On the Geothermal Potential of the Heyuan Fault, South China

Abstract

Geothermal energy potential in China is high, and although they currently lead the way in direct heat production, geothermal power generation is still low. Hot spring analysis and surface heat flux data indicate significant potential resources for the major industrial province of Guangdong, South China. This pilot study investigates the Heyuan Fault, Guangdong, as a potential site for a geothermal power plant. Here we line out (i) preferred locations of possible hot spots on fault intersections, (ii) the possible sources of the heat anomalies, (iii) potential pathways for hot fluid circulation in the upper crust, (iv) available hot spring data and (v) the future work plan to investigate the geothermal hot spots. We find that hot springs occur along the NE trending Heyuan Fault, clustering where NNW striking faults crosscut the Heyuan. The increased heat flow can be explained partly by radioactive decay of a large granite pluton beneath the fault, however, additional heat sources may need to be considered to explain the heat flow maxima of above 85 mWm-2. We postulate that advective (topographically driven) and convective (deep fluids ponding at the brittle-ductile transition) processes may be operating to generate these heat anomalies. Expansive quartz reef systems exposed on the Heyuan Fault, are proposed here, to represent uplifted sections of these deep fluid circulation patterns. A detailed systematic analysis of reef structures will reveal (i) the fluid provenance, (ii) precipitation conditions and (iii) deformation mechanisms, which will ultimately help us understand how fault intersection relations control fluid flow; which is of key significance if it can be utilised for targeting geothermal energy.