Abstract

Abstract A combination of petrography, geochemistry, Sm–Nd, Pb–Pb and U–Pb detrital zircon dating provide constraints to the provenance of Middle Ordovician to Early Silurian clastic sequences of the Precordillera s.s. as a part of the Cuyania terrane in western-central Argentina. The uniformity shown by the provenance proxies indicate that there were no important changes in the provenance within these units. A dominant upper crustal component is evident as well as a subordinate mafic input. Nd isotopes indicate e Nd of −5.4, ƒ Sm/Nd −0.34 and T DM 1.57 Ga in average for all the units studied. Pb-isotope ratios display average values for 206 Pb/ 204 Pb, 207 Pb/ 204 Pb, and 208 Pb/ 204 Pb of 19.37, 15.86 and 39.43 respectively. Detrital zircon dating further constraints the input as being dominantly of Mesoproterozoic age (51–83%), but with contributions from Neoproterozoic–Lower Cambrian (9–31%), Middle Cambrian to Ordovician grains (recorded up to 7%), and Palaeoproterozoic (2–7%) sources. The combination of the different provenance approaches applied indicates that the Mesoproterozoic Cuyania terrane basement, and partially the Pampia terrane were the main sources. The new information provided for the Ordovician to Silurian clastic sequences permitted enhanced the known geochemical and isotopic dataset to constrain the tectonic evolution of the Cuyania terrane. The interpretation of the obtained data supports that the terrane accretion to the proto-Andean margin of Gondwana probably occurred during Middle to early Upper Ordovician.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.