Fluid-rock interaction during early tectonic processes in northern Patagonia, Argentina

ORIOLO, SEBASTIÁN; VAN DEN KERKHOF, ALFONS; SOSA, GRACIELA M.

Simposio; Simposio Científico RCAA; 2020

The construction of the Patagonian continental crust is intimately related to Paleozoic and Mesozoic large-scale tectonic processes that took place prior to the Andean Orogeny, which ultimately shaped the present-day geography of the region. These processes occurred at relatively deep crustal levels (i.e., more than 15 km) and resulting high pressure-temperature conditions (i.e., more than ca. 6 kbar and 400 °C), thus implying a complex interaction of rock deformation, fluid circulation and magma flow in the roots of a pre-Andean volcanic belt. The aim of this study is to evaluate these metasomatic processes recorded by rocks of the Late Paleozoic metamorphic basement of northwestern Patagonia, which represents the oldest roots of continental crust in the region. In particular, this work provides new insights into genesis and equilibrium conditions of ferropyrosmalite, a mineral of rare occurrence worldwide.