Integrated Study of Gravity and Aeromagnetic Data over Malumfashi Area of Katsina State, Nigeria

Abstract

In this study, a geophysical study of the Malumfashi area of Katsina State was carried out using aeromagnetic and gravity data. The objective of the study was to investigate the subsurface geologic structures in the area. A 2½ -dimensional model of the subsurface structures showed that the thickness ranges between 3.5 km (for schist) and 879 km (for granite) while the width range between • 33 km (for schist) and 45 km (for granite). The gravity/magnetic measurements show large negative anomalies, ranging from -33 mGal to -65 mGal for gravity and 0.0 nT to 170 nT fir magnetic. A regional anomaly ranging from about -56 inGal in the southwestern part of survey area to about -44 nzGal in the northeastern part of the survey area is tentatively correlated with a gradual thinning of the crust from southwest to northeast while the magnetic regional anomaly showed an opposite of the gravity regional anomaly. High-gravity gradients of zip to 6mGal at some contact area between the schist and granite bodies are attributed to sharp contact; magmatic stopping is thought to be the nzost likely mode of emplacement of the granite bodies in the area. The bouguer anomalies observed over the schist have a maximum of only -34mGal these values are considered to be too low to allow for the existence of more mvic rock at depth and the schist in the area are therefore believed to have evolved in an ensialic environment.