The climatic pattern of East Asia shifted in response to cratonic thinning in the Early Cretaceous

Abstract

In response to westward subduction of the Paleo-Pacific, the North China Craton experienced the uplift of an eastern coastal plateau followed by subsidence in the Early Cretaceous, which potentially drove a shift in climatic patterns. Here we use the oxygen isotope ratios of garnets from magmatic-hydrothermal ore systems to infer the origins and signatures of mineralization fluids during this tectonic transition. The garnet oxygen isotope values range from approximately –11.4 to +13.5‰, with extremely depleted oxygen isotope ratios exclusively found in the northern margin, indicating extensive involvement of meteoric and lacustrine fluid in the back-arc hinterland. This geological record aligns with climate modeling exhibiting that the coastal plateau amplified northeastward transport of moisture from tropical Tethyan Ocean. The long-distance transport strongly depleted 18O and 2H (D). As the cratonic lithosphere thinned and the plateau subsided, the Pacific influences began to dominate the climatic pattern of East Asia. Regional climate of East Asia shifted in the Early Cretaceous in response to tectonic collapse of a coastal plateau and an increase in moisture sourced from the Pacific Ocean, according to geochemical data from skarn garnets sampled across the North China Craton, and climate models.