Chronology of deposition and unconformity development across the Cretaceous–Paleogene boundary, Magallanes-Austral Basin, Patagonian Andes

The role of slab geometry in the exhumation of cordilleran-type orogens and their forelands: Insights from northern Patagonia

“…The steepening of the slab is revealed by pervasive magmatism close to the Patagonian Precordillera (El Maitén Belt; Fig. 3; Iannelli et al, 2018;Paz et al, 2018;Rapela et al, 1988) and a modest extensional setting (Ventana Formation) reported in the whole Patagonia foreland (from Neuquén to Magallanes-Austral Basins; George et al, 2020;Orts et al, 2012). The Eocene-Miocene Somuncura Plateau and associated formations (e.g., El Buitre Formation) represented magmatism in the distal retroarc zone.…”

Erosional and Tectonic Evolution of a Retroarc Orogenic Wedge as Revealed by Sedimentary Provenance: Case of the Oligocene – Miocene Patagonian Andes

“…Few constraints on the timing and magnitude of Paleogene crustal shortening are available, but estimates based on cross-cutting relationships suggest ∼6.5 km of shortening occurred prior to 29 Ma . Early Eocene subduction of the Aluk-Farallon spreading ridge (Cande and Leslie, 1986;Breitsprecher and Thorkelson, 2009) resulted in a hiatus of arc volcanism that lasted from middle Eocene -latest Oligocene time (Ramos, 1989;Hervé et al, 2007), but produced regionally extensive plateau basalts (Ramos and Kay, 1992), and may have caused broad regional uplift that enhanced a basin-wide Paleogene unconformity within the foreland succession (Biddle et al, 1986;Fosdick et al, 2015;Schwartz et al, 2016;George et al, 2019).…”

“…Here we summarize the age, lithology, and tectonic association of potential sources [see Romans et al (2010), Fosdick et al (2015), Schwartz et al (2016), Daniels et al (2017), George et al (2019), Sickmann et al (2019)] for recent work of the detrital zircon geochronology from the Cretaceous basin fill).…”

Tectonic controls on the Maastrichtian-Danian transgression in the Magallanes-Austral foreland basin (Chile): Implications for the growth of the Southern Patagonian Andes

“…10c) that indicates the commencement of an HST. The uppermost sequence boundary is represented by the ~18 Myr unconformity between the Dorotea (Maastrichtian-Danian) and Rio Turbio (Eocene) formations in Journal Pre-proof the Ultima Esperanza Province (e.g., Malumián and Caramés, 1997;Gutiérrez et al, 2017;George et al, 2020). Farther south, in the Magallanes Province, the uppermost sequence boundary is represented by the ~3 Myr gap between the Chorrillo Chico and Agua Fresca formations (Rivera, 2017), manifested in outcrops as correlative conformity.…”