Preliminary interpretation of isotopic studies of geothermal waters from the Beijing region (P.R. China)

Isotopic studies of thermal and cold surface waters sampled in Beijing region have shown that the thermal waters are meteoric waters which have been precipitated in the mountainous area lying to the NW of Beijing. ΔD and over distances of more than 150 km in Sinian basement rocks which are 3 to 5 km in the SE sector of the region. Significant 18O 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 in corroborated by Δ34S data for the Beijing area and the Beijing geothermal field. The Beijing 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, terrestrial heat flow