Mineralogical and textural arguments for a metasomatic origin of the Ougnat pyrophyllite,Eastern Anti-Atlas,Morocco

The moroccan anti-atlas is rich by different types of mineralization such as precious metals,base metals and industrial minerals like talc,barite and pyrophyllite. at the extreme east of the anti-atlas,the precambrian exhumed anticline of ougnat contain several indices and deposits of pyrophyllite in the neoproterozoic volcanic rocks. two main deposits of the ougnat inlier were studied: the isk n'oudadène and the boumadine pyrophyllitic deposits. the observation and sampling concerned various evolution stages of the pyrophyllite from the intact rhyolitic protore to the most mature pyrophyllite. the mineralogical and textural analysis of the pyrophyllite and its immediate surrounding rocks shows a metasomatic origin of the pyrophyllite from the rhyolitic protolith. consequently,the mineralizing fluid induced a change in the overall chemical composition of the original rocks (rhyolite) and allowed the pyrophyllite crystallization in the two studied ore deposits.