Crustal structure and tectonic model of northeastern Baltica, based on deep seismic and potential field data

Abstract

The Early-Mid-Palaeozoic successions of the Pechora Basin along continent Baltica's northeastern margin unconformably overlie Neoproterozoic complexes of the Timanide orogen; further west, Palaeozoic platform strata cover the East European Craton basement. The latter is exposed in the northern parts of the Fennoscandian (Baltic) Shield and is also present beneath the Neoproterozoic (perhaps also Mesoproterozoic) and younger successions of the Mezen Basin. Geophysical data help define the crustal and upper mantle structures of this part of northwestern Russia, from the Kola Peninsula to the Uralide orogen. Within the Shield, seismic refraction and near-vertical reflection profiling allow the terranes of Archaean and Palaeoproterozoic age, defined at the surface (the Murmansk, Kola-Liinakhamary, Central Kola, Keivy and Belomorian terranes, and the Pechenga-Imandra-Varzuga and Lapland-Kolvitsa Granulite Belts constituting the Lapland-Kola orogen, and the West Karelian, Central Karelian and Vodlozer terranes forming the Karelian province), to be traced into the deeper crust, promoting interpretation of various early Precambrian compressional and extensional regimes. Thrusting, transcurrent and extensional faulting have been identified in a crust that has been partly thickened during late Archaean and Palaeoproterozoic collision and locally extended both in back-arc basin settings and during syn-post-collisional collapse. The main Fennoscandian terranes can be traced southeastwards beneath the Mezen Basin based on gravity and magnetic data. Seismic profiling shows that the Phanerozoic successions of this basin overlie intracratonic rifts of Neoproterozoic and possibly Mesoproterozoic age. The rifts are composed of a number of half-graben, the details of which are well defined by vibroseis reflection profiling. During the development of Mezen Basin rifts, a Neoproterozoic passive margin was established in the vicinity of what is now the Timan Range. Late Neoproterozoic (Vendian) orogeny emplaced slope-rise turbidite-dominated successions southwestwards onto the platform. Towards the hinterland of the Timanides (also referred to as Baikalides), beneath the Phanerozoic Pechora Basin, a combination of potential field and seismic surveys, both shallow reflection and deep refraction profiling, have allowed analysis of the crust and uppermost mantle. Neoproterozoic magmatic arcs, Grenville-age(?) microcontinents and possible oceanic domains are inferred to exist beneath the early Palaeozoic unconformity. A vast region of Neoproterozoic accretion reaches from the western Urals, northwards beneath the Pechora Basin and the eastern Barents Shelf.

The Moho depth map of the European Plate

“…3 (map Ko, for data examples see e.g. Kostyuchenko et al 1998Kostyuchenko et al , 1999Kostyuchenko et al , 2004Kostyuchenko et al , 2006Yegorova et al 2004b). Another compilation for the same territory was done by Erinchek et al 2006 (see map Er in Fig.…”

“…See the text for more description. Grad & Luosto 1987Grad & Tripolsky 1995;Grad et al 1991;Komminaho & Yliniemi 1992;Kortström et al 2006;Luosto 1986;Luosto et al 1989Luosto et al , 1990Luosto et al , 1994Olsson 2007;Środa & POLONAISE Working Group 1999;Thybo et al 2003;Wilde-Piórko et al 2002Bogdanova et al 2006Erinchek et al 2006;Korja et al 2001;Korsman et al 1999;Kostyuchenko et al 1999Kostyuchenko et al , 2004Kostyuchenko et al , 2006Luosto 1991;Yegorova et al 2004aCentral Europe Bleibinhaus et al 1999Grad et al 1999Grad et al , 2003Grad et al , 2005Grad et al , 2006Guterch & Grad 2006;Guterch et al 1994Guterch et al , 1999Hauser et al 2001Hauser et al , 2007Hrubcová et al 2005;Janik et al 2002Janik et al , 2005Jensen et al 1999;Lie & Andersson 1998;Majdański et al 2006;Malinowski et al 2005;Wilde-Piórko et al 2002Grad et al 2002Guterch et al 2007;…”

The crustal structure in the transition zone between the western and eastern Barents Sea

“…The Timanian orogeny influenced mostly the southeastern corner of the East Barents Sea, including the areas of the present Timan-Pechora Basin. Timan orogeny developed as fold-and-thrust belt along the northeastern margin of Baltica, during the late Neoprotorozoic-early Cambrian (Kostyuchenko et al 2006;Gee et al 2008). The general structural trends of the Timanian orogeny show NW-SE orientation, also in northeast Norway.…”

New data on detrital zircons from the sandstones of the lower Cambrian Brusov Formation (White Sea region, East-European Craton): unravelling the timing of the onset of the Arctida–Baltica collision

“…The scheme is based on maps from Bogdanov and Khain (1996) and Khain (1999). Configuration of White Sea Rift System after Baluev (2006 International Geology Review 3 (Timanian Active Margin of Baltica) and interprets the orogeny as a supra-subduction long-lived orogenic system that was active during the late Neoproterozoic, on the currently active northeastern Timanian margin of the palaeocontinent Baltica (see Gee and Pease 2004;Kostyuchenko et al 2006) (Figure 3). The second model is known under the abbreviation ABC (Arctida-Baltica Collision) and was developed by Kuznetsov et al (2007aKuznetsov et al ( , 2010a, who suggested that this orogen is collisional and formed during the convergence between the Arctida and Baltica palaeocontinents (Figure 4).…”

“…A number of complexes are exposed in the Polar Urals, the Timan Hills, Kanin peninsula, and the northeastern edge of the Kola peninsula (Figures 1 and 2). Samples were collected both from exposed surface and from boreholes for detailed studies (Kostyuchenko and Romanyuk 1997;Gee et al 2000;Dovzhikova et al 2004;Baluev 2006;Kostyuchenko et al 2006;Dovzhikova 2007;Kuznetsov et al 2007a). More than 250 isotopic dating analyses (a summary of U-Pb dating of magmatic zircons and their inherit cores, results of dating by Rb-Sr or Sm-Nd isochronic and others methods, see Supplementary Figure 2) obtained recently on the crystalline complexes of ca.…”