Yu. Borisova, E. V. Bibikova, A. B. Lvov, andYu. V. Miller, “U–Pb Age and Nature of MagmaticComplex of Seryak Mafic Zone (the BelomorianMobile Belt), Baltic Shield,” Terra Nova 9 (AbstractSuppl. 1), 132 (1997).

102. D. Bridgwater, D. J. Scott, V. V. Balagansky, et al., “Ageand Provenance of Early Precambrian MetasedimentaryRocks in the Lapland–Kola Belt, Russia: Evidence fromPb and Nd Isotopic Data,” Terra Nova 13, 32–37 (2001).

103. J. S. Daly, V. V. Balagansky, M. J. Timmerman, et al.,“Ion Microprobe U–Pb Zircon Geochronology and Iso-topic Evidence Supporting a Trans-Crustal Suture in theLapland Kola Orogen, Northern Fennoscandian Shield,”Precambrian Res. 105, 289–314 (2001).

104. P. M. Evins, J. Mansfeld, and K. Laajoki, “Geology andGeochronology of the Suomujärvi Complex: A NewArchaean Gneiss Region in the NE Baltic Shield, Fin-land,” Precambrian Res. 116, 285–306 (2002).

105. G. Gaál and R. Gorbatschev, “An Outline of the Pre-cambrian Evolution of the Baltic Shield,” PrecambrianRes. 35, 15–52 (1987).

106. Geological Development, Gold Mineralization andExploration Methods in the Late Archean Hattu SchistBelt, Ilomantsi, Eastern Finland, Ed. by P. A. Nurmiand and P. Sorjonen-Ward (Geol. Surv. Finland Spec.Pap. 17, 1993).

107. F. M. Gradstein, J. G. Ogg, A. G. Smith, et al., “A NewGeologic Time Scale, with Special Reference to Pre-cambrian and Neogene,” Episodes 27 (2), 83–100 (2004).

108. Greenstone Belts, Ed. by M. De Wit and L. D. Ashwal(Monographs on Geology and Geophysics 35, Oxford,1997).

109. J. Halla, “Late Archean High-Mg Granitoids (Sanuki-toids) in the Southern Karelian Domain, Eastern Fin-land: Pb and Nd Isotopic Constraints on Crust-MantleInteractions,” Lithos 79, 161–178 (2005).

110. H. Huhma, A. Kontinen, and K. Laajoki, “Age of theMetavolcanic-Sedimentary Units of the CentralPuolanka Group, Kainuu Schist Belt, Finland,” in Pro-ceedings of the 24th Nordic Geol. Winter Meeting(Geol. Surv. Norway, Trondheim, 2000), pp. 87–88.

111. P. Hölttä, H. Huhma, I. Mänttäri, and J. Paavola, “P–T-Time Development of Archaean Granulites inVarpaisjärvi, Central Finland: II. Dating of High-GradeMetamorphism with the U–Pb and Sm–Nd Methods,”Lithos 50, 121–136 (2000).

112. V. Hyppönen, Pre-Quaternary Rocks of the Ontojoki,Hiisijärvi, and Kuhmo Map-Sheet Areas (Geol. Surv.Finland, Espoo, 1983).

113. H. Juopperi and M. Vaasjoki, “U–Pb Mineral AgeDeterminations from Archean Rocks in Eastern Lap-land,” in Radiometric Age Determinations from FinnishLapland and Their Bearing on the Timing of Precam-brian Volcano-Sedimentary Sequences (Geol. Surv.Finland Spec. Pap. 33, 2001), pp. 209–227.

114. A. Kontinen, Evidence for a Significant ParagneissComponent within the Late Archean Nurmes GneissComplex, Eastern Finland (Geol. Surv. Finland Spec.Pap. 12, 1991), pp. 17–19.



115. T. Koistinen, M. B. Stephens, V. Bogachev, et al.,Geological Map of the Fennoscandian Shield, Scale1 : 2000000 (Geol. Survey of Finland, Norway, andSweden and North-West Department of NaturalResources of Russia, 2001).

116. K. Korsman, T. Koistinen, J. Kohonen, et al., BedrockMap of Finland, 1 : 1000000 (Geol. Surv. Finland,Espoo, 1997).

117. A. Kröner and W. Compston, “Archaean TonaliticGneiss of Finnish Lapland Revised: Zircon Ion-Micro-probe Ages,” Contrib. Mineral. Petrol. 104, 348–352(1990).

118. N. M. Kudryashov, T. B. Bayanova, B. V. Gavrilenko,et al., “Archaean Geochronology of the Kola Region,Northeastern Baltic Shield,” in Proceedings of the4th Intern. Archaean Symp. AGSO Geosci. Australia,2001 (2001), Vol. 37, pp. 58–60.

119. P. Lahtinen, A. Korja, and M. Nironen, “Paleoprotero-zoic Tectonic Evolution,” Ed. by M. Lehtinen, P. A. Nurm,and O. T. Ramo, in The Precambrian Geology of Fin-land: Key to the Evolution of the Fennoscandian Shield.Developments in Precambrian Geology 14 (Elsevier,Amsterdam, 2005), pp. 480–532.

120. O. A. Levchenkov, L. K. Levsky, Ø. Nordgulen, et al.,“U–Pb Zircon Ages from Sørvaranger, Norway, and theWestern Part of the Kola Peninsula, Russia,” in Geologyof the Eastern Finnmark–Western Kola PeninsulaRegion (Norges Geol. Unders. Spec. Publ. 7, 1995),pp. 29–47

121. S. B. Lobach-Zhuchenko, V. P. Chekulaev, S. A. Sergeyev,et al., “Archaean Rocks from Southeastern Karelia(Karelian Granite-Greenstone Terrain),” PrecambrianRes. 62, 375–388 (1993).

122. S. B. Lobach-Zhuchenko, H. R. Rollinson, V. P. Cheku-laev, et al., “The Archaean Sanukitoid Series of the Bal-tic Shield: Geological Setting, Geochemical Character-istics and Implications for Their Origin,” Lithos 79,107–128 (2005).

123. E. Luukkonen, “The Structure and Stratigraphy of theLate Archean Kuhmo Greenstone Belt, Eastern Fin-land,” in Archaean Geology of the Fennoscandian Shield(Geol. Surv. Finland Spec. Pap. 4, 1988), pp. 71–96.

124. I. Mänttäri and P. Hölttä, “U–Pb Dating of Zircons andMonazites from Archean Granulites in Varpaisjärvi,Central Finland,” Precambrian Res. 118, 101–131(2002).

125. T. Mutanen and H. Huhma, “The 3.5 Ga SiuruaTrondhjemite Gneiss in the Archaean Pudasjärvi Gran-ulite Belt, Northern Finland,” Geol. Soc. Finland Bull.75 (1/2), 51–68 (2003).

126. T. Piirainen, “The Geology of the Archaean Green-stone-Granitoid Terrain in Kuhmo, Eastern Finland,” inArchaean Geology of the Fennoscandian Shield (Geol.Surv. Finland Spec. Pap. 4, 1988), pp. 39–51

127. I. S. Puchtel, G. E. Brugmann, and A. W. Hofmann,“187Os-Enriched Domain in an Archean Mantle Plume:Evidence from 2.8 Ga Komatiites of the KostomukshaGreenstone Belt, NW Baltic Shield,” Earth Planet. Sci.Lett. 186, 513–526 (2001).

128. I. S. Puchtel, A. W. Hofmann, Yu. V. Amelin, et al.,“Combined Mantle Plume-Island Arc Model for theFormation of the 2.9 Ga Sumozero-Kenozero Green-

stone Belt, SE Baltic Shield: Isotope and Trace ElementConstraints,” Geochim. Cosmochim. Acta 63, 3579–3595 (1999).

129. I. S. Puchtel, A. W. Hofmann, K. Mezger, et al., “Oce-anic Plateau Model for Continental Crustal Growth inthe Archaean: A Case Study from the KostomukshaGreenstone Belt, NW Baltic Shield,” Earth Planet. Sci.Lett. 155, 57–74 (1998).

130. A. V. Samsonov, M. M. Bogina, E. V. Bibikova, et al.,“The Relationship between Adakitic, Calc-AlkalineVolcanic Rocks and TTGs: Implications for the Tec-tonic Setting of the Karelian Greenstone Belts, BalticShield,” Lithos 79, 83–106 (2005).

131. A. A. Shchipansky, A. V. Samsonov, E. V. Bibikova,et al., “2.8 Ga Boninite-Hosting Suprasubduction ZoneOphiolite Sequences from the North Karelian Green-stone Belt, NE Baltic Shield, Russia,” in PrecambrianOphiolites and Related Rocks. Developments in Pre-cambrian Geology 13 (Elsevier, Amsterdam, 2004),pp. 425–486.

132. A. I. Slabunov, S. B. Lobach-Zhuchenko, E. V. Bibi-kova, et al., “The Archean Nucleus of the Fennoscan-dian (Baltic) Shield,” in European Lithosphere Dynam-ics (Geol. Soc. London, London, 2006), pp. 18–38.

133. P. Sorjonen-Ward and E. Luukkonen, “Archean Rocks,”in The Precambrian Geology of Finland: Key to theEvolution of the Fennoscandian Shield. Developmentsin Precambrian Geology 14 (Elsevier, Amsterdam,2005), pp. 19–99.

134. S. A. Svetov, A. I. Svetova, and H. Huhma, “Geochem-istry of the Komatiite–Tholeiite Rock Association in theVedlozero-Segozero Archean Greenstone Belt, CentralKarelia,” Geochem. Intern. 39, 24–38 (2001).

135. K. Taipale, “Volcanism in the Archean Kuhmo Green-stone–Granite Terrain in the Tipasjärvi Area, EasternFinland,” in Archaean Geology of the FennoscandianShield (Geol. Surv. Finland Spec. Pap. 4, 1988),pp. 151–160.

136. M. J. Timmerman and J. S. Daly, “Sm–Nd Evidence forLate Archaean Crust Formation in the Lapland–KolaMobile Belt, Kola Peninsula, Russia and Norway,” Pre-cambrian Res. 72, 97–107 (1995).

137. M. Vaasjoki, K. Taipale, and I. Tuokko, “RadiometricAges and Other Isotopic Data Bearing on the Evolutionof Archaean Crust and Ores in the Kuhmo–Suomus-salmi Area, Eastern Finland,” Geol. Surv. Finland Bull.71, 155–176 (1999).

138. V. Vetrin, Ø. Nordgulen, J. Cobbing, et al., “The Pyrox-ene-Bearing Tonalite-Granodiorite-Monzonite Seriesof the Northern Baltic Shield: Correlation and Petrol-ogy,” in Geology of the Eastern Finnmark–WesternKola Peninsula Region (Norges Geol. Unders. Spec.Publ. 7, 1995), pp. 65–74.

139. V. R. Vetrin, O. M. Turkina, and D. Ludden, “Petrologyand Geochemistry of Rocks from the Basement of thePechenga Paleorift,” Russ. J. Earth Sci. 4, 121–151(2002).

Reviewers: M.V. Mints and V.E. Khain

The Archean of the Baltic Shield: Geology, Geochronology, and Geodynamic settings

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