The geodynamic history of the Famatinian arc, Argentina: A record of exposed geology over the type section (latitudes 27°- 33° south)

OTAMENDI, JUAN E.; CRISTOFOLINI, EBER A.; MOROSINI, AUGUSTO; ARMAS, PAULA; TIBALDI, ALINA M.; CAMILLETTI, GIULIANO C.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2020 vol. 100

0895-9811

The Famatinian arc, overcentral-western Argentina,is one of the few examples of exposed crustal arc cross-section in the world.This Paleozoic magmatic arc and orogenic system on the Earth?s surface offersunique insights into the nature of whole-arc processes, continental crustgeneration, and preservation. A detailed account of birth, growth, and closureis integrated throughout the region, and the entire geodynamic history of theFamatinian arc is presented. The Famatinian magmatic arc grew during asingle-cycle episode that spanned a few tens of million years. Upon waning ofthe Cambrian Pampean orogen, an Upper Cambrian ? Lower Ordovician marginal andopen sea basin developed mostly on the recently stabilized Cambrian crystallinecrust and was flooded by a turbidite wedge. Typical subduction zone magmatismresumed outboard of the Pampean orogen in the Lower Ordovician. After about 20My of magmatism driven by subduction zone dynamics at plate scale, magmatismwaned and stopped with the entry of a Laurentia-rifted continental microplatein the subduction zone. A full phase of a mountain-building process accompaniedthe continent-arc collision. The orogenic collapse occurred during theDevonian, ending the Famatinian system after nearly 150 My of magmatic arc,plate convergence, and continent-arc collision development on the proto-AndeanGondwana margin.