第七届青年地学论坛

The Asian Summer Monsoons (ASM) represent the main source of precipitation in China and East Asia with about one third of the world population and a region of widespread civilizations. Identifying the temporal and spatial patterns of these monsoonal events and related water vapor transportation during the Late Holocene to today has been a matter of debate amongst the scientific community. Here, we used ¹⁰Be data measured in soils distributed across Mainland China (MC) to explore the potential influence of meteorological and pedological conditions on the isotope concentrations and the implications of the summer monsoon precipitation patterns. The cosmogenic isotope of meteoric beryllium-10 (¹⁰Be) is commonly used as a proxy of landscape dynamics (erosion and sedimentation rates) and soil development. Soil represents the first-stage reservoir of meteoric ¹⁰Be, and variability in the concentration of the isotope in soils may be affected by soil properties and atmospheric deposition. The results indicated that there were significant negative correlations between precipitation and the soil ¹⁰Be concentration in high-precipitation regions (> 1200 mm·y^-1) and significant positive correlations for soils in low precipitation regions (< 1200 mm·y^-1). The data also revealed that precipitation is the most important variable controlling the ¹⁰Be concentration in soils of MC when compared with the effects of soil properties. Land use and soil erosion may have limited impacts on the distribution of ¹⁰Be in soils. Additionally, combined with the oceanic ¹²⁷I in soils, we show that the distribution patterns of both the ¹⁰Be and ¹²⁷I in the topsoil across MC exhibit imprints of the main ASM pathways. Our results indicate the monsoon precipitation patterns persisted for several millennia or more and suggest a strong bond between ¹⁰Be in soils and water vapor transport patterns.
 

Beryllium-10,Asian Summer Monsoon,Spatial precipitation pattern,Late Holocene,Topsoil