WEATHERING STUDY AND CONTROLS OF HYDROLOGY IN AGLAR WATERSHED

Abstract

A geo-electrical imaging survey was conducted at two different slopes in Aglar watershed, for shallow site investigation in order to determine the applicability of 2-D resistivity imaging in studying the weathered profile, which in turn determines how feasible the weathering is controlled by hydrology in the area. Geophysical survey was carried out using 2-D electrical resistivity imaging technique in the span of two days time. The Wenner-Schlumberger array was used. Field data were obtained for tree electrical imaging lines. The field data was subjected to inversion in order to remove geometrical effects from the pseudosection so that an image of true depth and true formation resistivity can be produced. The range of resistivities from 60 to 4227 Ohm-m for profile P1 was obtained and from 28 to 521 Ohm-m for profile P2 was obtained. Partially weathered basement were observed on some of the traverses with relatively high resistivity anomalies. The image lines clearly indicates that the subsurface material differs in terms of their competence. Different types of weathering pattern are shown.