92Nb-(92)Zr and the Early Differentiation History of Planetary Bodies.
92Nb-(92)Zr and the Early Differentiation History of Planetary Bodies.
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DOI：
10.1126/science.289.5484.1538
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发表时间：
2000-09
期刊：
影响因子：
56.9
通讯作者：
Münker;Weyer;Mezger;Rehkämper;Wombacher;Bischoff
中科院分区：
文献类型：
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作者：
Münker;Weyer;Mezger;Rehkämper;Wombacher;Bischoff
铌-92-锆-92 ((92)Nb-(92)Zr) 灭绝的放射性衰变系统（半衰期约为 3600 万年）可以对行星和陨石的硅酸盐部分的早期分化过程施加新的时间限制。锆同位素数据显示，地球和最古老的月壳具有与球粒陨石相同的 (92)Zr 相对丰度。阿连德陨石中富含钙铝包裹体的 (92)Zr 缺陷将太阳系初始 (92)Nb/(93)Nb 比率的最小值限制为 0.001。陆地和月球样本中不存在 (92)Zr 异常，这表明地球和月球上的大型硅酸盐储层（例如岩浆海洋残留物、贫化的地幔或地壳）是在最古老的陨石形成后 5000 万年以上形成的。
The niobium-92-zirconium-92 ((92)Nb-(92)Zr) extinct radioactive decay system (half-life of about 36 million years) can place new time constraints on early differentiation processes in the silicate portion of planets and meteorites. Zirconium isotope data show that Earth and the oldest lunar crust have the same relative abundances of (92)Zr as chondrites. (92)Zr deficits in calcium-aluminum-rich inclusions from the Allende meteorite constrain the minimum value for the initial (92)Nb/(93)Nb ratio of the solar system to 0.001. The absence of (92)Zr anomalies in terrestrial and lunar samples indicates that large silicate reservoirs on Earth and the moon (such as a magma ocean residue, a depleted mantle, or a crust) formed more than 50 million years after the oldest meteorites formed.