Use of thermal springs for geochemical exploration in Ethiopia

Abstract

Large continental-scale rift valley systems provide in Ethiopia a unique setting for a range of industrial mineral deposits. However, the issues of exploration and exploitation remain expensive. It is pragmatic to look for easy techniques for locating precious metals. In this study an attempt was made to examine precious metals in the localities of the hydrothermal areas in the central Rift valley with the objective of whether thermal springs can hit mineral deposits. Thus, Filwoha, Sodere, Ambo and Wondogenet thermal spring areas were selected and specimens were collected for gold, silver, lead, manganese, cobalt, zinc, copper and iron determination. The analysis revealed that manganese was the dominant metal with the concentrations of 1980, 1510, 535 and 375 ppm in the chemical precipitates of Filwoha, Wondogenet, Ambo and Sodere areas, respectively. Zn was the
largest deposit in the chemical precipitates of Ambo and Filwoha areas with the levels of 355 and 154 ppm, respectively. The concentration of Au was 0.02 ppm in all sites whereas the level of Ag was ranged from 0.5 ppm in Filwoha to 2.2 ppm in Wondogenet. All these metals were found in good deposit range of ore grades for mining. Hence, hot spring water anomalous in Au, Mn, Zn, Pb, Cu, Co and Ag could be a proxy for precious metal searching in epithermal systems associated with thermal springs.

Keywords: Epithermal system, Ethiopian Rift Valley, geochemical exploration, thermal springs

Ethiopian Journal of Environmental Studies and Management Vol. 1 (3) 2008: pp. 1-7