Réinterprétation par approche multi-échelle et de déconvolution d’euler des données gravimétriques de mamfé

Abstract

The gravities data are most often analyzed and interpreted in geophysics to study of structures basement of an area, or in the prospection to the exploitation mining and gas. For example, They can help to identification of the zones of contacts and networks of faults, that is of an interest for mining or for the geological investigations. By consequent, of the studies geophysics were led in there area of South-west Cameroon, and particularly in the zone of Mamfe, with an aim of making an interpretation of the data gravimetric obtained by Fairhead and al., (1991) and Legeley-Padovaniand al., (1996). These gravities data are resulting from the variation of measurements of pesentor from different points of area. this variation show the gravimetric map presents (positive/negative) anomalies separated by strong gradient zones. We used various filtering techniques to delineate the major geological structures such as faults and basins : vertical and horizontal derivatives, upward continuation, and Euler deconvolution. Interpretation makes it possible to associate the negative anomalies with deep basins, domes or granites. The positive anomalies are associated to basement uplift or outcrop. The statistical analysis of the anomalies allows identifying the major structural trends of the region. The vertical gradient allowed us to amplify short waves and to reduce interferences between anomalies.Superimposition of the interpreted major faults to the geological map, indicate that NS, WNW-ESE, NW-SE, NE-SW and NNW-SSE system are well developed and represented by several faults with regional importance, with a clear predominance of the last trend. Euler deconvolution was used to determine source depths and their location. The values of sources depth can reach 3.2 km for the superficial contacts and 5 km for deep contacts. Established results of this study provide new elements which allow improvement of knowledge on the structure of the sector of study.