A gravity interpretation of the Liruei Younger Granite Ring Complex of Northern Nigeria

Abstract

Gravity readings were taken on a 40-km traverse running roughly NE-SW across the Liruei Younger Granite ring complex of Nigeria. A negative Bouguer gravity anomaly of about 16 milligals amplitude was observed over the complex.Electronic computing methods were used in the interpretation to obtain the best 2-dimensional and 3-dimensional structures which would fit the observed anomaly. The best computed models indicate that the contacts between the Liruei Complex and the surrounding Basement Complex dip outwards from the ring complex and, based on the surface density contrast of 0·10 gm/cc, the depth to the base of the density contrast is of the order of 7,500 metres.