Quantificational research on the slope development of loess tableland in the Holocene

摘要

It is important approach to recognize natural evolution of environment on the Chinese Loess Plateau that researches on evolution of loess landform and soil erosion in the Holocene. In this study, radiocarbon age of soil, loess deposition rate and magnetic susceptibility soil from YCT and YCS profiles which respectively located on loess tableland and an adjacent slope in Yanchang County in northern Shaanxi, were used to reconstruct the landform at about 12000 a B.P. on the slope. The results indicated that the average loess deposition rate of YCT profile in the Holocene was 0.0153 cm/a, and that of YCS profile was 0.0162cm/a during 12295∼20416 a B.P‥ The slope landform had formed before about 12000 a B.P., but its gradient was smaller than the modern slope. So the soil erosion rate greater than the loess deposition rate on the slope, which was the comprehensive result of natural erosion and artificial acceleration erosion. It was proved that this method could be used to quantificational research on loess landform and soil erosion in the geological period, and provided a new idea and method in this study area.