CONTRIBUTION DES OUTILS DE SIG ET GEOPHYSIQUE DANS L’IDENTIFICATION DE L’AQUIFERE LIASIQUE. CAS DE LA REGION DE MRIRT, CAUSSE DU MOYEN ATLAS (MAROC)

Abstract

A geophysical prospecting by electrical method has been carried out in the region of Mrirt located in the heart of the causse of the Middle Atlas. The purpose of this geophysical study is to identify the geometry and the deep structure of the aquifer of the Lias and draw the schema of its hydrogeological function to determine the potential areas for the implantation of the Surveys of recognition. To achieve this objective, 39 Schlumberger Electrical Soundings have been carried out in the study area. The treatment of the geophysical measures has been achieved by using the software WinSEV 6 of GEOSOFT. The interpretation of the results has allowed revealing two aquifers assigned to the limestones and dolomitic lands of the middle and lower Lias, separated by a clay layer whose thickness varies between 5 and 10m. The roof of these two aquifers presents a wave structure, which goes back and thickens toward the south east of the study area in the direction of the outcrops of limestone and dolomitic lands of the Lias generally fractured where their thickness reaches a maximum value of 52 m. The compilation of the geophysical prospecting results with the geological and hydrogeological data and their integration into a GIS database has allowed creating a map of high productivity areas of the aquifers found in the study area. This card is a basic document to determine the sites with the greatest potential for the implantation of the drilling with high probability of success