中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
Molybdenum isotope evidence for recycled oceanic crust in the mantle sources of continental intraplate mafic lavas, Emeishan Large Igneous Province

文献类型:期刊论文

作者Li, Jiyong3; Liu, Yi2; Chen, Shuo1
刊名CHEMICAL GEOLOGY
出版日期2024-11-20
卷号668页码:14
关键词Mantle heterogeneity Molybdenum isotope Recycled oceanic crust Continental intraplate mafic lavas Emeishan Large Igneous Province
ISSN号0009-2541
DOI10.1016/j.chemgeo.2024.122347
通讯作者Liu, Yi(yiliu168@foxmail.com) ; Chen, Shuo(shuochen@qdio.ac.cn)
英文摘要The chemical and lithological heterogeneities of Earth's mantle in oceanic settings have long been attributed to the presence of recycled materials such as subducted crust, oceanic or subcontinental lithosphere mantle and sediment, as evidenced by Mid-Ocean Ridge Basalts (MORB) and Ocean Island Basalts (OIB). However, the extent to which recycled materials contribute to mantle heterogeneity in continental settings remains uncertain. Here we present systematic Sr-Nd-Pb-Mo isotope data for the Pingchuan picritic porphyries and associated mafic rocks (basalts and gabbros) in the central Emeishan Large Igneous Province, southwestern China, to resolve this issue. In contrast to the gabbro samples that show continental crust contamination in variations of delta Mo-98/95 (relative to NIST SRM 3134, -0.35 +/- 0.03 to 0.03 +/- 0.02 parts per thousand), the Pingchuan picritic porphyries and basalts show a large range of delta Mo-98/95 (-0.32 +/- 0.01 to -0.15 +/- 0.06 parts per thousand) and broadly negative trend between delta Mo-98/95 and Ce/Mo ratios, which cannot be explained by post-magmatic alteration, crustal contamination, fractional crystallization, olivine accumulation, metasomatism or fluid-activity in the mantle source. They were most likely derived from incongruent melting of a heterogeneous mantle source, i.e., a deep mantle with chondritic-like delta Mo-98/95 (-0.15 +/- 0.01 parts per thousand) containing recycled oceanic crust (+ sediment) with light delta Mo-98/95 (< -0.32 parts per thousand). The basalts display low delta Mo-98/95 (-0.32 +/- 0.01 to -0.24 +/- 0.04 parts per thousand), high Sr-87/Sr-86(i) (0.7046 to 0.7059), TiO2, Sm/Yb, Dy/Yb and Ce/Mo, pointing to characteristics of melts produced by MORB-type eclogite (+ sediment) at relatively low degrees of partial melting. With increasing degrees of partial melting, melts produced by peridotite (Sr-87/Sr-86(i) = 0.7035 to 0.7043, chondritic-like delta Mo-98/95 = -0.18 +/- 0.03 to -0.15 +/- 0.06 parts per thousand) come to dominate, resulting in low TiO2, Sm/Yb, Dy/Yb and Ce/Mo of the Pingchuan picritic porphyries. From a global perspective, continental basalts also plot on the negative trend defined by the OIB datasets (delta Mo-98/95 vs. Ce/Mo). As such, Mo isotope may provide a robust tracer of recycled oceanic crust in shaping mantle heterogeneities that occur in both oceanic and continental settings.
WOS关键词TRACE-ELEMENT ; FLOOD BASALTS ; SOUTHWESTERN CHINA ; SW CHINA ; MAGMATIC DIFFERENTIATION ; PRIMITIVE MAGMAS ; IRON ISOTOPES ; U-PB ; FRACTIONATION ; GEOCHEMISTRY
资助项目National Natural Science Foundation of China[42322605] ; National Natural Science Foundation of China[42176087] ; National Natural Science Foundation of China[41906050] ; Laoshan Laboratory[LSKJ202204100] ; Youth Innovation Promotion Association, Chinese Academy of Sciences[2021206] ; Natural Science Fund of Southwest University of Science and Technology[22zx7172]
WOS研究方向Geochemistry & Geophysics
语种英语
WOS记录号WOS:001307754700001
出版者ELSEVIER
源URL[http://ir.qdio.ac.cn/handle/337002/198282]  
专题海洋研究所_海洋地质与环境重点实验室
通讯作者Liu, Yi; Chen, Shuo
作者单位1.Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Key Lab Ocean Observat & Forecasting, Qingdao 266071, Peoples R China
2.Kunming Univ Sci & Technol, Fac Land Resources Engn, Kunming 650093, Peoples R China
3.Southwest Univ Sci & Technol, Sch Environm & Resource, Key Lab Solid Waste Treatment & Resource Recycle, Minist Educ, Mianyang 621010, Peoples R China
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GB/T 7714
Li, Jiyong,Liu, Yi,Chen, Shuo. Molybdenum isotope evidence for recycled oceanic crust in the mantle sources of continental intraplate mafic lavas, Emeishan Large Igneous Province[J]. CHEMICAL GEOLOGY,2024,668:14.
APA Li, Jiyong,Liu, Yi,&Chen, Shuo.(2024).Molybdenum isotope evidence for recycled oceanic crust in the mantle sources of continental intraplate mafic lavas, Emeishan Large Igneous Province.CHEMICAL GEOLOGY,668,14.
MLA Li, Jiyong,et al."Molybdenum isotope evidence for recycled oceanic crust in the mantle sources of continental intraplate mafic lavas, Emeishan Large Igneous Province".CHEMICAL GEOLOGY 668(2024):14.

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来源:海洋研究所

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