CO2 in Soil Gases of the Silali Geothermal Prospect Kenya

Abstract

The present study is aimed at using probability plots and the partitioning procedure of Sinclair as well as suitable geostatistical tools (e.g., semivariograms and Kriging) in assessing the source of CO2 in the soil gases of the Silali prospect in the Kenyan Rift. Numerous manifestations occur, in form of hot grounds and fumaroles, in the lower eastern half of the Silali caldera, on the walls of the eastern half of the caldera, and on the eastern outer flanks of the shield volcano. The results of the soil gas survey indicate that most CO2 anomalies are situated inside the Silali caldera or close to it and there is a close spatial correspondence between most CO2 anomalies and areas of fumaroles and steaming grounds. This correspondence corroborates the hypothesis concerning the geothermal and structural control on the anomalous population, which is evidently attributable to uprising of deep CO2-rich geothermal gases towards the surface.