39Ar recoil losses and presolar ages in Allende inclusions
39Ar recoil losses and presolar ages in Allende inclusions
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阿连德包裹体中的 39Ar 反冲损失和太阳前年龄
DOI：
10.1016/0012-821x(83)90017-1
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发表时间：
1983
影响因子：
5.3
通讯作者：
G. Wasserburg
中科院分区：
文献类型：
--
作者：
I. Villa;J. Huneke;G. Wasserburg
据报告，对阿连德陨石中的五种粗粒、富含 Ca-Al 的包裹体进行了 Ar 分析。在各个真空安瓿中对样品进行中子照射，并对安瓿中的Ar气以及样品进行分析。来自 39 K (n, p) 反应的大部分（高达 60%） 39 Ar 从内含物中损失到安瓿中。 39 Ar损失导致样品的表观40 Ar- 39 Ar年龄显着增加。中子辐照过程中的39 Ar反冲损失是主要影响并且必须在40 Ar- 39 Ar测年中加以考虑。研究的所有阿连德包裹体均含有大量被捕获的 36 Ar。被捕获的 36 Ar 的来源未知，并且不能排除被捕获的 40 Ar 的可能存在。对已产生异常老年的阿连德包裹体的 Ar 测量必须在 39 Ar 反冲损失和捕获的 40 Ar 的可能贡献的背景下重新检查。从这两个方面来看，阿连德包裹体似乎不太适合寻找具有明确 K/Ar 年龄的太阳前物质遗迹。
Ar analyses are reported for five coarse-grained, Ca-Al-rich inclusions from the Allende meteorite. The samples were neutron-irradiated in individual evacuated ampoules, and the Ar gas in the ampoules as well as the samples was analyzed. A large fraction (up to 60%) of the39Ar from39K (n, p) reactions was lost out of the inclusions into the ampoules. The39Ar losses resulted in substantial increases in the apparent40Ar-39Ar ages of the samples.39Ar recoil loss during neutron-irradiation is a major effect and must be accounted for in40Ar-39Ar dating. All of the Allende inclusions studied contained substantial trapped36Ar. The origin of the trapped36Ar is unknown, and the possible presence of trapped40Ar cannot be excluded. Ar measurements on Allende inclusions which have yielded anomalously old ages must be re-examined in the context of39Ar recoil loss and possible contributions of trapped40Ar. Allende inclusions appear on both accounts to be poor candidates to search for relicts of presolar materials with well-defined K/Ar ages.