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dc.contributor.authorFu, B.
dc.contributor.authorKita, N.
dc.contributor.authorWilde, Simon
dc.contributor.authorLiu, X.
dc.contributor.authorCliff, J.
dc.contributor.authorGreig, A.
dc.identifier.citationFu, Bin and Kita, Noriko T. and Wilde, Simon A. and Liu, Xiaochun and Cliff, John and Greig, Alan. 2013. Origin of the Tongbai-Dabie-Sulu Neoproterozoic low-δ18O igneous province, east-central China. Contributions to Mineralogy and Petrology. 165 (4): pp. 641-662.

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 situ 18O/16O ratio and/or U–Pb age to further constrain the spatial distribution and genesis of Neoproterozoic low-δ 18O magmas, that is, δ 18O(zircon) ≤4 ‰ VSMOW. In many metaigneous rock samples from Tongbai-Dabie-Sulu, including high-pressure and ultrahigh-pressure eclogites and associated granitic orthogneisses, average δ 18O values for Neoproterozoic “igneous” zircon cores (i.e., 800–600 Ma) vary from −0.9 to 6.9 ‰, and from −9.9 to 6.8 ‰ for Triassic metamorphic rims (i.e., 245–200 Ma). The former extend to values lower than zircons in primitive magmas from the Earth’s mantle (ca. 5–6 ‰). The average Δ 18O (metamorphic zircon − “igneous” zircon) values vary from −11.6 to 0.9 ‰.The large volume of Neoproterozoic low-δ 18O igneous protoliths at Tongbai-Dabie-Sulu is matched only by the felsic volcanic rocks of the Snake River Plain hotspot track, which terminates at the Yellowstone Plateau. Hence, the low-δ 18O values at Tongbai-Dabie-Sulu are proposed to result from shallow subcaldera processes by comparison with Yellowstone, where repeated caldera-forming magmatism and hydrothermal alteration created similar low-δ 18O magmas. However, the possibility of involvement of meltwaters from local continental glaciations, rather than global Neoproterozoic glaciations, cannot be precluded. Our data indicate that Neoproterozoic low-δ 18O magmas that are either subduction- or rift-related are present locally along the western margin of the South China Block (e.g., Baoxing Complex). It appears that Neoproterozoic 18O-depletion events in the South China Block as the result of hydrothermal alteration and magmatism affected a much larger area than was previously recognized.

dc.subjectOxygen isotopes
dc.subjectQinling-Tongbai-Dabie-Sulu orogenic belt
dc.subjectUltrahigh-pressure metamorphism
dc.subjectSouth China Block
dc.titleOrigin of the Tongbai-Dabie-Sulu Neoproterozoic low-δ18O igneous province, east-central China
dc.typeJournal Article
dcterms.source.titleContributions to Mineralogy and Petrology
curtin.accessStatusFulltext not available

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