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Orisin of chondrites interms of metal-sulfide

金属硫化物球粒陨石的起源

基本信息

批准号：
11304035
负责人：
TSUCHIYAMA Akira
金额：
$ 16.67万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

Chondrites are primitive meteorites, which preserve information about primordial solar nebula. We set a working hypothesis that metel-sulfide grains in, chondrites have been once formed as molten droplets like silicate chondrules during chondrule formaticm and deformedduring of after accumulation as a parent body. The purpose of this study is to verify the hypothesis rniainly by analyzing three-dimensional structure of a chondrite with high-resolution X-ray CT system.An industrial high-resolution X-ray CT scanner was equipped at Osaka Uniyersity in the present project. The evaluation X-ray CT Scanner was successfully made, Such as quantification of contrasts in CT images. Based on this result, three demensional description of the Kobe meteorite was made and possibility of three-demensional curation of meteorite samples was discussed. Furthermore, X-ray CT system with higher resolution using synchrotron radiation was developed at Spring-8.Samples of carbonaceous chondrite, Y77003 (CO3.5), were imaged with these CT apparatuses. Analysis of three-dimensional CT images showed that the hypothesis is correct. Detailed three-dimensional structures suggested that metal-sulfide grains were deformed during accumulation as a parent body. So far, research of chondrites has been made mainly on silicates. In the present study, the origin of metal-sulfide grains was systematically understood with formation of silicate chondrules as a comprehensive model for chondrites formation.

球粒陨石是原始的陨石，它保存了原始太阳星云的信息。我们提出了一个工作假设，即球粒陨石中的金属硫化物颗粒在球粒形成过程中曾以硅酸盐球粒的熔融液滴形式形成，并在积聚后作为母体发生变形。本研究的目的是通过高分辨率x射线CT系统分析球粒陨石的三维结构来验证这一假设。在本项目中，大阪大学配备了一台工业高分辨率x射线CT扫描仪。成功地完成了对x线CT扫描仪的评价，如CT图像对比度的量化。在此基础上，对神户陨石进行了三维描述，并探讨了陨石样品三维管理的可能性。此外，Spring-8还开发了采用同步辐射的高分辨率x射线CT系统。碳质球粒陨石Y77003 （CO3.5）的样品用这些CT设备成像。三维CT图像分析表明，该假设是正确的。详细的三维结构表明，金属硫化物颗粒作为母体在堆积过程中发生了变形。迄今为止，球粒陨石的研究主要集中在硅酸盐上。本研究系统地了解了金属硫化物颗粒的起源，并将硅酸盐球粒的形成作为球粒陨石形成的综合模型。