Groundwater chemistry and water-rock interactions at Stripa☆
Groundwater chemistry and water-rock interactions at Stripa☆
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DOI：
10.1016/0016-7037(89)90294-9
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发表时间：
1989-08
影响因子：
5
通讯作者：
D. Nordstrom;J. W. Ball;R. Donahoe;D. Whittemore
中科院分区：
文献类型：
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作者：
D. Nordstrom;J. W. Ball;R. Donahoe;D. Whittemore
对 Stripa 花岗岩中从近地表到 1232 m 深度的地下水进行了采样并分析了主要和微量成分。地下水成分主要由两种类型组成：典型的 Ca-HCO3 型补给水（<300 m 深度）和更深的 Na-Ca-Cl 型（>700 m 深度），pH 值较高（8-10），总溶解固体 (TDS) 最高可达 1250 mg/L。中间深度显示两种类型的混合，它们高度依赖于裂缝而不是深度依赖。任何钻孔的水平或垂直方向的 TDS 都可能发生显着且不稳定的变化。从 Ca-HCO3 型到 Na-Ca-Cl 型的总体转变与导水率从 10−8m/s 下降到 10−11m/s 或更低的深度剖面相关。热机械应力（来自加热器实验）清楚地显示了对地下水成分的影响，这可能是由流动路径改变、流体包裹体泄漏或两者兼而有之引起的。方解石、萤石和重晶石的溶解和沉淀、硅铝酸盐水解以及盐源的添加（可能是流体包裹体泄漏）在确定地下水成分中发挥着主要作用。 Stripa 花岗岩的低渗透性产生了一种介于结晶岩石地形补给典型的稀浅地下水和深层克拉通地盾区域典型的咸水和盐水之间的地下水成分。
Groundwaters from near surface to a depth of 1232 m in the Stripa granite have been sampled and analyzed for major and trace constituents. The groundwater composition consists of two general types: a typical recharge water of Ca-HCO3type (<300 m depth) and a deeper Na-Ca-Cl type (>700 m depth) of high pH (8–10) that reaches a maximum of 1250 mg/L in total dissolved solids (TDS). Intermediate depths show mixtures of the two types that are highly fracture-dependent rather than depth-dependent. Any borehole can vary significantly and erratically in TDS for either a horizontal or vertical direction. The general transition from Ca-HCO3type to Na-Ca-Cl type correlates with the depth profile for hydraulic conductivity that drops from 10−8m/s to 10−11m/s or lower. Thermomechanical stress (from heater experiments) clearly shows an effect on the groundwater composition that could be caused by changing flow paths, leakage of fluid inclusions or both.Dissolution and precipitation of calcite, fluorite and barite, aluminosilicate hydrolysis, and addition of a saline source (possibly fluid inclusion leakage) play the major roles in defining the groundwater composition. The low permeability of the Stripa granite has produced a groundwater composition that appears intermediate between the dilute, shallow groundwaters typical of recharge in a crystalline rock terrain and the saline waters and brines typical of cratonic shield areas at depth.