Automated Geological lineaments mapping for groundwater exploration in the basement complex terrain of Akoko-Edo area, Edo-State Nigeria using remote sensing techniques

Abstract

This study aims to map geological structures (lineaments) which are indications of sustainable groundwater supply in a hard rock terrain of Akoko-Edo local government area of Edo State, Nigeria. Landsat-OLI imagery, topographical map and geological map of Nigeria were used for this study. The methodology involves subjecting the imagery to preprocessing algorithms, linear/edge enhancement, directional filtering, contrast stretching using ENVI 4.7 software. The lineaments were extracted automatically using PCI Geomatica software while ArcGIS and Rockworks software were used to plot the lineament density map and lineament trend respectively. The result shows the total number and length of lineaments to be 197 and 278.85 km respectively. Shorter lineaments constitute about 40% of the total number of lineaments. The lineaments density varies from 0 to 2.40 km/sq.km, and areas with 1.32–2.40 km/sq.km and 0.82 km/sq.km reflect high and moderate degree of rock fracturing which makes these areas suitable target for groundwater exploitation as they possess more lineaments. The lineament trend results showed two prominent trends E–W, N–S and ENE–WSW. Other minor trends are also observed in the study area. These trends validate with results of earlier local studies and with directions of prominent geological structures and features of the study area. The discovery and delineation of the geological structures (lineaments) will serve as direct guides for decision makers to accurately site productive boreholes that will solve the problem of water scarcity in the study area, thereby promoting good developmental policy.