Famatinian orogen on the South American plate: An introduction

ALASINO, PABLO H.; CASQUET, CÉSAR; LARROVERE, MARIANO; DAHLQUIST, JUAN A.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2021 vol. 105

0895-9811

This Special Issue gathers together a series of contributions related to the Famatinian orogen in the South American plate. This orogen was initially defined in northwestern Argentina by Aceñolaza and Toselli (1976) and is currently understood as a subduction-related accretionary orogen that formed during the Ordovician. It extends along the proto-Andean margin of Gondwana from Venezuela to Patagonia (Cawood et al., 2009). Magmatism took place mostly between c. 490 and 460 Ma along the entire proto-margin, suggesting global geodynamics as the prime controlling factor. Recently, Rapela et al. (2018) published a detailed isotope-geochemical review of Famatinian magmatism in the Argentinean Sierras Pampeanas where its areal extension is greatest. They concluded that recycling of mainly Mesoproterozoic subcontinental mantle and mafic lower crust on one hand, and crustal melting of Early Paleozoic supracrustal rocks on the other, account for most of the magma generation (Cordilleran-type and metamorphic related respectively). There are at least four main areas that expose the internal part of the Famatinian orogen along Western South American: Santander-Mérida and Marañón in Colombia, the Sierras Pampeanas, and the North Patagonian Massif in Argentina. These domains are flanked by outcrops of shallower sections of the orogen such as the Quetame in Colombia, the Vilcabamba in Perú, and the Puna Eruptive Belt in northern Argentina (Ramos 2018). The articles in this issue cover a variety of topics on the Southern Puna, Sierras Pampeanas, and the Patagonian massif (Fig. 1), ranging from field and structural analyses to geochemical studies and U-Pb zircon dating. They contribute to a better understanding of the still poorly explained Famatinian orogeny.