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

    Melting controls on the lutetium–hafnium evolution of Archaean crust

    Access Status
    Fulltext not available
    Authors
    Gardiner, Nicholas
    Johnson, Tim
    Kirkland, Chris
    Smithies, R.
    Date
    2018
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Gardiner, N. and Johnson, T. and Kirkland, C. and Smithies, R. 2018. Melting controls on the lutetium–hafnium evolution of Archaean crust. Precambrian Research. 305: pp. 479-488.
    Source Title
    Precambrian Research
    DOI
    10.1016/j.precamres.2017.12.026
    ISSN
    0301-9268
    School
    School of Earth and Planetary Sciences (EPS)
    URI
    http://hdl.handle.net/20.500.11937/66422
    Collection
    • Curtin Research Publications
    Abstract

    © 2017 Elsevier B.V. The lutetium–hafnium (Lu–Hf) isotope record, typically measured in zircon crystals, provides a major tool for the study of crustal growth and differentiation. Interpretations of Hf isotope datasets use an evolution array defined by source 176 Lu/ 177 Hf. However, the very process that drives crustal differentiation to produce such arrays – partial melting – is precisely that which may modify the trajectory of the array due to variable degrees of anatexis allied with the differing compatibilities of Lu and Hf in residual minerals. Further, Lu/Hf estimates derived from the composition of present-day continental crust may be inappropriate for modelling Archaean crustal evolution, where different geodynamic styles and magmatic sources prevailed. Using an approach combining phase equilibria, and trace element and isotopic modelling, we quantify the effects of partial melting of both a modern (N-MORB) and Archaean (C-F2) mafic source on melt Lu/Hf. Melting N-MORB shows that the 176 Lu/ 177 Hf of the melt, which modelling predicts to be between 0.015 and 0.022, is sensitive to the degree of melting. This difference results in a variation of 4.5 epsilon units/billion years. By contrast, anatexis of C-F2 yields melts with 176 Lu/ 177 Hf ~0.009 that are less affected by the degree of melting. Remelting TTG yields K-rich granitic melts (TTG + G) with 176 Lu/ 177 Hf ~0.005. Thus, a partial melting event imposes a greater control on the resulting crustal reservoir Lu/Hf than the degree of melting. Archaean continental crust has a lower Lu/Hf than that of the average mid to upper continental crust, and therefore a lower 176 Lu/ 177 Hf (here 0.005–0.009) is appropriate to modelling its Hf isotopic evolution. There has been a secular change in average crustal Lu/Hf, with the median Lu/Hf of Proterozoic and Phanerozoic magmatic rocks being higher than that of Archaean TTG + G. We show that an enriched Archaean mafic source (C-F2) with a Lu/Hf ratio of ~0.12 may produce TTG continental crust with a 176 Lu/ 177 Hf approaching that calculated in real rocks worldwide.

    Related items

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

    • Paleoproterozoic formation age for the Siberian cratonic mantle: Hf and Nd isotope data on refractory peridotite xenoliths from the Udachnaya kimberlite
      Doucet, Luc-Serge; Ionov, D.; Golovin, A. (2015)
      © 2014 Elsevier B.V. The formation age of the Siberian cratonic mantle is not well established as yet. Re-Os data on various mantle-derived materials have shown that it contains Archaean components, but the reported ...
    • Applications of Pb isotopes in granite K-feldspar and Pb evolution in the Yilgarn Craton
      Zametzer, Andreas; Kirkland, Christopher ; Hartnady, Michael ; Barham, Milo ; Champion, D.C.; Bodorkos, S.; Smithies, R. Hugh; Johnson, S.P. (2022)
      The isotopic composition of Pb in a mineral or rock at the moment it formed – often referred to as common Pb – provides an important tool to track geological processes through time and space. There is a wide range of ...
    • Pb isotope insight into the formation of the Earth's first stable continents
      Hartnady, Michael ; Kirkland, Christopher ; Smithies, R. Hugh; Johnson, S.P.; Johnson, Tim (2022)
      The formation of stable buoyant continental crust during the Archaean Eon was fundamental in establishing the planet's geochemical reservoirs. However, the processes that created Earth's first continents and the timescales ...
    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.