Preliminary Interpretation of Isotopic Studies of Geothermal Waters from the Beijing Region (P.R. China)

Abstract

Isotopic studies of thermal and cold surface waters sampled in the Beijing Region have shown that the thermal waters are meteoric waters which have been precipitated in the mountainous area lying to the of Beijing. 6D and 6 data indicate that these waters move laterally in SE direction over distances of more than 150 km in Sinian basement rocks which are uplifted in the NW but occur at depths of 3 to 5 km in the SE sector of the region. Significant exchange with basement rocks occurs in the Jizhong Depression about 60 km to the SE of Beijing. On a smaller scale, a SE flow of thermal waters in basement rocks is corroborated by data for the Beijing area and the Bei jing geothermal field. The Bei j in g geothermal field and other geothermal fields in the SE sector of the Beijing Region are an example for low temperature systems where the heat is derived from a normal or slightly greater than normal trial heatflow.