Redistribution of alkaline elements in association with aqueous activity in the early solar system
Redistribution of alkaline elements in association with aqueous activity in the early solar system
复制标题
早期太阳系中与水活动相关的碱性元素的重新分布
DOI：
10.1088/0004-637x/815/1/76
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
T. Higuch and S. Yoneda
中科院分区：
文献类型：
--
作者：
H. Hidaka;T. Higuch and S. Yoneda
已知Sayama陨石(CM2)在陨石母体上表现出广泛的水蚀变特征，并且由于水蚀变，球粒中的大部分原生矿物被层状硅酸盐取代。本文通过对Sayama球粒陨石的二维拉曼光谱的观察，证实了Sayama球粒陨石中的部分橄榄石是蛇纹岩。球粒陨石的离子探针分析表明，Rb、Cs等碱性元素在球粒陨石中分布不均。球粒陨石蛇纹岩中Rb和Cs含量较高的结果表明，碱性元素在蛇纹石中的选择性吸附与陨石母体早期的水活动有关。此外，通过对球粒陨石的同位素分析，得出球粒陨石中的135Ba/138Ba值和137Ba值/138Ba值。这一结果与我们之前的同位素数据一致，表明Sayama陨石中存在现已灭绝的核素135Cs，但由于巨大的分析不确定性，太阳系中135Cs的丰度仍不清楚。
It is known that the Sayama meteorite (CM2) shows an extensive signature for aqueous alteration on the meteorite parent body, and that most of the primary minerals in the chondrules are replaced with phyllosilicates as the result of the aqueous alteration. In this paper, it is confirmed from the observation of two-dimensional Raman spectra that a part of olivine in a chondrule collected from the Sayama chondrite is serperntinized. Ion microprobe analysis of the chondrule showed that alkaline elements such as Rb and Cs are heterogeneously redistributed in the chondrule. The result of higher Rb and Cs contents in serpentinized phases in the chondrule rather than in other parts suggested the selective adsorption of alkaline elements into the serpentine in association with early aqueous activity on the meteorite parent body. Furthermore Ba isotopic analysis provided variations of 135 Ba/138 Ba and 137 Ba/138 Ba in the chondrule. This result was consistent with our previous isotopic data suggesting isotopic evidence for the existence of the presently extinct nuclide 135 Cs in the Sayama meteorite, but the abundance of 135 Cs in the solar system remains unclear because of large analytical uncertainties.