Choice of suitable regional and residual gravity maps, the case of the South-West Cameroon zone

The quantitative interpretation of gravity anomalies due to shallow structures needs separation between long wavelength anomalies（regional anomalies） and short wavelength anomalies（residual anomalies）.The regional-residual field separation can be carried out using the polynomial method.In this case, the so-called regional field of order n is treated as a polynomial of degree n.The present study shows that the degree n must vary between a smallest value n;and a maximum value n;.This article presents a method to process gravity data that allows determination of n;and n;for a given study area.We apply the method to gravity data of the South-West Cameroon zone.In this chosen study area, we find that regional anomaly maps of orders ranging from 1 to 9 and residual anomaly maps of orders ranging from 1 to 8 can be used for suitable interpretation.The analyses show that one may need residual anomaly maps of several orders to perform satisfactory quantitative interpretation of the different intrusive bodies found in a given area.