A magnetic and gravity investigation of the Liberia Basin, West Africa

Gravity and magnetic analysis provide an opportunity to deduce and understand to a large extent the stratigraphy, structure and shape of the substructure. Euler deconvolution is a useful tool for providing estimates of the localities and depth of magnetic and gravity sources. Wavelet analysis is an interesting tool for filtering and improving geophysical data. The application of these two methods to gravity and magnetic data of the Liberia Basin enable the definition of the geometry and depth of the subsurface geologic structures. The study reveals the basin is sub-divided and the depth to basement of the basin structure ranges from about 5 km at its North West end to 10 km at its broadest section eastward. Magnetic data analysis indicates shallow intrusives ranging from a depth of 0.09 km to 0.42 km with an average depth of 0.25 km along the margin. Other intrusives can be found at average depths of 0.6 km and 1.7 km respectively within the confines of the basin. An analysis of the gravity data indicated deep faults intersecting the transform zone.

Research highlights
► We use potential field data to estimate the depth to basement of the Liberia basin to be 5 km in its shallower parts and above 10 km at its broadest portion.
► Average depths of intrusives along the Liberia margin are estimated to range from a few meters to about 1.7 km.
► The Liberia basin can be considered to be subdivided into three basins separated by uplifts and complex fault systems.
► The broadest and deepest section is located at its eastern end when considering its structure at the continental slope.