论文部分内容阅读
鄂尔多斯白垩系地下水盆地天然水体的环境同位素组成表明,区内各种地表水体(河流和湖淖)在δ18O和δD图上主要分布在雨水线右侧,其关系线的斜率明显小于雨水线的蒸发线,集中反映蒸发作用对地表水体的影响。盆地内地下水大致集中沿雨水线分布,反映了白垩系盆地内地下水为大气降水成因。盆地南北两区地下水的环境同位素具有明显差异性特点,集中体现了盆地南北两区水循环条件的差异。盆地北区各含水岩组间地下水垂向水力联系比较密切,垂向运动特点比较明显,现代水积极循环带的深度为200 m;南区地下水分层性明显,以水平径流为主,现代水积极循环带的深度为160 m。区内浅层地下水以富氚和高14C含量为特征,反映为现代水补给;而中、深层地下水则以贫氚和低14C含量为特征,反映为地质历史时期补给。
The environmental isotopic compositions of natural water bodies in Cretaceous groundwater basins in Ordos show that the surface water bodies (rivers and lakes) on the δ18O and δD maps are mainly located on the right side of the rainwater line, and the slope of the line is significantly smaller than that of the rain line Line, focusing on the impact of evaporation on the surface water body. Groundwater in the basin is generally concentrated along the rainwater line, reflecting groundwater in the Cretaceous basin as a cause of atmospheric precipitation. The environmental isotopes of groundwater in north and south of basin have obvious difference characteristics, which mainly embody the difference of water cycle conditions in north and south of basin. The vertical hydraulic characteristics of the groundwater between the water-bearing rocks in the northern area of the basin are relatively close, and the vertical movement is obvious. The depth of the modern water active circulation zone is 200 m. The groundwater in the southern area has obvious stratification, with horizontal runoff and modern water The depth of the active loop is 160 m. The shallow groundwater in the area is characterized by tritium enrichment and high 14C content, which is reflected in modern water recharge. However, the middle and deep groundwater is characterized by tritium depletion and low 14C content, which is reflected in the recharge during geological history.