Preliminary investigation of kaolin mineralization zones within the Oligocene-Miocene sediments of the Niger Delta basin using electrical resistivity

Abstract

This paper presents preliminary findings from electric resistivity study on OligoceneMiocene sediments of the Niger Delta with emphasis on identification of mineralization zones of kaolin. Fifteen (15) vertical electrical soundings (VES) data were obtained using Schlumberger   configuration with maximum electrode spacing of 600 m. The results of the VES correlated with borehole data shows five (5) to six (6)   geoelectric layers: top soil, sand/clay, kaolin/sand, sand/clay/kaolin, sand/clay and sand. The area is characterized by lateral lithologic heterogeneity resulting from gradational lithologic contacts, thus lithologic units are quite impersistent over a small area. Kaolin mineralization occur mainly in the third geoelectric layer, with resistivity values varying between 108 – 675 Ωm; thickness of kaolin increases from about 0.5 m around outcrops to 7.1 m in the study area. Depth to kaolin varied from 1.3 m at Ukwu-nzu to 19.1 m at Ubulu-uku; depth to mineralization generally increase with elevation in the area.