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 andNorthern Patagonian Andes between 35°30?S to 48°S with the aim to spotlight earlycontractional phases on Andean orogenic building and to analyze their potential drivingprocesses. We examine early tectonic stages of the different fold and thrust belts that composethis Andean segment. Additionally, we study the magmatic arc behavior from a regionalperspective as an indicator of potential past subduction configurations during critical tectonicstages of orogenic construction. This revision proposes the existence of a continuous large-scaleflat subduction with a similar size to the present-largest flat-slab setting on earth. This particularprocess would have initiated diachronically in late Early Cretaceous times and achieved fulldevelopment in Late Cretaceous to earliest Paleocene, constructing a series of fold - thrust beltson the retro-arc zone from 35°30?S to 48°S. Furthermore, dynamic subsidence focused at theedges of the slab flattening before re-steepening beneath the foreland zone may explain suddenpaleogeographic changes in Maastrichtian-Danian times previously linked to continental tiltingand orogenic loading during a high sea level global stage.