Geothermal resource potential assessment of Erdaobaihe, Changbaishan volcanic field: Constraints from geophysics

Abstract

Geothermal resources occurring in the Changbaishan volcanic field are directly or indirectly controlled by volcanic activity and exhibit a close correlation with deep-seated faults. Energy and thermal transfer are generally controlled by groundwater circulation and hot gas emission. This article considers the detectability of hot water and gas by geophysical methods. The controlled source acoustic magnetotelluric (CSAMT) and radon (222Rn) gas methods give straightforward information on electrical resistivity and natural radon emissions, respectively, to assess the geothermal condition. The CSAMT method detected five-banded low-apparent resistivity bodies (decreasing from 3,000 to 300 Ωm), indicating that there exists a high degree of water-bearing capacities in the subsurface. The radon (222Rn) gas concentrations were monitored in two rapid growth zones: one zone showing values ranging from 3,000 to 23,000 Bq/m3, and the other with values from 4,000 to 24,000 Bq/m3. These changes demonstrate that the heat energies available in these areas were very high and that there is potential for geothermal resources in those zones. Combining with previously published data from geothermometry and geothermal drilling, we argue that there is great potential in Erdaobaihe for geothermal exploitation and that the geothermal resource type should be classified into uplift mountain geothermal system no magma type.

Keywords

• geothermal resource
• changbaishan volcanic field
• controlled source acoustic magnetotelluric
• radon gas