Medium-high grade igneous-metamorphic basement unit in Central Patagonia, Argentina at its relation with the Terra Australis Orogen.

• Autores: Renda, Emiliano Manuel; González, Pablo Diego; Oriolo, Sebastián; Marcos, Paulo; Suárez, Rodrigo Javier
• Año de publicación: 2021
• Idioma: inglés
• Tipo de recurso: documento de conferencia
• Materia: Ciencias de la Tierra (General); Patagonia; Paleozoic; Igneous-metamorphic Basement; Metamorphism; Th–U–Pb Monazite; Ciencias de la Tierra (General)
• Institución: Universidad Nacional de Río Negro

Fil: Renda, Emiliano Manuel. Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología, Río Negro, Argentina. Río Negro, Argentina.
Fil: González, Pablo Diego. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina. Servicio Geológico Minero Argentino, Centro General Roca, Río Negro, SEGEMAR Regional Sur, Independencia 1495, Parque Industrial 1, Gral. Roca, (Río Negro), C. P. 8332, Casilla, Correo, Argentina.
Fil: Oriolo, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Universidad de Buenos Aires (UBA), Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires (IGEBA), CABA, Argentina.
Fil: Marcos, Paulo. Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología, Río Negro, Argentina. Río Negro, Argentina.
Fil: Suárez, Rodrigo Javier. Instituto de Estudios Andinos IDEAN (Universidad de Buenos Aires - CONICET), CABA, Argentina.
Renda, E., González, P.D., Oriolo, S., Marcos P., Suarez, R. 2021. Medium-high grade igneous-metamorphic basement unit in Central Patagonia, Argentina at its relation with the Terra Australis Orogen. Metamorphic Studies Group Research in Progress Meeting. The Mineralogical Society. Abstract Volume, p. 59. Virtual meeting 29-31 March 2021.
During the Late Neoproterozoic to middle Paleozoic time span, the southwestern margin of Gondwana has been exposed to protracted subduction [1,2,3,4], which has been considered as part of the widespread Gondwanan Terra Australis Orogen (TAO) [2]. In southwestern Gondwana, the TAO comprises a series of accretionary systems which are associated with crustal extension and back-arc basin development [2]. This tectonic setting alternates with sporadic contractional episodes related with increased plate coupling, accretion of oceanic material, or collision of allochthonous/para-autochthonous crustal blocks [1,2,3,4]. In this context, the Patagonian continental block has been considered as a peri-Gondwanan block, accreted either in Early or Late Paleozoic times [5,6,7]. In recent years, compelling evidence points out to an Early Paleozoic accretion of the northern part of Patagonia [7,8], within the tectonic framework of TAO. However, the Middle to Late Paleozoic tectonic history of central and southern Patagonia, the tectonic setting of Gondwanide orogeny, and therefore the proper assessment of the culmination of TAO in this area are yet a matter of debate [9,10]. In the past decades, a Middle-Late Paleozoic igneous-metamorphic belt was described in Central Patagonia[5,6], a key area for integrating central and southern Patagonia, and its precise location, crossing this area with a ~NNW-SSE structural trend, was defined by geophysical means [9]. This belt comprises a series of fault-controlled basement blocks, formed by medium-high grade metamorphic complexes and coeval magmatism [5,10,11]. Recently, the Lagunita Salada Igneous-Metamorphic Complex was defined in this area. The regional metamorphism of this complex attained upper amphibolite-lower granulite facies, constrained by Th-U-Pb EPMA monazite ages between ca- 379-320 My [12]. Based on dated syn- and post-tectonic granitoid intrusions in the area an isotopic system re-opening could not be discarded for the ~320 Ma isochron monazite model age. Moreover, a magmatic lull of ~20 My coeval or slightly posterior to the medium-high grade metamorphism [12], could present important implications for the tectonic regime for the the TAO in this area, previous to the syn- to postectonic Upper Carboniferous – Early Permian magmatism and the initiation of Gondwanide orogeny in southwestern Gondwana. References: [1] Dalziel I W D (1997) GSA Bulletin 109:16-42 [2] Cawood P A (2005) Earth-Science Review 69:249-279 [3] Cawood P A & Buchan C (2007) Earth-Science Reviews 82:217-256 [4] Oriolo S et al. (2021) Geoscience Frontiers 12:109-130 [5] Pankhurst R et al. (2006) Earth-Science Reviews 76:235-257 [6] Ramos et al. (2020) Ameghiniana 57:464-479 [7] González P D et al. (2018) Gondwana Research 63:186-225 [8] González P D et al. (2020) International Journal of Earth Sciences in press [9] Calderón, M. et al. (2016) Geodynamic evolution of Southernmost Andes pp- 7-36 [10] Suárez et al. (2019) Journal of South American Earth Sciences 102256 [11] Renda E M et al. (2019) Tectonophysics 772:228232 [12] Marcos P et al. (2020) Lithos 376-377:105801 [13] Renda E M et al. (2021) Journal of South American Earth Sciences 106:103045