Tungsten-182 heterogeneity in modern ocean island basalts
Tungsten-182 heterogeneity in modern ocean island basalts
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DOI：
10.1126/science.aal4179
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发表时间：
2017-04-07
期刊：
影响因子：
56.9
通讯作者：
Walker, Richard J.
中科院分区：
文献类型：
--
作者：
Mundl, Andrea;Touboul, Mathieu;Walker, Richard J.
来自夏威夷、萨摩亚和冰岛的现代洋岛玄武岩(OIB)的新钨同位素数据揭示了不同的W-182/W-184，范围从周围上地幔的比率到低至百万分之18的比率。钨同位素数据与He-3/He-4呈负相关。这些数据表明，每个OIB系统都访问了地球内在太阳系历史最初6000万年内形成的领域。这些古域的同位素和化学组合特征表明，它们含有金属，是惰性气体的储存库。我们认为，最有可能的震源候选者是位于夏威夷、萨摩亚和冰岛之下的超低速带，而不是位于OIB产量正常的W-182和均匀低的He-3/He-4的热点之下。
New tungsten isotope data for modern ocean island basalts (OIB) from Hawaii, Samoa, and Iceland reveal variable W-182/W-184, ranging from that of the ambient upper mantle to ratios as much as 18 parts per million lower. The tungsten isotopic data negatively correlate with He-3/He-4. These data indicate that each OIB system accesses domains within Earth that formed within the first 60 million years of solar system history. Combined isotopic and chemical characteristics projected for these ancient domains indicate that they contain metal and are repositories of noble gases. We suggest that the most likely source candidates are mega-ultralow-velocity zones, which lie beneath Hawaii, Samoa, and Iceland but not beneath hot spots whose OIB yield normal W-182 and homogeneously low He-3/He-4.