BE-10 AND BE-9 IN MARINE-SEDIMENTS AND THEIR POTENTIAL FOR DATING
BE-10 AND BE-9 IN MARINE-SEDIMENTS AND THEIR POTENTIAL FOR DATING
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DOI：
10.1016/0016-7037(89)90395-5
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发表时间：
1989-02-01
影响因子：
5
通讯作者：
YIOU, F
中科院分区：
文献类型：
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作者：
BOURLES, D;RAISBECK, GM;YIOU, F
使用连续的浸出实验，我们已经测量了宇宙成因同位素10 Be（半衰期1.5我）的分数，其稳定的同位素9 Be，共同提取与以下阶段的海洋沉积物：可交换的，碳酸钙，铁和锰的羟基氧化物，有机，蛋白石和碎屑。自生相的萃取通常释放约70%的10 Be，但仅释放约40%的9 Be。为了验证其在海洋沉积物定年中的潜力，我们测量了17个来自不同海洋盆地的表层沉积物样品中的自生10 Be/9 Be。所观察到的空间变化，这似乎是由接近大陆输入的9 Be的影响，排除了一般和精确的应用程序浸出10 Be/9 Be测年。然而，在太平洋，印度洋和南大西洋大面积的表层沉积物中观察到的相对恒定的值显示了相当大的前景，为近似定年的开放海洋sediment. To测试时间的变化，已在独立定年的中太平洋岩芯，RC 12 -65的autogenically associated 10 Be/9 Be的比例配置文件进行了测量。在过去的900年中，观测到的10 Be/9 Be的变化大约是仅根据10 Be衰变所预期的变化的两倍。几种可能的解释，这种行为和使用浸出10 Be/9 Be的约会的潜在后果进行了讨论。
Using sequential leaching experiments we have measured the fraction of the cosmogenic isotope10Be (half-life 1.5 My), and its stable isotope9Be, co-extracted with the following phases in marine sediments: exchangeable, calcium carbonate, Fe and Mn oxyhydroxides, organic, opal and detrital. The extraction of the authigenic phases typically release ∼70% of the10Be but only ∼40% of the9Be. In order to test its potential for dating marine sediments, we have measured the authigeniccally associated10Be/9Be in 17 surface sediment samples from different ocean basins. The observed spatial variability, which appears to be influenced by proximity to continental input of9Be, precludes the general and precise applications of leached10Be/9Be for dating. However, the relatively constant value observed in surface sediments over large areas of the Pacific, Indian and Southern Atlantic oceans shows considerable promise for approximate dating of open oceans sediments.In order to test temporal variability, a profile of the authigenically associated10Be/9Be ratio has been measured in the independently dated Central Pacific core, RC12-65. The observed variation in10Be/9Be over the past nine My is approximately twice that expected on the basis of10Be decay alone. Several possible explanations for such behavior and their potential consequences for the use of leached10Be/9Be for dating are discussed.