Deciphering Tectonic Mechanism and Origin of T85 Horizon in Lishui Depression,East China Sea Basin
To unravel the difference of rift evolution between the sub-and supra-T85 horizon,and illustrate the formation mechanism of the tectonic transition,the rift architecture,fault activity and spatio-temporal variations of subsidence were investigated by using high-quality seismic data and borehole data.Dividing by the T85 angular unconformity,the Lishui depression exhibits two distinct rift architecture:the underlying fault-controlled,wedge-shaped packages and the overlying saucer-shaped packages.Subsidence within the Lishui depression migrated westward during the faulting stage,while it progressively migrated eastward during the subsequent faulting and sagging stage.Together with the regional geodynamic context and advances in rift research,the study proposes that either the thermal subsidence caused by tectonic migration or the shallow response to the ductile deformation of lower crust resulted in the tectonic transition within the Lishui depression.The study significantly improves the understanding of rift evolution and its controlling factors.
tectonic transitionrift evolutionunconformityLishui depressionEast China Sea basinpetroleum geology
NETL
NSTL
万方数据
