info:eu-repo/semantics/article
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 Patagonia
Fecha
2021-06Registro en:
Gonzalez, Pablo Diego; Giacosa, Raúl E.; Lagorio, Silvia; Ballivian Justiniano, Carlos Alberto; Sato, Ana Maria; et al.; 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 Patagonia; Pergamon-Elsevier Science Ltd; Journal of South American Earth Sciences; 108; 6-2021; 1-19
0895-9811
CONICET Digital
CONICET
Autor
Gonzalez, Pablo Diego
Giacosa, Raúl E.
Lagorio, Silvia
Ballivian Justiniano, Carlos Alberto
Sato, Ana Maria
Cábana, María Cecilia
Stipp Basei, Miguel Angelo
Busteros, Alicia
Silva Nieto, Diego Gonzalo
Resumen
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 Lipetrén 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.