皮山河绿洲带大气降水同位素特征及其应用

Isotope Characteristics and Application of Precipitation in the Oasis of Pishan River

采用稳定同位素D、^(18)O对塔里木盆地南缘皮山河绿洲带主要水体进行研究,探明其在空间上的变化规律,弄清各水体之间的相互联系。通过对样品D、^(18)O的分析,结合全球大气降水同位素监测网(GNIP)和田站1988-1992年的降水同位素数据和前人研究成果开展研究,结果表明:研究区全年降水同位素值具有明显的季节差异,大致可分为4-10月、12-3月2部分,4-10月降水同位素相对富集,12-3月降水同位素相对贫化;由于不同时期内各水体受到不同季节降水和冰雪融水持续补给的影响,研究区不同时期的水体在区域降水线的同一块区域交错分布,具有相似性;对于南疆地区主要接受冰雪消融、降水混合补给的河流,在应用各水体稳定同位素D、^(18)O差异判别地表水地下水转化关系时,需要对由接受补给造成的各水体之间的同位素差异进行充分考虑。

The hydrogen and oxygen isotopic are used to carry out a detailed investigation of the characteristics of spatial isotopic variation in the oasis of Pishan River,which is located in the southern margin of the Tarim Basin,and to understand the interrelations of different water bodies in the same area. The hydrogen and oxygen isotopic compositions of all the samples are analyzed and by combining them with isotopic data obtained from previous research achievements and the precipitation in Hotan from 1988 to 1992,published by the global network of isotopes in precipitation（ GNIP）,the previous research results have also been used for reference. It is fiound that： the annual precipitation isotope values in the study area have obvious seasonal differences,which can be roughly divided into two parts,the first part is from April to October,the precipitation isotopes in this part are relatively enriched and secondary from December to March,and the precipitation isotopes are relatively poor. In the same time period,each water body receives from different months of rainfall and ice snow recharge,the distributions of surface water and groundwater are similar,and the relationship between water bodies is close. For the rivers which are mainly recharged by glacial melting water,snow melting water and precipitation in the southern Xinjiang,the isotopic differences between the water bodies caused by recharge should be fully considered when the stable isotopes of D and ^18O are used to distinguish the relationship between surface water and surface water.