CRUSTAL STRUCTURE AND MODELLING OF PARTS OF ANAMBRA BASIN NIGERIA, USING BOUGUER GRAVITY DATA

Abstract

The bouguer gravity map covering the study area were digitized, merged, contoured and subjected to Spectral depth analysis and Two-dimensional (2-D) gravity Modeling to determine the crustal structure and Mohorovicic Discontinuity beneath parts of Anambra Basin, Nigeria. Nine Spectral sections and four two-dimensional (2-D) gravity Models were constructed for the study area bounded by Longitudes 5° 00' to 6°00' E and Latitudes 6° 00' to 7° 00' N as with gravity data, relationship between crustal structure and crustal density can be established. With the Bouguer gravity anomalies and the available geological and geophysical information for the study area. The obtained results indicates that: 1) the migmatitic crust is underlain by upper mantle. 2) The highest sedimentary thickness for the study area is about 14.5 km- a good sign for mineral exploration. 3) the crustal thickness ranges from 31.0 km to 41.5 km. 4) The average densities for the different rock layers are: 2.623 g/cm3 for sediments, 2.65g/cm3 for the crustal layer, and 3.2 g/cm3 for the upper mantle.