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

    Nonglacial origin for low-δ18O Neoproterozoic magmas in the South China Block: Evidence from new in-situ oxygen isotope analyses using SIMS

    Access Status
    Fulltext not available
    Authors
    Wang, Xuan-Ce
    Li, Zheng-Xiang
    Li, X.
    Li, Q.
    Tang, G.
    Zhang, Q.
    Liu, Y.
    Date
    2011
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Wang, Xuan-Ce and Li, Zheng-Xiang and Li, Xian-Hua and Li, Qiu-Li and Tang, Guo-Qiang and Zhang, Qi-Rui and Liu, Yu. 2011. Nonglacial origin for low-δ18O Neoproterozoic magmas in the South China Block: Evidence from new in-situ oxygen isotope analyses using SIMS. Geology. 39 (8): pp. 735-738.
    Source Title
    Geology
    DOI
    10.1130/G31991.1
    ISSN
    00917613
    School
    Department of Applied Geology
    URI
    http://hdl.handle.net/20.500.11937/46319
    Collection
    • Curtin Research Publications
    Abstract

    Low-δ18O signatures in supracrustal rocks have been used as geochemical proxies for cold paleoclimates, e.g., glaciations. Unusual low-δ18O values found in Neoproterozoic igneous rocks in parts of the South China Block have thus been genetically linked to Neoproterozoic glaciation events. However, we report here new oxygen isotope compositions from Neoproterozoic magmatic zircons in central southern China using in-situ techniques that argue against such an interpretation.Our results show that (1) low-δ18O magmatic zircons started to appear in the South China Block from ca. 870 Ma, coinciding with the tectonic switching from Sibao orogenesis to postorogenic extension, which occurred more than 150 m.y. prior to the first glaciation event. The most abundant low-δ18O magmatic zircons have ages of 800–700 Ma. (2) The 830–700 Ma magmatic zircons are characterized by their bimodal nature of oxygen isotope compositions, i.e., mantle-like δ18O values (+4.4‰ to +5.8‰) and high-δ18O values (+9.3‰ to +10.8‰). (3) A sharp temporal change in maximum zircon δ18O values in the South China Block coincided with the onset of continental rifting and the possible arrival of a plume head. (4) No negative δ18O zircons have been identified in this study, contrary to previous studies. These features strongly argue against a glaciation origin for low to negative δ18O values in Neoproterozoic magmatic zircons from southern China. We propose that two stages of high-temperature water-magma interaction during plume-driven magmatism and continental rifting best explain the low-δ18O magmas. The most important implication of this study is that formation of such low-δ18O magmatic zircons was not necessarily related to glacial events and should not be used as a geochemical proxy for a cold paleoclimate.

    Related items

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

    • Integrated in situ U–Pb age and Hf–O analyses of zircon from Suixian Group in northern Yangtze: New insights into the Neoproterozoic low-δ18O magmas in the South China Block
      Yang, Y.; Wang, Xuan-Ce; Li, Q.; Li, X. (2016)
      The mid- to late-Neoproterozoic magmatic rocks from the northern margin of the Yangtze Block are major protoliths of high-pressure (HP) and ultrahigh-pressure (UHP) metamorphic rocks in the Dabie–Sulu orogenic belt along ...
    • Origin of the Tongbai-Dabie-Sulu Neoproterozoic low-δ18O igneous province, east-central China
      Fu, B.; Kita, N.; Wilde, Simon; Liu, X.; Cliff, J.; Greig, A. (2013)
      Zircons from 71 diverse rocks from the Qinling-Tongbai-Dabie-Sulu orogenic belt in east-central China and, for comparison, eight from adjoining areas in the South China and North China blocks, have been analyzed for in ...
    • Mid-Neoproterozoic angular unconformity in the Yangtze Block revisited: Insights from detrital zircon U-Pb age and Hf-O isotopes
      Yang, C.; Li, X.; Wang, Xuan-Ce; Lan, Z. (2015)
      Middle Neoproterozoic sedimentary rocks are widespread in the South China Block, especially around the periphery of the Yangtze Block. They are separated into the Sibao and Danzhou groups (and their equivalents) by a ...
    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.