GRAVITY AND MAGNETIC STUDIES AROUND LOTAPAHAR, SINGHBHUM DISTRICT, BIHAR - AN APPLICATION TO URANIUM EXPLORATION

The potential capabilities of gravity and magnetic methods in the eval uation of geologic structures have been effectively utilised. Using th ese methods, semi-detailed surveys were conducted around the radioacti ve occurrences at Lotapahar (22 degrees 36'30 '' N. and 85 degrees 35' E.), in the western sector of the Singhbhum shear zone, primarily to d ecipher structural features, the common host for Uranium mineralisatio n. The interpretation of gravity and magnetic data enabled delineation of a ENE-WSW trending fracture zone. Forward modelling of a gravity p rofile yields the sub-surface disposition of this fracture zone and fa cilitated planning of boreholes for uranium exploration in the area. T he magnetic and the regional gravity maps indicated the contact of Cha kradharpur granite and metasediments of the Iron Ore Group which is in distinct on the surface.