Application of geochemistry to resource assessment and geothermal development projects

Systematic Analysis of Geothermal Resources in the Coastal Bedrock Area of Chunxiao Town (China) by Using Geochemistry and Geophysics Methods

“…There is a significant chemical composition difference between geothermal water and shallow groundwater or surface water. These hydrochemical anomalies tend to transfer to groundwater or even surface water through water circulation [25]. By analyzing the hydrogeochemical characteristics of groundwater and surface water samples in the study area, it is possible to confirm whether there are signs of deep hot groundwater circulation.…”

“…The hydrochemistry data was used to plot a Langelier-Ludwig diagram ( Figure 3) to analyze the possibility of the geothermal water in this area. In the Langelier-Ludwig diagram (Figure 3), the region in upper left corner of the diagram presents typical geothermal water; the region in the bottom right corner of the diagram presents typical cold water; and the region in the center of the diagram belongs to the mixed type of cold and geothermal water with different proportions [25]. As shown in Figure 3, the M3, M4, and M5 samples are located in the geothermal anomaly region, which indicate the possibility of thermal groundwater.…”

Geothermal energy resources in Ethiopia: Status review and insights from hydrochemistry of surface and groundwaters

“…To allow assessment of the chemical quality of Ethiopian waters, the selected samples were classified into water types following the method outlined by Cloutier (2004), with each concentration of major ion expressed as a percentage of Afar Depression samples plot closely to "mature waters," corresponding to highly concentrated chloride brines representative of thoroughlyequilibrated fluids from major up-flow zones. The chemistry of steam-heated and volcanic waters are typically related to gas absorption and oxidation processes (Giggenbach, 1988;Haizlip, 2016;Younger, 2014) the sum of concentrations (in meq/L). The water-type is defined by the dominant cation and anion concentrations in excess of 20% of total fluid composition (usually one of each).…”

“…The spatial distribution of the sampling points for δ 2 H and δ 18 O isotope data is shown in Figure 7. Under two-phase conditions, the heavier stable isotopes ( 18 O and 2 H) preferentially partition into the liquid phase and lighter stable isotopes ( 16 O and 1 H) partition into the vapor phase (Haizlip, 2016). Natural variation of isotopic signatures can be used to determine water source and subsequent alteration processes.…”

“…A generally linear relationship exists between δ 2 H and δ 18 O called the global meteoric water line (GMWL; Craig, 1961). Deviations in the stable isotope composition from this line may indicate processes such as: (1) increasing δ 18 O (enrichment) but little change in δ 2 H compared to meteoric waters, evidencing water‐rock interactions in excess of 150°C (Craig, 1963; Kato, 2000); (2) mixing with other water and fluids resulting in shifts for both δ 2 H and δ 18 O; or (3) evaporation or boiling and precipitation or condensation producing isotopically depleted steam and enriched residual water (Haizlip, 2016). Isotopic investigations have demonstrated the presence of δ 18 O enrichment in waters believed to be from a vapor‐dominated section of a geothermal reservoir (Montcoudiol et al, 2019), suggesting that such deviations can be used to help identify high enthalpy zones within geothermal prospects.…”