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

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 easternmost occurrence late Oligocene to early Miocene marine volcano-sedimentary Traiguén Formation; previous correlation with Paleozoic basement this sector North Patagonian Andes is thus refuted. A similar and provenance were obtained for a paraconglomerate bed La Junta Formation ca. 80 km north, which thought high-energy lateral facies variation Formation. plutonic Batholith intruded these metasedimentary rocks, generating contact aureole that reaches biotite grade overprints fabric probably formed during closure Basin. Similar young ages located immediately west Liquiñe-Ofqui Fault Zone 300 near Ayacara, suggest regional pattern earliest Neogene metamorphism rapid exhumation in segment Andes.