神府矿区直罗组含水层水质形成的水文地球化学过程研究

Research of hydrogeochemical process of water quality formation of Zhiluo Formation Aquifer in Shenfu Mining area

【目的】为探究神府矿区直罗组含水层地下水化学形成机制和控制因素,【方法】选取侏罗系直罗组风化基岩层和基岩层地下水为研究对象,综合运用Piper图、反距离权重法、Spearman相关性分析、离子比例关系和反向水文地球化学模拟等方法进行分析。【结果】结果表明:神府矿区直罗组地下水呈弱碱性,风化基岩含水层为低矿化度HCO_(3)型水,基岩含水层为高矿化度HCO_(3)型水。沿西北向东南方向,地下水由补给区流向排泄区,水化学类型复杂,演化规律为HCO_(3)型→HCO_(3)·SO_(4)型,局部出现SO_(4)型和Cl型。直罗组风化基岩层地下水主要水文地球化学作用为方解石、石膏、钾长石沉淀和白云石、岩盐和钠长石溶解,其次是Na-Ca阳离子交替吸附作用和黄铁矿氧化作用;基岩层地下水质形成主要受方解石、石膏、岩盐和钾长石沉淀与白云石和钠长石溶解等岩石风化作用控制,其次是Na-Ca阳离子交换、脱碳酸作用和混合作用。【结论】研究结果能够为区域地下水资源开发利用提供理论支持。

[Objective] In order to explore the chemical formation mechanism and controlling factors of groundwater in Zhiluo Formation aquifer in Shenfu Mining area, [Methods]selected the weathered bedrock layer and groundwater in bedrock layer of Jurassic Zhiluo Formation as the research object. Piper trilinear diagram, inverse distance weighting method, Spearman correlation analysis, ion proportional relationship and reverse hydrogeochemical simulation were used comprehensively. [Results] The results show that the deep groundwater in Shenfu Mining area is weakly alkaline, the weathered bedrock aquifer is HCO_(3) type water with low salinity, and the bedrock aquifer is HCO_(3) type water with high salinity. In the direction from northwest to southeast, the groundwater flows from recharge area to discharge area, and the hydrochemical types are complex. The evolution law is HCO_(3) type→HCO_(3) ·SO_(4) type, and local SO_(4) type and Cl type appear. The main hydrogeochemical processes of groundwater in the weathered bedrock of Zhiluo Formation are precipitation of calcite, gypsum and potassium feldspar and dissolution of dolomite, rock salt and albitase, followed by alternate adsorption of Na-Ca cation and pyrite oxidation. The formation of groundwater quality in bedrock layer is mainly controlled by rock weathering, such as precipitation of calcite, gypsum, rock salt and potassium feldspar and dissolution of dolomite and alspar, followed by Na-Ca cation exchange, decarbonation and mixing. [Conclusion] The result can provide theoretical support for the development and utilization of regional groundwater resources.