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Pre-Orogenic Successions and Foreland Basins |
Institute of Geology and Geochemistry, Urals Branch of RAS, 7, Pochtovy per., 620151, Ekaterinburg, Russia
The northeastern and eastern margin of the East European Craton exposes numerous Riphean and Vendian (Meso- and Neoproterozoic) sedimentary successions that were deposited in alluvial and shallow-marine environments in intra- and pericratonic basins. A review is presented of the lithostratigraphy, sedimentary environments and architectural style of these sedimentary sequences in the Southern, Middle, Subarctic and Polar Urals, on the Poludov Range, and in the Volga-Urals and Timan-Pechora regions. The Riphean sequences are subdivided into three major sedimentary units: Lower, Middle and Upper, based on type areas in the Bashkirian Anticlinorium. During the Early and Middle Riphean, in the Southern Urals there were several short episodes of ‘diffuse’ and linear rifting and long intervals of more stable development in intracratonic sedimentary basins. During the Late Riphean, in the territory under review, larger shallow marine basin developed. Two laterally connected zones existed along the eastern periphery of the East European Craton: one in the Southern and Middle Urals, with a predominance of shallow marine arkosic deposits, and the other, with moderately deep marine (continental slope and rise) turbidities in the Timan-Pechora region. Subsequent Vendian successions were largely shallow marine and deposited in epicratonic basins; they generally give way upwards in the Late Vendian into non-marine clastic formations, derived from the east.
