Mechanisms of Magma Generation Beneath Hawaii and Mid-Ocean Ridges: Uranium/Thorium and Samarium/Neodymium Isotopic Evidence
Mechanisms of Magma Generation Beneath Hawaii and Mid-Ocean Ridges: Uranium/Thorium and Samarium/Neodymium Isotopic Evidence
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夏威夷和大洋中脊下方岩浆生成机制：铀/钍和钐/钕同位素证据
作者：
K. Sims;D. DePaolo;M. Murrell;W. S. Baldridge;S. J. Goldstein;D. Clague
对一套夏威夷玄武岩的铀/钍和钐/钕同位素和浓度的测量表明，铀/钍的分馏程度随钐/钕的分馏和主元素组成的不同而有系统的变化；这种相关性可以用含石榴石的橄榄岩岩浆来源和熔体分数为0.25-6.5%的简单批量熔融模型来理解。大洋中脊玄武岩显示了铀/钍分馏和钐/钕分馏之间的系统但截然不同的关系，尽管这与含石榴石橄榄岩来源的熔融大致一致，但需要更复杂的熔融模式。
Measurements of uranium/thorium and samarium/neodymium isotopes and concentrations in a suite of Hawaiian basalts show that uranium/thorium fractionation varies systematically with samarium/neodymium fractionation and major-element composition; these correlations can be understood in terms of simple batch melting models with a garnet-bearing peridotite magma source and melt fractions of 0.25 to 6.5 percent. Midocean ridge basalts shows a systematic but much different relation between uranium/thorium fractionation and samarium/neodymium fractionation, which, although broadly consistent with melting of a garnet-bearing peridotite source, requires a more complex melting model.