Tectonic evolution of the northern Austral-Magallanes basin in the Southern Patagonian Andes from provenance analysis. (November 2019)

• Record Type: Journal Article
• Authors: Barberón, Vanesa; Ronda, Gonzalo; Aramendía, Inés; Suárez, Rodrigo J.; Ramos, Miguel E.; Naipauer, Maximiliano; Sue, Christian; Ghiglione, Matías C.
• Is Part Of: Journal of South American earth sciences. Volume 95(2019)
• Publication Date: 2019-11
• Subjects: Southern Patagonian Andes -- Geodynamics -- Tectonostratigraphic units -- Sedimentary petrography -- Provenance analysis; Geology -- Latin America -- Periodicals; Earth sciences -- Latin America -- Periodicals; Geology -- Antarctica -- Periodicals; Earth sciences -- Antarctica -- Periodicals; Geology -- Caribbean Area -- Periodicals; Earth sciences -- Caribbean Area -- Periodicals; Géologie -- Amérique latine -- Périodiques; Sciences de la terre -- Amérique latine -- Périodiques; Géologie -- Antarctique -- Périodiques; Sciences de la terre -- Antarctique -- Périodiques; Géologie -- Caraïbes (Région) -- Périodiques; Sciences de la terre -- Caraïbes (Région) -- Périodiques; Earth sciences; Geology; Antarctica; Caribbean Area; Latin America; Periodicals; 550.5
• DOI: 10.1016/j.jsames.2019.102234
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: We studied the northern tip of the Austral-Magallanes basin in the Southern Patagonian Andes, between the Buenos Aires Lake and the Mayer River at 46°35′ SL and 48°35′ SL, respectively. Proposed objectives were: i) to differentiate Mesozoic-Cenozoic tectonostratigraphic units and, ii) to characterize the different deformational events that took place in the area linked to a variable regional geodynamic context. Sandstones provenance analysis was performed on the Aptian - Albian compressive retroarc deposits and Cenozoic foreland deposits. Studied samples were classified using tectonic discrimination diagrams which show: i) for Cretaceous rocks a dominant sediment source from a recycled orogen and, to a lesser extent, a dissected to transitional arc whereas ii) the Cenozoic rocks show a magmatic arc provenance. According to the performed analyses, the evolution of the northern sector of the Austral-Magallanes basin is proposed to include four tectonostratigraphic units related to: i) a Late Jurassic rift stage; ii) a Berriasian – Barremian thermal subsidence stage; iii) an Aptian – Albian compressive retroarc stage; and iv) a Miocene foreland stage s.s . The Late Cretaceous-Paleocene was a time for compression and uplift, represented in the study zone by a paraconcordance/angular unconformity with an extended hiatus between Albian/Cenomanian rocks and the Eocene. Highlights: An integrate study allow us to unravel the different deformational events that took place in the area linked to variable regional geodynamic contexts. We propose an evolution model for the northern sector of the Southern Patagonian Andes and define four tectonostratigraphic stages. A major change in the provenance pattern is detected between Cretaceous and Cenozoic rocks.