The Vendian-Early Palaeozoic sedimentary basins of the East European Craton

Abstract

abstractVendian-Early Palaeozoic sedimentation on the East European Craton (EEC) was confined to the cratonic margins with limited intracratonic subsidence. Generally, there are two geodynamic stages involved: in stage 1, basins formed in response to continental break-up processes; in stage 2, basins formed in response to the reassembly of continental lithosphere fragments and associated continental accretionary processes. The establishment of the Peri-Tornquist passive margin was a polyphase process that commenced in the Early Vendian in the SW and ended in the Cambrian in the NW. Neoproterozoic rifting along the Scandinavian margin was essentially a long process (250 Ma), whereas the fragmentation of the continent along the earlier Timanian orogen in the east and establishment of Peri-Uralian basins took place in a rather short time span. A similar scenario is suggested for the basement of the Peri-Caspian Basin. The rift-to-drift transition is expressed differently on the various EEC margins and this could be a reflection of the relative strengths of the underlying lithosphere. The change to a convergent margin setting is recorded in Peri-Tornquist basins in the Late Ordovician, climaxing with high rates of subsidence during Late Silurian time. Subsidence rates on the cratonic margins were governed by the emplacement of orogenic loads. Where there was a short time span between Stages 1 and 2, continuing thermal subsidence from the former was superimposed onto the flexural subsidence of the latter, such as on the Dnestr margin. Other processes, such as dynamic loading related to mantle flow, are implied for the anomalously broad Stage 2 Baltic Basin. Peri-Uralian basins developed as passive continental margin basins throughout the Early Palaeozoic. Stress regime changes generated at the craton margins are reflected in the structure and subsidence patterns recorded in the intracratonic Moscow Basin.