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The Bohai Bay Basin, a typical intracontinental rift basin, records East Asia's kinematic plate history during the Cenozoic. The rifting process was driven by the counterclockwise rotation in the direction of the Pacific Plate subduction. From the early Eocene to the Oligocene, the rifting process can be divided into three stages: extension initiation, peak extension, and post-extension. The corresponding rifting rate was calculated based on 40Ar-39Ar data. Then, the provenance area evolution of the above three rifting stages was established by combining the detrital zircon U–Pb data and heavy mineral assemblage data (ZTR, GZi, and ATi). According to the results calculated by 40Ar/39Ar analysis, the topography of the sink area in the western Bohai bay basin was characterized by moderately rising subsidence rates (100 m/Ma) during the extension initiation stage (Paleocene-Early Eocene), when surface drainage was restricted to a limited area with steep channel slopes. During this stage, referring to the core description and seismic interpretation results, the fan delta distributes most of the sediment, most of which migrates from the proximal region. Until the peak extension stage, the source-sink system develops as the rate of subsidence increases (200 m/Ma), making the sink area larger, and this period involves multiple types of pathways, including synsedimentary faults and erosional valleys. Sediments from Taihang Massif and Jiaoliao Massif infill the subsidence zone at the distal end. Then, in the post-extension stage, the source-sink systems involve a multi-provenance area (i.e., sourcing from both proximal and distal areas), a large sink area, and a gentle channel gradient due to a decrease in subsidence rate (60–80 m/Ma). Catchment relief, sediment migration distance, and average fault displacement were used, and these parameters were related to the sediment supply (Qs) for the three rifting stages. We find that during extension initiation and peak extension, the source-to-sink systems show a high amount of sand influx (Q sand /) and that the ratio Q sand /Qs total shows a proportional relationship with catchment relief and average fault displacement; this relationship is inversely proportional to the catchment-unit area. Also, according to the types of pathways, we classified the source-to-sink systems during this period into three types, steep eroded pathway (Type-I S2S), gentle slope developed with several boundary faults (Type-II S2S), steep slope with observably eroded valleys or fault-troughs (Type-III S2S). The ratio of Q sand /Qs is only related to the sediment migration distance and average fault displacement in the post-extension stage. Besides the above three types of source-to-sink systems, we found that multi-stage faults developed along the slope (Type-IV S2S) predominated during this stage. • Calculated rifting rate in Bozhong Depression. • Identified the provenance area evolution in Bozhong Depression during Paleogene. • Classified four types of Source-to-sink patterns corresponding to the rifting stage. • Put out the dominated factors to S2S system developed during various rifting stages. [ABSTRACT FROM AUTHOR]

In multi-phase rift basins, the links between fault activities and sequence stratigraphic architectures are still poorly understood compared to single-rift basins. The purpose of this work is to give implications for tectono-stratigraphic signatures in multiphase rifts based on seismic data from the Zhu-3 Depression in the Pearl River Mouth Basin, China. Stratigraphically, three composite sequences (CS1-3) defined by major unconformities in the Paleogene successions of the Zhu-3 Depression are interpreted, with each one subdivided into two or three third-order sequences. Regional unconformities and basin configurations indicate two episodic rift phases, termed rift phase 1 (formed CS1), and rift phase 2 (formed CS2) followed by a lithospheric breakup phase (formed CS3). From rift phase 1 to rift phase 2, the basin evolved from small-sized, independent half-grabens into relatively large-scale grabens and finally a dish-like basin configuration. Fault displacement and stratigraphic stacking patterns revealed three distinctive structural stages of rift phase 1: rift initiation (WC-SQ1), rift development (WC-SQ2), and rift termination (WC-SQ3) stages. However, an immediate decrease in fault activity was recorded in the rift phase 2. Immediate strain localization under rotated extension fields during episodic rift phases led to variabilities in tectono-stratigraphic architectures. In turn, this transition may likely contribute to interpreting the depositional pattern from balanced infill during rift phase 1 to an overfilled pattern during rift phase 2 as well as the breakup stage in response to possible enhanced sediment supply. This work enhanced our understanding of additional hydrocarbon evaluations in the Zhu-3 Depression, South China Sea. • The Eocene-Oligocene sequence framework in the Zhu-3 rift are systematically reported. • Fault pattern, basin geometry and drainages basin in episodic rift phases are illustrated. • Tectono-stratigraphic signatures of three rift cycles in the Zhu-3 rift are proposed. • Controls of boundary fault arrays evolution on two-phase rift development are discussed. [ABSTRACT FROM AUTHOR]