Petrogenesis of Dacites in a Triassic Volcanic Arc in the South China Sea: Constraints From Whole Rock and Mineral Geochemistry
文献类型：期刊论文
| 作者 | Wei, Wu2,4; Liu, Chuan-Zhou2,3,4; Mitchell, Ross N.2,4; Yan, Wen1,4 |
| 刊名 | FRONTIERS IN EARTH SCIENCE
 |
| 出版日期 | 2022-01-10 |
| 卷号 | 9页码:17 |
| 关键词 | dacites apatite volcanic arc Paleo-Pacific subduction Late Triassic South China sea |
| DOI | 10.3389/feart.2021.780007 |
| 英文摘要 | Triassic volcanic rocks, including basalts and dacites, were drilled from Meiji Atoll in the South China Sea (SCS), which represents a rifted slice from the active continental margin along the Cathaysia Block. In this study, we present apatite and whole rock geochemistry of Meiji dacites to decipher their petrogenesis. Apatite geochronology yielded U-Pb ages of 204-221 Ma, which are identical to zircon U-Pb ages within uncertainty and thus corroborate the formation of the Meiji volcanic rocks during the Late Triassic. Whole rock major elements suggest that Meiji dacites mainly belong to the high-K calc-alkaline series. They display enriched patterns in light rare earth elements (LREE) and flat patterns in heavy rare earth elements (HREE). They show enrichment in large-ion lithophile elements (LILE) and negative anomalies in Eu, Sr, P, Nb, Ta, and Ti. The dacites have initial Sr-87/Sr-86 ratios of 0.7094-0.7113, epsilon(Nd)(t) values of -5.9--5.4 and epsilon(Hf)(t) values of -2.9--1.7, whereas the apatite has relatively higher initial Sr-87/Sr-86 ratios (0.71289-0.71968) and similar epsilon(Nd)(t) (-8.13--4.56) values. The dacites have homogeneous Pb isotopes, with initial Pb-206/Pb-204 of 18.73-18.87, Pb-207/Pb-204 of 15.75-15.80, and Pb-208/Pb-204 of 38.97-39.17. Modeling results suggest that Meiji dacites can be generated by <40% partial melting of amphibolites containing similar to 10% garnet. Therefore, we propose that the Meiji dacites were produced by partial melting of the lower continental crust beneath the South China block, triggered by the underplating of mafic magmas as a response to Paleo-Pacific (Panthalassa) subduction during the Triassic. Meiji Atoll, together with other microblocks in the SCS, were rifted from the South China block and drifted southward due to continental extension and the opening of the SCS. |
| WOS关键词 | TECTONIC EVOLUTION ; CONTINENTAL-MARGIN ; TRACE-ELEMENT ; LITHOSPHERIC EXTENSION ; MAGNETIC-ANOMALIES ; MAFIC ROCKS ; ANDEAN-TYPE ; LOWER CRUST ; REED BANK ; APATITE |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000748061200001 |
| 出版者 | FRONTIERS MEDIA SA |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/104014]  |
| 专题 | 地质与地球物理研究所_岩石圈演化国家重点实验室 |
| 通讯作者 | Liu, Chuan-Zhou |
| 作者单位 | 1.Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Ocean & Marginal Sea Geol, Guangzhou, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing, Peoples R China 3.CAS Ctr Excellence Deep Earth Sci, Guangzhou, Peoples R China 4.Univ Chinese Acad Sci, Beijing, Peoples R China |
| 推荐引用方式 GB/T 7714 | Wei, Wu,Liu, Chuan-Zhou,Mitchell, Ross N.,et al. Petrogenesis of Dacites in a Triassic Volcanic Arc in the South China Sea: Constraints From Whole Rock and Mineral Geochemistry[J]. FRONTIERS IN EARTH SCIENCE,2022,9:17. |
| APA | Wei, Wu,Liu, Chuan-Zhou,Mitchell, Ross N.,&Yan, Wen.(2022).Petrogenesis of Dacites in a Triassic Volcanic Arc in the South China Sea: Constraints From Whole Rock and Mineral Geochemistry.FRONTIERS IN EARTH SCIENCE,9,17. |
| MLA | Wei, Wu,et al."Petrogenesis of Dacites in a Triassic Volcanic Arc in the South China Sea: Constraints From Whole Rock and Mineral Geochemistry".FRONTIERS IN EARTH SCIENCE 9(2022):17. |
入库方式： OAI收割
来源：地质与地球物理研究所
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