辽宁省地震监测站地下水化学类型及成因分析

通过测试辽宁省15个地震监测站泉水或井水的氢、氧同位素组成及主要离子组分含量,讨论了泉水或井水的化学类型及其成因.测得泉水或井水的δD和δ~(18)O值范围分别为-82.5‰--54.4‰和-11.4‰—-7.3‰,表明所测泉水和井水的主要来源为大气降水.研究区低温泉水为低矿化度的Ca-SO_4·HCO_3型或Ca-HCO_3·SO_4型;而较高温度的花岗岩裂隙水中溶解了较多的钠硅酸盐矿物,水化学类型主要为Na-HCO_3·SO_4型;碳酸盐岩及含砾砂岩含水层分别分布于辽宁省西部及中部地区,水温略低于高温花岗岩裂隙水,水化学类型为Na·Ca-HCO_3型.水中F~-含量较高,且F~-含量与温度、pH值、Na~+和HCO_3~-的浓度呈正相关,表明泉水或井水的化学类型是深部富CO_2流体及大气降水与花岗岩反应的结果.

Hydrochemical types and origins analysis of groundwater at the seismic monitoring stations in Liaoning Province

The hydrochemical types and origins of underground waters collected from 15 seismic monitoring stations in Liaoning Province are discussed based on the isotope ratios of hydrogen and oxygen as well as ion concentrations. δD and δ18O values of underground water ranged from ?82.5‰ to ?54.4‰ and from ?11.4 ‰ to ?7.3‰, respectively, which indicates that the waters had a meteoric origin. Granite is widely distributed in the studied area. The cold spring waters were the type of Ca-SO₄·HCO₃ and Ca-HCO₃·SO₄, while the hot spring waters from fractured granite were mainly type of Na-HCO₃·SO₄ due to the dissolution of silicate minerals. The water samples with moderate temperature in the western and middle parts of Liaoning Province were the type of Na·Ca-HCO₃, resulting from dissolution of silicate minerals and carbonate. The concentration of F ? is positively correlated with temperature, pH, concentrations of Na＋ and HCO₃ ?, indicating reaction between the granite and the fluids enriched in CO₂ .