Литосфера (Aug 2016)
Strike-slip related continental rifting of the eastern margin of Asia
Abstract
The present paper considers the research of the Cretaceous-Cenozoic rifting for the Eastern margin of Asia occurring under the strike-slip related geodynamic regime, which resulted from development of the Eastern Asian global strike-slip fault zone (EAGSSFZ). The EAGSSFZ infrastructure proves to be recognized. It includes the longitudinal system of the NE (25-30°) trending sinistral faults, which form the through strike-slip fault zone to be pivot for the EAGSSFZ, together with two diagonal systems: the NE (50-70°) trending near-continental system of obligue-reverse-slip faults and the N-S trending near-oceanic fault system, which are feathering for the pivot zone. The paragenesis of the longitudinal and diagonal near-continental systems is studied. There are two paragenetic stages of their development: 1) the Jurassic-to-Early-Cretaceous orogenic stage is to be an effect of the formation of the diagonal system of the fold-thrust dislocations as compression structures of the longitudinal sinistral fault system (orogenic strike-slip related constriction of masses continued through the end of Early Cretaceous); 2) the Late-Cretaceous-to-Cenozoic riftogenic stage is to be an effect of riftogenic extension (pulling apart) of the crustal block bounded by the sinistral faults of the longitudinal system and due to the rifting that was caused by substitution (within the diagonal system) of predominantly reverse-and-thrust fault kinematics (of the 1st stage) for sinistral slips with development of the riftogenic extension structures controlling sedimentary basins along the strike-slip faults. At the same time, the sinistral activation of the diagonal fault system comprising the Bohai-Amur (BA) zone caused transformation of the Tan-Lu (TL) strike-slip fault into the extension structure, forming here the up-to-80-km-wide riftogenic trough with subsidence of its sides that led to formation of the North Chinese sedimentary basin up-to-700-km-wide. Being identical with the TL rift by orientation, morphology, and depth of initiation, the Eastern Amur rift formed also synchronously with the TL rift that corroborates opening of the latter via south-westward displacements of the NW sides of the BA system’s strike-slip faults. The established sinistral displacements of the NW sides for the faults belonging to both the diagonal and longitudinal systems to the south-westward (the total displacements’ sector is SW 205-250°) show dynamo-kinematic activity of the Asian continent in the processes of rifting of the Eastern margin of Asia.
