Abstract Geothermal energy exploitation in the Upper Rhine Graben (URG) chiefly has targeted faults and fractures within or connected with the crystalline basement, where hot fluids of c. 200 °C circulate at depths of c. 5 km. Formation fluids of the crystalline basement are highly saline, NaCl-dominated brines, whereas shallow crystalline basement water ( The trace element concentrations of the leachates are hereby related to the composition and stability of minerals in the rocks and can be directly linked to the proposed and observed dissolution processes at the different temperatures. In experiments with pure water at 70 °C, representing the recharge or infiltration conditions, water-rock interaction mobilized K, Cl, Fe, Mn, Mg, Cu, Zn, Cr, Sc, V, and Li (dissolution of biotite/chlorite) and Si, Al, K, Ca, Na, Ba, Sc, Pb, Sr, Rb, and Eu (dissolution of plagioclase, K-feldspar, and quartz) into the fluid. According to calculated activity diagrams, alteration at these temperatures may result in the formation of illite, kaolinite, Ca-beidellite, and stilbite. In experiments at higher temperatures of 200 °C, according to reservoir conditions, the net output of most elements was increased, but especially of those contained in feldspar, i.e. K, Ca, Al, Si, Ba, Rb, Cs, and Pb, suggesting that fluid-rock interaction is dominated by feldspar dissolution. This alteration is followed by albitization of feldspar surfaces, chloritization of biotite, and precipitation of illite and hematite. In Si-poor samples, analcime occurs in and around porous reaction zones, in agreement with calculated activity diagrams. The amount of dissolution mainly depends on the temperature and the mineralogy of the rock types, in particular on the anorthite-component of plagioclase. Certain elements (e.g., Na, Fe, Mg, Al) were subsequently incorporated into the solids precipitated during the experiments and thus cannot be considered as conservative.

中文翻译：

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花岗岩实验改造：对德国莱茵河上地堑地热卤水演化的启示

摘要 上莱茵地堑（URG）的地热能开发主要针对结晶基底内或与结晶基底相连的断层和裂缝，其中c．200 °C 在 c 的深度循环。5 公里。结晶基底的地层流体是高盐分、以 NaCl 为主的盐水，而浅结晶基底水（因此渗滤液的微量元素浓度与岩石中矿物的组成和稳定性有关，可以直接与拟议和观察不同温度下的溶解过程。在 70 °C 的纯水实验中，代表补给或渗透条件，水-岩相互作用动员了 K、Cl、Fe、Mn、Mg、Cu、Zn、Cr、Sc、V，和 Li（黑云母/绿泥石的溶解）和 Si、Al、K、Ca、Na、Ba、Sc、Pb、Sr、Rb，和 Eu（斜长石、钾长石和石英的溶解）到流体中。根据计算的活动图，这些温度下的蚀变可能导致伊利石、高岭石、钙贝得石和辉沸石的形成。在 200 °C 较高温度的实验中，根据储层条件，大多数元素的净产量增加，尤其是长石中所含的元素，即 K、Ca、Al、Si、Ba、Rb、Cs 和 Pb，表明流体-岩石相互作用以长石溶解为主。这种改变之后是长石表面的钠长石化、黑云母的绿泥石化以及伊利石和赤铁矿的沉淀。在贫硅样品中，方沸石存在于多孔反应区及其周围，与计算的活性图一致。溶解量主要取决于岩石类型的温度和矿物学，特别是斜长石的钙长石成分。某些元素（例如，Na、Fe、Mg、Al）随后被掺入在实验过程中沉淀的固体中，因此不能被认为是保守的。