Paleogeography of the southwestern Ordos Basin and exhumation history of the Liupan Shan area

Abstract

The Liupan Shan, situated on the southwestern Ordos Basin, underwent Cenozoic uplift caused by the India-Asia collision and subsequent northeastward tectonic movements. The strata in this region record both the paleogeography of the southwestern Ordos Basin and the uplift history of the Tibetan Plateau. However, past studies have rarely analyzed the strata comprehensively, resulting in overlooked information within them. We present the first detrital zircon (U-Th)/He (ZHe) data from the Lower Cretaceous deposits of the Liupan Shan and the Upper Miocene red clay of Chaona, constraining a maximum burial depth of less than 6–7 km at 60 Ma for the Liupan area. By integrating zircon U-Pb ages, paleocurrent data, and sedimentary facies, we found a primary ZHe age peak (∼210 Ma) indicating that the Lower Cretaceous deposits were sourced from the Qinling Orogenic Belt, while the red clay was likely originated from the Liupan Shan. Although the Chaona strata are not preserved in the Liupan Shan, our results suggest that the Miocene Chaona section is crucial for understanding the Late Cenozoic uplift of the Liupan Shan. The distinct stratigraphic ages and source areas reflect the complex depositional and tectonic history of the region. Thermal modeling results revealed three stages of tectonic events (Late Cretaceous, Late Paleocene-Early Eocene, and Late Cenozoic), which are linked to plate interaction. Our findings offer new insights into the long-term tectonic evolution of the Tibetan Plateau.