Microcontinents among the accretionary complexes of the Central Asia Orogenic Belt: In situ Re-Os evidence

Kuo Lung Wang, Suzanne Y. O'Reilly, Victor Kovach, William L. Griffin, Norman J. Pearson, Vladimir Yarmolyuk, Mikhail I. Kuzmin, Chia Ju Chieh, J. Gregory Shellnutt, Yoshiyuki Iizuka

    Research output: Contribution to journalArticlepeer-review

    12 Citations (Scopus)

    Abstract

    Major elements and Re-Os isotope ratios were analysed in situ on individual sulfide grains in spinel peridotite xenoliths hosted by Quaternary intraplate basalts from the Tariat volcanic field, Central Mongolia. The sulfides are dominantly high-temperature (>900°C) Fe-rich monosulfide solid solution (MSS). Some sulfides with low Ni contents may be residual MSS, whereas other sulfides defining a negative Ni-Cu correlation may be crystallization products of fractionated sulfide melts. The subchondritic 187Re/188Os and 187Os/188Os of some sulfides also indicate they are residual MSS. Os isotope compositions of sulfides reveal the presence of Archean to Proterozoic lithospheric mantle beneath the region. The sulfides have TRD model ages ranging from 3.0 to 0.2Ga, with peaks at 1.5-1.3, 1 and 0.7-0.5Ga. The peak ages are indicative of significant events in the lithospheric mantle at those times. The timing of these events is remarkably consistent with those of the major crust-building events within the Tarvagatay Terrane where the Tariat volcanic field is located. The similarity in the ranges of crustal U-Pb ages and Nd model ages, and our sulfide Os model ages, suggests that the sulfide ages may date metasomatic events in the underlying lithospheric mantle, which were related to tectonothermal events that affected the overlying crust. Radiometric ages from the Tarvagatay Terrane appear to correspond to the Archean model ages from its SCLM counterpart. The last two events (1.1 and 0.7-0.5Ga) recorded in the Tarvagatay Terrane suggest involvement of the " CAOB mantle" and development of significant juvenile crustal growth in the orogeny.

    Original languageEnglish
    Pages (from-to)37-50
    Number of pages14
    JournalJournal of Asian Earth Sciences
    Volume62
    DOIs
    Publication statusPublished - 2013 Jan 30

    Keywords

    • Central Asia Orogenic Belt (CAOB)
    • In situ Re-Os isotopes
    • Lithosphere evolution
    • Mantle sulfides
    • Os model ages
    • Tavargatay Terrane

    ASJC Scopus subject areas

    • Geology
    • Earth-Surface Processes

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