Characteristics and Mechanism of Anomalous Post-rift Subsidence Episode and its Hydrocarbon Resources Effect of Northern Continental of South China Sea

Chao Lei
Faculty of Earth Resources, China University of Geosciences, Wuhan, Hubei Province, P.R. China.
[email protected]

The South China Sea (SCS) is one of the biggest marginal seas of the West Pacific, which is tectonically within the conjunction area of the Eurasian, Indo-Australian, Pacific, and Philippine Plates and presents varied and colorful geological phenomena. At the Northern of SCS, there are several hydrocarbon-rich sedimentary basins, such as Yinggehai basin, Qiongdongnan Basin, Beibuwan Basin and Pearl River Mouth Basin. The features of the basins are typical for passive continental margins with a two-layered structure consisting of a lower syn-rift sequence and upper post-rift sequence. According to previous woks about anomalous post-rift subsidence episode, there are at least two episodes. But their work only focused on one basin or two. This time we systematically study this phenomenon in Northern margin of SCS as a whole body.

In this study, based on integration of core-log-seismic data, we studied anomaly post-rift subsidence in details. The filling sequence during Cenozoic are studied from the aspects of tectonics, depositional filling, heat, continental dynamics, and as well quantitative basin dynamics modeling will be tried in our work. Then, filling sequence and sequence stratigraphic framework styles are set up; Episodes and scales subsidence in study area are redefined; stress field characteristics of different stages are discussed; Subsequently relationship between anomalous post-rift subsidence and hydrocarbon accumulation are discussed in details.

This study will be helpful to understand the relationship between Cenozoic reorganization events of surrounding plates and anomalous post-rift subsidence episodes, and will further improve the late hydrocarbon accumulation theory.

AAPG Search and Discovery Article #90094 © 2009 AAPG Foundation Grants in Aid