THE DEVONIAN TO PERMIAN SEDIMENTATION OF THE RUSSIAN PLATFORM - AN EXAMPLE OF SUBDUCTION-CONTROLLED LONG-WAVELENGTH TILTING OF CONTINENTS

Stratigraphic evidence indicates that the Russian, or East European, P latform experienced two distinct episodes of long-wavelength down to t he east tilting during the Devonian to Permian period. We demonstrate a correlation between these tilting events and two separate periods of inferred west-dipping subduction under the platform (active between 4 00-340 Ma and 311-290 Ma). These subduction events consumed the ancien t Uralian Ocean and ended with the onset of Uralian orogeny. We propos e that the platform tilting episodes were due to the dynamic response of the Euramerican plate to mantle flow viscously coupled to these con temporaneous subduction events. We present numerical simulations of ma ntle convection driven by descending viscous slabs which are able to r econcile the thickness of the sediment deposition, the maximum horizon tal wavelength of the tilt, and the onlap/offlap (sea level transgress ion/regression) sequence for each tilting event on the platform. These simulations also require high plate convergence rates during active s ubduction which are consistent with the geological record. Copyright ( C) 1996 Elsevier Science Ltd