Interpretation of the locally high gravity anomalies using terrestrial gravity data in Bagodo, North Cameroon

Abstract

In this work, we interpreted gravity data to determine the structural characteristics responsible for high-gravity anomalies in Bagodo, North Cameroon. These anomalies had not previously been characterized through a local study. Thus, we undertook a regional–residual separation of the gravity anomalies by using the polynomial method. Geophysical signatures of near-surface small-extent geological structures were revealed. To conduct a quantitative interpretation of the gravity anomalies, one profile was drawn on a residual Bouguer anomaly map and then interpreted by spectral analysis, the ideal body solution, and 2.5-dimensional modeling. Our results showed that the intrusive body in the Bagodo area consists of two trapezoidal blocks. The first and second blocks have roofs approximately 7.5 and 14 km deep, respectively, whereas their bases are approximately 17 km deep. These values are in agreement with those obtained by the ideal body solution, which showed two cells with a density contrast of 0.3 g·cm⁻³ in comparison with the surrounding rocks. The density of this body was estimated to be approximately 3 g·cm⁻³. The topography of these rocks showed that they are basaltic rocks that would have cooled in fracture zones as an intrusion.