Insights into the Paleozoic tectonic evolution of the North Patagonian Massif: start up -hypothesis on a sequence of collisional events

LOPEZ DE LUCHI, MÓNICA; RAPALINI, AUGUSTO E.; MARTINEZ DOPICO, CARMEN; CERREDO, MARÍA ELENA; WEMMER, KLAUS

Neuquén

Congreso; 18 congreso Geológico Argentino; 2011

Asociación Geológica Argentina

The igneous and metamorphic evolution of the northern border of the North Patagonian Massif (NPM) during the Cambrian-Permian interval involves deformational events during Lower Paleozoic times, a Silurian extensional regime and compressive conditions in the Late Paleozoic (Ramos 2008, Rapalini et al., 2010). Gondwanide orogeny is represented in this area (Pankhurst et al., 2006).  An extension of the Famatinian and Pampean events towards the NPM was proposed by many authors (see Rapalini et al., 2010 and references therein). This constitutes a remarkable difference with the westernmost sector of the NPM where pre-Silurian magmatism has not been reported. Widespread Permian and Triassic magmatism is present in both sectors with variable controls by the regional deformational events (Von Gosen 2003, 2008). The geodynamic evolution and linking geological processes between the orogenic belts in the N and W NPM together with the Sierras Pampeanas, Río de la Plata craton and other blocks are still a matter of debate (Ramos 2008). In order to constrain the previous tectonic models for the origin of northern Patagonia (Pankhurst et al., 2006; Gregori et al., 2008, Rapalini et al., 2010, among others) and its relations with the South American crustal blocks, geology, geochemistry, isotopic dating and tectonic characterization of the NPM lead us to point out that: