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DOI	10.1016/j.epsl.2020.116707
	Nitrogen and noble gases reveal a complex history of metasomatism in the Siberian lithospheric mantle
	Barry P.H.; Broadley M.W.
发表日期	2021
ISSN	0012821X
卷号	556
英文摘要	The Siberian flood basalts (SFB) erupted at the end of the Permian period (∼250 Ma) in response to a deep-rooted mantle plume beneath the Siberian Sub-Continental Lithospheric Mantle (SCLM). Plume-lithosphere interaction can lead to significant changes in the structure and chemistry of the SCLM and trigger the release of metasomatic material that was previously stored within the stable craton. Here, we investigate the nature of the Siberian-SCLM (S-SCLM) by measuring nitrogen abundances and isotopes (δ15N) in 11 samples of two petrologically-distinct suites of peridotitic xenoliths recovered from kimberlites which bracket the eruption of the SFB: the 360 Myr old Udachnaya and 160 Myr old Obnazhennaya pipes. Nitrogen isotope (δ15N) values range from -5.85 ± 1.29‰ to +3.94 ± 0.63‰, which encompasses the entire range between depleted Mid-Ocean Ridge Basalt (MORB) mantle (DMM; -5 ± 2‰) and plume-derived (+3 ± 2‰) endmembers. In addition, we present neon (n=7) and argon (n=8) abundance and isotope results for the same two suites of samples. The 20Ne/22Ne and 21Ne/22Ne range from atmospheric-like values of 9.88 up to 11.35 and from 0.0303 to 0.0385, respectively, suggesting an admixture of DMM and plume-derived components. Argon isotopes (40Ar/36Ar) range from 336.7 to 1122 and correlate positively with 40Ar contents. We show that volatile systematics of Siberian xenoliths: (1) exhibit evidence of ancient metasomatic and/or recycled signatures, and (2) show evidence of subsequent plume-like re-fertilization, which we attribute to the emplacement of the SFB. Metasomatic fluids are highly enriched in radiogenic gases and have elevated Br/Cl and I/Cl values, consistent with an ancient subducted crustal component. The metasomatic component is marked by light N isotope signatures, suggesting it may be derived from an anoxic Archean subducted source. Taken together, these N2-Ne-Ar isotope results suggest that mantle plume impingement has profoundly modified the S-SCLM, and that N, Ne and Ar isotopes are sensitive tracers of metasomatism in the S-SCLM. Metasomatic fluids that permeate the S-SCLM act to archive a “subduction-fingerprint” that can be used to probe relative volatile-element recycling efficiencies and thus provide insight into volatile transport between the surface and mantle reservoirs over Earth history. © 2020 Elsevier B.V.
关键词	argon metasomatism neon nitrogen plume SCLM
英文关键词	Argon; Basalt; Isotopes; Mineralogy; Minerals; Nitrogen; Recycling; Structural geology; Thermal plumes; Transport properties; Lithospheric mantle; Mantle reservoirs; Mid ocean ridge basalts; Nitrogen isotopes; Plume-lithosphere interactions; Sub-continental lithospheric mantles; Subducted crustal component; Volatile elements; Radiogenic gases; complexity; emplacement; flood basalt; lithospheric structure; mantle plume; mantle structure; metasomatism; mid-ocean ridge basalt; nitrogen; noble gas; peridotite; Permian; petrogenesis; xenolith; Siberia
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203027
作者单位	Woods Hole Oceanographic Institution, MC&G Dept., Woods Hole, MA 02543, United States; Centre de Recherches Pétrographiques et Géochimiques, Université de Lorraine, Nancy, France
推荐引用方式 GB/T 7714	Barry P.H.,Broadley M.W.. Nitrogen and noble gases reveal a complex history of metasomatism in the Siberian lithospheric mantle[J],2021,556.
APA	Barry P.H.,&Broadley M.W..(2021).Nitrogen and noble gases reveal a complex history of metasomatism in the Siberian lithospheric mantle.Earth and Planetary Science Letters,556.
MLA	Barry P.H.,et al."Nitrogen and noble gases reveal a complex history of metasomatism in the Siberian lithospheric mantle".Earth and Planetary Science Letters 556(2021).