Stepwise global cooling drove Pleistocene lake regression in northern China

The early Pleistocene represents a critical period for understanding the formation and evolution of the modern East Asian landscape. During this period, the intensification of Northern Hemisphere glaciation and the East Asian summer monsoon system exerted a strong influence on landscape evolution through hydrologic shifts and surface erosion and deposition in East Asia, while tectonic processes, another significant driver, shaped landforms through mountain growth and basin subsidence. Intermontane basins record the interplay among climatic variability, tectonic activity, and sediment supply, providing archives for evaluating their relative contributions. The Shanxi Rift in northern China is a prominent example, where thick late Cenozoic lacustrine successions record long-term tectonic regimes and East Asian summer monsoon variability through changes in sediment supply. Here we present a new lacustrine−deltaic succession and high-resolution magnetic susceptibility data to reconstruct lake-level evolution in the Taiyuan Basin, central Shanxi Rift, northern China. Using magnetostratigraphy combined with 10Be burial dating, we establish a robust age framework from 2.59 Ma to 2.14 Ma and constrain a major lake regression to ca. 2.2 Ma. Our anisotropy of magnetic susceptibility results show no tectonic overprinting, supporting a tectonically quiescent state during the early Pleistocene. In contrast, a regional stepwise cooling and drying trend associated with the weakening of the East Asian summer monsoon is closely coupled with paleolake evolution in the Taiyuan Basin. These results demonstrate that climate forcing outweighed tectonics in controlling lake-level fluctuations in the Taiyuan Basin, highlighting the dominant role of climate change in shaping the modern East Asian landscape during key periods.