松嫩平原地下水流动模式的环境同位素标记

采用同位素水文学方法并结合传统水文地质方法,识别松嫩平原地下水流动模式。氢氧稳定同位素和地下水年龄分布表明该区地下水流动系统流动模式呈现出局部流、中间流和区域流系统。地下水中氚分布深度指示局部水流系统为现代水循环系统,以垂向运动为主要特征,循环深度一般小于50 m,山前区可达100m以下;区域流系统存在于深部承压含水层,以侧向水平径流为主要运动特征。松辽边界附近的环境同位素特征存在明显的差别,指示天然状态下可视为零通量边界。同位素示踪剂也反映出嫩江和地下水的相互作用关系,在齐齐哈尔以北,江水补给地下水;在齐齐哈尔以南,地下水向嫩江排泄。

The environmental isotope markers of groundwater flow patterns of the Song-Nen Plain

Isotopic data from groundwater and surface water are used together with classical hydrogeological information to study groundwater flow pattern throughout the Song-Nen Plain.The δ18O,δD values and ages of groundwater indicate that the groundwater flow patterns are characterized by local flow systems,intermediate flow systems and regional flow systems.The depth distribution of tritium in groundwater suggests that local groundwater flow system is a modern water circulating system which penetrates by a depth of ～100 m in the piedmont and 50 m in the central plain.Regional groundwater flow system is characterized by lateral flow and occurs in deep confined aquifers.The distinction of environmental isotope characteristics around the phreatic divide between the Song-Nen basin and Liaohe basin indicates that the divide should be regarded as a zero flux boundary at the natural state.The δ18O(δD) value and 3H isotope tracers reflect the interactions of groundwater and surface-water,i.e.,groundwater obtains recharge from seepage along the Nenjiang River in the north of Qiqihaer,and discharges into the river in the south of Qiqihaer.