Structural Interpretation of Part of Anambra Basin Nigeria using Aeromagnetic and Landsat ETM data

Abstract

This paper presents the results of the structural interpretation over part of Anambra Basin carried out using Aeromagnetic and Landsat-ETM data. The study area is part of Anambra Basin, south Eastern Nigeria. Geographically, it is situated between Longitude 7000’E – 7030’E and Latitude 6000’N – 6030N. The study is aimed at giving a structural interpretation of the area by identifying the lineaments associated with the study area and to infer the effect of structures on the drainage system and its potential for hydrocarbon. The work demonstrates the advantages of using digitally processed Landsat-ETM data and Aeromagnetic data for geologic mapping. The data was processed and enhanced to give colour composites, geologic maps, drainage pattern, and fractures/lineaments. Trend analysis of the lineaments revealed on a rose diagram and from the regional plots showed structural trends of the study area to be in NW-SE, NE-SW, N-S, and E-W directions, but NW-SE was the most dominant. When the Landsat and aeromagnetic data were compared, 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 1.86km to 5.34km (Umuagu and Ugbene regions) with an average of 3.95km which is unsuitable for the production of hydrocarbons.