Numerical modeling on the relationship between thermal uplift and subsequent rapid subsidence: Discussions on the evolution of the Tainan Basin

Abstract

Existing evidence shows that an Oligocene erosion event occurred on the northern continental margin of the South China Sea, and the Tainan Basin area might be at the center of this event, followed by a rapid tectonic subsidence in the late Oligocene and early Miocene period. The rapid tectonic subsidence is mainly thermal-controlled, and the effect of the Yichu Fault on the Tainan Basin is limited to the basin's eastern part. We develop a 2-D thermal-mechanical kinematic numerical model to explore the relationship between thermal uplift and subsequent rapid subsidence in the Tainan Basin. Our modeling indicates that the Oligocene uplift, erosion, and subsequent rapid subsidence could be caused by a thermal event, and the differential subsidence of the basement caused by thermal contraction can initiate the development of small faults. However, it also suggests that other mechanisms might be needed to jointly account for the observed erosions. Copyright 2008 by the American Geophysical Union.