Characteristics of geochemistry in Ordovician Limestone Groundwater

Abstract studying the Characteristics of groundwater geochemistry in arid area in northwest China, is important for coal mine water prevention. 34 groundwater samples were collected for hydrogeochemical analyses and piper trilinear diagram were used to study groundwater Characteristics of geochemistry. The results show that the concentration of Na⁺+ K⁺, HCO₃⁻, Cl⁻, SO₄²⁻, TDS, and pH increase from the recharge area to the discharge area, however, that of Ca²⁺ and Mg²⁺ decreases.And each indicator varied greatly in the north and south of the coalfield. Hydrogeochemical types of the runoff from Zhuozishan Mountain to Gongdeer Mountain and then to the south-north directional change. And the groundwater process is controlled by rock weathering action and cation exchange. Whereas the hydrochemical type of the runoff from Zhuozishan Mountain to the south is always SO4▪Cl-Ca▪Na type