Origin of the Tongbai-Dabie-Sulu Neoproterozoic low-δ18O igneous province, east-central China
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...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
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Springer
2013
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| Online Access: | http://hdl.handle.net/20.500.11937/9745 |
| _version_ | 1848746038260662272 |
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| author | Fu, B. Kita, N. Wilde, Simon Liu, X. Cliff, J. Greig, A. |
| author_facet | Fu, B. Kita, N. Wilde, Simon Liu, X. Cliff, J. Greig, A. |
| author_sort | Fu, B. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | 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. |
| first_indexed | 2025-11-14T06:26:54Z |
| format | Journal Article |
| id | curtin-20.500.11937-9745 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T06:26:54Z |
| publishDate | 2013 |
| publisher | Springer |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-97452017-09-13T14:50:15Z 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. Oxygen isotopes Qinling-Tongbai-Dabie-Sulu orogenic belt Ultrahigh-pressure metamorphism South China Block Zircon 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. 2013 Journal Article http://hdl.handle.net/20.500.11937/9745 10.1007/s00410-012-0828-3 Springer restricted |
| spellingShingle | Oxygen isotopes Qinling-Tongbai-Dabie-Sulu orogenic belt Ultrahigh-pressure metamorphism South China Block Zircon Fu, B. Kita, N. Wilde, Simon Liu, X. Cliff, J. Greig, A. Origin of the Tongbai-Dabie-Sulu Neoproterozoic low-δ18O igneous province, east-central China |
| title | Origin of the Tongbai-Dabie-Sulu Neoproterozoic low-δ18O igneous province, east-central China |
| title_full | Origin of the Tongbai-Dabie-Sulu Neoproterozoic low-δ18O igneous province, east-central China |
| title_fullStr | Origin of the Tongbai-Dabie-Sulu Neoproterozoic low-δ18O igneous province, east-central China |
| title_full_unstemmed | Origin of the Tongbai-Dabie-Sulu Neoproterozoic low-δ18O igneous province, east-central China |
| title_short | Origin of the Tongbai-Dabie-Sulu Neoproterozoic low-δ18O igneous province, east-central China |
| title_sort | origin of the tongbai-dabie-sulu neoproterozoic low-δ18o igneous province, east-central china |
| topic | Oxygen isotopes Qinling-Tongbai-Dabie-Sulu orogenic belt Ultrahigh-pressure metamorphism South China Block Zircon |
| url | http://hdl.handle.net/20.500.11937/9745 |