岩溶水锶元素水文地球化学特征

通过对桂林地区地下河系统不同类型岩溶水水样Sr2+含量和87Sr/86Sr值分析,得到如下结论:(1)桂林地区岩溶水中Sr2+含量普遍较低,流经不同岩层的地下水Sr2+含量不同,岩溶水中Sr2+含量随着Ca2+含量的增大而增大,随着Mg2+含量的增大而减小;地下河水中的Sr2+含量始终介于表层岩溶带水、饱水带裂隙水、地表坡面流和外源水(如果存在外源水补给)的最大、最小值之间.(2)流经不同岩层地下水的87Sr/86Sr值不同,流经砂岩层地下水87Sr/86Sr值较高,其次为流经白云岩层和灰岩层的地下水;地下河水87Sr/86Sr值也是介于表层岩溶带水、饱水带裂隙水、地表坡面流和外源水(如果有外源水补给)的最大、最小值之间.因此Sr2+和87Sr/86Sr能反映岩溶水形成的信息,是较理想的天然示踪剂,在岩溶水研究中具有很广阔的应用前景.

HYDROGEOCHEMICAL CHARACTERISTICS OF THE STRONTIUM IN KARST WATER

Strontium is the richest trace element in the upper lithosphere.It is inactive to most substances in natural conditions due to its stable chemical characteristics.The Sr~(2 ) concentration and~(87)Sr/~(86)Sr value have obvious differences in various conditions and settings.Through analyzing the Sr~(2 ) concentration and (the~(87)Sr/~(86))Sr value in different karst water samples from the underground river systems in Guilin, the following conclusions are drawn: (1) Sr~(2 ) concentration of the karst water in Guilin is low. Flowing through different kind of stratum, the underground river water has different Sr~(2 ) concentration. Sr~(2 ) concentration of karst water increases as Ca~(2 ) concentration increases and decreases as Mg~(2 ) concentration increases. Sr~(2 ) concentration of the underground river water is between maximal and minimal Sr~(2 ) concentrations of the epi-karst water, cranny water, upper flow water and allogenic water (if allogenic water supplies underground river). (2) Flowing through different stratum, groundwater has different~(87)Sr/~(86)Sr value. Sandstone stratum water has the highest~(87)Sr/~(86)Sr value, next is dolomite stratum water and the lowest is limestone stratum water. The~(87)Sr/~(86)Sr value of underground river water is between maximal and minimal~(87)Sr/~(86)Sr values of the epi-karst water, cranny water, upper flow water and allogenic water water (if allogenic water supplies underground river). So,Sr~(2 ) and~(87)Sr/~(86)Sr can provide information on how karst water comes into being. They are ideal natural tracers and may have a wide application in karst water research.