South-western Gondwana Proterozoic to Paleozoic evolution: Suture zones of the Cuyania terrane

VUJOVICH, G.I.

Buzios

Congreso; Gondwana 14; 2011

Universidad de Rio de Janeiro

In central Argentina the Cuyania terrane (Ramos 2004) is composed of the Pie de Palo and Precordillera terranes in contact via a Mesoproterozoic ophiolite interpreted as a Grenvillian suture between the terranes (Vujovich et al. 2004, Chernicoff et al. 2009). The Cuyania terrane is in tectonic contact with the Pampia Block at its eastern boundary. Structural and metamorphic studies of the crystalline basement and cover metasequences in Sierra de Pie de Palo (van Staal et al. 2011, Mulcahy et al. 2011) support a west-vergent A-type collisional zone between the Cuyania terrane and the Pampia Block. Similar structural patterns are described by Thomas and Astini (2007) in the Eastern Precordillera. Most of the crystalline basement of this terrane is unconformably covered by Paleozoic to Tertiary sediments. Seismic analysis of the basement between Precordillera and Western Sierras Pampeanas reveals imbricate structures that are interpreted as a west-vergent thrust and fold belt (Cominguez and Ramos 1991, Zapata 1998). The summary of the overall structural patterns and metamorphic evolution of the central part of the Cuyania terrane suggest a west-vergent shortening of the crystalline basement and the cover sequences consistent with the development of a continent-continent collisional zone during the Upper Ordovician.