中国阿尔泰山流域侵蚀速率及其控制因素

The spatiotemporal patterns of catchment basin erosion rate is vital for understanding the geomorphic evolution of active orogenic belts. Based on the hydrological data from 1964 to 2011, decadal-scale erosion rates of eight rivers(Haba River, Burjin River, Kelan River, Zhuolut River, Kuyiltes River, Zingali River, Burgun River and Ulungu River)basins are estimated by river sediment transport method. The contributions of suspended load, bed load and solute load to river sediment transport are first determined, and then decadal-scale erosion rates are calculated for each analyzed catchment basin. Here, we focus on the decadal-scale catchment basin erosion rate and its controlling factors in the Altai Mountains. The results show that the average erosion rate of the eight basins is 0. 03 mm·a^-1, among which the minimum erosion rate of 0. 01 mm·a^-1 is in Ulungu River, and the maximum erosion rate of 0. 05 mm·a^-1 is in Klan River, a tributary of the Irtysh River. Furthermore, in order to explore the potential effects of climate, topography, lithology, tectonics and vegetation on catchment basin erosion, correlation analyses were conducted between these factors and the erosion rate. It is found that there is a strong correlation between erosion rate and topographic factors(basin area, slope, and basin relief)and climatic factors(runoff depth and mean temperature), which may indicate that these factors have a major impact on erosion in the Altai Mountains. Compared with the million-year scales erosion rate(0. 07~ 0. 3 mm·a^-1)existed now, the low decadal-scale erosion rate could imply that the continuous arid climate since late Cenozoic limited the surface erosion process of the Altai Mountains.