From sedimentary precursor to anatectic products: Petrographic and Geochemical constraints, Pringles Metamorphic Complex, Sierra de San Luis, Argentina

RUEDA, M. F; DELPINO S. H.; URRAZA I. A.; GRASEMANN, B.

San Juan

Congreso; XI Congreso de Mineralogía y Metalogenia; 2013

Universidad de San Juan

Lower Paleozoic mafic‐ultramafic bodies (MUB) emplaced during the first stages of the Famatinian Orogenic Cycle(FOC), constitute lenticular outcrops distributed with a NNE trend for more than 100 km along the central sector ofthe Pringles Metamorphic Complex (PMC). The thermal input related to the intrusion of these MUB, is considered tobe the cause of the high‐grade metamorphism and the associated widespread partial melting of the adjacentmetapelitic country‐rocks. At both sides (W and E) of the MUB central strip, a geothermal gradient from granulite togreenschist facies is evident. In this contribution, results of careful petrographic and geochemical analysis of selectedsamples are presented. Detailed sampling along profiles normal to the general trend ‐and towards both sides‐ of theMUB bodies, were carried out in order to characterize the sedimentary precursor to metamorphic rocks and track itstransformation with increasing temperature as distance from the MUB decrease. This methodology allowed us tofollow the subsolidus transformation of metamorphic rocks, identify the most probable protolith previous to thebeginning of partial melting, and establish the spatial, petrographic and geochemical interrelationship between thecomplex set of anatectic products.