Abstract

MOROSINI, Augusto  and  ORTIZ SUAREZ, Ariel. Contact metamorphism of the La Escalerilla Granite, in the area La Carolina, San Luis. Rev. Asoc. Geol. Argent. [online]. 2011, vol.68, n.2, pp.275-289. ISSN 0004-4822.

Pressure and temperature conditions in samples from the northern portion of the La Escalerilla Granite were determined, together with the host rocks metamorphic that corresponds to the San Luis Formation, at different distances from the contact with intrusion. The results allow to determine the thermal gradients of the host rock for different times (t₀, t₁ y t₂), related to the La Escalerilla pluton emplacement. It is estimated that the metamorphic rocks located approximately at a distance greater to 1 kilometer from the contact with the La Escalerilla Granite, would not have received the heat of the same, because of the absorbed dissipation within the rocks located on the edge inmediate of the intrusion. This led to the development of an aureole of schists, characterized by higher grade metamorphic conditions, within the San Luis formation. The values determined of geothermal gradient are relatively low and indicate a regional medium-pressure metamorphism, which probably represent an a late stage in the development of a famatinian magmatic arc, or represent a marginal area thereof, widely developed to the north. It is also suggested that during the intruded of the La Escalerilla Granite, and probably during the cooling stage, significantly increased lithostatic pressure, due to fast stacking tectonic, did not allowed the rise of the geothermal gradient.

Keywords : Intrusion; Host rock; Thermal diffusion; Geothermobarometry; Garnet.

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