Several central volcanoes are present along the axial portion of the rift, which offeredrnopportunities for potential geothermal resource investigations. The Gedemsa caldera,rnwhich is a Holocene volcanic complex in the central sector of the Main Ethiopian Riftrn(MER), is among those promoted for detailed investigation. Results of theserninvestigations have, inturn, generated great interest in studying epithermal phenomenarnrelated to these volcanics. However, studies aimed at delineating epithermal-typernmineralization of precious metals (mainly gold) within the MER is a relatively recentphenomena.rnThe present work deals with preliminary geological and geochemicalrnexploration for these occurrences within the Gedemsa caldera.rnPropylitic, potassic and silicification with minor argillic alteration characterize thernGedemsa Caldera. In addition to field observations, alteration is diagnosed by thernpresence of mineral assemblages including epidote/chlorite, calcite, quartz, k-feldspar,rnand oxides with some clay minerals. Ore minerals observed include pyrite, chalcopyriternwith malachite/azurites, magnetite and hematite. Features indicative of epithermalrnactivities include deposition of fine silica in the oxidized pumiceous deposits, and the thinrnveins of chalcedonic quartz and k-feldspar, which are intensely brecciated together withrnthe enclosing wall rock. Occurrences of several active thermal manifestations are alsornknown along NNE fault lines immediately outside the caldera.rnA total of 79 samples (stream sediment, soil, rock/chip and drill cutting) have beenrnassayed (ICP-MS) for Au, Ag, As, Sb, Tl, Te, Pb, Zn, Cu, Mn, U and other tracernelements. Statistical parameters were computed in order to define the threshold value andrnto separate background from anomalous ones. Anomalous values for most elements arernconcentrated along the E-W running central chain of hills and at the vicinity of NNESSWrntrending faults both in the western and eastern part within the caldera . In terms ofrnaverage crustal abundance, the surveyed region is of relatively higher background contentrnfor Au, Ag, Zn and Mn. Analyses of rock/chip and drill cutting samples (ICP-MS) fromGedemsa range in value from 0.1 to 4.16 g/t Ag and from hundreds of ppb to 0.375 g/trnAu, respectively. Gold values between 100-200 ppb are quite common throughout therngeological profile as observed from drill hole section. The occurrence of many high goldrnintervals (zone) within the geologic sections reflect-different levels of mineralization. Onrnthe basis of alteration mineral assemblages and the Ag /Au ratios, a low sulphidation typernof epithermal system is suggested. A preliminary reserve estimation of the goldrndisseminated in the upper porous pumice is discussed.rnFrom the results obtained in this work, evidence for the presence of ore-formingrnphenomena is positively identified, and the study, the first of its kind, offers thernpreliminary results of the investigation on the occurrences of epithermal typernprecious(Au and Ag) metallic mineralizations in the Gedemsa caldera