Features and Age of Recycled Material in Mantle Source of Cenozoic Basaltic Lavas in Hainan Island: Evidence from Hf-Sr-Nd-Pb Isotopic Compositions

被引：0
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作者：
Mei S. [1 ,2 ]
Ren Z. [1 ]
机构：
[1] State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, Guangdong
[2] University of Chinese Academy of Sciences, Beijing
来源：
Geotectonica et Metallogenia | 2019年 / 43卷 / 05期
关键词：
Cenozoic basaltic lavas; Hainan Island; Recycled oceanic crust; Recycled sediment;
D O I：
10.16539/j.ddgzyckx.2019.03.013
中图分类号：
学科分类号：
摘要：
Recycling of oceanic crust and sediments into mantle plays an important role in the chemical evolution of the Earth's crust-mantle system. Previous studies established potential dynamic linkages between the plate subduction and Hainan plume generation, so recycled materials have great effects on mantle source of the Hainan basaltic lavas. However, the existence of recycled sediments in the source is still unknown. In this paper, we report, for the first time, the Hf isotope data of the Cenozoic basaltic lavas in Hainan Island, and combine the new Sr, Nd, and Pb isotope data together with the previous data to constrain the composition and age of the recycled materials. Compared with the Mantle Array, εHf values of Hainan lavas are lower relative to given εNd. Moreover, the lavas have the characteristics of Eu/Eu*> 1 and Sr/Sr*> 1, but neither of them has correlation with Al2O3 and MgO, indicating that the positive anomalies of Eu and Sr are the characteristics of the source. These serval lines of evidence suggest that recycled oceanic crust plays a significant role in mantle source. The Ce/Pb ratios of Hainan lavas are positively correlated with εNd and εHf, and Nd/Pb ratios are negatively correlated with 87Sr/86Sr, pointing to the subducted oceanic sediments end member. According to the evolution model of the εHf-εNd and Pb isotopes, we conclude that the recycled oceanic crust and sediments in the source region are relatively young, and its age should be less than 1.0 Ga. The high-density eclogite derived from a mixture of recycled oceanic crust and sediments drives the material to sink into the lower mantle and even as deep as the core-mantle boundary, which then reacts with the ambient peridotite and produces the solid pyroxenite in the rising plume. With Hainan plume rising, the pyroxenite bodies melt continually to generate magma for the Hainan basalts. © 2019, Science Press. All right reserved.
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页码：1036 / 1051
页数：15
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  • [1] Blichert-Toft J., Albarede F., The Lu-Hf isotope geochemistry of chondrites and the evolution of the mantle-crust system, Earth and Planetary Science Letters, 148, 1, pp. 243-258, (1998)
  • [2] Blichert-Toft J., Frey F.A., Albarede F., Hf isotope evidence for pelagic sediments in the source of Hawaiian basalts, Science, 285, 5429, (1999)
  • [3] Blichert-Toft J., Weis D., Maerschalk C., Agranier A., Albarede F., Hawaiian hot spot dynamics as inferred from the Hf and Pb isotope evolution of Mauna Kea volcano, Geochemistry Geophysics Geosystems, 4, 2, (2003)
  • [4] Chan L.H., Lassiter J.C., Hauri E.H., Hart S.R., Blusztajn J., Lithium isotope systematics of lavas from the Cook-Austral Islands: Constraints on the origin of HIMU mantle, Earth and Planetary Science Letters, 277, 3-4, pp. 433-442, (2009)
  • [5] Chauvel C., Hemond C., Melting of a complete section of recycled oceanic crust: Trace element and Pb isotopic evidence from Iceland, Geochemistry Geophysics Geosystems, 2, pp. 1-21, (2000)
  • [6] Chauvel C., Hofmann A.W., Vidal P., HIMU-EM: The French Polynesian connection, Earth and Planetary Science Letters, 110, pp. 99-119, (1992)
  • [7] Chauvel C., Lewin E., Carpentier M., Arndt N.T., Marini J.C., Role of recycled oceanic basalt and sediment in generating the Hf-Nd mantle array, Nature Geoscience, 1, 1, pp. 64-67, (2008)
  • [8] Danyushevsky L.V., Leslie R.A.J., Crawford A.J., Durance P., Melt inclusions in primitive olivine phenocrysts: The role of localized reaction processes in the origin of anomalous compositions, Journal of Petrology, 45, 12, pp. 2531-2553, (2004)
  • [9] Delavault H., Chauvel C., Sobolev A., Batanova V., Combined petrological, geochemical and isotopic modeling of a plume source: Example of Gambier Island, Pitcairn chain, Earth and Planetary Science Letters, 426, pp. 23-35, (2015)
  • [10] Eisele J., Sharma M., Galer S.J.G., Blichert-Toft J., Devey C.W., Hofmann A.W., The role of sediment recycling in EM-1 inferred from Os, Pb, Hf, Nd, Sr isotope and trace element systematics of the Pitcairn hotspot, Earth and Planetary Science Letters, 196, 3-4, pp. 197-212, (2002)
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