Geología de la zona del Cerro Fitz Roy, Provincia de Santa Cruz

Abstract

Geology of the Cerro Fitz Roy area, province of Santa Cruz. The surveyed Cerro Fitz Roy area (73º15’-72º50’ W Long., 49º25’-49º17’ S Lat., southernmost Andes) is located between the Electrico River to the north and the Tunel River to the south, and limited to the east by the Las Vueltas River and to the west by the Campo Sur del Hielo Patagónico. The stratigraphy record starts with Devonian-Carboniferous leptometamorphic sedimentary rocks of the Bahía La Lancha Formation, which are unconformably overlayed by conglomerates of the Arroyo de la Mina Formation, a basal unit of the Jurassic volcano-sedimentary El Quemado Complex. A low angle unconformity separates this Complex from the Early Cretaceous black pelites of the Río Mayer Formation. Miocene Fitz Roy Granite intrudes the whole column. Overthrusting of the Jurassic volcanics that acted like a rigid body over the Cretaceous pelites that deformed plastically with an intense folding, indicates a strong tectonic overprint. The later intrusion of the granites generates a contact aureole that attains amphibolite grade. A younger extensional tectonic is responsible for the gravitational faulting. An ill-defined sinistral E-W strike-slip faulting associated to the Mackena and Viedma megastructures is recognized.