Basin Research最新文献

The submarine Miocene Central Canyon and Pleistocene channel systems in the Qiongdongnan Basin constitute valuable sedimentary records that provide insight into the depositional processes and sediment routing from the hinterland to the deep sea. However, the primary source of sediment for the Pleistocene channel systems and the variation in relative sediment contributions since the Miocene from potential source terranes remain unknown. We have integrated new and published detrital zircon U–Pb ages and rare earth elements (REEs) from Pleistocene channel sands and late Miocene Central Canyon sands in the Qiongdongnan Basin to analyse the sediment routing system of these channel systems since the Miocene. Qualitative analyses of REEs, comparisons of detrital zircon age spectra, and multidimensional scaling plots suggest that the Red River is a significant source of sediment supply. The quantitative analysis of sediment mixing models indicates that the Pleistocene channel sands were mainly sourced from the Red River (62.8%–85.7%), followed by Central Vietnam rivers (4.8%–27.1%), with a minor amount derived from rivers in Hainan Island, Northern Vietnam and Southern Vietnam. Sand sediments, mainly from the Red River system, were deposited in the Yinggehai Basin, then transported and deposited again in the Qiongdongnan Basin. The relatively stable and major sediment supply from the Red River since the Miocene may have been driven by the uplift of the Tibetan Plateau. This study quantifies the relative provenance contributions to submarine channel systems in the Qiongdongnan Basin since the Miocene. It provides crucial geological implications for tectonic responses to channel migrations and the prediction of gas hydrates in sandy reservoirs.

Exhumation affects sedimentary basin evolution by influencing structural, pressure and temperature dynamics, thereby impacting energy resource formation. Compaction-based methods are widely used to quantify exhumation, utilising sonic and porosity data to track sediment uplift from its maximum burial depths. However, uncertainties arise from applying empirical compaction models developed for specific geological regions, highlighting the need for region-specific models. Even such region-specific models contain uncertainties, which can compromise exhumation estimates. We, therefore, develop a probabilistic compaction model for the Northwest Shelf Basins using sonic data from normally compacted and unexhumed shales from the Northern Carnarvon Basin (NCB). The model's robustness is estimated using MCMC, and uncertainty propagation analysis is employed to assess the impact of model uncertainty on the model's predictive applications. The model shows exponential porosity reduction with depth, demonstrating rapid compaction from the surface to ca. 2 km and slower compaction thereafter. The model is then applied to interpret new datasets from the Canning, Gippsland and NCB regions. The results reveal that while some parts of the NCB exhibit normal compaction without exhumation, others were significantly exhumed. Conversely, Canning and Gippsland Basin data indicate signs of significant exhumation, as suggested by previous studies, thereby confirming the model's effectiveness outside the Northwest Shelf. Since the model could not explain data from exhumed regions, we inferred new models incorporating “exhumation” parameters to interpret the complex compaction histories of these areas, and the best-fitting models were selected using the Bayes Factor method. Uncertainty analysis revealed that the impacts of model uncertainty on exhumation estimates are consistent across wide depth ranges. Our findings highlight the need to refine compaction models for better predictive reliability and informed resource exploration in sedimentary basins.

Detachment fault system associated with a mature metamorphic core complex (MCC) is still not well understood. Using high-resolution 3D seismic data, we analyse the geometries and kinematic development of detachment fault system associated with a mature and exhumated MCC in the northern South China Sea rifted margin, with an emphasis on the MCC-associated faults within the supra-detachment basin. Faults within the supra-detachment basin can be classified into three stages, the pre-MCC, syn-MCC and post-MCC faults, based on their formation time relative to the MCC. The NE to NEE-striking pre-MCC faults developed in the early syn-rift 1 stage, and the NW to WNW-striking post-MCC faults were both dominated by the regional tectonics and are perpendicular to the extension directions. While the syn-MCC faults, synchronous with the MCC development in the late syn-rift 1 stage, show overall EW-striking, consistent with the long axis of the KP MCC. These syn-MCC faults were well developed and are significant in shaping the basin architecture. Besides, the syn-MCC faults are regularly distributed in the four zones overlying the convex-upward master detachment fault surface, and are defined in this study as a synthetic fault zone, an upper collapse synformal-graben fault zone, a lower collapse antiformal-graben fault zone and an antithetic fault zone respectively. These four fault zones show distinct features and evolutionary patterns, and have a closed relationship with the rolling-hinge process of the KP MCC. An evolutionary model is established for the development of MCC-associated detachment fault system which should have global implications.