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

    Mafic dykes intrusive into Pre-Cambrian rocks of the São Luís cratonic fragment and Gurupi Belt (Parnaíba Province), north-northeastern Brazil: Geochemistry, Sr-Nd-Pb-O isotopes, 40Ar/39Ar geochronology, and relationships to CAMP magmatism

    Access Status
    Fulltext not available
    Authors
    Klein, E.L.
    Angélica, R.S.
    Jourdan, Fred
    Babinski, M.
    Harris, C.
    Date
    2013
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Klein, Evandro L. and Angélica, Rômulo S. and Harris, Chris and Jourdan, Fred and Babinski, Marly. 2013. Mafic dykes intrusive into Pre-Cambrian rocks of the São Luís cratonic fragment and Gurupi Belt (Parnaíba Province), north-northeastern Brazil: Geochemistry, Sr-Nd-Pb-O isotopes, 40Ar/39Ar geochronology, and relationships to CAMP magmatism. Lithos. 172-173: pp. 222-242.
    Source Title
    Lithos
    DOI
    10.1016/j.lithos.2013.04.015
    ISSN
    0024-4937
    URI
    http://hdl.handle.net/20.500.11937/16934
    Collection
    • Curtin Research Publications
    Abstract

    Dykes of diabase and microgabbro intruded into Pre-Cambrian rocks of the São Luís cratonic fragment and Gurupi Belt, which are tectonic and erosive windows of the Parnaíba Basin in north–northeastern Brazil. Ar–Ar ages were determined, and major, trace element, and Nd–Sr–Pb–O isotopic compositions of these dykes were measured to provide insights into their age, and into the nature of their mantle sources and petrogenetic processes. The data have also been used to compare the chemical and isotopic signatures of the dykes with those of the Central Atlantic Magmatic Province (CAMP). Four chemical groups of mafic dykes have been identified. These comprise two subtypes of high-Ti rocks (i) HTi-1 (TiO2 < 2.3 wt.%; SiO2 > 47 wt.%), (ii) HTi-2 (TiO2 > 2.7 wt.%; SiO2 > 47 wt.%), in addition to (iii) evolved high-Ti (TiO2 > 4 wt.%; SiO2 of ~ 46 wt.%) and (iv) low-Si (TiO2 > 2.2 wt.%; SiO2 < 45 wt.%) rocks. 40Ar/39Ar geochronology of plagioclase returned ages of 201 ± 4 Ma and 193 ± 10 Ma for the HTi-2 subtype, and of 201 ± 2 Ma and 207 ± 9 Ma for the evolved high-Ti group. The HTi-1 and low-Si groups presented highly disturbed age spectra, and did not allow the definition of their emplacement ages. The Argon data indicate an age > 200 Ma for the low-Si group and are dubious with respect to the age of theHTi-1 subtype, if coeval with (i.e., ~ 200 Ma), or older than, the HTi-2 and evolved high-Ti types.All groups present δ18O values of pyroxene that are compatible with uncontaminated mantle-derived magmas. The HTi-1 subtype (average 143Nd/144Nd200 = 0.512644; 87Sr/86Sr200 = 0.7035; 206Pb/204Pb of 17.86) shows the less enriched and less fractionated (more primitive) trace element distribution of all groups. The HTi-2 subtype shows enriched trace element pattern and depleted Nd–Sr signature (143Nd/144Nd200 = 0.512610; 87Sr/86Sr200 = 0.7037) and average 206Pb/204Pb ratios of 17.23. The evolved high-Ti chemical group shows average ratios of 143Nd/144Nd200 = 0.512558, 87Sr/86Sr200 = 0.7035, and 206Pb/204Pb of 16.88, and the more enriched trace-elements signature among the four groups. The chemical and isotopic compositions and trends of the HTi-1/HTi-2/EHTi types are consistent with their derivation from an asthenosphere-derived parental magma further modified by differentiation and minimal crust contamination (higher in the HTi-2 and EHTi types), and by the derivation of one type from another via fractional crystallization. These high- and evolved high-TiO2 types show ages and some chemical and isotopic features that are consistent with those of the CAMP magmatism. Some differences found are ascribed to petrogenetic processes, such as magma differentiation.A combination of warming of the mantle and edge-driven convection beneath the Pangea supercontinent after the closure of the Neoproterozoic (Brasiliano/Pan-African) orogenies in the Ediacaran–Cambrian boundary might have triggered the magmatic event. The low-Si type shows paired Ta–Nb and Zr–Hf depletions, and depleted Sr–Nd (average 143Nd/144Nd200 = 0.512687; 87Sr/86Sr200 = 0.703) and enriched Pb (206Pb/204Pb of 18.66) isotopic compositions that may be interpreted to result either from interaction of a subcontinental lithospheric mantle with products of an earlier subduction or by contamination of the mantle-derived magma during ascent and emplacement in the continental crust. It is hypothesized that these dykes were emplaced in the Ediacaran–Cambrian boundary, after the Neoproterozoic orogeny that built up the Gurupi Belt and in the early extensional stages that preceded the formation of the Parnaíba Basin.

    Related items

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

    • Depleted Mantle-sourced CFB Magmatism in the Jurassic Africa–Antarctica Rift: Petrology and 40Ar/39Ar and U/Pb Chronology of the Vestfjella Dyke Swarm, Dronning Maud Land, Antarctica
      Luttinen, A.; Heinonen, J.; Kurhila, M.; Jourdan, Fred; Mänttäri, I.; Vuori, S.; Huhma, H. (2015)
      The Jurassic Vestfjella dyke swarm at the volcanic rifted margin of western Dronning Maud Land represents magmatism related to the incipient Africa–Antarctica rift zone; that is, rift-assemblage magmatism of the Karoo ...
    • Sr, Nd, Pb and Os isotope systematics of CAMP tholeiites from Eastern North America (ENA): Evidence of a subduction-enriched mantle source
      Merle, Renaud; Marzoli, A.; Reisberg, L.; Bertrand, H.; Nemchin, Alexander; Chiaradia, M.; Callegaro, S.; Jourdan, Fred; Bellieni, G.; Kontak, D.; Puffer, J.; Gregory McHone, J. (2014)
      The Central Atlantic Magmatic Province (CAMP) is one of the largest igneous provinces on Earth, with an areal extent exceeding 107km2. Here we document the geochemical characteristics of CAMP basalts fromTriassic-Jurassic ...
    • Upper and lower crust recycling in the source of CAMP basaltic dykes from southeastern North America
      Callegaro, S.; Marzoli, A.; Bertrand, H.; Chiaradia, M.; Reisberg, L.; Meyzen, C.; Bellieni, G.; Weems, R.; Merle, Renaud (2013)
      The densest dykes swarm of the Central Atlantic magmatic province (CAMP) occur in southeastern North America (SENA) and were intruded between 202 and 195 Ma during Pangea break-up. New combined geochemical data (major and ...
    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.