HEAT-FLOW ACROSS THE EAST-AFRICAN PLATEAU

Four new heat flow measurements from western Tanzania are combined wit h existing data from non-rifted areas of East Africa to determine if t here is a broad heat flow anomaly associated with the East African Pla teau. Three of the new data sites lie in the Kibaran Belt and yield he at flows of 60, 68, and 74 mW m(2), The fourth new site is in the inte rior of the Tanzania Craton and gives a heat flow of 33 mW m(2). The e nsemble of heat flow data from the interior of East Africa, when compa red to the global distribution of heat flow in tectonically undisturbe d Precambrian terrains of similar age, indicates that heat flow from t he center of the Plateau is not elevated. This finding suggests that i f the lithosphere beneath the interior of the Plateau lithosphere has been thermally perturbed, as proposed previously by many investigators , then the thermal anomaly must be of insufficient magnitude and/or ha s not existed for an adequate length of time to affect surface heat fl ow.