Abstract

ACOSTA NAGLE, Ana E  and  LOPEZ, Juan P. Geología y petrología del granito tres cerritos, extremo meridional de la sierra de Quilmes y su relación con el magmatismo devónico-carbonífero de las sierras Pampeanas. Rev. Asoc. Geol. Argent. [online]. 2014, vol.71, n.3, pp.434-443. ISSN 0004-4822.

Tres Cerritos granite is located in the extreme southern of Quilmes range, Catamarca province, in the Sierras Pampeanas Septentrionales. The metamorphic basement is composed of low to medium grade schists belonging to Tolombón Complex. It presents thermal metamorphism with development of porfiroblasts of cordierite and biotite. The Tres Cerritos granite crops out in two sectors, one more extensive, with an area of 6 Km² of surface, with its major axis of 4 Km of course submeridional, and other smaller, outcropping to west of study zone, of 1,9 km long by 250 m wide. Compositionally varies between sienogranite and monzogranite and presents three facies: porfhiric biotitic, porfiric moscovitic and equigranular moscovitic. Geochemically is a calc-alkaline granite, peraluminous, rich in potassium. According datings K / Ar would this granite top Carboniferous age. The petrological, geochemical and geochronological characteristics are similar to that of the devonian-carboniferous intrusives of the Sierras Pampeanas of Catamarca, La Rioja, Córdoba and San Luis, so the Granite Tres Cerritos could be part of a post-orogenic or intraplate large magmatic event of regional extension that affected the Sierras Pampeanas during the Devonian-Carboniferous.

Keywords : Sierras Pampeanas Septentrionales; Tolombón Complex.

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