Dating of meteorites by the high-temperature release of iodine-correlated Xe129
Dating of meteorites by the high-temperature release of iodine-correlated Xe129
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通过高温释放与碘相关的 Xe129 对陨石进行年代测定
DOI：
10.1016/0016-7037(70)90111-0
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发表时间：
1970
影响因子：
5
通讯作者：
F. Podosek
中科院分区：
文献类型：
--
作者：
F. Podosek
在中子辐照陨石的逐步加热中释放的Xe 129 和Xe 128 量之间的相关性用于确定初始比率I 129 I 127 ，从而确定各种样品的相对形成时间。在这样的实验中，我们获得了九个样本的数百万年的形成时间（相对于 L4 球粒陨石 Bjurböle）：− Karoonda（C4 球粒陨石）为 3.9±0.7； Chainpur (LL3) 的基质和球粒分别为 3.1±0.6 和 10.5±0.7；圣塞维林 (LL6) 为 7.5±1.0； Allegan (H5) 的基质和球粒分别为 3.9±2.9 和− 2.3±1.0； Peña Blanca Spring 为 3.6±0.7，Bishopville（奥布里特）为 20.8±9.5；铁陨石 El Taco (Campo del Cielo) 的硅酸盐包裹体为 3.8±0.7。没有对捕获气体中 Xe 129 的含量做出任何假设。之前发布的数据的相关性也以同样的方式重新计算，没有对捕获的 Xe 129 进行任何假设。对于之前报道的一组平均同时性为 250 万年的球粒陨石，重新计算证实了这种平均同时性，但形成时间的显着差异得到了解决。从无球粒陨石拉斐特未发表的数据中获得了 53±9 百万年的碘-氙年龄（比约伯勒之后）。考虑了单个陨石碘氙年龄的可靠性；特别是，毕夏普维尔和拉斐特的年龄不如大多数其他研究过的陨石的年龄可靠，特别是考虑到报告的异常年龄。讨论了碘-氙年代测定与核合成理论、早期太阳系年代学和陨石母体形成理论的相关性。
Correlations between the amounts of Xe 129 and Xe 128 released in stepwise heating of neutron-irradiated meteorites are used to determine the initial ratio I 129 I 127 and hence a relative formation time for the various samples. In such an experiment, we obtain the formation times in millions of years (relative to the L4 chondrite Bjurböle) of nine specimens:− 3.9±0.7 for Karoonda (C4 chondrite); 3.1±0.6 and 10.5±0.7 for the matrix and chondrules, respectively, of Chainpur (LL3); 7.5±1.0 for St. Severin (LL6); 3.9±2.9 and− 2.3±1.0 for the matrix and chondrules, respectively, of Allegan (H5); 3.6±0.7 for Peña Blanca Spring and 20.8±9.5 for Bishopville (aubrites); 3.8±0.7 for a silicate inclusion of the iron meteorite El Taco (Campo del Cielo). No assumptions are made about the amount of Xe 129 in the trapped gas. The correlations for previously published data have also been recalculated in the same way, with no assumptions about trapped Xe 129. For a group of chondrites previously reported to be isochronous with a mean simultaneity of 2.5 million years, the recalculation confirms this mean simultaneity, but significant differences in formation times are resolved. An iodine-xenon age of 53±9 million years (after Bjurböle) is obtained from unpublished data for the achondrite Lafayette. The reliability of iodine-xenon ages of individual meteorites is considered; in particular, the ages of Bishopville and Lafayette are less reliable than those of most other meteorites studied, especially in view of the anomalous ages reported. The relevance of iodine-xenon dating to theories of nucleosynthesis, early solar system chronology, and theories of meteorite parent-body formation is discussed.