Selective release of D and 13C from insoluble organic matter of the Murchison meteorite by impact shock
Selective release of D and 13C from insoluble organic matter of the Murchison meteorite by impact shock
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DOI：
10.1111/j.1945-5100.2007.tb00238.x
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发表时间：
2007-03-01
影响因子：
2.2
通讯作者：
Hashimoto, Shigemasa
中科院分区：
文献类型：
--
作者：
Mimura, Koichi;Okamoto, Michioki;Hashimoto, Shigemasa
对墨尔奇逊陨石中提纯的不溶有机物(IOM)进行了冲击恢复实验，测定了冲击后IOM样品中氢、碳的丰度和碳的同位素比值。我们还对III型干酪根进行了冲击实验，并将这些实验结果与关于IOM的实验结果进行了比较，发现冲击从IOM中选择性地释放出D和C-13，而从干酪根中优先释放H和C-12。这些元素从IOM中的释放不能用同位素效应来解释，而它们从干酪根中的释放可以用这种效应来解释。IOM选择性释放较重的同位素是由于其结构，其中富含D和C-13的部分以不均匀形式存在，并与主网络连接较弱。与IOM的分级加热相比，即使在较低的脱氢程度下，冲击也会导致D的高释放。这种D的有效释放可能是冲击的内在结果，在冲击中，动态的高压和高温条件占优势。因此，激波将有效地控制太阳星云演化过程中地外有机质的氢同位素行为。
We performed shock-recovery experiments on insoluble organic matter (IOM) purified from the Murchison meteorite, and determined the abundances and isotope ratios of hydrogen and carbon in the shocked IOM sample. We also performed shock experiments on type III kerogen and compared the results of these experiments with the experimental results regarding IOM.The shock selectively released D and C-13 from the IOM, while it preferably released H and C-12 from the kerogen. The release of these elements from IOM cannot be explained in terms of the isotope effect, whereas their release from kerogen can be explained by this effect. The selective release of heavier isotopes from IOM would be due to its structure, in which D and C-13-enriched parts are present as an inhomogeneity and are weakly attached to the main network. Shock gave rise to a high release of D even at a lower degree of dehydrogenation compared with the stepwise heating of IOM. This effective release of D is probably an inherent result of shock, in which a dynamic high-pressure and high-temperature condition prevails. Thus, shock would effectively control the hydrogen isotope behavior of extraterrestrial organic matter during the evolution of the solar nebula.