Zeolites in acid vitreous rocks, southern Mendoza, Argentina

MARFIL S; MAIZA P; CRAVERO FERNANDA; L. LESCANO; F. LOCATI; MADSEN L.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2020 vol. 98 p. 1 - 45

0895-9811

A mordenite-rich deposit located in the south of the province of Mendoza (Argentina) wasstudied. The host rock in this area has not been previously described and corresponds to rhyolitic lavas of high-K calc-alkaline series. Petrographic, mineralogical and geochemical analyses of fresh and altered rocks are shown, and a proposal for the alteration process andthe stratigraphic position of the protolith is presented. The main mordenite-rich sectors developed in zones of autobreccias of high permeability, with minor clinoptilolite, smectites, secondary K-feldspars, and colloform silica. The proportion of relict glass vs. alteration minerals is variable and mainly depends on the texture (permeability) of the host rock. The studied rhyolites overlie the Upper Cretaceous sediments of the Neuquén and are covered by Tertiary basalts of the Molle Eruptive Cycle and Quaternary 24 sediments.Geochemically, they present similarities with rhyolitic rocks of Cordón del BurreroVolcanic Complex of Lower to Middle Miocene age.