Combined U–Pb and Lu–Hf isotope data on turbidites of the Paleozoic basement of NW Argentina and petrology of associated igneous rocks: Implications for the tectonic evolution of western Gondwana between 560 and 460 Ma.

HAUSER, N., MATTEINI, M., OMARINI, R.H., PIMENTEL, M.M.

GONDWANA RESEARCH

ELSEVIER SCIENCE BV

Lugar: New York; Año: 2010 vol. 19 p. 100 - 127

1342-937X

a b s t r a c t Article history: Received 14 October 2009 Received in revised form 22 April 2010 Accepted 22 April 2010 Available online 31 May 2010 Keywords: Western Gondwana Puncoviscana Formation Zircon geochronology Provenance U–Pb Lu–Hf New combined U–Pb and Lu–Hf isotope analyses on zircon from three turbidite deposits, and petrologic data for associated igneous rocks were used to study the evolution of the Paleozoic basement of Eastern Cordillera, NW Argentina. Maximum and minimum ages for turbidite deposits, considered to be part of the Puncoviscana Fm., are reported. In the Tastil area, turbidites were deposited in a fore-arc setting after 560 Ma and intruded at 534 Ma by the Tastil batholith. In the El Niño Muerto Hill area turbidites with maximum depositional age of 496±11 Ma were intruded by high-K dacites at 483±3 Ma. In the Río Blanco Valley, the turbiditic/hemipelagitic sediments, with maximum depositional age of 463±11 Ma were contemporaneous with E-MORB/OIB volcanism. The U–Pb and Lu–Hf data permitted to distinguish two major periods of magmatic activity during Late Mesoproterozoic–Early Neoproterozoic (0.95 to 1.2 Ga) and Late Neoproterozoic– Early Paleozoic (0.75 to 0.46 Ga) times, the former dominated by the input of juvenile crust and the latter by arc magmatism and recycling of Meso- to Paleoproterozoic crust. On the basis of new data we suggest that western margin of Gondwana was controlled by subduction processes and accretion of small terrains during Neoproterozoic–Early Paleozoic times. © 2010 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.