Assessment of helium potential proximal to the geothermal settings

Abstract

Global and society is faced with significant shortages of helium supply. Successful exploration for further helium resources requires a thorough understanding of a wide range of suitable geologic settings. Geothermally active regions are the critical sources of high heat flow required for helium release unlike their ‘dry’ helium-rich lithospheric counterparts. This study reviews the similarities and differences of three geological provinces located within geothermally active regions; Bakreswar-Tantloi (India), Yellowstone (U.S.A.) and the Rukwa Rift (Tanzania). Combination of geological, geochemical and structural evidences from these three regions show high helium concentration content above 0.3% which occur along deep-rooted fault systems suggesting the possibility of such faults being the main migration conduits. These regions also exhibit high heat flow ~>99 mW/m2 and geothermal gradient ~>39 °C/km sufficient to trigger helium release from the underlying Precambrian basements and enhance migration of deep crustal fluids containing helium. This study concludes that, it is not the extreme thermal conditions which matter to release radiogenic helium but the attainment of thermal condition above closure conditions for most helium-retentive minerals. These findings provide an innovative approach to understanding and assessing the helium potential in similar tectonic settings elsewhere in the world.