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


Conclusion

[56]  The comparative analysis of the development of structure, sedimentation, and magmatism during late Proterozoic through Paleozoic history of East European platform evidently shows that all these processes were obviously connected. Excluding magmatism, the character of this relationship was outlined by N. S. Shatsky. Its nature was understood later when it became clear that aulacogens have riftogenic provenance [Grachev and Fedorovsky, 1970], while syneclises or sedimentary basins correspond to the post-rift stage (the Shatsky's rule) [Grachev, 1987].

[57]  Each of three depicted characteristics numerously changed through time. Nevertheless, main turning-points in the history of the platform development could be distinguished viacoincidence in time of all three processes. There are three prominent turning-points and each of them were comparatively short in geological sense. At the Riphean to Vendian boundary sharp change in structural plans and geodynamic setting occurred. It correlates with increase in the area of sea basins and change in sedimentary environment. Intensive domi-nantly tholeiitic magmatism also ceased at this time. The next large reconstruction in structural plan occurred between early and middle Devonian. This period is characterized by decrease in marine basin area and by repetition of alkaline-basaltic magmatic activity. Finally, at the end of Permian the formation of sharp structural forms ceased. Territory of the platform was highly uplifted. Sedimentation rates decreased.

[58]  It is possible that conclusions of some authors about the correlation of large turning-points in the platform with events in surrounding paleooceanic areas are true. Event at Riphean to Vendian boundary coincides with opening of the Japetus ocean. Events at early and middle Devonian coincide with the opening of the Paleo-Uralian ocean. The turning-point at the end of Permian was possibly caused by the closing of the Paleo-Uralian ocean. Basing on this point of view the platform development was understood by Khain [1986] (from general positions), by Aparin et al. [1988] (from positions of sedimentary formations in East European platform) and others. At the same time it is difficult to make nowadays simple correlation of events in the platform and adjacent areas because the interference of processes in neighboring areas occurred within the platform (ex.: closing of Japetus and opening of the Paleo-Uralian oceans). This interpretation was complicated by intraplate processes.

[59]  As in other platforms development of magmatism within East European platform was connected with changes in thermal conditions in the upper mantle during aulacogen or rift stage of development. Two types of magmatism development could be distinguished according to the character of development of structure and sedimentary formations. The first one is the pre-rift type (part of the Baltic shield in the Late Proterozoic), when lava fields covered large territories without structural speciality. The second one is the rift type. But even in this case magmatism took place not only in rifts but abroad.

[60]  Thus, an important conclusion could be made on the basis of East European platform example. This is the conclusion about the absence of platform volcanism as a specific type. Another conclusion is that the Late Pre-Cambrian riftogenic stage within East European platform was the most active.

[61]  The area covered by aulacogens and volumes of sedimentary and volcano-plutonic complexes according to preliminary calculations were significantly larger than in the Middle Paleozoic. Tectonic activity if all three parameters are taken together seem to decrease from the Riphean to Mesozoic through Cenozoic.

[62]  Studying the development of sedimentary formations it is impossible to ignore the influence of processes on active margins (Scandinavian and Uralian) on the development of sedimentary basins both immediately adjacent to them and located in hundreds of kilometers afar.


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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