Sedimentary provenance constraints on the Cretaceous to Cenozoic palaeogeography of the western margin of the Jianghan Basin, South China

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Provenance analysis of sedimentary basins is a direct way to understand the uplift of orogenic belts, basin deposition, and evolution of large rivers. A series of Mesozoic and Cenozoic strata from the western Jianghan Basin provides key sedimentary archives for investigating the growth of the surrounding orogenic belts and the evolution of the Yangtze drainage. However, the provenance of these sediments remains unclear. In this study, we report U–Pb data for 1098 detrital zircons from the western Jianghan Basin. We combine these data with published zircon U–Pb ages of potential source areas, paleocurrent data, and paleomagnetic age constraints to reconstruct provenance areas and establish related mountain-building processes. All Cretaceous and Early Cenozoic samples show five major age peaks at 131–210, 432–461, 720–986, 1836–1908, and 2470–2552 Ma. We infer that these sediments are primarily derived from recycled sediments associated with the uplift of the western Jiangnan Orogen. The tectonic uplift of the Jiangnan orogenic belt in the Cretaceous and Early Cenozoic was mainly controlled by the subduction of the Pacific and Indian plates underneath Eurasia. The detritus in the current upper reaches of the Yangtze River did not enter the Jianghan Basin before the Late Eocene (34 Ma). Early Pleistocene strata (1.2–0.7 Ma) show a distinct Cenozoic zircon U–Pb (41 Ma) peak age, which is mainly derived from the detrital sediments of the upper reaches of the Yangtze River. The combination of these data with published provenance tracing results for boreholes in the Jianghan Basin and Yangtze River Delta indicates that the Yangtze River was completely connected between 34 and 1.2 Ma. Such a long time interval may correspond to the tectonic uplift of the Tibetan Plateau and environmental changes during the Late Cenozoic.