DOI: http://dx.doi.org/10.5027/andgeoV48n1-3282

Mid-Cenozoic SHRIMP U-Pb detrital zircon ages from metasedimentary rocks in the North Patagonian Andes of Aysén, Chile

Paulo Quezada, Francisco Hervé, Mauricio Calderón, Mark Fanning, Robert Pankhurst, Estanislao Godoy, Octavio Urbina, Rodrigo Suárez

Abstract


Previously undated low-grade metamorphic rocks from the Puerto Cisnes-Queulat area (44°30’ S) contain detrital zircons of mid-Oligocene age (ca. 28 Ma). Their outcrops represent the easternmost occurrence of the late Oligocene to early Miocene marine volcano-sedimentary Traiguén Formation; previous correlation with the Paleozoic metamorphic basement of this sector of the North Patagonian Andes is thus refuted. A similar age and provenance were obtained for a paraconglomerate bed of the La Junta Formation ca. 80 km to the north, which is thought to represent a high-energy lateral facies variation of the Traiguén Formation. Miocene plutonic rocks of the North Patagonian Batholith intruded these metasedimentary rocks, generating a contact metamorphic aureole that reaches biotite grade and overprints a previous metamorphic fabric probably formed during closure of the Traiguén Basin. Similar young ages for metamorphic rocks located immediately west of the Liquiñe-Ofqui Fault Zone 300 km north, near Ayacara, suggest a regional pattern of earliest Neogene metamorphism and rapid exhumation in this segment of the Patagonian Andes.

Keywords


Traiguén Formation; Liquiñe-Ofqui Fault Zone

How to cite this article Quezada, P.; Hervé, F.; Calderón, M.; Fanning, M.; Pankhurst, R.; Godoy, E.; Urbina, O.; Suárez, R. 2021, Mid-Cenozoic SHRIMP U-Pb detrital zircon ages from metasedimentary rocks in the North Patagonian Andes of Aysén, Chile. Andean Geology 48 (1): 54-74. [doi:http://dx.doi.org/10.5027/andgeoV48n1-3282]