Geological Records of the Fuegian Andes Deformed Complex Outlined in a Patagonian Orogenic Belt Regional Context

Abstract

The Fuegian Andes show simple and complex aspects in the Argentine portion. The simple aspects refer to the general stratigraphy and the complex ones result from tectonic characteristics. In a stratigraphic point of view an appraisal of the denomination and valorization of formations of the Jurassic and early Cretaceous periods, which has become entangled in recent years with new formational denominations, is performed here, so as to reach the simple scheme of the Fuegian-Patagonian continuity under the name of ?Fuegian Andes Deformed Complex?. As an essay, the formational nomenclature is simplified and the local concept of basement is re-evaluated. In the structural aspect, it is assumed that the formation of the orogenic Fuegian arc and the folding of the Mesozoic and early Tertiary layers are connected phenomena. Geologic forces from the West, the Northeast and the South, active in the formation of the tectonic arc, have taken place. The lithostatic column pressure was added once the layers were folded and thrusted upwards during the younger generation of the Fuegian Andes. Even the speculation of a great main fold overturned to the North, as an abstraction, is herein considered. Instead, the Magallanes-Fagnano fault is appreciated only as a product of the transcurrent Quaternary movements without associated eruptive processes that contribute to define plate borders.