平凉隐伏岩溶水环境同位素研究  

ENVIRONMENTAL ISOTOPE STUDY ON GROUNDWATER IN A COVERED ORDOVICIAN CARBONATE ROCK OF PINGLIANG,NW CHINA

作　　者：马致远[1] 马蒂尔.亨德尔 

机构地区：[1]长安大学水资源与环境工程系,陕西西安710054 [2]土宾根大学地质研究所,德国土宾根72076

出　　处：《长安大学学报（地球科学版）》2003年第4期60-66,共7页

摘　　要：　地下水资源可持续利用的一个急待解决的重要问题,是对地下水补给和更新能力的评价。利用环境同位素技术研究地下水的补给和可更新性是当前较为新颖的方法之一。在西北干旱、半干旱的隐伏岩溶地区,地下水埋藏条件复杂,常规的地质勘探方法所能提供的水文地质信息有限,环境同位素方法在研究地下水的补给及可更新能力方面发挥了优势,可对传统方法进行补充和验证。其结果表明,研究区隐伏岩溶水形成较早,且有大量现代水的混入,平均混入量为54%。说明区内隐伏岩溶水的补给和更新能力较好。环境同位素分析结果还显示,大岔河隐伏岩溶水为一相对独立、半开放的水文地质单元,其补给来源部分为流域内大气降水、地表水的补给,部分为东南部三道沟岩溶地下水的补给;根据环境同位素EPM模型计算,地下水的滞留时间为36a。地下水储存量为1.314×108m3;储水系数为7.29×10-3。这一结果与传统勘探方法的计算结果基本吻合,说明环境同位素方法的实用性。An example is given for the application of environmental isotope techniques in interpreting recharge mechanisms and renew-ability evaluation of covered karst aquifer in semiarid area, NW China. Based on the isotope analysis, the Ordovician carbonate rock aquifer in the study area mainly originate from direct infiltration of atmospheric water in carbonate outcrops in Sandao and Dazha valley. Stable isotopes show that the karst groundwater in Dazha valley, seems to be recharged in a catchment area with a mean elevation of 1685～1854 m. The temporal evolution of stable isotopes, tritium content, hydrochemistry show the existence of an interconnection between Dazha and Sando Ordovician limestone. The isotopes composition also show that the groundwater in Ordovician limestone is a mixture of an old groundwater and modern recharge by local infiltration. The mean percentage of modern water account for 54%, which was found usually at the intensively fractured areas, suggesting good renew-ability of the aquifer . Adopting a model with exponential and piston time distribution, the mean residence time of groundwater in the Ordovician carbonate rocks was evaluated to be 36 years. On the basis of this evaluation, the size of the groundwater reservoir and the mean storage coefficient have been calculated to be 0.134 billion m^3 and 0.007 3 respectively.

关 键 词：隐伏岩溶水 地下水 滞留时间 储存量 环境同位素 

分 类 号：P641.3[天文地球—地质矿产勘探] P597[天文地球—地质学]