Deep mantle origin of kimberlite magmas revealed by neon isotopes
Deep mantle origin of kimberlite magmas revealed by neon isotopes
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氖同位素揭示金伯利岩岩浆的深部地幔起源
DOI：
10.1029/2006gl027144
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发表时间：
2006
影响因子：
5.2
通讯作者：
A. Sobolev
中科院分区：
文献类型：
--
作者：
H. Sumino;I. Kaneoka;K. Matsufuji;A. Sobolev
我们测量了从东西伯利亚Udachnaya-East金伯利岩管的未蚀变样品中提取的橄榄石中的惰性气体。Ne同位素比值表明，金伯利岩比典型的大洋中脊玄武岩(MORB)源具有较少的成核Ne特征，这与与MORB和次大陆岩石圈地幔(SCLM)源相比放射性成因较低的40Ar/36Ar值一致。根据He-Ne系统学，Udachnaya金伯利岩柱状源的3He/4He比值应大于15Ra，这是岩浆上升过程中SCLm和/或地壳物质同化获得的岩浆的主要氦特征。结果表明，Udachnaya金伯利岩具有与洋岛玄武岩(OIB)相似的惰性气体特征。因此，它的起源比MORB源地幔深，可能与OIB源地幔相同。
We measured noble gases in olivines extracted from alteration‐free samples of the Udachnaya‐East kimberlite pipe, eastern Siberia. Neon isotope ratios indicate that the kimberlite has a less nucleogenic Ne signature than a typical mid‐ocean ridge basalt (MORB) source, which is consistent with the less radiogenic 40Ar/36Ar ratio compared to MORB and subcontinental lithospheric mantle (SCLM) sources. Based on He‐Ne systematics, the 3He/4He ratio of the plume source of the Udachnaya kimberlite pipe would be higher than 15 RA with the dominant He signature of the magma acquired by assimilation of SCLM and/or crustal material during magma ascent. Our results indicate that the source of the Udachnaya kimberlite has similar noble gas characteristics to those of ocean island basalts (OIBs). Its origin is therefore deeper than that of the MORB source mantle, and probably is the same as the OIB‐source mantle.