USE AND CONTRIBUTION OF THE GEOCHEMISTRY OF GOSSAN TO THE PROSPECTING FOR MASSIVE SULPHIDE DEPOSIT : CASE OF THE KOUDIAT AICHA DEPOSIT IN CENTRAL JEBILET - MOROCCO

The central Jebilets located to the south west of the Moroccan meseta represent a metalliferous province containing numerous deposits and massive sulphide index, of which the Koudiat Aicha deposit is one of them. This last enclosed in the series of Saghlef attributed to the upper visean. It is predominantly pyrrhotite, contains minerals of the base metals such as sphalerite, galena, chalcopyrite, arsenopyrite and some traces of stannite. The orebody is enclosed in argillites interspersed with gabbroic magmatic sills at the footwall and hanging wall of the mineralization. It is materialized on the surface by the development of a gossan with iron oxides and hydroxides (hematite, magnetite, goethite, limonite, malachite ...), and shows an NS orientation according to the direction of the orebody. This study intersted with the search for distinctive criteria between gossan assigned to mineralization of economic interest in relation to massive sulphide and those developed on iron deposits or other non-economic iron indices near the sector of Koudiat Aicha. This approach has made it possible to identify criteria that make it possible to distinguish the gossan of products directly from polymetallic base metal mineralization. The elements analyzed, such as Ag, As, Bi and Sn, in addition to the elements searched, made it possible to identify the gossan directly assigned to the Koudiat Aicha deposit and to pinpoint its location. The results obtained are in good agreement with the data of the magnetic and gravimetric studies realized in carried out around the area of Koudiat Aicha deposit. These results can be applied to all the ferruginous indices near the sector of Koudiat Aicha in the Central Jebilet, see its extrapolation towards all the Hercynian lands.