湟水河流域化学风化过程及原因探析

选择湟水河流域湟源至乐都段为研究点,采集并分析了湟水河及支流北川河、南川河河道不同地点25个河床泥沙样品的常量元素地球化学特征。通过化学风化强度指标(CIA)分析,发现从湟源—湟中(多巴)—西宁—平安—乐都段,化学风化强度呈现出高—低—稍高的趋势。通过化学风化强度与影响因素(温度、降水、海拔高度、植被覆盖和人口因素)的对比分析,发现湟水河流域引起化学风化强度明显变化的主要因素是降水量的变差系数。

Preliminary Analysis for Chemical Alternation Index of Riverbed Sediments in Huangshui River

Twenty-five riverbed sediments from Huangyuan to Ledu were collected in Huangshui River,and their trace element contents were meacured by XRF(X-Ray Fluorecence).The results indicate that chemical index of alternation(CIA) of these sediments in different sites are difference.The CIA in HuangYuan is the highest and that in Huangzhong(Duoba) is gradually decreased;the CIA in Xining is the lowest and that in Ping’an and Ledu is slightly increased.The CIA takes on a trend of high-low-slightly high from upper reaches to lower reaches of Huangshui River.By comparison CIA with other factors(including annual average temperature,annual average precipitation,elevation,vegetation conditions and population in sampling sites),we found that the CIA of sampling sites in Huangshui River mainly resulted from precipitation coefficient of variation.