Development characteristics of the fault system and its control on basin structure, Bodong Sag, East China

Abstract

The Bodong Sag, located in the Bohai Sea, offshore China, is one of the most petroliferous basins in China. Based on three dimensional seismic reflection data and time slice data, we analyze the fault system of the Bodong area in detail, establish the fault structure pattern of different types and summarize the distribution of the fault system. It is concluded that the development characteristics of the a brush structure with NNE strike-slip faults as its principal faults, NE-trending extensional faults as secondary faults and EW-trending faults as minor faults. Faults can be divided into (1) strike-slip type, (2) extensional type, (3) strike-slip extensional type and (4) extensional strike-slip type. The spatial structures of different faults have obvious differences because of the fault properties and activity intensity. The fault system at different stages shows tremendous differences because of the transition of the Tanlu Fault from sinistral strike-slip to dextral strike-slip, the transition between extension and strike-slip, and the transition from mantle upwelling to thermal subsidence. According to the controlling effect of faults on basin structure, the Cenozoic basin experienced four evolutionary stages, (a) transition stage from sinistral strike-slip to dextral strike-slip, (b) strike-slip extensional faulted stage, (c) extensional strike-slip faulted

Cenozoic evolution of Zhangjiakou‐Penglai Fault Zone in the western offshore Bohai Bay Basin: Evidence from 3D seismic data

“…This kind of the “flower‐structure” with a dip‐slip component is widely observed in the BBB (Hu, Jiang, Fu, Li, & Chen, 2016; Wu et al, 2013; Xu et al, 2015) and sometimes noted as the “flower‐like structure” (Liu, Dong, & Wang, 2010; Zhan et al, 2012). The formation mechanism was studied and illustrated as a result of wrench activity imposed on pre‐existing extension faults (Wu et al, 2013; Yixin et al, 2018), which has also been confirmed by physical modelling experiments (Richard & Krantz, 1991; Hu et al, 2019).…”

“…The dashed grey frames give the locations of the seismic slices discussed in Figures 5 and 7 [Colour figure can be viewed at wileyonlinelibrary.com] strata thickness of the hanging and the footwall varies a lot. This kind of the "flower-structure" with a dip-slip component is widely observed in the BBB (Hu, Jiang, Fu, Li, & Chen, 2016;Wu et al, 2013; and sometimes noted as the "flower-like structure" (Liu, Dong, & Wang, 2010;Zhan et al, 2012). The formation mechanism was studied and illustrated as a result of wrench activity imposed on pre-existing extension faults (Wu et al, 2013;Yixin et al, 2018), which has also been confirmed by physical modelling experiments (Richard & Krantz, 1991;Hu et al, 2019).…”

Early Paleogene strike‐slip transition of the Tan–Lu Fault Zone across the southeast Bohai Bay Basin: Constraints from fault characteristics in its adjacent basins

“…It is well accepted that the sinistral motion of the TLZF is triggered by the NNW‐directed subduction of the Pacific to the Eurasian plates in the Early Paleogene, and its dextral motion is attributed to the sudden kinematic adjustment of the Pacific Plate from NNW to WNW at about 43 Ma, corresponding to the bend point of the Hawaiian–Emperor chain (e.g., Huang et al, ; Wu et al, ; Zhou, ). However, this viewpoint is not only too general to match what we found in the Weibei, Qingdong, and Dongying sags but also has intrinsic weaknesses.…”

“…However, the strike‐slip transition time of the TLFZ is still controversial. Some scholars held the opinion that this transition occurred between the Mesozoic and Cenozoic (e.g., Cai, Luo, & Yao, ; Cheng et al, ; Wan & Zhu, ; Zhang & Qi, ), but more and more authors considered that it happened in Early Paleogene, for example, in the depositional stage of (1) the second member of the Kongdian Formation (designated as E k 2 ; e.g., Sun et al, ; Zhou, ), (2) E k (Chen, ; Chen, ; Wang, ), (3) E k to the fourth member of the Shahejie Formation (E k ‐E s 4 ; e.g., Cao, ; Guo, ; Gao, ; Huang, Wang, Wu & Wang, ; Huang, Liu, Zhou & Wang, ; Jia et al, ; Wu et al, ; Zheng et al, ; Zhang, Wang, Ding, & Zhong, ; Zhao & Li, ), (4) E k to the lower sub‐member of E s 4 (E k ‐E k 4 L ; e.g., Jia et al, ; Jia et al, ; Wang et al, ; Wei et al, ; Wu et al, ; Yang, ; Zhang, ; Zheng et al, ), or (5) E s 4 (e.g., Chen, ) and in geological time (1) in the Palaeocene (e.g., Shi, ), (2) from the Palaeocene to the Early Eocene (e.g., Han et al, ; Hsiao et al, ; Huang, Yu, Zhang, Fu, Yuan, & Fan, ; Li et al, ; Teng, Zou, & Hao, ; Xia, Liu, & Chen, ; Xu et al, ; Zhang et al, ; Zhang, ; Zhang et al, ; Zhang, Xue, Wu, Nie, & Hu, ; Zheng, ; Zhou, ), or (3) in the Early Eocene (e.g., Gao, ; Wang, Zhang, & Li, ). Besides, they did not explain how exactly the TLFZ turned into dextral motion from sinistral motion during the above transition stage as well (e.g., Gao, ; Huang et al, ; Jia et al, ; Wu et al, ; Zhao & Li, ; Zheng et al, ; Zhou, ).…”

“…However, the strike-slip transition time of the TLFZ is still controversial. Some scholars held the opinion that this transition occurred between the Mesozoic and Cenozoic (e.g., Cai, Luo, & Yao, 2001;Cheng et al, 2016;Wan & Zhu, 1996;Zhang & Qi, 2005), but more and more authors considered that it happened in Early Paleogene, for example, in the depositional stage of (1) the second member of the Kongdian Formation (designated as Ek 2 ; e.g., Sun et al, 2016;Zhou, 2005), (2) Ek (Chen, 2004a;Chen, 2004b;Wang, 2010), (3) Ek to the fourth member of the Shahejie Formation (Ek-Es 4 ; e.g., Cao, 2008;Guo, 2010;Gao, 2011;Huang, Wang, Wu & Wang, 2012;Huang, Liu, Zhou & Wang, 2012;Jia et al, 2007;Wu et al, 2013;Zheng et al, 2005;Zhang, Wang, Ding, & Zhong, 2006;, (4) Ek to the lower sub-member of Es 4 (Ek-Ek 4 L ; e.g., Jia et al, 2007;Jia et al, 2013;Wang et al, 2012;Wei et al, 2014;Wu et al, 2012;Yang, 2011;Zhang, 2012;Zheng et al, 2014), or (5) Es 4 (e.g., Chen, 1993) and in geological time (1) in the Palaeocene (e.g., Shi, 2010), (2) from the Palaeocene to the Early Eocene (e.g., Han et al, 2005;Hsiao et al, 2004;Huang, Yu, Zhang, Fu, Yuan, & Fan, 2013;Li et al, 2015;Teng, Zou, & Hao, 2014;Xia, Liu, & Chen, 2006;Xu et al, 2008;…”