Exploring mildly acidic to neutral hot fluids through carbonate clumped isotope (?47) thermometer in the Liuhuangtzuping Area

Abstract

The Liuhuangtzuping area, located in the northeastern part of the geothermally active Tatun Volcano Group (TVG), is situated adjacent to the She-Huang-Ping steaming ground(SHP) and Geng-Zi-Ping (GZP) steaming ground. Historically, SHP was deemed unsuitable for geothermal power generation due to its high corrosion potential with a pH value of hot springs ranging between 2-3. However, in recent years, Fabulous Power Co. has successfully drilled dry steam in SHP and is currently underway with the construction of a 1.4MW geothermal power plant. Liuhuangtzuping, in close proximity, presents an intriguing prospect for future Enhanced Geothermal Systems (EGS) development, featuring substantial layers of lava flows beneath.
In this study, we examined clumped isotope compositions for carbonates precipitating from near-neutral fluids in drilled cores of the Liuhuangtzuping area. The ?47 values for five carbonate samples ranged from 0.434±0.012 ‰ to 0.512±0.020 ‰, corresponding to the estimated temperatures ranging from 184±6? to 114±7?. Overall, these results suggest the existence of a subsurface reservoir where fluids are neutral in pH and sufficiently hot (180-185?) for geothermal energy exploration.