DETERMINATION OF THE DEPTH TO MOHOROVICIC DISCONTINUITY IN THE MINNA AREA IN NIGERIA USING BOUGUER GRAVITY DATA

Abstract

The present study deals with the determination of depth to Mohorovicic discontinuity beneath the Minna area, Nigeria the Bouguer gravity data covering the study area. Three emperical relations were used to mathematically compute the mohorovicic depth for the area. From spectral analysis carried out on the gravity data, depth to major density boundaries was obtained which are the Basement depth. Conrad discontinuity and moho discontinuity. The moho depth results obtained from Emperical Analysis and Spectral analysis, summed and average were used on straight line equation to obtain the relationship between the moho depth Hc in kilometer. Two 2-D gravity models along two profiles trending NW-SE and N-S direction were constructed with the available geological and geophysical information to obtain a correlated moho depth for the Study Area. The obtained result from the model indicates that the average density of the upper mantle is 3.2g/cm3 underlying the Migmatite-Gniess, lower crust of average density 2.8g/cm3. The considerable moho depth range of 30 to 47 km and conrad depth range of 4 to 24 km obtained for the study area gives an indication that the tectonic stability of the area is further enhanced.