U-Pb geochronology of the meta-volcanic rocks from Sierra de Calcatapul: implications for the Middle Triassic syn-rift volcanism and tectonic evolution of Northern extra-Andean Pat...

• Autores: González, Pablo Diego; Giacosa, Raúl Eduardo; Lagorio, Silvia; Ballivian Justiniano, Carlos; Sato, Ana María; Cábana, María Cecilia; Basei, Miguel Angel Stip; Busteros, Alicia; Silva Nieto, Diego
• Año de publicación: 2021
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Ambientales y de la Tierra; Zircon ages; Half-graben; Extensional tectonics; Post-Choiyoi magmatism; Patagonia; Ciencias Ambientales y de la Tierra
• Institución: Universidad Nacional de Río Negro

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: Giacosa, Raúl Eduardo. 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: Lagorio, Silvia. Servicio Geológico Minero Argentino (SEGEMAR), Instituto de Geología y Recursos Minerales, Av. General Paz 5445, B 1650 WAB, Buenos Aires, Argentina.
Fil: Ballivian Justiniano, Carlos. CONICET, Instituto de Recursos Minerales (UNLP-CICBA), Calle 64 Esquina 120, 1er Piso, (1900) La Plata, Buenos Aires, Argentina.
Fil: Sato, Ana María. Centro de Investigaciones Geológicas (UNLP-CONICET), Diagonal 113 Nro. 275, B1904DPK, La Plata, Buenos Aires, Argentina.
Fil: Cábana, María Cecilia. Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología. Río Negro, Argentina.
Fil: Basei, Miguel Angel Stip. Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Centro de Pesquisas Geocronológicas (CPGeo), Instituto de Geociencias, Universidade de Sao Paulo, Cidade Universitaria, Rua Do Lago 562, CEP 05508-080, Sao Paulo, Brazil.
Fil: Busteros, Alicica. Servicio Geológico Minero Argentino (SEGEMAR), Instituto de Geología y Recursos Minerales, Av. General Paz 5445, B 1650 WAB, Buenos Aires, Argentina.
Fil: Silva Nieto, Diego. Servicio Geológico Minero Argentino (SEGEMAR), Instituto de Geología y Recursos Minerales, Av. General Paz 5445, B 1650 WAB, Buenos Aires, Argentina.
This contribution deals first new ICP-MS U–Pb zircon ages that indicate Middle- and Late Triassic magmatic episode and tectonometamorphic events, respectively, for the central Patagonia region, instead of a Paleozoic history as previously estimated. The Calcatapul Formation consists of a (meta-) volcano-sedimentary syn-rift sequence deposited unconformably, shortly after the extensional Gondwanide orogenic collapse, over a basement composed of Permian granites. Two 206Pb/238U ages yielded 245.1 ±2.8 and 244.8 ±4.1 Ma to magmatic crystallization of ignimbrites, along with another weighted mean of 226.7 ±4.4 Ma interpreted as the age of the tectonometamorphic event D1-M1 affecting the Calcatapul sequence. U–Pb ages open new insights into the tectonomagmatic evolution of the area because the syn-rift wedge deposited in the Uribe and Yancamil half- grabens under the extensional tectonic regime was then inverted along the basin-bounding faults like the Yancamil fault. Inversion tectonics involved reverse fault-related uplift against a buttress of the rigid granitic block, and under dynamic greenschist-to-amphibolite facies metamorphic conditions, before the Late-Triassic granitic magmatism of the Lipetr´en Suite took place. The pre-rift granitic basement represents the southern extension of the main magmatic phase of Choiyoi Province in Patagonia, whereas the Middle Triassic recorded the extensional, post-Choiyoi magmatism. The local, compressive D1 event punctuated an overall widespread lithospheric extension that leads to Gondwana breakup since the earliest Jurassic times.
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