Mesozoic and Cenozoic paleogeography reconstruction of the western Jianghan Basin (Central China): Revealed by apatite fission track dating

The Jianghan Basin is situated within the northern part of the South China Block, adjacent to the suture zone between the South China Block and North China Craton, a strategic position to investigate syn- and post-tectonic processes during continental accretion. However, the precise timing of coeval evolution between the Jianghan Basin and the surrounding orogenic belts remains contentious. Similarly, the exact timing of the Yangtze River's incursion into the Jianghan Basin, which represents a major tipping point in the regional geomorphology, is poorly constrained. We selected nine clastic samples from the Cretaceous and Paleogene strata of the Zhijiang Depression (western Jianghan Basin) to perform detrital apatite fission track thermochronology to investigate sediment provenance and thermal history of the basin. A comparison of the decomposed apatite fission track ages with the depositional ages of the corresponding sedimentary strata and published regional research suggests Jurassic (178–160 Ma) to early Cretaceous (143–96 Ma) exhumation events in the Jiangnan orogenic belt, associated with compressional deformation of the South China Block, induced by the subduction of the Paleo-Pacific Plate. Additionally, several late Cretaceous to Cenozoic apatite fission track peak ages (71–56, 37–33, 23–14, and 5–3 Ma) are younger than the depositional sedimentary ages of the corresponding strata, indicating subsequent tectono-thermal events in the Zhijiang Depression. The 71–56 Ma event is explained as an intra-plate response triggered by the late Cretaceous retreat of the Paleo-Pacific Plate. The Cenozoic events are thought to result from exhumation accompanying the eastward extrusion of the Tibetan crust. The Yangtze River, flowing from west to east, cuts through the Huangling Anticline and enters the Jianghan Basin, leading to a transition from a Paleogene drainage endorheic water system to exoreism during the Neogene.