General geology and evolutionary history of the early proterozoic Polmak-Pasvik-Pechenga-Imandra/Varzuga-Ust'Ponoy greenstone belt in the northeastern Baltic Shield

Melezhik, Victor A.; Sturt, B. A.

doi:10.1016/0012-8252(94)90058-2

Cited by 118 publications

(99 citation statements)

References 7 publications

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“…High-Mg basalts (basaltic komatiites) are less abundant. The section is completed with dacite and rhyolite dated at 2.44-2.42 Ga and 2.32 Ga subaerial andesite [Melezhik, Sturt, 1994;Smolkin et al, 1995;Amelin et al, 1995;Mints et al, 1996;Puchtel et al, 1996;Melezhik et al, 2012]. The geochemistry of the mafic volcanic rocks indicates relations to plume or T-MORB types.…”

Section: Evidence Of Initial Riftingmentioning

confidence: 99%

“…The T-MORB-type tholeiitic pillow lavas in the Pechenga Structure (2.11-1.92 Ga) are combined with picritic lava flows and felsic ash flows that geochemically resemble the products of volcanic eruptions on oceanic islands. Subvolcanic gabbro-wehrlite bodies related to the activity of these volcanoes intruded the lower portion of the tholeiitic sequence, but are more abundant as lenticular tectonic boudins in the imbricate complex of sulphidated terrigenous rocks [Melezhik, Sturt, 1994;Mints et al, 1996;Sharkov, Smolkin, 1997;Skuf'in, Theart, 2005;Melezhik et al, 2012]. This complex, known as a productive layer of the Pechenga Cu-Ni ore field, was interpreted as a fragment of the accretionary prism [Mints et al, 1996].…”

Section: Rifting and Partial Disruption Of Lauroscandiamentioning

confidence: 99%

“…This complex, known as a productive layer of the Pechenga Cu-Ni ore field, was interpreted as a fragment of the accretionary prism [Mints et al, 1996]. The youngest (1.87-1.86 Ga) rock complexes of the Pechenga-Varzuga Belt include rhyolite, dacite, andesite, picrite, and high-Mg basalt of the suprasubduction type; N-MORB in association with volcaniclastic rocks and black shale occur in subordinate amounts [Melezhik, Sturt, 1994;Sharkov, Smolkin, 1997].…”

Section: Rifting and Partial Disruption Of Lauroscandiamentioning

confidence: 99%

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Age and isotopic geochemical characteristics of Archean carbonatites and alkaline rocks of the Baltic shield

2007

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Paradoxically, the lists of "proxies" of both plate-and plume-related settings are devoid of even a mention of the high-grade metamorphic rocks (granulite, amphibolite and high-temperature eclogite facies). However, the granulite-gneiss belts and areas which contain these rocks, have a regional distribution in both the Precambrian and the Phanerozoic records. The origin and evolution of the granulite-gneiss belts correspond to the activity of plumes expressed in vigorous heating of the continental crust; intraplate magmatism; formation of rift depressions filled with sediments, juvenile lavas, and pyroclastic flow deposits; and metamorphism of lower and middle crustal complexes under conditions of granulite and high-temperature amphibolite facies that spreads over the fill of rift depressions also. Granulite-gneiss complexes of the East European Craton form one of the main components of the large oval intracontinental tectonic terranes of regional or continental rank. Inclusion of the granulite-gneiss complexes from Eastern Europe, North and South America, Africa, India, China and Australia in discussion of the problem indicated in the title to this paper, suggests consideration of a significant change in existing views on the relations between the plate-and plume-tectonic processes in geological history, as well as in supercontinent assembly and decay. The East European and North American cratons are fragments of the long-lived supercontinent Lauroscandia. After its appearance at ~2.8 Ga, the crust of this supercontinent evolved under the influence of the sequence of powerful mantle plumes (superplumes) up to ~0.85 Ga. During this time Lauroscandia was subjected to rifting, partial breakup and the following reconstruction of the continent. The processes of plate-tectonic type (rifting with the transition to spreading and closing of the short-lived ocean with subduction) within Lauroscandia were controlled by the superplumes. Revision of the nature of the granulite-gneiss complexes has led to a fundamental new understanding of: a more important role than envisaged previously for mantle-plume processes in the juvenile additions to the continental crust, especially during the Neoarchaean-Proterozoic; the existence of the supercontinent Lauroscandia from ~2.80 to 0.85 Ga; the leading role of mantle plumes in the interaction of plate-and plume-tectonics in the Neoarchaean-Proterozoic history of Lauroscandia and perhaps of the continental crust as a whole. We propose that the evolution of the geodynamic settings of the Earth's crust origin can be represented as a spiral sequence: the interaction of mantle-plume processes and embryonic microplate tectonics during the Palaeo-Mezoarchaean (~3.8-2.8 Ga) → plume-tectonics and local plume-driven plate-tectonics (~2.80-0.55 Ga) → Phanerozoic plate tectonics along with a reduced role of mantle plumes.Key words: Precambrian; plate-tectonics; plume-tectonics; granulite-gneiss belts; supercontinent; intracontinent oval orogenRecommended by E.V. Sklyarov Аннотация: Ка...

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Section: Evidence Of Initial Riftingmentioning

confidence: 99%

Section: Rifting and Partial Disruption Of Lauroscandiamentioning

confidence: 99%

Section: Rifting and Partial Disruption Of Lauroscandiamentioning

confidence: 99%

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Age and isotopic geochemical characteristics of Archean carbonatites and alkaline rocks of the Baltic shield

2007

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“…2; Dobrzhinetskaya et al, 1995), south of Varangerfjorden, with zircon ages on orthogneisses of 2.9-2.65 Ga (Dobrzhinetskaya et al, 1995;Levchenkov et al, 1995). Bordering the Sørvaranger-Kola Terrane to the southwest is the Polmak-Pasvik-Pechenga greenstone belt (PPP) which represents a former rifted ocean basin (Kola Ocean; Lahtinen et al, 2008), interpreted by Berthelsen & Marker (1986) and Melezhik & Sturt (1994) as a collisional suture zone. West of the PPP is the Inari Terrane (IT) (Fig.…”

Section: Geology Of Finnmark and North Tromsmentioning

confidence: 99%

New high-resolution aeromagnetic and radiometric surveys in Finnmark and North Troms: linking anomaly patterns to bedrock geology and structure

Nasuti¹,

Roberts²,

Dumais³

et al. 2016

NJG

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New high-resolution aeromagnetic data from the Caledonides and Archaean-Palaeoproterozoic crystalline basement of Finnmark and North Troms derived from surveys conducted as part of NGU's MINN programme provide spectacular and confirmatory evidence for the continuation of diverse, Precambrian greenstone belts and granulite terranes beneath the magnetically transparent Caledonian nappes. Complementary airborne radiometric data collected in the same survey contribute to the analytical process and to an evaluation of the mineral potential in the area. Some parts of existing data have also been reprocessed using new techniques and software to reach the same level as the newly acquired data. The new compiled data provide images of the magnetic field at sufficiently high resolution to allow us to examine finer details of the bedrock geology. One of the principal outcomes of the analysis is a picture of the detailed structural fabric of the region provided by images of tilt derivatives of the magnetic field that enhance anomalies. This fabric is an important framework for developing exploration strategies. Patterns and other characteristics of the magnetic field have been used to revise positions of some geological boundaries, especially in poorly exposed areas, and delineate specific domains within northern Norway. Radiometric data have been used to supplement the magnetic interpretations in some cases. In general, there is a good correlation between the radiometric data and magnetic anomaly maps which can be utilised to re-evaluate the geological boundaries. Several such features of interest are discussed. As an example, NW-SE-trending, fault-bounded terranes or belts which extend from Finnmark and Troms through northern Finland, Sweden and Russia can be easily followed on the high-resolution data. In this contribution, all the main geological terranes from the Archaean-Palaeoproterozoic belt to the Caledonian nappes in northern Norway will be discussed in relation to their magnetic patterns and radiometric anomalies.

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“…The evolution of the Fennoscandian Shield in the Early Palaeoproterozoic is known to have been dominated by multiple intracratonic rifting episodes and the development of short-lived oceanic domains (Melezhik & Sturt, 1994;Melezhik & Hanski, 2013a). This is reflected by the numerous and voluminous greenstone belts of this age that extend all the way from Russia to northern Norway (Fig.…”

Section: Tectonic Setting and Regional Correlationsmentioning

confidence: 99%

Revised structure and stratigraphy of the northwestern Repparfjord Tectonic Window, northern Norway

Torgersen¹,

Viola²,

Sandstad³

2016

NJG

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The Repparfjord Tectonic Window (RTW) consists of a ~8 km-thick low-grade, weakly deformed Early Palaeoproterozoic volcano-sedimentary succession that hosts abundant Cu mineralisations. Two major, sediment-hosted, Cu-deposits occur in the Saltvatnet Group, a <6 km-thick sequence of mainly coarse-grained clastic rocks that forms the core subject of the present study. Results from new mapping, structural analysis and whole-rock geochemistry from the northwestern part of the RTW are presented and used in association with high-resolution geophysical data to propose a revised stratigraphy of the Repparfjord volcano-sedimentary succession and its tectonic and geodynamic settings. The Saltvatnet Group is better characterised as containing four formations, now including also the uppermost volcaniclastic siltstones and dolostone members of the herein newly defined Gorahatjohka Formation. Field oberservations and structural analysis show that the current geometry of the Saltvatnet Group is that of a km-scale, upright, NE-SW-trending anticline, the Ulveryggen anticline, cored by the Saltvatnet Group, which thus represents the lowermost exposed rocks of the RTW. New and existing geochemical data are used to demonstrate that the two volcanic-dominated Nussir and Holmvatnet groups, which crop out on either side of the Ulveryggen anticline, have similar geochemical character and can be interpreted as temporal and lateral correlatives. The basaltic Ulveryggen intrusions within the Saltvatnet Group are geochemically different from any other igneous rocks in the RTW, suggesting that these intruded prior to the volcanic-dominated groups in the RTW. The revised stratigraphy of the RTW is interpreted as reflecting deposition and volcanism in an evolving continental back-arc, which contrasts with the purely intraplate rift setting inferred for most parts of the Fennoscandian Shield in the Early Palaeoproterozoic.

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General geology and evolutionary history of the early proterozoic Polmak-Pasvik-Pechenga-Imandra/Varzuga-Ust'Ponoy greenstone belt in the northeastern Baltic Shield

Cited by 118 publications

References 7 publications

Age and isotopic geochemical characteristics of Archean carbonatites and alkaline rocks of the Baltic shield

Age and isotopic geochemical characteristics of Archean carbonatites and alkaline rocks of the Baltic shield

New high-resolution aeromagnetic and radiometric surveys in Finnmark and North Troms: linking anomaly patterns to bedrock geology and structure

Revised structure and stratigraphy of the northwestern Repparfjord Tectonic Window, northern Norway

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