Señal isotópica de Plomo del magmatismo gondwánico geneticamente vinculado a mineralizaciones de tipo pórfido de Cu, Mendoza

Abstract

Isotopic signature of lead of gondwanic magmatism genetically linked to mineralization of cu- porphyry type, Mendoza. The Choiyoi magmatism in the province of Mendoza is characterized by widespread volcanic and pyroclastic rocks of Gondwanic age. Two different sections can be differentiated in this volcanic sequence. The lower section consisting of andesites, andesitic breccias and dacitic to low-silica rhyolitic ignimbrites has geochemical characteristics that indicate a subduction zone setting. The upper section composed of rhyolitic ignimbrites and lava flows and dacitic to rhyolitic subvolcanics has geochemical characteristics transitional between subduction and continental intraplate settings. According to stratigraphic constraints, several Cu?(Mo) porphyry deposits are genetically linked to the lower section. New lead isotopes data of the mineralized lower section volcanics were analyzed in order to generate a robust plumbotectonic model for lead sources. The resulting linear array of the data is interpreted as a mixing process between a mantle-derived component and a lower crustal component. Thus, it is possible to conclude that the ores were emplaced during Gondwanic arc evolution.