APPLICATION OF AEROMAGNETIC AND LANDSAT ETM-DATA IN THE INTERPRETATION OF STRUCTURES IN PARTS OF ANAMBRA BASIN, SOUTH-EASTERN NIGERIA

Abstract

Structural interpretation in parts of Anambra Basin in south-eastern Nigeria was conducted using aeromagnetic and Landsat-ETM data to identify the lineaments associated with the study area and to construe the effect of structures on the drainage system and its potential for hydrocarbon. The study area is geographically situated between longitude 7⁰00'E – 7⁰30'E and latitude 6⁰00'N – 6⁰30'N. The study demonstrates the advantages of applying digitally processed Landsat-ETM data and Aeromagnetic data for geologic mapping. The data was processed and enhanced to give fractures /lineaments, geologic maps, drainage pattern, and colour composites. Trend analysis of the lineaments revealed on a rose diagram and from the regional plots displayed structural trends of the study area to be in NW-SE, NE-SW, N-S and E-W directions respectively but NW-SE was the most prevailing. When the Landsat data was compared with the aeromagnetic data, it was observed that the areas with high lineament density are also the areas with high basement relief where as low lineament density areas are characteristic of low basement relief. The spectral analysis of the study area revealed a depth to basement ranging from 1.9 km to 5.3 km with an average of 4.0 km which is unsuitable for the production of hydrocarbon. These shallower depths could be as a result of basement rocks that intruded into the sedimentary formations.