Paleogene Tectonic Evolution Controls on Sequence Stratigraphic Patterns in the Fushan Sag, Northern South China Sea  

作　　者：Guanhong Wang Hua Wang Huajun Gan Entao Liu Cunyin Xia Yingdong Zhao Shanbin Chen Chengcheng Zhang 

机构地区：[1]Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education, China University of Geosciences [2]Faculty of Earth Resources, China University of Geosciences [3]School of Earth Sciences, The University of Queensland [4]Exploration and Development Corporation,Petro China

出　　处：《Journal of Earth Science》2016年第4期654-669,共16页地球科学学刊（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos. 41272122, 41202074)

摘　　要：Tectonism is of extreme importance to sequence stratigraphic patterns in continental sedimentary basins, affecting both the architectures and internal makeup of sequences. Sequence stratigraphic framework of the Paleogene system in the Fushan sag, northern South China Sea, was built using 3D and 2D seismic data, complemented by drilling cores and well logs data. One first-order, three second-order and seven third-order sequences were identified. Analysis of paleotectonic stress field, unconformities and subsidence history showed that the Paleogene tectonic evolution presented significant characteristics of multistage and episode, and can be divided into three stages： rifting stage I（initial rifting period）, rifting stage II（rapid subsidence period）, rifting stage III（fault-depressed diversionary period）. Partition of the west and east in tectonic activity was obvious. The west area showed relatively stronger tectonic activity than the east area, especially during the rifting stage II. Episodic rifting and lateral variations in tectonic activity resulted in a wide variety of structural slope break belts, which controlled both the sequence architectures and interval makeup, and strongly constrained the development of special facies zones or sand bodies that tended to form hydrocarbon accumulation. This paper classifies the genetic types of slope break belts and their relevant sequence stratigraphic patterns within the Fushan sag, and further discusses the tectonic evolution controls on sequence stratigraphic patterns, which suggests that vertical evolution paths of structural slope break belts and relevant sequence stratigraphic patterns as a response to the Paleogene tectonic evolution were strongly controlled by sag margin types and lateral variations of tectonic activity.Tectonism is of extreme importance to sequence stratigraphic patterns in continental sedimentary basins, affecting both the architectures and internal makeup of sequences. Sequence stratigraphic framework of the Paleogene system in the Fushan sag, northern South China Sea, was built using 3D and 2D seismic data, complemented by drilling cores and well logs data. One first-order, three second-order and seven third-order sequences were identified. Analysis of paleotectonic stress field, unconformities and subsidence history showed that the Paleogene tectonic evolution presented significant characteristics of multistage and episode, and can be divided into three stages： rifting stage I（initial rifting period）, rifting stage II（rapid subsidence period）, rifting stage III（fault-depressed diversionary period）. Partition of the west and east in tectonic activity was obvious. The west area showed relatively stronger tectonic activity than the east area, especially during the rifting stage II. Episodic rifting and lateral variations in tectonic activity resulted in a wide variety of structural slope break belts, which controlled both the sequence architectures and interval makeup, and strongly constrained the development of special facies zones or sand bodies that tended to form hydrocarbon accumulation. This paper classifies the genetic types of slope break belts and their relevant sequence stratigraphic patterns within the Fushan sag, and further discusses the tectonic evolution controls on sequence stratigraphic patterns, which suggests that vertical evolution paths of structural slope break belts and relevant sequence stratigraphic patterns as a response to the Paleogene tectonic evolution were strongly controlled by sag margin types and lateral variations of tectonic activity.

关 键 词：South China Sea Fushan sag tectonic evolution structural slope break belt sequencestratigraphic pattern. 

分 类 号：P618.13[天文地球—矿床学] P736[天文地球—地质学]