Heat Source Characteristics of Some Warm and Hot Spring Systems in China and Thailand

Abstract

The conductive heat flow associated with some warm and hot springs systems in China and Thailand has been modeled. Using simplified 2D thermal conductivity models for the Beijing graben (China) it was found that about half of the observed anomalous flux can be explained by the geometry and the low thermal conductivity of the graben. Since the observed flux within the deepest part of the graben is significantly lower than the predicted by the conductivity model, it is proposed that fluid movement at the base of the graben transfers heat to the flanks. The high heat generating capacity of massive granites in northern Thailand caused anomalously high heat flows; modeling the heat flow associated with the granites showed that high temperatures between 150 to 175°C can occur between 4 and 5 km depth beneath most hot spring systems in that region. These temperatures are near to resource base temperatures as inferred from the Na-K-Ca geothermometers.