Paleozoic-early Mesozoic structural evolution of the West Gondwana accretionary margin in southern Patagonia, Argentina. (March 2021)

• Record Type: Journal Article
• Authors: Suárez, Rodrigo; Ghiglione, Matías C.; Sue, Christian; Quezada, Paulo; Roy, Sandrine; Rojo, Diego; Calderón, Mauricio
• Is Part Of: Journal of South American earth sciences. Volume 106(2021)
• Publication Date: 2021-03
• Subjects: Metasedimentary rocks -- Stages of structure development -- Accretionary orogenesis -- South Patagonian Andes -- Gondwanide orogeny -- Chonide orogeny -- Fold-and-thrust belts; 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.2020.103062
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: The Upper Devonian-Upper Triassic low-grade metasedimentary rocks exposed along the South Patagonian Andes preserve the structural record of deformation associated with pre-Andean orogenic phases that predated the inception of the Jurassic rift during Gondwana fragmentation. Through the structural analysis at different scales, we identified deformation structures mainly with cratonward vergence, produced at two stages of structure development for the Bahía de la Lancha (early Carboniferous) and Río Lácteo (Middle Devonian-early Carboniferous) formations, and in a single one, for the Nunatak Viedma Unit (Late Triassic). The structural features were integrated with available U–Pb detrital zircon ages and fission-track cooling ages from those units. It leads us to identify a westward younging of sedimentation (i.e. protolith deposition) and widening of the continental margin throughout Paleozoic-early Mesozoic times, tectonically stabilized during the late Carboniferous-middle Permian Gondwanide orogeny and the Late Triassic-Early Jurassic Chonide orogeny. The structural style holds features of fold-and-thrust belts, which is discussed in a context of accretionary tectonics inherent to the Terra Australis exterior orogen. Highlights: We perform a structural analysis of metasedimentary rocks along the South Patagonian Andes. The basement is constituted by very low-to low-grade, quartz-rich metasedimentary rocks. The ductile tectonic structures developed at pre-Mid Jurassic times. Fold-and-thrust belts could be a possible deformation setting. The Permian Gondwanide Orogeny and the Late Triassic-Early Jurassic Chonide Orogeny taken place in southern Patagonia.