Geostatistical Modelling on CO2 and Mercury Content in Soil and Its Implication for Geothermal Exploration in Bittuang

Soil Geochemistry survey is an effective and efficient method on preliminary study of geothermal exploration. The Spatial variation of soil geochemistry data such as CO2 and mercury can provide information such as: tracks of permeable zones on high temperature hydrothermal fluids flow, occurence of faults and near surface heat flow, thermal anomalous occurence and zonation, etc. The purpose of the research is to determine the spatial distribution of CO2 and mercury content in soil using Ordinary Kriging in order to delineate geothermal prospect area in Bittuang, South Sulawesi. Data used in this analysis are 96 samples of CO2 and mercury content in soil from Center of Mineral, Coal, and Geothermal Resources. The data is then analyzed statistically to determine its spatial characteristics. The result of kriging CO2 map shows that there are three zones that have value above the threshold value (> 2.1269%) while kriging map of mercury shows two zones that have values on range of second-highest class (157.47- 467.47 ppb). In general the presence of CO2 and mercury gas enrichment is caused by fault with North-South trend which is also convinced by the appearance of manifestations.