阳山矿区水文地球化学特征及成因分析

对阳山矿区内38件水样进行分析，结合区内地层岩石的地球化学特征，发现区内地下水组成以Ca^2＋、Mg^2＋、HCO3^-；、SO4^2-为主，其水化学类型则以HCO3-Ca为主，地下水化学特征与区内地层岩石化学特征相一致。研究还发现，区内地下水在空间分布上也有一定的特征，在地下水的补给区地表分水岭附近形成了以HCO3-Ca为主的地下水，而在径流区及排泄区地下水类型不一，总体而言，地下水水化学成分的形成以区内岩石的分解和水解等化学风化作用为主。区内含砷矿物及黄铁矿的溶解，导致水中SO4^2-及As元素含量的异常，也反映了矿区的2种金矿化蚀变现象，为下一步水化学异常圈定及水文地球化学找矿提供了依据。

Analysis on the characteristics and genesis of hydrogeochemistry in Yangshan gold district in Gansu Province

Based on Yangshan gold district studies, analysis of the 38 groundwater samples as well as the geo- chemistry of stratum rock in the region,it is discovered that the groundwater is made up with Ca2 ＋ , Mg2 ＋ , HCO3- , and SO42- ; the primary groundwater type is HCO3-Ca; and the characteristics of hydrogeochemistry are in conformity with geochemistry that of the stratum rock. Moreover, the groundwater interspace distribution also is characterized by that HCO3-Ca dominates at groundwater supply area of the earth＇s surface watershed and the groundwater types are different in the run off area or drainage area. In general, chemical composition of the groundwater is determined mainly by chemical weatherings such as resolving and hydrolysis of the silicate mineral in the district. The resolution of arsenic mineral and pyrite leads to the abnormal contents of SO42- and As in the groundwater, and also explains the two miner- alization alteration in mine, which paves the groundwork for the following work such as determining the hydrogeochemi- cal anomaly area and looking for gold with hydrogeochemistry.