阿拉善高原地下水的稳定同位素异常

Isotopically Anomalous Groudwater of Alxa Plateau, Inner Mongolia

１９８７～１９９５年对降水、黑河水和古日乃草原地下水作了定位观测，在巴丹吉林沙漠水文探险中采集了沙漠和戈壁地下水及湖水。降水同位素组成δＤ～δ１８Ｏ与Ｃｒａｉｇ线相同，但发现了地下水的δＤ～δ１８Ｄ关系平行于降水线且有氘盈余为负且达－２２‰的异常，其成因不明。由地表、地下水环境同位素组成，分析了黑河治理规划实施后可能对地下水资源产生的工程影响，它近期不会成为古日乃草原沙漠化进程的因素，但对额济纳绿洲的影响却不容忽视。

In 1987～1995, precipitation, water from Black River, groundwater from Gurinai grassland and its vicinity were sampled positionally and periodically, groundwater and lake water from gobi and desert were sampled stochastically during the expedition into Badain Jaran Desert. Isotope composition of precipitation with its δD～δ 18 O fits the Craig Line while that of groundwater with an unusual deuterium excess of about-22‰ was found in this area. The formation of this isotopically anomalous groundwater, however, is still not clear. The engineering impact of the planned Black River Project on groundwater is evaluated from comparing isotopic composition of waters. It seems unlikely that it would intensify the ongoing desertification of the Gurinai grassland area in the near future. But it seems to be important for the area by the Black River and, the Ejin Oases.