沂沭断裂带临沂段地热资源水化学及环境同位素特征

Hydrochemical and environmentalisotopiccharacteristics of geothermal resources in the Linyi segment of the Yishu fault zone

地热水的化学、环境同位素组成,记录了地热水补给来源、循环条件、水岩反应等很多基础信息,对这些信息认识的正确与否决定了地热资源开发的成败。沂沭断裂带临沂段地热资源十分丰富,近年来各地勘单位在区内开展了多个地热勘查项目,但对地热水特征性研究有限。本文在分析研究区地质和地热背景条件的基础上,研究了地热水的主要化学成分、环境同位素特征。区内不同位置水化学类型多样,矿化度差异较大,但主要受大气降水补给。地热水富含对人体有益的FSr Li偏硅酸,具有较高的医疗价值。3H 14C特征表明地热水滞留时间比较长,在3500a以上。地热温标计算的温度与出水口温度差异较大,表明开采过程中有大量浅层冷水混合。

The result of geothermal resources development is dependent on whether some important information such as supply source, circulation condition, and water-rock reaction of geothermal water recorded in chemical and environmental isotopic composition are understood. Geothermal resources in the Linyi segment of the Yishu Fault Zone are very rich. During recent years, many geological prospecting units have been carried out in the area, though lacking a system of research regarding the characteristics of geothermal water. Based on an analysis of geological and geothermal background conditions, we studied the main chemical composition and environmental isotopic characteristics of the geothermal water. The types of water chemistry difer in diferent locations; the diference intotal dissolved solids is large, but all are mainly afected by the atmospheric precipitation. Geothermal water is rich in F, Sr, Li, and silicic acid, which has a high medical value. 3H and 14C characteristics showed that the geothermal water retention time is longer than 3500a. The calculated temperature using a geothermometer difers from the outlet temperature, which shows that abundant shallow water is mixed during the mining process.