Cretaceous Orogeny and Marine Transgression in the Southern Central and Northern Patagonian Andes: Aftermath of a Large-Scale Flat-Subduction Event?

Abstract

This review synthesizes the tectonomagmatic evolution of the southern Central and Northern Patagonian Andes between 35°30′S and 48° S with the aim to spotlight early contractional phases on Andean orogenic building and to analyze their potential driving processes. We examine early tectonic stages of the different fold and thrust belts that compose this Andean segment. Additionally, we study the magmatic arc behavior from a regional perspective as an indicator of potential past subduction configurations during critical tectonic stages of orogenic construction. This revision proposes the existence of a continuous large-scale flat-subduction with a similar size to the present-largest flat-slab setting on earth. This particular process would have initiated diachronically in late Early Cretaceous times and achieved full development in Late Cretaceous to earliest Paleocene, constructing a series of fold-thrust belts on the retroarc zone from 35°30′S to 48° S. Furthermore, dynamic subsidence focused at the edges of the slab flattening before re-steepening beneath the foreland zone may explain sudden paleogeographic changes in Maastrichtian–Danian times previously linked to continental tilting and orogenic loading during a high sea level global stage.