Recherche de gisements de perlites dans le Nord- Est de l’Algérie. Exemple du volcan rhyolitique du Kef Chéraïa (Collo)

Abstract

Perlite is a hydrated acid volcanic glass, having physico-chemical properties acquired after its heating which are diverse applications in the industrial sector. In Algeria, only one perlite deposit is known at Hammam Boughrara (Maghnia). The purpose of our study is to locate other perlite indices in Algeria. The geological, petrographic and geochemical characteristics of the perlites mentioned in the literature have guided us in choosing the rhyolitic dome of Kef Chéraïa (Collo) as the object of our study. The geological study indicates that the formations of the volcanic dome of Kef Chéraïa consist of rhyolites with different aspects: massive, fluidal and pyroclastic. The splintering fracture of the rock indicates a rather abundant glassy proportion, which favors the search for perlite. The petrographic examination of the samples shows a typical texture of perlite, called perlitic texture. The geochemical comparison between Kef Chéraïa formations, Hammam Boughrara perlite and some perlites described in the literature has shown that the formations of the Kef Chéraïa rhyolitic dome have characteristics quite similar to those of perlites. The thermal tests carried out in the laboratory showed that the samples reacted in the same way as perlite, that is to say, a volume expansion after heating. Our study indicates that the formations of the Kef Chéraïa rhyolitic dome constitute the second perlite indice in Algeria after that of Hammam Boughrara Maghnia).