Evidence for extreme mantle fractionation in early Archaean ultramafic rocks from northern Labrador
Evidence for extreme mantle fractionation in early Archaean ultramafic rocks from northern Labrador
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DOI：
10.1038/349209a0
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发表时间：
1991-01
期刊：
影响因子：
64.8
通讯作者：
K. Collerson;L. Campbell;B. Weaver;Z. Palacz
中科院分区：
文献类型：
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作者：
K. Collerson;L. Campbell;B. Weaver;Z. Palacz
来自北大西洋克拉通的岩石圈地幔和变质科马提岩的构造交错碎片的钐钕同位素数据提供了3r8亿年前地幔分异的第一个直接记录。结果证实了早期地幔轻稀土元素亏损的幅度，以及亏损的钕同位素组成。地幔碎片之所以能够保留这些古老的地球化学特征，是因为它们在技术上被纳入了有浮力的长英质地壳中，从而逃脱了地幔对流的再循环和均质化。
Samarium–neodymium isotope data for tectonically interleaved fragments of lithospheric mantle and meta-komatiite from the North Atlantic craton provide the first direct record of mantle differentiation before 3r800 Myr ago. The results confirm the magnitude of light-rare-earth-element depletion in the early mantle, and also its depleted neodymium isotope composition. The mantle fragments were able to retain these ancient geochemical signatures by virtue of having been technically incorporated in buoyant felsic crust, thus escaping recycling and homogenization by mantle convection.