Oil & Gas Geology ›› 2023, Vol. 44 ›› Issue (5): 1188-1202.doi: 10.11743/ogg20230509

• Petroleum Geology • Previous Articles     Next Articles

Multistage structural superimposition and its control on buried hills in the Lyuda uplift zone, Bohai Bay Basin

Shujuan ZHAO1,2(), Sanzhong LI1,2(), Chengmin NIU3, Jiangtao ZHANG3, Zhen ZHANG3, Liming DAI1,2, Yu YANG1,2, Jinyue LI1,2   

  1. 1.Frontiers Science Center for Deep Ocean Multispheres and Earth System,Key Lab of Submarine Geosciences and Prospecting Techniques,MOE and College of Marine Geosciences,Ocean University of China,Qingdao,Shandong 266100,China
    2.Laboratory for Marine Mineral Resources,Laoshan Laboratory,Qingdao,Shandong 266100,China
    3.Tianjin Branch of CNOOC (China) Limited,Tianjin 300452,China
  • Received:2022-12-12 Revised:2023-06-15 Online:2023-10-19 Published:2023-10-19
  • Contact: Sanzhong LI E-mail:zhaoshujuan@ouc.edu.cn;sanzhong@ouc.edu.cn

Abstract:

The Lyuda uplift zone, situated in the northwestern Bohai Sea area, Bohai Bay Basin, experienced multiphase tectonic events in superimposition during the Mesozoic-Cenozoic, leading to the formation of various interior faults with intricate deformations. However, the Paleozoic and Mesozoic structures within this zone remain understudied. Based on a detailed structural analysis with 3D seismic data, this study presents the following findings. (1) The Lyuda uplift zone predominantly experienced top-to-north thrusting during the Indosinian, forming NW- to nearly EW-trending open folds and thrust-nappe faults; (2) The uplift zone primarily underwent localized extension and deposition under compression during the Early and Middle Yanshanian, with the absence of significant angular unconformity between the Middle-Lower Jurassic and the Upper Jurassic-Lower Cretaceous strata; (3) The uplift zone principally experienced top-to-northwest thrusting during the Late Yanshanian; (4) The uplift zone witnessed the emergence of domino-style extensional-detached faults and the deposition in half grabens due to NW-SE directed extension during the Early Himalayan. Among these structures, the Indosinian NW- to nearly EW-trending thrust faults shape the basement tectonic framework for the Lyuda uplift zone, while the Late Yanshanian and Early Himalayan movements either inherited or modified the earlier fault system. The Late Cretaceous marked a pivotal transition for the Lyuda uplift zone’s tectonic framework from trending NW to nearly EW to NE. The Qinhuangdao 30-1 and Lyuda 25-1 structural buried hills, located in the tectonic transition zone, emerged from the superimposition of the Indosinian nearly S-N directed compression, the Late Yanshanian NW-SE directed compression, and the Early Himalayan NW-SE directed extension. In contrast, 428 structural buried hill in the south is controlled by the nearly E-W-trending thrust during the Indosinian and the extensional fault system during the Yanshanian and Early Himalayan.

Key words: thrust nappe, extensional detachment, superimposed modification, tectonic evolution, Mesozoic, Lyuda uplift zone, Bohai Bay Basin

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