RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 8, ES4001, doi:10.2205/2006ES000203, 2006


Main Features of the Sedimentation and Paleogeography

[5]  Initiation of aulacogen system in East European platform occurred in the end of Early Riphean. Sedimentation started with the deposition of coarse red-bed sediments. In middle Riphean these aulacogens were infilled by the finer marine terrigeneous sediments which are represented in a number of suits. These are Krestetskaya (Volyno-Krestetskiy area), Salminskaya (Ladozhskiy area), Salozerskaya (Onego-Kandalakshskiy area) and others. The thickness of these complexes is about several hundreds of meters in the Moscow (Srednerusskiy) aulacogen. The thickness increase up to 2-3 km in the Ryazano-Saratovskiy (Pachelmskiy) aulacogen. In the South-East of the platform the carbonate-terrigeneous complex was formed. This complex includes lower Riphean Tyrnitskaya, Inkashskaya, and Otrogovskaya suits of the Pachelmskiy aulacogen.

[6]  Development of the aulacogen system continued in the Late Riphean. Main configuration of this system did not change significantly. Aulacogens were infilled with marine dominantly sandy complexes (ex.: Byelorussian series in the Srednerusskiy aulacogen; Somovskaya, Peresypkinskaya, and Pachelmskaya series in the Pachelmskiy aulacogen). Rates and scales of subsidience decreased in the South-East of the platform. Nevertheless, thickness of the Upper Riphean formations is about 2 km, while thickness of aulacogens infillings do not exceed first hundreds of meters. Basic, intermediate, and acid effusives formed in the Pechora-Kolvinskiy aulacogen in the end of the Late Riphean.

[7]  The formation of continuous sedimentary cover began in Middle Vendian about 650 Ma. The quantitative analysis of paleogeography and sedimentation in sedimentary basins revealed that their subsequent Paleozoic history of evolution could be clearly divided into several tectonic cycles. These cycles generally correspond to stages in evolution of active margins of the platform. These are Baikalian Timano-Uralian and Bretono-Galitskaya, Caledonian Skandinavian, and Hercynian Uralian and Central-Dobruzhinsko-Caucasian [Seslavinsky, 1987].

2006ES000203-fig01
Figure 1
[8]  At the first stage since Vendian through Early and Middle Cambrian the main areas subsidience were situated in Pritiman'e, in Priural'e, and in Prikarpat'e (Vislyandsko-Dnestrovskiy pericratonic basin). Subsidience also occurred around Srednerusskiy and Pachelmskiy aulacogens that led to formation of the large Baltic-Moscow basin, which occupied central part of the platform (Figure 1).

[9]  The strong sheet-like glaciation affected larger part of the platform in the second half of the Early Vendian. Basaltic volcanism occurred in the south-western part of the platform (Volynskaya series). Marine deposits that were being formed during this stage in all inner basins are represented by terrigeneous mainly clayey rocks as thick as the first hundreds of meters. Thickness increased in marginal basins where sandy facies were widespread.

[10]  In general, the role of uplifts was gradually increasing during the first stage. Before the Late Cambrian areas of marine basins and sedimentation rates decreased up to 14% in comparison with the total platform area.

[11]  The development of the Baltic-Moscow basin continued during the next Late Cambrian to Early Devonian stage. This basin was parallel in strike with the Scandinavian fold belt system being separated from it by the Baltic shield. The Vislyandsko-Dnestrovskiy and Pricaspian basins also continued their development. Besides the east margin of the platform was submerged in the end of the stage and the sedimentary complexes of the Pechorskiy and Priuralian basins were being formed at this margin.

[12]  Subsidence and marine sedimentary environments gradually occupied an ever-encreasing areas of the Baltic-Moscow basin during the first half of Ordovician. In the Middle Ordovician sea invaded in the Pechorskiy basin. These events caused the total increase (up to 35%) of areas covered by marine basins to the beginning of the Middle Ordovician. Simultaneously, mean sedimentation rates increased indicating tectonic activisation. The comparison of these data with the mean sedimentation rates in the shelf zones of the Scandinavian foldbelt system indicates synchronous occurrence of the Middle Ordovician event. This corroborates the idea about the influence of Scandinavian Caledonides on tectonic development of sedimentary basins located in the north-western part of the platform.

[13]  After the insignificant the Early Silurian regression in the Baltic-Moscow basin the total area covered by sea increased to more than 30% with subsequent decrease in the Early Devonian up to 10%, that was the minimum for Paleozoic. All marine basins suffered global regression in the end of the Early Devonian stage. As an example, the Baltic-Moscow basin was transformed into the intracontinental drying up saline reservoir, where sandy-clayey alluvial and carbonate-terrigeneous lake sediments tens of meters in thickness were being formed.

[14]  The composition of sediments deposited during this stage is more diverse than the composition of Vendian to Cambrian sediments. The presence of shallow carbonate muds, detrital limestones, and reef facies indicate the increasing role of carbonates. The reef facies are especially characteristic of Silurian deposits in the Priuralian basin. The highest mean sedimentation rate within the platform occurred in late Silurian during the final period of the stage.

[15]  The significant reconstruction of platform structure occurred during the third stage in Devonian through Permian. Subsidence of the eastern and southern parts of the platform occurred in Middle to Late Devonian (see Figure 1, panel D 2 ). This period of time was characterized by effusive and intrusive magmatism and by the formation of the Pripyatsko-Dneprovsko-Donetskiy aulacogen, the Donetsko-Caspian system of basins, and the Byelorussian-Voronezhskaya zone of uplifts. The latter jutted out as a narrow ridge of the basement. The furrow of the Kamsko-Kinel'skiy basins stretched parallel to the Urals in the East. Intensive subsidence of the entire eastern part of the platform that took place in the end of this stage led to formation of the large East Russian basin. The southern part of this basin had a junction with the Pricaspian basin (see Figure 1, panels C1 and P1 ). Since the Kungurian age the latter became a depocenter of the saliferous complex that was followed in Permian to Triassic by the red-beds clastic complex.

[16]  Thus, under the evident influence of intensive development of the Uralian and the Dobruzhinsko-Caucasian foldbelt systems the entire southern and eastern parts of the platform were affected by the largest Middle Devonian transgression which prograded westward from the Uralian system in the East. The very beginning of the Middle Devonian is characterized by sharp increase in sedimentation rates in Uralian basins and marine area became maximum to the end of the Givetian age. The correlation between the development of inner basins and mobile margin accompanied by some delay, which is underlined by the data on the Late Devonian and Late Permian formations. The increase in rates of subsidence within the platform up to 23times10-6 m years-1 in Late Devonian and up to 30times10-6 m years-1 in late Permian was the reaction on intensive tectonic processes in the Uralian system in the Middle Devonian and Early Permian respectively.

[17]  In general, the unstable regime existed within the platform during this stage. Regressions were followed by transgressions in some basins, and shallow-water sedimentary environments were transformed to relatively deep-water ones against the background of repeatedly occurring magmatism. Relatively dissected relief was being formed in land areas that resulted in the appearance of clastic continental rocks in appreciable amounts. These rocks exceeded 30% in abundance in the Late Permian. Carbonate sedimentation, including reef sedimentation, generally dominated and was extremely significant in the Late Devonian, Late Carboniferous, and Early Permian. Bituminous clays and oil shales (domanic) were widespread in the Priuralian basin in the Late Devonian. Gypsum and sporadically salt were deposited in several basins. Maximum salinization occurred in the second half of the Kungurian age. Since the Middle Devonian to the end of Carboniferous marine basins covered more than 2/3 of the platform.


RJES

Citation: Grachev, A. F., V. A. Nikolaev, and V. G. Nikolaev (2006), East European platform development in the Late Precambrian and Paleozoic: Structure and sedimentation, Russ. J. Earth Sci., 8, ES4001, doi:10.2205/2006ES000203.

Copyright 2006 by the Russian Journal of Earth Sciences

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