Coupling relationship between sedimentary basin and Moho morphology in the South Yellow Sea, East China

Abstract

The development of the sedimentary basin in the South Yellow Sea that lies between the Chinese mainland and the Korean Peninsula well documents the tectonic evolution of eastern China. However, the Moho morphology and its relationship with the basin in this area remain poorly understood. Here we used high‐resolution 2D seismic lines and well data to map the geometry, structure, and distribution of the sedimentary basin in the South Yellow Sea. Our results suggest that the South Yellow Sea Basin can be divided into two distinct depressions and three uplifts. The depressions consist of eight depositional sags that are largely controlled by ENE‐, EW‐, and WNW‐striking normal faults. The basin depth reaches 9,500 m in the depressions, but is only <2000 m in the uplift zones. Calculated using a gravity stripping method, the Moho depth varies between 27.4 and 31.5 km. The basin is isostatically compensated and the Moho morphology approximately mirrors that of the basin basement. The Moho lows correspond to the uplift zones and Moho highs correspond to the depression zones, with exception of a sag in the Northern Depression. This exception is caused by the presence of a geological body of high velocity and high density beneath the sag. This body is likely to represent high‐pressure metamorphic rock that initially formed during the collision between the Sino‐Korean and Yangtze cratons and are currently overlain by the sedimentary basin. Based on the stretching factors and strain rates of the South Yellow Sea Basin, we propose that development of the basin was primarily driven by the subduction and retreat of the Pacific Plate since the Late Cretaceous, combined by far‐field effects from the convergence between the Indian and Eurasian plates during the Cenozoic.

Research on the Tectonic Characteristics and Hydrocarbon Prospects in the Northern Area of the South Yellow Sea Based on Gravity and Magnetic Data

“…[46] employed advanced gravity edge detection methods to map the structural configuration of the western part of the Gulf of Guinea. Likewise, significant progress has been made in researching geological structures, hydrocarbon potential, and other aspects in the SYS using gravity and magnetic data [14,[47][48][49][50][51][52][53][54][55][56][57]. Nevertheless, considerable controversies still exist in understanding the fault characteristics, basement structure, and stratigraphic distribution due to the long-time span, inconsistent quality, data precision, poor short-wave signal, and single or limited gravity and magnetic data processing methods.…”