Enhanced cosmic‐ray production of 10Be coincident with the Mono Lake and Laschamp Geomagnetic Excursions
Enhanced cosmic‐ray production of 10Be coincident with the Mono Lake and Laschamp Geomagnetic Excursions
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DOI：
10.1029/95gl00169
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发表时间：
1995-03
影响因子：
5.2
通讯作者：
L. McHargue;P. Damon;D. Donahue
中科院分区：
文献类型：
--
作者：
L. McHargue;P. Damon;D. Donahue
对加利福尼亚州海湾段480岩芯上部50m的部分变异沉积物中的宇宙成因同位素10Be、总Be和Al进行了测定。10Be的浓度从1到50Kyr与从考古地磁和海洋岩心研究中获得的地磁偶极矩的估计值基本一致。在32KYR和43KYR还发现了10个Be异常，分别与莫诺湖和拉尚漂移同期。解释这些异常所需的10BE的产量太高了，特别是对于莫诺湖漂移来说，这是由地磁场减弱和前所未有的长期太阳活动共同产生的。我们得出的结论是，原因是银河系宇宙射线流量的变化与超新星事件一致。这两次旅行的巧合仍然是一个悖论。
The cosmogenic isotope 10 Be , total Be, and Al were measured in partly varved sediments from the upper 50 m of core 480, leg 64 (DSDP), Gulf of California. The concentration of 10 Be from 1 to 50 kyr is in general agreement with estimates of the geomagnetic dipole moment obtained from archaeomagnetic and marine core research. 10 Be anomalies were also found at 32 kyr and 43 kyr, contemporaneous with the Mono Lake and Laschamp excursions, respectively. The production of 10 Be required to explain these anomalies is too high, particularly for the Mono Lake excursion, to be produced by a combination of decreased geomagnetic field and unprecedented long-term solar activity. We conclude that the cause is a change in the galactic cosmic-ray flux consistent with a supernova event. The coincidence with the two excursions remains a paradox.