Abstract

MAS, Graciela; RUIZ, Dora L  and  AVILA, Julio C. Study of the fluid inclusions of the quartz-veins from the Rodeo de los Funes granite, Sierra de la Ramada, Tucuman. Ser. correl. geol. [online]. 2012, vol.28, n.2, pp.85-92. ISSN 1666-9479.

The study area is located on the eastern flank of the Sierra de La Ramada, which, together with the sierras del Campo, Nogalito and Medina integrate the Sierras del Noreste de Tucumán, belonging to the Sistema de Santa Bárbara. The basement of the range is formed by phyllites and slates of the Medina Formation of precambrian - eocambrian age and the Rodeo de Los Funes granitic stock of possible palaeozoic age. The granitic rocks are sienogranites and monzogranites with hipogenic and supergenic alteration. Quartz veins up to 30 cm of thick are located in the granitic rocks and present abundant fluid inclusions (FI). Two types of FI have been determined: aqueous and aqueous with carbon dioxide. The first, two-phase, are the most abundant and constitute 80% of the observed FI approximately. These inclusions homogenize to a liquid phase at temperatures that vary between 248° and 265°C, with very scarce dispersion. The second FI are three phase aqueous inclusions. They represent 10 - 20% of the total of the analyzed inclusions approximately. They have dispersed homogenisation temperatures, but most concentrates between 240º and 320ºC. The characteristics of the observed FI are distinctive features of FI in mesothermal deposits of gold or veins of auriferous quartz in metamorphic rocks. It is suggested that the quartz veins were formed during a late magmatic hydrothermal stage genetically linked to the Rodeo de Los Funes granite.

Keywords : Sierra de La Ramada; Granites; Quartz veins; Fluid Inclusions.

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