Mapping Gully Erosion Using Remote Sensing Technique: A Case Study Of Okigwe Area, Southeastern Nigeria

摘要

The study area is part of the Upper Benue Trough comprising of Yola and its adjoining areas and lies within latitudes 90 00 ? - 100 00 ?N and longitudes 110 30 ? - 120 30 ?E. The objective of the study is to identify and delineate the structures associated with the area and also the trends/patterns of such structures and infer their relationship with basin formation and dynamics. And also to determine the thickness of the basement, the basement topography and the hydrocarbon potential and groundwater availability of the study area. The landsat imagery generated was processed using ILWIS 3.2 Academic and Erdas imaging softwares. The structural trend is predominantly in the NE-SW direction. The drainage pattern is dendritic which is indicative of lithological, structural and topographic differences and also indicative of alluvial rocks, which is typical of the geology of the area that consists mainly of sedimentary rocks. Areas of topographic heights averaging about 500m are potential region for groundwater assessment. These areas agree with areas in the lineament map where the lineament density is high. It was observed that these regions have a lot of lineaments crossing each other which is indicative of groundwater availability. Results of the magnetic data revealed two depths: a shallow layer of magnetization with depths ranging from 0.223km to 0.934km with an average depth of 0.546km while the deeper layer of magnetization has its depths ranging from 1.233km to 4.013km with an average depth of 2.788km. The depths show that the basin is good for mineral prospecting and not favourable for hydrocarbon prospecting. The dominant trend of the magnetic data is the NE-SW direction which agrees with the landsat data