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- Title
- A refractory mantle protolith in younger continental crust, east-central China : age and composition of zircon in the Sulu ultrahigh-pressure peridotite
- Related
- Geology, Vol. 34, Issue 9, p.705-708
- DOI
- 10.1130/G22569.1
- Publisher
- Geological Society of America
- Date
- 2006
- Author/Creator
- Zheng, Jianping
- Author/Creator
- Griffin, W. L
- Author/Creator
- O'Reilly, Suzanne Y
- Author/Creator
- Yang, J. S
- Author/Creator
- Zhang, R. Y
- Description
- Zircons have been extracted from garnet peridotite and its wall rock (gneiss), which was intersected by the pre–pilot hole of the Chinese Continental Scientific Drilling project (CCSD-PP1) in the Sulu ultrahigh-pressure (UHP) metamorphic belt. The peridotitic zircons record early Mesozoic UHP metamorphism (²⁰⁶Pb/²³⁸U age of 223.5 ± 7.5 Ma), but their Hf isotope compositions indicate that the protolith of the peridotite is at least Mesoproterozoic in age (minimum depleted-mantle ages [T<sub>DM</sub>] of 1.4 Ga). Zircons from the gneiss also reflect the Mesozoic metamorphism, with a cluster of ²⁰⁶Pb/²³⁸U ages at 224.5 ± 11.5 Ma; a trail of discordant grains indicates a protolith age older than 800 Ma, consistent with T<sub>DM</sub> model ages of younger than 1.2 Ga. The peridotitic zircons have trace-element patterns similar to kimberlitic and/or carbonatitic zircons, while those from the gneiss have affinities with zircons from syenites/monzonites. The differences suggest that the metasomatic agents that affected the peridotitic zircons were derived from the asthenospheric mantle rather than from subducted continental crust. The strong depletion of the CCSD-PP1 peridotite in basaltic components, and the relatively unradiogenic Hf isotopic compositions (e.g., −16.3 to ~−13.8 ε<sub>Hf</sub>) of the peridotitic zircons, indicate that the peridotitic body is a fragment of refractory Archean mantle that experienced Mesoproterozoic metasomatism and represents a tectonic intrusion into younger crust.
- Description
- 4 page(s)
- Subject Keyword
- 040200 Geochemistry
- Subject Keyword
- 040300 Geology
- Subject Keyword
- peridotitic zircon
- Subject Keyword
- Hf isotope
- Subject Keyword
- trace element
- Subject Keyword
- U-Pb dating
- Subject Keyword
- Sulu UHP terrane
- Subject Keyword
- China
- Resource Type
- journal article
- Organisation
- Macquarie University. National Key Centre for Geochemical Evolution and Metallogeny of Continents (GEMOC)
- Identifier
- http://hdl.handle.net/1959.14/10128
- Identifier
- mq:975
- Identifier
- ISSN:0091-7613
- Identifier
- mq-rm-2006000154
- Language
- eng
- Reviewed
Macquarie University ResearchOnline
