| タイトル | Clues to the origin of sulfide minerals in CI chondrites |
| 著者（英） | Kerridge, J. F.; Marti, K.; Macdougall, J. D. |
| 著者所属（英） | California Univ.|California Univ. |
| 発行日 | 1979-06-01 |
| 言語 | eng |
| 内容記述 | The dominant sulfide in CI carbonaceous chondrites is an Fe-deficient pyrrhotite containing about 1% Ni, Alais, Ivuna, and Orgueil also contain minor cubanite, CuFe2S3, and Alais minor pentlandite, (Fe,Ni)9S8. All pyrrhotites contain 39.4 + or - 0.1% S; Ni contents range from 0.7 to 1.3%. The phase diagrams reveal no temperature at which the observed pentlandite-pyrrhotite assemblage is at equilibrium. Similarly, the pyrrhotite composition alone are inconsistent with equilibrium formation from a gas of solar composition. In Xe from high-purity submilligram Orgueil pyrrhotite separates, the ratios Xe-129/Xe-132 are not significantly larger than those in trapped meteoritic Xe. The lack of positive evidence for extinct I-129 in pyrrhotite does not permit any inferences regarding cooling rates in the early solar nebula. It is concluded that sulfides in CI chondrites cannot be nebular condensates formed under equilibrium conditions. Argon isotopic abundances reveal the presence of significant spallation and trapped gas components in Orgueil pyrrhotite. The Orgueil exposure age is calculated to be at least about 10 m.y. |
| NASA分類 | LUNAR AND PLANETARY EXPLORATION |
| レポートNO | 79A44866 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/426126 |
|
