第25卷第6期 2011年12月
现代地质 GEOSCIENCE
Vol 25 Na. 6 Der.2011
中国西北于旱区多级洼地地下水环境同位素分布
特征及指示意义
孙琦2，余翔，周训”，陈剑杰，高为超”
（1.西北核技术研究所，陕西西安710024；2.中国地质大学水资源与环境学院，北京100083）
摘要：研究区位于西北干旱区，有两级储水洼地，地下水由山区侧向补给一级洼地，一级洼地通过泉水排泄地下水继而补给二级洼地，同时大气降水直接人渗、洪流间接人渗补给各储水洼地。通过氢氧同位索比例公式计算得到一级注地大气降水占总补给量60%，其中直接补给量约占21%，山区洪流补给量约占79%，另外，山前侧向补给占40%；二级洼地降水补给量占38%，上游泉水补给量占62%。通过氟值指示，二级洼地不受现代降水影响；.活塞流与全混合模
型计算得到一级洼地浅层孔隙水平均年龄为32~60a。关键词：氢氧同位索；氛同位素；干早地区；中国西北
中图分类号：P641.3
文献标志码：A
文章编号：10008527(2011)06-119506
Distribution Characteristics of Groundwater Environmental Isotopes in a MultilevelBasin inArid Areaof the NorthwesternChinaandTheirIndication
SUN Qi'-,YU Xiang',ZHOU Xun’, CHEN Jian-jie', GAO Wei-chao"
(1. Northext Inatitale of Nuclear Technology, Xian, Shaanxi710024, Chine;
2. School gf Waler Resouroes and Ersironment, China Usitersity of Geocienos, Bejing100083, China
Abstract: The study area is located in the arid area in the Northwestem China and two levels of water storage basins exist. The first-level basin receives the lateral recharge from the southern mountain area. Spring dis-charge from the first-level basin flows into and recharges the next basin, at the same time groundwater in each levels of basin receives recharge from direct precipitation and indirect infiltration of flood flow. Based on hydro-gen and oxygen isotope mixture formula, the precipitation amount accounts for 60% of the total recharges, of which, direct recharge from precipitation is estimated 21% , and recharge from flood flow is estimated 79%. Lateral recharge from the mountain area is about 40%, The second-level basin receives 38% recharge from pre-cipitation, and the upstream spring discharge accounts for 62%, The quantity of tritium indicates that the se-cond-level basin is not affected by present precipitation. Using the piston model and the complete mixing model, the age of shallow groundwater in the first-level basin is estimated to range from 32 to 60 a.
Key words: stable hydrogen and oxygen isotopes; tritium isotope; arid area; Northwestem China
0引言
历时短、雨量小以及包气带厚度较大等原因，大气降水又可分为直接人渗和山区洪流间接人渗。
中国西北干旱区（简称西北干旱区)降水稀少，：
第四系储水量的多少一般取决于沉积物分布规模
蒸发强烈，水资源空间分布不均，山前冲洪积扇及其补给量。研究第四系地下水资源量必须关注及山间洼地第四系成为主要储水单元。地下水多三水转化问题，传统的三水转化研究方法主要涉来自山前侧向补给与大气降水人渗补给，因降水及介质场、水动力场、水化学场和温度场等方
收璃日期：2011-07-10；改回日期：2011-09-22；责任编辑：或开静。
作者简介：孙璃，男，工程师，1982年出生，水文地质专业，主要从事地下水水化学研究。Email；19444942qqcom。