A synsedimentary structure formation model for the Far East Jurassic-Early Cretaceous basins and uplifts,Russia

This article is to reveal and corroborate the geodynamic conditions for the formation of Cretaceous sedimentary basins of the Russian Far East. The conclusions are based on the comprehensive analysis of the extensive mapping materials and special structural field studies. It has been found that sedimentary basins developed as rift-grabens were synchronous with formation of horsts separating the basins. The imbricated-thrust structures, which are morphologically similar to the subduction-related accretionary prisms but nevertheless different in nature, were formed within the transition zone between the uplifted structures and basins. A synsedimentary supply of a mantle-derived material into basins points to a temporarily continual extension of continental lithosphere. The lithospheric plates moved apart during the strike slip faulting with the subsequent involvement of convective mantle flows and plume diapirism (continental spreading?). Because of horizontal movement of lithospheric plates, horstlike uplifts were formed in the frontal zones. In sedimentary formations overlapping the lithospheric plates, the synsedimentary imbricated-thrust structures were developed, favouring a growth of the uplifts in lateral direction toward the axial zones of rift-grabens. Synchronously with basaltic volcanic activity in the rift-graben zones, basic-ultrabasic intrusive magmatism occurred within the limits of the contiguous uplifts.