Formation and syn-rifting process of the Wan'an Basin, South China Sea  

作　　者：吕彩丽 姚永坚 吴时国 董冬冬 

机构地区：[1]Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences [2]Graduate University of Chinese Academy of Sciences [3]Guangzhou Marine Geological Survey

出　　处：《Chinese Journal of Oceanology and Limnology》2013年第1期190-201,共12页中国海洋湖沼学报（英文版）

基　　金：Supported by the National Basic Research Program of China (973 Program) (No. 2009CB219406);the National Natural Science Foundation of China (No. 40930845)

摘　　要：Based on seismic and drilling data, we calculated tectonic subsidence amounts and rates of the Wan'an Basin by backstripping. The genetic mechanism and syn-rifting process of the basin were analyzed in combination with the regional geological setting. The results reveal that the basin syn-rifted in the Eocene and early Miocene under the control of the dextral strike-slip Wan'an Fault Zone. The transtensional/ extentional stresses along this fault zone may be attributed to seafloor spreading of the South China Sea (SCS) in multiple episodes. Extensive basal faults and some small initial rifts in the early Paleogene can be related to southeastward extrusion and clockwise rotation of the Indochina Block. During the Oligocene, the nearly N-S directed spreading of the SCS derived the transtensional stresses in a roughly NW-SE orientation. The basin subsided rapidly in the middle and north to form two major subsidence centers. In the early Miocene, the SCS spread again in a nearly NW-SE direction, resulting in rapid subsidence in the southern basin continuous extending until the period ～16.3 Ma.Based on seismic and drilling data, we calculated tectonic subsidence amounts and rates of the Wan＇an Basin by backstripping. The genetic mechanism and syn-rifting process of the basin were analyzed in combination with the regional geological setting. The results reveal that the basin syn-rifted in the Eocene and early Miocene under the control of the dextral strike-slip Wan＇an Fault Zone. The transtensional/ extentional stresses along this fault zone may be attributed to seafloor spreading of the South China Sea （SCS） in multiple episodes. Extensive basal faults and some small initial rifts in the early Paleogene can be related to southeastward extrusion and clockwise rotation of the Indochina Block. During the Oligocene, the nearly N-S directed spreading of the SCS derived the transtensional stresses in a roughly NW-SE orientation. The basin subsided rapidly in the middle and north to form two major subsidence centers. In the early Miocene, the SCS spread again in a nearly NW-SE direction, resulting in rapid subsidence in the southern basin continuous extending until the period -16.3 Ma.

关 键 词：tectonic subsidence RIFT Wan＇an Basin South China Sea （SCS） 

分 类 号：P618.13[天文地球—矿床学]