Intensive soil erosion periods of Pleistocene on the Central South Loess Plateau

Abstract

Summary. Quantitative information on the soil erosion periods of Pleistocene on the Loess Plateau is rare. Here, we present results of the field work at Luochuan, Weinan, Tongchuan, Fufeng, Baoji, and Yangling, and a comparison between the SPECMAP, ODP-677 δ 18 O curve, and the magnetic susceptibility curve of loess-paleosol sequence. We took the conformity surfaces between the loess and paleosol layers as credible erosion surfaces. After some field work and analyses on the erosion surfaces, we concluded that intensive soil erosion had occurred during the climate transform period, especially when the climate changed from cool-dry to warm-wet. After comparing the SPECMAP, ODP-677 δ 18 O curve, and the magnetic susceptibility curve of the loess, the simultaneous leaps of these curves might show climate transition periods and also erosion events that could occur. This comparison suggested that there might be 13 erosion periods, which existed at 2.580 MaBP, 2.190 MaBP, 1.870 MaBP, 1.240 MaBP, 1.120 MaBP, 0.964 MaBP, 0.865 MaBP, 0.760/0.780 MaBP, 0.621 ~ 0.479 MaBP, 0.412 MaBP, 0.336 MaBP, 0.245 MaBP, and 0.128 MaBP. Among these erosion periods, nine of them were identified by the erosion surfaces; four of them had more than two sites. Especially, the erosion happened at ~ 0.128 MaBP was identified by more than ten erosion surfaces, this erosion period had laid a foundation for the modern landform of the central south Loess Plateau.