Geothermal Resources of Tanzania

Abstract

At least 15 thermal areas with hot (T > 40?C) spring activity occur in Tanzania. Ten of these occur over and near to active rift segments with Quaternary volcanism; the others lie over the Tanzanian (Archean) craton and its Precambrian surrounds. In N Tanzania, at the S end of the Gregory Rift, a few advective, low temperature systems can be found which have little development potential, despite the large heat output (at least 50 MW) of one, the Lake Natron system. In S Tanzania, over the northern extension of the Malawi Rift, up to three high (intermediate) temperature reservoirs are indicated by the occurrence of hot springs at the foot of long, concealed outflows discharging neutral pH bicarbonate water depositing travertine. The largest prospect is that at the Songwe River, transferring c. 10 MW of heat. Thermal springs over the craton and its surrounds are supplied by small, low temperature fracture zone reservoirs; they have small natural outputs and little development potential. The known geothermal resources of Tanzania are therefore limited in terms of present technology.