Asynchronous palaeosol development during the past 20 ka in response to climate change across the dune fields of the Asian summer monsoonal boundary, northern China

Aeolian landscapes dominate the semiarid dune fields across the Asian summer monsoonal boundary (ASMB) of northern China, where the widespread palaeosols are usually regarded as indicators of enhanced monsoonal precipitation (moisture) during the Late Quaternary. However, the processes of palaeosol development, and their response to climate change, remain controversial due to the complex land-atmosphere interactions within different bioclimatic zones. Here, we review the patterns of palaeosol development, precipitation/moisture (P/M) evolution, and lake level fluctuations across different sub-regions of the ASMB. With the aid of typical temperature and vegetation records, we qualitatively and quantitatively distinguish the contributions of different climatic factors to palaeosol development since 20 ka (1 ka = 1000 cal yr BP) and elucidate the underlying mechanisms. Our results indicate an asynchronous pattern of palaeosol development, with optimum development during 10–4, 8–4, and 6–2 ka in northeastern (NE) China, north central (NC) China, and on the NE Qinghai-Tibetan Plateau (QTP), respectively. This implies a transmeridional asynchronous pattern of palaeosol development on the scale of the ASMB. Our qualitative and quantitative analysis of the contributions of climatic variables elucidates the various relationships between palaeosol development and the climatic background across different sub-regions of the ASMB. The results demonstrate that temperature and precipitation are the dominant factors for palaeosol development in NE and NC China, respectively; whereas effective moisture, rather than temperature and precipitation alone, controls palaeosol development on the NE QTP, demonstrating different pedogenic responses against the same overall climatic background. These mechanisms are supported by the results of multiple studies of Holocene vegetation evolution and the associated climatic conditions. We conclude that the asynchronous pattern of palaeosol development across the ASMB was caused by variations in different dominant climatic factors, highlighting the diverse and complex interactions of climate change and Earth surface processes, even within the relatively uniform climatic environment of semiarid northern China. Our findings emphasize the differing responses of palaeosol development to regional climate change and provide new insights into the interactions of the land-atmosphere system in the critical zone of northern China. Patterns of palaeosol development across different sub-regions of the ASMB, northern China during the past 20 ka • Asynchronous palaeosol development demonstrates transmeridional characteristics of pedogenesis across the ASMB of northern China • Various qualitative and quantitative relationships are demonstrated between palaeosol development and climate • Asynchronous palaeosol development in the ASMB since 20 ka was caused by variations in different dominant climatic factors