Geological Analysis f Gravity Data Over Part of Nigeria's NorthCentral Basement Complex

Abstract

This work analyses filtered gravity data over Kaduna and Katsina State of Nigeria.The region is part of the north central Precambrian basement Complex of Nigeria. It is marked by migmatite- gneiss complex which constitute the dominant rocks. This group is followed by quarzite- schist complex, and the intrusive pan African granites. The Jurassic granites also occur as younger intrusives in the basement. Cretaceous and Quarternary sediments occur respectively in the northeast of the area. The present work attempts to interprete the gravity data in the light of available geological and regional tectonic data. Residual, horizontal derivative, upward and downward continuation maps (at 1.0 and 0.4 km respectively) have been done. Subsurface modelling of some residual gravity profiles have been done to generate 2-D models. The software used is WinGLink (version 2.03.01). The filtered gravity maps show prominent NE, NW, and N-S anomalous zones. These align with prominent geological lineaments and emplacement directions of the basement complex rocks such as the schists and the granites. They also reflect the poly-cyclic nature of the area's basement particularly and that of Nigeria generally. Results of 2-D modelling gave depths to the fresh basement of not more than 305 m. The overlying material to the basement are interpreted as lithosols (laterites).The novelty of the present work is the recognition of a prominent zone of NE-SW anomalies with sharp gradient on the Bouguer anomaly map. This extends from the town of Malumfashi to Sabon Birni Gwari (over 200 km). This is interpreted as a major fault zone based on geological data, it is an extension of Ifewara fault zone of southwest Nigeria. This fault zone is a plate tectonic feature which has its origin in the Atlantic ocean

Publication Info:

Author: Akintoye, G.S. , Bassey, N.E. and Udoh, A.C. *

Volume: 59

Issue: March

Published By: Journal of Mining and Geology Vol. 59(1) 2023. pp. 87 - 99, 2023-03-01