贵州汇善谷锶-偏硅酸复合型天然饮用矿泉水成因探讨

Discussion on Strontium-Metasilicic Acid CompositeType Natural Drinking Mineral Water Genesis in Huishangu,Guizhou

绥阳汇善谷温泉是贵州省内碳酸盐岩分布区十分少有的锶-偏硅酸复合型天然温矿泉水。通过对研究区水文地质条件、温矿泉水的水文地球化学及环境同位素特征分析,认为汇善谷复合型温矿泉水的形成受水-岩作用和构造作用控制。温矿泉水中δ87Sr/86Sr同位素值0.7091~0.7092,指示锶元素来源于碳酸盐岩-蒸发盐岩建造中的含锶矿物,未见幔源锶供给。δD-18O、δ34SO42-同位素表明,该温泉矿泉水在区域内接受大气降水后沿构造面向地下深部渗透循环增温,形成较高温度的地热水,并在CO2参与下与娄山关组天青石(SrSO4)和蒸发岩(CaSO4)及类质同象于石膏、文石、方解石等矿物发生水-岩作用形成富Sr-SO4^2-·HCO3^--Ca·Mg型水。H2SiO3形成在热储深度2172.8~2811.2m,热储温度68.9~85.4℃的地质条件下石英矿物的水解和地热水沿断裂对流循环过程中溶滤先期形成的硅化碳酸盐岩、石英脉矿物,使SiO2不断迁移、富集并结合水体中H^+形成H2SiO3型温矿泉水。

The Huishangu hot spring in Suiyang County carbonate rock distributed area is a very rare strontium-metasilicic acid composite type natural hot mineral spring in the Guizhou Province.Through study area hydrogeological condition,hot mineral spring water hydro-geochemical and environmental isotopic features analysis has considered that the genesis of the spring water is controlled by water-rock interaction and tectonic process.Theδ87Sr/86Sr isotope values 0.7091~0.7092 indicate strontium element is come from strontium containing minerals in carbonate rock-evaporite formation and without strontium from mantle.TheδD-18O、δ34 SO42-isotopes have shown that the hot spring water in the area after receiving atmospheric precipitation seeping along structural plane toward deep underground and cyclic warming formed higher temperature geothermal water.Under CO2 participating in arises water-rock interaction with the Loushanguan Formation celestite(SrSO4),evaporite(CaSO4)and gypsum,aragonite and calcite isomorphic minerals formed rich Sr-SO4^2-·HCO3^--Ca·Mg type water.H2SiO3 has formed in geothermal reservoir depth 2172.8~2811.2 m,under reservoir temperature 68.9~85.4℃geological condition,the hydrolysis of quartz minerals and geothermal water along fault plane convective circulation process lixiviated previous formed silicated carbonate rock,quartz vein minerals made SiO2 ceaselessly migrated,enriched and combined with H+in water formed H2SiO3 type mineral water.