Subsurface Structural Features of Nasarawa State, Nigeria, from Aerogravity Data

Abstract

Subsurface structural and content information of the earth are usually needed to evaluate the geology and explore the natural minerals underground. With no direct access to the details of the subsurface, geophysical methods provide the needed data. In this study, extracted aerogravity data from a pool of data collected by Bureau Gravimétrique International (BGI) has been interpreted for subsurface information on sedimentary thickness; structural types and basement depths of Nasarawa state, Nigeria. This was achieved with the aid of Oasis Montaj software using the principles of data enhancement, separation of regional and residual effects, gridding, contouring, Euler depth estimation and forward/inverse modelling. The results indicate subsurface formations with high mass density in the central and northern parts of the state and low mass density formations in the northwestern and southwestern parts of the state. The structures trend mostly in east-west, northeast-southwest, north-south and northwest-southeast directions. Models reveal syncline and anticline structures with strike-slip faults at varying depths from 4141 m. The depth estimate results show sediment depths of 15 m and above which also corresponds to the basement depth variations in the state. The structures and sediment depths in some regions make them possible hydrocarbon sources/reservoirs, just as in the adjacent Bida Basin and hence it is recommended that geophysical prospecting for hydrocarbons should be carried out in these areas.