Abstract

A ground radioactivity survey report and it geological analyses are presented in this work. The survey was aimed at delineating possible zones of concentration of pegmatite intrusions, a rock whose components are useful in the in the electrical and ceramic industries among others. The survey covers longitude 12°54’-13°00’E and latitude 10°7’-10°15’N, with a total surface area of 155.52 km2. Dominant plutonic rocks in the area are coarse grained/pegmatitic granites which occur as intrusion in the metamorphic rocks (gneiss and migmatite). The survey was undertaken with a Geiger counter at station spacing of 1 min (1ꞌ) following mostly a system of grid lines. A total of 48 stations were occupied and measurements of the radiometric field variations were made. Thirteen radio-lineaments have been mapped, majority (7) align with pan African deformational direction (N-S, NE-SW). Others align in the NW and E-W directions. Some radio-lineaments correlate or align with geomorphologic features of hills and straight channel streams. Based on high radiometry and ground truthing results the northern sector of the study area is designated as a pegmatite zone. Other high radiometric zones are suggested as targets for investigation for possible pegmatite occurrences because of the economic importance of this rock.

Key words: Radiometric anomalies, basement complex rocks, pegmatites, lineaments and geomorphic features.