[关键词]
[摘要]
通过测量辽宁省鞍山-海城地区地震重点监测区地下水离子浓度和氢、氧同位素组成,讨论了该区地下水化学类型的时空变化及其成因。测量结果表明,取样点水温变化范围为11.0~97.0℃,水样的总固溶物(TDS)在197.89~829.99mg/L之间,水样分为8种化学类型。大部分水样的δD、δ18O值均沿中国东北地区大气降水线分布,少数有所偏离,表明该区的地下水主要接受大气降水的补给,并可能有深部水的供给。研究区Ca-HCO3和Ca·Mg-HCO3型水主要是岩石风化溶解和阳离子交换作用的结果;Ca-HCO3·Cl和Ca·Na-Cl·SO4型水主要受岩石风化溶解、阳离子交换作用、深部卤水混入或人类活动影响;Ca-HCO3·SO4和Ca-SO4·HCO3型水与岩石风化溶解以及深部流体混入有关;Na-SO4·HCO3和Na-HCO3·SO4型水主要是深部来源水体的混入造成的。采样期间研究区发生2次ML≥3.0地震,采样点在地震发生月份出现了明显的离子浓度异常变化;Na+、Mg2+、Ca2+、Cl-和SO42-浓度变化明显,对地震活动响应较灵敏。
[Key word]
[Abstract]
The spatial and temporal variations of groundwater chemical types and their genesis were discussed by measuring ion concentration and hydrogen and oxygen isotopic compositions in the Anshan-Haicheng area,Liaoning Province. The measurements showed that the water temperatures ranged from 11.0℃ to 97.0℃,and the total dissolved solids(TDS)of the water samples ranged from 197.89mg/L to 829.99mg/L. The water samples can be divided into 8 chemical types. The δD and δ18O values of the most water samples are distributed along the atmospheric precipitation line in the eastern monsoon region of China. A few deviations indicated that the well water in the study area was mainly recharged by atmospheric precipitation,but the hot spring water mixed with small amount of deep fluids. The Ca-HCO3 and Ca·Mg-HCO3 waters resulted mainly from rock weathering dissolution and cation exchange;Ca-HCO3·Cl and Ca·Na-Cl·SO4,waters from rock weathering dissolution with deep brine mixing or likely sewage pollution;Ca-HCO3·SO4 and Ca-SO4·HCO3 waters from rock weathering dissolution and deep fluid mixing;Na-SO4·HCO3 and Na-HCO3·SO4 waters from atmospheric precipitation with the mixing of deep source fluids. The obvious chemical anomalies of the ground waters were well correspond to two earthquakes of ML ≥ 3.0 in the study area during the sampling duration. The Na+,Mg2+,Ca2+,Cl-,and SO42- can be considered as the sensitive indicators to local seismic activity.
[中图分类号]
P315
[基金项目]
中国地震局基本科研业务费专项“辽宁地区流体地球化学特征成因及机理研究”(2018IEF010204)和国家自然科学基金“非静水压下水岩反应的实验研究”(41373059)共同资助