Evidence of Middle Jurassic magmatism within the Seychelles microcontinent: Implications for the breakup of Gondwana

J. G. Shellnutt, T. Y. Lee, H. Y. Chiu, Y. H. Lee, J. Wong

    Research output: Contribution to journalArticlepeer-review

    5 Citations (Scopus)

    Abstract

    The breakup of East and West Gondwana occurred during the Jurassic, but the exact timing is uncertain due to the limited exposure of rocks suitable for radioisotopic dating. Trachytic rocks from Silhouette Island, Seychelles, yielded a range of zircon ages from Paleoproterozoic to Cenozoic. The 206Pb/238U age of the trachyte is 64.9 ± 1.6 Ma (Danian) but the majority of zircons yielded an age of 163.8 ± 1.8 Ma (Callovian) with a small subset yielding an age of 147.7 ± 4.5 Ma (Tithonian). The Hf isotopes of the Callovian (εHf(t) = +4.1 to +13.4) and Danian (εHf(t) = +1.9 to +7.1) zircons indicate that they were derived from moderately depleted mantle sources whereas the Tithonian zircons (εHf(t) = -7.0 to -7.3) were derived from an enriched source. The identification of middle Jurassic zircons indicates that rifting and magmatism were likely contemporaneous during the initial separation of East and West Gondwana.

    Original languageEnglish
    Pages (from-to)10207-10215
    Number of pages9
    JournalGeophysical Research Letters
    Volume42
    Issue number23
    DOIs
    Publication statusPublished - 2015 Dec 16

    Keywords

    • Callovian
    • Gondwana
    • Hf Isotopes
    • Seychelles
    • Tithonian
    • U/Pb dating

    ASJC Scopus subject areas

    • Geophysics
    • Earth and Planetary Sciences(all)

    Fingerprint

    Dive into the research topics of 'Evidence of Middle Jurassic magmatism within the Seychelles microcontinent: Implications for the breakup of Gondwana'. Together they form a unique fingerprint.

    Cite this