阿连德陨石中难熔包体与太阳星云气体之间的氧同位素交换。

Oxygen isotope exchange between refractory inclusion in allende and solar nebula Gas.

作者信息

Yurimoto H, Ito M, Nagasawa H

机构信息

H. Yurimoto, Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Ookayama, Meguro, Tokyo 152-8551, Japan. M. Ito and H. Nagasawa, Department of Chemistry, Gakushuin University, Mejiro, Toshima, Tokyo 171-8588, Japan.

出版信息

Science. 1998 Dec 4;282(5395):1874-7.

PMID:9836634

Abstract

A calcium-aluminum-rich inclusion (CAI) from the Allende meteorite was analyzed and found to contain melilite crystals with extreme oxygen-isotope compositions ( approximately 5 percent oxygen-16 enrichment relative to terrestrial oxygen-16). Some of the melilite is also anomalously enriched in oxygen-16 compared with oxygen isotopes measured in other CAIs. The oxygen isotopic variation measured among the minerals (melilite, spinel, and fassaite) indicates that crystallization of the CAI started from oxygen-16-rich materials that were probably liquid droplets in the solar nebula, and oxygen isotope exchange with the surrounding oxygen-16-poor nebular gas progressed through the crystallization of the CAI. Additional oxygen isotope exchange also occurred during subsequent reheating events in the solar nebula.

摘要

对来自阿连德陨石的一颗富钙铝包体（CAI）进行了分析，发现其中含有氧同位素组成极为特殊的黄长石晶体（相对于地球的氧 - 16，氧 - 16富集约5%）。与在其他CAIs中测得的氧同位素相比，一些黄长石的氧 - 16也异常富集。在矿物（黄长石、尖晶石和斜硅钙钛矿）中测得的氧同位素变化表明，CAI的结晶始于富含氧 - 16的物质，这些物质可能是太阳星云里的液滴，并且随着CAI的结晶过程，与周围贫氧 - 16的星云气体发生了氧同位素交换。在太阳星云随后的再加热事件中也发生了额外的氧同位素交换。