利用TDS和δ^(18)O确定溶滤和蒸发作用对内陆干旱区地下水咸化贡献的一种方法

溶滤和蒸发作用是内陆干旱盆地平原区松散沉积层地下水咸化的主要原因。地下水的ＴＤＳ直接表达了其咸化程度，δ１８ Ｏ值的变化主要受蒸发作用影响。在地下水ＴＤＳ－δ１８ Ｏ关系图中，以各样点为起点，做蒸发线的平行线，与溶滤线交于ｃ点，则ｃ点两侧的ａ 段和ｂ段分别代表溶滤和蒸发作用对该样品的咸化贡献。ａ＝ （ＴＤＳ３ － ＴＤＳ１ － ｂ）／（ＴＤＳ３ －ＴＤＳ１ ）×１００，ｂ＝ ｋ（δ１８Ｏ３ － δ１８Ｏ１）／（ＴＤＳ３－ ＴＤＳ１）×１００％ 。该方法应用于塔克拉玛干沙漠地下水咸化特征的分析，证明虽气候干旱，蒸发作用强烈，但地下水的咸化仍以溶滤作用为主。

Lixiviation and evaporation are main salinization processes of groundwater stored in loose sediments in inland arid basins.The TDS indicates the salinity of groundwater directly,and the variations of δ 18 O are mainly influenced by evaporation.We can draw a line parallel to the evaporation line from each sample point on the TDS\| δ 18 O relationship diagram.This parallel line will intersect the lixiviation line at c.The section a and b on both sides of c in the lixiviation line represent the contribution of lixiviation and evaporation to the sample's salinization respective.a=( TDS\-3-TDS\-1 -b)/(TDS 3-TDS 1)×100%,b=k(δ 18 O\-3 -δ 18 O\-1)/(TDS 3-TDS 1)×100%. Applyng this method to analyze the groundwater salinization features in Taklimakan Desert,lixiviation is proved to be the main salinization process of groundwater though there is an arid climate and a high evaporation.