Studies on the origin of inclusions and chondrules in meteorites based on isotopic microanalyzes

基于同位素微量分析的陨石包裹体和球粒起源研究

• 批准号: 12440153
• 负责人: HIYAGON Hajime
• 金额: $ 3.52万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12440153/
• 关键词: secondary ion mass spectrometry; refractory inclusion; chondrule; magnesium isotopes; oxygen isotopes; rare earth elements; ultra-refractory component; 炭素質隕石; リム; 同位体異常; 微量元素; エネルギーフィルター法; フリーズソー; イオンマイクロプローブ

In this project, I conducted microanalyzes of oxygen (O) isotopes, magnesium (Mg) isotopes and rare earth elements (REE) using secondary ion mass spectrometry (SIMS) on refractory inclusions (CAIs) and chondrules in primitive meteorites and obtained important information on their origin and formation conditions. (1) I studied an inclusion from a CV chondrite and found large vatiations in oxygen isotopes in anorthite grains. I discussed the cause for such isotopic heterogeneity. (2) I studied rim of CAIs using Mg, O and REE analyzes. It was found that Mg isotopes in CAI rims are not fractionated, suggesting that the rims formed not by evaporation, but by condensation from a hot gas. (3) I conducted O, Mg and REE analyzes on an ultra-refractory nodule found in a fine-grained inclusion from the Allende meteorite. I discussed high temperature processes and gas-dust separation in the early solar nebula. (4) I conducted O and REE analyzes on CAIs found in most primitive ordinary chondrites and enstatite chondrites and found similarities between them and those in carbonaceous chondrites, which suggests a common origin for CAIs. (5) I studied O isotopes in FeO-rich and FeO-poor olivine grains in chondrules. I found similarities in their O isotopes in spite of the difference in the redox condition during their formation.

在这个项目中，我利用二次离子质谱（SIMS）对原始陨石中的难熔包裹体（CAI）和球粒进行了氧（O）同位素、镁（Mg）同位素和稀土元素（REE）的微量分析，并获得了重要信息它们的起源和形成条件。 (1) 我研究了 CV 球粒陨石中的包裹体，发现钙长石颗粒中的氧同位素存在较大变化。我讨论了这种同位素异质性的原因。 (2) 我使用 Mg、O 和 REE 分析研究了 CAI 的边缘。结果发现，CAI 边缘中的镁同位素没有分馏，这表明边缘不是通过蒸发形成的，而是通过热气体冷凝形成的。 (3) 我对阿连德陨石细粒包裹体中发现的超难熔结核进行了 O、Mg 和 REE 分析。我讨论了早期太阳星云中的高温过程和气体尘埃分离。 (4)我对最原始的普通球粒陨石和顽火辉石球粒陨石中发现的CAI进行了O和REE分析，发现它们与碳质球粒陨石中的CAI有相似之处，这表明CAI具有共同的起源。 (5) 我研究了球粒中富 FeO 和贫 FeO 橄榄石颗粒中的 O 同位素。尽管它们形成过程中的氧化还原条件不同，但我发现它们的 O 同位素有相似之处。

项目成果

Y.Lin, et al.: "Unusually abundant refractory inclusions from Sahara 97159 (EH3) : A comparative study with other groups of chondrules"Geochimica et Cosmochimica Acta. (in press). (2003)

Y.Lin 等人：“来自撒哈拉 97159 (EH3) 的异常丰富的难熔包裹体：与其他球粒组的比较研究”Geochimica et Cosmochimica Acta。

M. Kimuia, H. Hiyagon, H. Palme, B Spettel, D. Wolf, R. N. Clayton, T. K. Mayeda, T. Sato, A. Suzuki and H. Kojima: "The most primitive H chondrites, with abundant refractory inclusions"Meteoritics and Planetary Science. 37. 1417-1434 (2002)

M. Kimuia、H. Hiyagon、H. Palme、B Spettel、D. Wolf、R. N. Clayton、T. K. Mayeda、T. Sato、A. Suzuki 和 H. Kojima：“最原始的 H 球粒陨石，具有丰富的难熔包裹体” 流星学

M.Kimura, et al.: "The most primitive H chondrites, with abundant refractory inclusions"Meteoritics and Planetary Science. 37. 1417-1434 (2002)

M.Kimura 等人：“最原始的 H 球粒陨石，具有丰富的耐火包裹体”流星学和行星科学。

M.Kimura, et al.: "FeO-rich silicates in the Sahara 97159 (EH3) enstatite chondrite : Their mineralogy, oxygen isotopic compositions and origin"Meteoritics and Planetary Science. (in press). (2003)

M.Kimura 等人：“撒哈拉 97159 (EH3) 顽辉石球粒陨石中富含 FeO 的硅酸盐：它们的矿物学、氧同位素组成和起源”流星学和行星科学。

M. Kimura, H. Hiyagon, Y. Lin and M. K. Weisberg: "FeO-rich silicates in the Sahara 97159 (EH3) enstatite chondrite : Their mineralogy, oxygen isotopic compositions and origin"Meteoritics and Planetary Science. in press. (2003)

M. Kimura、H. Hiyagon、Y. Lin 和 M. K. Weisberg：“撒哈拉 97159 (EH3) 顽火辉石球粒陨石中富含 FeO 的硅酸盐：它们的矿物学、氧同位素组成和起源”流星学和行星科学。