The Relationship between Tectonic Subsidence and BSR of Upper Neogene in the Deep‐Water Area of the Northern Continental Slope, South China Sea

Abstract:BSR (Bottom Simulating Reflector) occurs widely in the strata since the late Miocene in the deep‐water area of the northern continental slope of South China Sea (SCS). It is an important seismic reference mark which identifies the gas hydrate and its distribution influenced by the tectonic movements. Single‐point basin modeling was conducted using 473 points in the study area. To discuss the relationships between the tectonic subsidence and BSR, the volume and rate of tectonic subsidence in each geological time have been simulated. The results show that there are three tectonic accelerate subsidence processes in the study area since the late Miocene, especially since 1.8Ma the tectonic subsidence accelerates more apparently. Since the Late Miocene to Pleistocene, the rate of tectonic subsidence in deep‐water underwent a transformation from weak to strong. The ratio of tectonic subsidence to the total subsidence was relatively high (65–70%). Through the superposition of the BSR developed areas and the contours of tectonic subsidence in this area, it was discovered that more than 80% of BSR tend to be distributed at the slope break or depression‐uplift structural transfer zone and the average tectonic subsidence rate ranges from 70 m/Ma to 125 m/Ma.