Cenozoic structure and tectonics of North subbasins in Beibu Gulf Basin, northern South China Sea
Cenozoic structure and tectonics of North subbasins in Beibu Gulf Basin, northern South China Sea
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DOI：
10.1016/j.tecto.2021.228912
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发表时间：
2021-08
期刊：
影响因子：
2.9
通讯作者：
Yiming Liu;Zhiping Wu;Lijun Liu;Shiyong Yan;Lin Hu;Ming-Ming Ping-Ming;Meng Zhang
中科院分区：
文献类型：
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作者：
Yiming Liu;Zhiping Wu;Lijun Liu;Shiyong Yan;Lin Hu;Ming-Ming Ping-Ming;Meng Zhang
南海北方边缘裂谷作用与红河断裂带剪切作用的时空相互作用是理解区域地球动力学的关键。它们之间的模糊关系导致了对南海东北缘北部湾盆地起源的争议模式。新发布的地震反射数据和测井记录允许对构造-沉积历史进行新的全面分析，这对盆地形成历史提供了重要的制约。在三维多道地震资料解释的基础上，分析了地震地层、断层发育和构造沉降，并通过模拟实验进行了补充验证。结果表明，几个关键的不整合面将北部次盆地的裂陷历史分为三个不同的阶段。在前两个阶段，同沉积断裂和沉积中心经历了由NE向向到NNE向的构造转换。第三阶段（30-23 Ma），伸展构造被共轭走滑断层叠加，表现为北东东向的优势断层和北西向隐伏断层的复活。结合其他区域地质记录和板块重建历史，我们提出了该地区构造历史的最新观点。新生代初开始形成北东向裂谷系。~40 Ma的构造重组使区域应力场发生了南北向伸展的变化，导致了盆地的构造转型。受RRFZ区域性剪切活动以及额外的南北向伸展的影响，盆地受到广泛的走滑变形的改造。因此，我们强调，虽然盆地的整体结构是由东北向裂谷的发展，既重新配置的应力场作用于预先存在的故障和走滑复活的盲断层导致盆地目前的复杂结构。
The spatial and temporal interaction of rifting at the northern South China Sea (SCS) margin and shearing along Red River Fault Zone (RRFZ) is crucial to understanding the regional geodynamics. Their obscure relationship has led to controversial models for the origin of the Beibu Gulf basin within the northeast edge of the SCS. Newly released seismic-reflection data and well logs permit a new comprehensive analysis of the tectono-sedimentary history, which provides important constraints on the basin-forming history. Based on the interpretation of 3D multi-channel seismic data, we analyzed the seismic stratigraphy, fault development and tectonic subsidence, with additional confirmation from analogue modelling. The results suggest that several key unconformities separate the rifting history of North subbasins into three distinct phases. Thesyn-depositional faults and depocenters experienced a tectonic transition from NE- to NNE-orientated during the first two stages. The extensional structures were overprinted by the conjugate strike-slip faulting during stage III (30–23 Ma), as evidenced by the NEE-trending predominant faults and reactivation of NW-trending blind faults. Together with other regional geologic records and plate reconstruction history, we propose an updated view of the region's tectonic history. The NE-trending rift system initiated at the beginning of the Cenozoic. Tectonic reconfiguration at ~40 Ma induced a regional change of stress field to become north-south stretching that caused a tectonic transition of the basin. Influenced by the regional shearing activity of the RRFZ as well as additional north-south stretching, the basin was reworked by widespread strike-slip deformation. We therefore emphasize that while the basin's overall architecture was defined by the development of NE-trending rifts, both reconfiguration of the stress field acting on pre-existing faults and strike-slip reactivation of blind faults led to the basin's current intricate structure.