Water-Rock Interactions: An Investigation of the Relationships Between Mineralogy and Groundwater Composition and Flow in a Subtropical Basalt Aquifer
Water-Rock Interactions: An Investigation of the Relationships Between Mineralogy and Groundwater Composition and Flow in a Subtropical Basalt Aquifer
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DOI：
10.1007/s10498-011-9148-x
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发表时间：
2012-01-01
影响因子：
1.6
通讯作者：
Cox, Malcolm E.
中科院分区：
文献类型：
--
作者：
Locsey, Katrina L.;Grigorescu, Micaela;Cox, Malcolm E.
对澳大利亚昆士兰州阿瑟顿高原地区玄武岩地下水的组成进行了全面研究，以阐明这些含盐量极低、富含二氧化硅和碳酸氢盐的地下水演化的可能机制。认为铝硅酸盐矿物风化是影响玄武岩地下水整体成分的主要过程。地下水接近平衡，相对于主要矿物的pH值增加，大多是在平衡与主要的次生矿物（高岭石和蒙皂石），和其他次要阶段，如针铁矿，赤铁矿，三水铝石，这是常见的辅助矿物在阿瑟顿玄武岩。已使用X射线衍射和全岩地球化学方法对玄武岩的矿物学进行了检查，支持这些地下水水文地球化学演化的拟议模型：降水+ CO2（大气+土壤）+辉石+晶石+橄榄石产生H4 SiO 4、HCO 3（-）、Mg 2+、Na+，Ca 2 + +高岭石和蒙脱石粘土+无定形或结晶二氧化硅+辅助矿物（赤铁矿、针铁矿、三水铝石、碳酸盐、沸石和黄铁矿）。这些玄武岩的矿物学含量的变化也提供了深入了解地下水储存和运动在这个含水层系统的控制。新鲜和风化的泡状玄武岩被认为是重要的地下水赋存带，而在块状玄武岩的裂缝是地下水运动的重要途径。
A holistic study of the composition of the basalt groundwaters of the Atherton Tablelands region in Queensland, Australia was undertaken to elucidate possible mechanisms for the evolution of these very low salinity, silica- and bicarbonate-rich groundwaters. It is proposed that aluminosilicate mineral weathering is the major contributing process to the overall composition of the basalt groundwaters. The groundwaters approach equilibrium with respect to the primary minerals with increasing pH and are mostly in equilibrium with the major secondary minerals (kaolinite and smectite), and other secondary phases such as goethite, hematite, and gibbsite, which are common accessory minerals in the Atherton basalts. The mineralogy of the basalt rocks, which has been examined using X-ray diffraction and whole rock geochemistry methods, supports the proposed model for the hydrogeochemical evolution of these groundwaters: precipitation + CO2 (atmospheric + soil) + pyroxene + feldspars + olivine yields H4SiO4, HCO3 (-), Mg2+, Na+, Ca2+ + kaolinite and smectite clays + amorphous or crystalline silica + accessory minerals (hematite, goethite, gibbsite, carbonates, zeolites, and pyrite). The variations in the mineralogical content of these basalts also provide insights into the controls on groundwater storage and movement in this aquifer system. The fresh and weathered vesicular basalts are considered to be important in terms of zones of groundwater occurrence, while the fractures in the massive basalt are important pathways for groundwater movement.