Curtin University Homepage
  • Library
  • Help
    • Admin

    espace - Curtin’s institutional repository

    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item

    Identification and isotopic studies of early Cambrian magmatism (El Carancho Igneous Complex) at the boundary between Pampia terrane and the Río de la Plata craton, La Pampa province, Argentina

    Access Status
    Fulltext not available
    Authors
    Chernicoff, C.
    Zappettini, E.
    Santos, J.
    Godeas, M.
    Belousova, E.
    McNaughton, Neal
    Date
    2012
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Chernicoff, Carlos and Zappettini, Eduardo and Santos, Joao and Godeas, Marta and Belousova, E. and McNaughton, Neal. 2012. Identification and isotopic studies of early Cambrian magmatism (El Carancho Igneous Complex) at the boundary between Pampia terrane and the Río de la Plata craton, La Pampa province, Argentina. Gondwana Research. 21 (2-3): pp. 378-393.
    Source Title
    Gondwana Research
    DOI
    10.1016/j.gr.2011.04.007
    ISSN
    1342-937X
    URI
    http://hdl.handle.net/20.500.11937/29194
    Collection
    • Curtin Research Publications
    Abstract

    We have identified late Early Cambrian metaigneous rocks very poorly exposed at the Estancia El Carancho, in central La Pampa province, Argentina. They comprise calc–alkaline metadiorite and metagranite, and tholeiitic metapyroxenite and metagabbro. They are jointly referred to as the El Carancho Igneous Complex, and regarded to pertain to the Pampean magmatic arc and backarc, respectively. Titanite U–Pb SHRIMP dating of the metapyroxenite yielded 528 ± 5 Ma, and zircon U–Pb SHRIMP dating of the metadiorite yielded 520 ± 1.4 Ma. Hafnium isotope determinations on the dated zircons show 176Hf/177Hf ratios corresponding to positive εHf values from + 7.18 to + 9.37; Hf model ages of the Cambrian zircons yielded 884 Ma. It is interpreted that the metadiorites of the Complex crystallized from an Early Neoproterozoic (Tonian) juvenile source. We argue that the inferred occurrence of juvenile Tonian magmatic rocks in the (otherwise, mostly Paleo-Mesoproterozoic) substratum of the southern Pampia terrane could indicate a zone of thinned basement possibly associated with the early stage of Rodinia's breakup. In addition, the studied segment of the Pampean magmatic arc is contaminated by also juvenile, Late Mesoproterozoic crust, as evidenced by the presence of xenocrystic cores of 1140–1194 Ma – TDM-Hf 1720 Ma and εHf values of + 3.24 to + 4.85 – in the Cambrian zircons, hence suggesting that the studied segment of the Pampean magmatic arc was intruded into juvenile Late Mesoproterozoic magmatic arc rocks.The El Carancho Igneous Complex would be located at the tectonic boundary between the Pampia terrane and the Río de la Plata craton. This boundary stands out in the aeromagnetic data as a change in the structural orientation about a roughly N-S line located approximately at 65° W and representing the suture zone between the Pampia terrane and the Río de la Plata craton. Our geotectonic model envisages westward dipping subduction of oceanic crust beneath the Pampia terrane; the El Carancho Igneous Complex would, therefore, have been originated on the Pampia side (upper plate) of the suture. Slivers of the arc- and backarc-type rocks would have been tectonically imbricated in the suture zone during the Pampean orogeny.

    Related items

    Showing items related by title, author, creator and subject.

    • Processes of crust formation in the early Earth imaged through Hf isotopes from the East Pilbara Terrane
      Gardiner, Nicholas; Hickman, A.; Kirkland, C.; Lu, Y.; Johnson, T.; Zhao, J. (2017)
      The Pilbara Craton, Western Australia, is one of the best preserved Palaeo- to Mesoarchaean terrains on Earth. The East Pilbara Terrane is the archetypical granite-greenstone belt, the dome-like complexes of which were ...
    • U–Pb zircon geochronology of the eastern part of the Southern Ethiopian Shield
      Stern, R.; Ali, K.; Abdelsalam, M.; Wilde, Simon; Zhou, Q. (2012)
      The Southern Ethiopian Shield (SES) in the central East African Orogen lies at the junction of Neoproterozoic (880–550 Ma) largely greenschist-facies juvenile crust of the Arabian-Nubian Shield in the north and more ...
    • Beneath the Perth Basin : new U-Pb SHRIMP zircon ages from the Pinjarra Orogen, Western Australia, 2016
      Bodorkos, S.; Fitzsimons, Ian; Hall, L.; Sircombe, K.; Lewis, C. (2016)
      This Record contains new zircon U Pb geochronological data, obtained via Sensitive High-Resolution Ion Micro Probe (SHRIMP), from two samples of metamorphosed felsic igneous rocks from the Proterozoic Pinjarra Orogen ...
    Advanced search

    Browse

    Communities & CollectionsIssue DateAuthorTitleSubjectDocument TypeThis CollectionIssue DateAuthorTitleSubjectDocument Type

    My Account

    Admin

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Follow Curtin

    • 
    • 
    • 
    • 
    • 

    CRICOS Provider Code: 00301JABN: 99 143 842 569TEQSA: PRV12158

    Copyright | Disclaimer | Privacy statement | Accessibility

    Curtin would like to pay respect to the Aboriginal and Torres Strait Islander members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Whadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.