Paleozoic-cenozoic evolution of the East Gobi Fault Zone, Southern Mongolia: a protracted record of intracontinental deformation and basin evolution, with implications for tectonics in Eurasia

The East Gobi Fault Zone is southeastern Mongolia and associated the East Gobi Basin, is an ideal laboratory for delineating polyphase deformation and basin evolution in an intracontinental setting. Structural interpretation of proprietary 2-D seismic reflection data and correlation to subsurface ace interpretations reveals six distinct phases of deformation recorded in the Paleozoic basement rocks and Mesozoic-Cenozoic basin-fill of the East Gobi Basin. These phases include arc accretion and arc-continent collision in the late Paleozoic, Early Triassic sinistral shear-zone development, Early Jurassic fold and thrust belt style compression, Middle Jurassic-Lower Cretaceous extension and rift basin development, middle Cretaceous compression with basin inversion and regional unconformity development, and Late Cretaceous-Oligocene left-lateral strike slip faulting across the fault zone. The five postamalgamation deformation phases are localized along the East Gobi Fault Zone, suggesting that preexisting structures and boundary conditions exert fundamental controls on the long term evolution of intracontinental basin such as the East Gobi Basin.