The geophysical identification, characteristics, and petroliferous significance of sublacustrine fan deposits in the second member of Dongying Formation in Liaozhong Depression, Bohai Bay Basin

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The Zhangjiakou‐Penglai Fault Zone (ZPFZ) is an NW‐trending strike‐slip fault zone in Eastern China that contains abundant petroleum resources and has induced massive seismic hazards. It is left‐lateral and behaves as a conjugate relationship with the Tan‐Lu Fault Zone (TLFZ). Present studies on the ZPFZ are mainly conducted on its seismology and field exposure features, with subsurface characteristics and evolution history poorly understood. In this study, we investigated the ZPFZ in the western offshore Bohai Bay Basin based on the detailed interpretation of 3D seismic data, specializing in subsurface geometric characters and evolution history. The profile flower structure and plan broom‐like pattern featured the ZPFZ in the study area and indicate its sinistral strike‐slipping. We further investigated and discusssd the Cenozoic evolution history based on evidence in (a) distinguished tectonics in fault releasing and restraining bends, (b) strata thickness map before and after the strike‐slipping, and (c) geometry of composite flower structures. The result suggests the evolution of the ZPFZ mainly comprises three stages: (a) the initial extension from 65 to 38 Ma, (b) the sinistral strike‐slipping in transtension from 38 to 25 Ma, and (3) the sinistral strike‐slipping in transpression from 25 Ma to present. The proposed evolution of the ZPFZ had good consistency with that of the conjugate TLFZ and was closely related to the Cenozoic surrounding plate tectonism, especially the Pacific Plate subduction.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 91%

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

Liu

Lin

et al. 2021

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“…During this period, a series of grabens and half-grabens were well developed along major NW-and NEtrending fault sets (Yang & Xu, 2004). The syn-rift sediments (65-24.6 Ma) unconformably overlying the Mesozoic basement, from bottom to top, mainly comprises the Paleogene Kongdian (Ek), Shahejie (Es), and Dongying formations (Ed) that were deposited primarily in fluvial-lacustrine environments (Jiu et al, 2013;Li, Liu, Niu, & Guo, 2014;Xia et al, 2017). When entered the post-rift period (24.6 Ma to the present), the entire basin experienced thermal subsidence without intensive tectonism (Hao, Zhou, Zhu, Zou, & Yang, 2010;Li et al, 2014).…”

Section: Geological Settingmentioning

confidence: 99%

Sedimentary features and their controls in a mixed siliciclastic–carbonate system in a shallow lake area: An example from the BZ‐X block in the Huanghekou Sag, Bohai Bay Basin, Eastern China

Xie

et al. 2018

Mixed siliciclastic–carbonate sediments were well developed in the BZ‐X block as a subunit in the Huanghekou Sag in the southeastern part of the Bohai Bay Basin (China) during the Member 1 of the Shahejie Formation. An integrated approach based on detailed microscopic observation and core descriptions was applied to characterize the lithofacies types, facies associations, and depositional environment of the mixed sediments system. A detailed sedimentary facies analysis suggests that various lithofacies types can be grouped into four facies associations: mixed bioclastic sandy beaches (FA1), mixed clastic bioclastic shoal (FA2), mixed sandy oolitic shoals (FA3), and mixed distal bioclastic sandy beaches (FA4). These facies associations are interpreted to be deposited in varying depositional environments ranging from foreshore to shoreface setting in a shallow lake setting. An interplay of the climate regime, nearshore carbonate productivity, and current activity was proved to control the lithofacies types, dispersion and depositional environment change of mixed sediments in different depositional phases. Meter‐scale mixed cycles were found in this shallow lake setting and their features seem to differ from the classical mixed sediment models. It is suggested that these particular cycles in the stratigraphic record might indicate a typical mark of mixed sediment system in shallow areas of the lacustrine basin.

“…In recent years, the researches on extensional process, associated mechanism and significances of petroliferous basins have become hot topics for sedimentary geology and petroliferous basin analysis at home and abroad (Hsiao, Graham, & Tilander, 2004, 2010; Ren, Tamaki, & Li, 2002; Yu & Koyi, 2016; Zhang, Wu, Li, Xiao, & Qi, 2017; Zhao et al, 2016; Zhu et al, 2015; Zhu, Jiang, Zhang, & Chen, 2012; Zhu, Liu, Zhang, Gurnis, & Ma, 2021). Liaodong Bay, which is situated in northeastern Bohai Bay Basin, as a key and potential area of hydrocarbon reserves, has been paid wide attentions by scholars and oil industry (Xia et al, 2018, 2018; Xia, Lin, Wu, & Du, 2022; Zhu et al, 2015; Zhu et al, 2021). The scholars have conducted numerous researches on tectonics, sequence stratigraphy, sedimentology, reservoir mechanism, which have achieved effective and fruitful results (Qi, Li, Yu, & Yu, 2013; Qi & Yang, 2010; Ren et al, 2002; Xia et al, 2022; Xia, Lin, et al, 2018; Xia, Liu, et al, 2018; Xu et al, 2008; Xu, Xu, Qiu, Lai, & Zhou, 2005; Yu & Koyi, 2016; Zhu et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Liaodong Bay, which is situated in northeastern Bohai Bay Basin, as a key and potential area of hydrocarbon reserves, has been paid wide attentions by scholars and oil industry (Xia et al, 2018, 2018; Xia, Lin, Wu, & Du, 2022; Zhu et al, 2015; Zhu et al, 2021). The scholars have conducted numerous researches on tectonics, sequence stratigraphy, sedimentology, reservoir mechanism, which have achieved effective and fruitful results (Qi, Li, Yu, & Yu, 2013; Qi & Yang, 2010; Ren et al, 2002; Xia et al, 2022; Xia, Lin, et al, 2018; Xia, Liu, et al, 2018; Xu et al, 2008; Xu, Xu, Qiu, Lai, & Zhou, 2005; Yu & Koyi, 2016; Zhu et al, 2015). Extensional deformation, as an important indicator that can reflect structural characteristics and analyse geometric structure of sedimentary basins, has been used to carry out researches in different regions of Bohai Bay Basin (Dong, Qi, Yang, & Yuan, 2013; Hsiao et al, 2004, 2010; Qi, Zhou, & Wang, 2010).…”

Section: Introductionmentioning

confidence: 99%

Spatio‐temporal distribution and genetic mechanism of Paleogene extension amounts in the Liaodong Bay, Bohai Bay Basin

Xia

Lin

et al. 2022

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Based on seismic interpretation of 18 regional 3D high‐resolution seismic sections across Liaodong Bay, extension amounts, extension rates and extension coefficients of different seismic sections from the south to the north are calculated by employing balanced section technique. Then, spatio‐temporal distribution of extension amounts is characterized and interpreted. Finally, the analysis of genetic mechanism is conducted and analysed. The results indicate that tectonic evolution in the Paleogene of Liaodong Bay is characterized by episodic extension. Furthermore, spatio‐temporal distribution of extension amounts is relatively uneven. In terms of space, extension amounts are mainly caused by extensional displacement of main depression‐controlled boundary faults and syn‐depositional faults in the depression. In addition, extensional amounts along main depression‐controlled boundary faults are characterized by larger displacement. In terms of time, the periods for horizontal extensional movement can be divided into three stages: The Palaeocene‐Early Eocene (Kongdian Formation‐third member of Shahejie Formation), Middle‐Late Eocene‐Early Oligocene (first and second member of Shahejie Formation) and Middle‐Late Oligocene (Dongying Formation). Among them, extension during the Palaeocene‐Early Eocene occurs both in the north and south of Liaodong Bay. However, extension intensity in the north is stronger than that in the south. Extension intensity in the middle and north during Middle‐Late Eocene‐Early Oligocene obviously increases. In contrast, it is dominated by strike‐slip movement during depositional period of Dongying Formation. Therefore, extension intensity is characterized by significant inheritance. Spatial–temporal distribution of extension amounts is predominantly controlled by tectonic evolution and associated tectonic deformation.