华南典型地区化学侵蚀与风化壳发育过程研究

Abstract: Several weathering crust sections locating at the mid-low latitude zone, i.e., southern China and Qinghai-Xizang plateau areas, were selected as the investigating objects, the funding item have mainly studied the modern chemical weathering processes of the southern China, the typical monsoon humid subtropical area, and the sedimentary recordeds in the Tertiary polaeo-weathering crust in Qinghai-Xizang Plateau. The annual weathering flux of riverine bicarbonate ion is 1103′103 mol?km-2? yr -1 for the Xijiang drainage area, and 1289′103 mol?km-2? yr -1 for the Beijiang drainage area, the main factors that influence the weathering flux of riverine bicarbonate ion in Zhujiang river drainage are the outcrop percentage of carbonate rocks and the runoff depth. The weathering flux of organic carbon is about 10.18′106g?km-2? yr -1 for the Xijiang River drainage area, and 10.01′106g?km-2? yr -1 for the Beijiang River drainage area, which is two to three times in quality of the average value in the global external drainage area, and of which the portion of POC take up from 65% to 85%. This pattern of organic carbon weathering flux in Zhujiang drainage basin is consistent with that of most of the monsoon drainage basins, and reflecting the intense mechanical erosion in this drainage area. The principal chemical components of the clay portion of the residuum in Qinghai-Xizang Plateau consist mainly of SiO2, Al2O3 and Fe2O3. The clay minerals composition of the clay portion belongs to illite-kaolinite-type for most of the residuum samples, and kaolinite-illite-type for a few the samples, which reflected that the formation of the residuum of the Qinghai-Xizang Plateau was in its initial phase. The surface textures of quartz grains in the residuum produced by chemical erosion, revealed a long term of humid-tropical environment when the residuum formed.Chemical weathering;

研究华南典型基岩及风化壳剖面之化学、矿物学组成，和大气降水、风化壳孔隙水及径流的水化学组成。对典型基岩的化学侵蚀过程进行定性和定量模拟实验，以确定华南湿热气候环境下的地表化学侵蚀及风化成土速率。对解决季风型湿热流域的化学侵蚀与全球变化问题，认识华南地表的侵蚀夷平过程及红壤系列土壤的地质演化背景等问题有重要意义。