Thèse de doctorat en Géologie appliquée
Sous la direction de JEAN-LUIS TANE.
Soutenue en 1989
à Grenoble 1 .
Pas de résumé disponible.
The au-mo-cu mineralisations of the eastern part of the tichka massif and their geological setting. (western high atlas, maroc)
The tichka massif is one of the hercynian "granitic "plutons of morocco. It is located in the western high atlas, about 100 km south-west of marrakech. This study shows that the eastern part of this massif is characterised by five petrographic groups(granitoide to dioritic facies). The surrounding rocks are a paleozoic volcano-detritic formation these terranes have been structured and metamorphosed during the hercy- nian orogen. Three mineralysed occurences have been studied:molybdenite(ikissane area),copper(tizi n'israquen area) and especially gold(oukilal). The problem of ore genesis is studied: -molybdenum occurence has evolved in two stages;the molybdenum rich occurence is in quartz-feldspathic gangue and the poorer one in quartz only. -a vertical zonation of sulphide observed in copper occurence is related to the variation of physical and chemecal properties of ore-forming fluids. Different stages have been distinguished in the formation of the gold mineralization. The first can be characterized by the deposition of low auriferous arsenopyrite. The second is low auriferous pyrrhotite and pyrite. The third, with complexe paragenesis, has involved cu, pb,zn, te,bi andau rich fluids.