Late Triassic Hydroclimatic Changes in Central China Linked to Evolving Mountain Topography

Abstract During the Late Triassic, tropical Pangea drifted northward into subtropical latitudes and became progressively drier. In contrast, South China, despite experiencing a similar latitudinal shift, transitioned from an arid to humid climate. Based on the sedimentary record of the Zigui Basin, this study constrains the arid to humid climatic shift to the period of ca. 228−207 Ma in northern South China. Detrital zircons of Triassic ages were derived from the Qinling Orogen. They show an increase in Eu/Eu* ratios and a marked decrease in εHf(t) values. These geochemical trends suggest an increase in crustal thickness from ca. 40−50 km to >60 km in the Late Triassic in the Qinling Orogen and reveal a strong mountain building event with surface elevations of up to 5,000 m. Using these geological records, climate modeling indicates a significant orographic effect on regional precipitation during the Late Triassic in the Eastern Tethys.