Impact of neogene tectonic subsidence characteristics on the BSR Distribution in Qiongdongnan Basin

Abstract：BSR found in the formation has been distributed since Late Miocene in the deep water area of Qiongdongnan (Southeast Hainan) Basin, influenced by the tectonic movements. The BSR is one of the important indicators to identify gas hydrate. Based on data analyses from 301 virtual points, the authors worked out the relationship between the BSR’s distribution and the tectonic subsidence. The study shows that under the influence of the Red River strike slip motion and mantle-derived basic magma eruption, there are three different tectonic subsidence acceleration periods bounded by 5.3Ma and 1.8Ma in the deep water area of the Qiongdongnan Basin, of which the third phase (since 1.8Ma) is the fastest stage. From border to center, the tectonic subsidence rate is getting higher and higher, and it changes faster in the central hollow zone than in the southern uplift zone. In the area between them it remains high. BSR is mainly observed in the borderland between secondary structure unit where the tectonic subsidence rate is high and changes faster and the area which can afford higher tectonic subsidence rates varying from 70m/Ma to 110m/Ma.