Holocene erosion triggered by climate change in the central Loess Plateau of China

Abstract

Understanding changes in Holocene erosion is essential for predicting soil erosion in the future. However, the quantitative response of natural erosion to Holocene climate change is limited for the Loess Plateau of China. In this study, two soil profiles were investigated on the Luochuan and Yanchang sites in the central Loess Plateau of China; and four climate indicators, i.e. magnetic susceptibility, calcium carbonate content, total organic carbon content, and clay content (<0.005mm), were analyzed to describe climate change. The equations fitted using modern pedogenic susceptibility, precipitation, and temperature were used to quantitatively reconstruct paleoprecipitation and paleotemperature in the Holocene. The current relationship between soil erosion intensity and precipitation was determined and used to estimate historical erosion. Results indicated that climate was coldest and driest between 12,000 and 8500cal.yrBP, and became warmer and wetter during 8500 to 5500cal.yrBP. The warmest and wettest climate was from 5500 to 3000cal.yrBP and was getting colder and dryer over the last 3000years. Holocene erosion intensity changed with fluctuation of mean annual precipitation, and these changes were different on both sites. The peak erosion values were 20,966t·km−2·yr−1 in 7500cal.yrBP and 21,148t·km−2·yr−1 in 3300cal.yrBP on the Luochuan and Yanchang sites, respectively. Furthermore, more severe soil erosion with a faster increase was estimated on the Yanchang site than Luochuan site with a range between 6547 and 11,177t·km−2·yr−1 during the last 1800years. This study proposed a new method to quantify historical soil erosion triggered by climate change, which not only can derive detailed soil erosion intensity change with variation of climate, but also provide a way to compare soil losses between different areas.