| タイトル | A Bi-Modal Distribution of ALHA77307 Matrix Olivine: Evidence for Fine-Grained Mixing from Multiple Reservoirs in the CO Formation Zone |
| 本文（外部サイト） | http://hdl.handle.net/2060/20110014557 |
| 著者（英） | Zolensky, Michael E.; Frank, D.; Le, L.; Brearley, A. |
| 著者所属（英） | NASA Johnson Space Center |
| 発行日 | 2011-08-08 |
| 言語 | eng |
| 内容記述 | The CO 3.0 chondrite ALHA77307 is thought to be the least metamorphosed of all the CO chondrites [1]. As such, the fine-grained (<30 m) olivine found in its matrix is a valuable resource for investigating the CO formation environment since its compositions should be primary. In the CO matrix, we indeed find a wide range of major element compositions (Fa(0.5-71)). However, more importantly, we find that the olivines make up two compositionally distinct populations (Fa(0.5-5) and Fa(21-71)). Grains from both populations are found within an extremely close proximity and we see no obvious evidence of two distinct lithologies within our samples. Therefore, we conclude that the olivine grains found in the ALHA77307 matrix must have crystallized within two unique formation conditions and were later mixed at a very fine scale during the accretion epoch. Here, we propose a possible explanation based on Cr and Mn concentrations in the olivine. |
| NASA分類 | Geophysics |
| レポートNO | JSC-CN-24362 |
| 権利 | Copyright, Distribution as joint owner in the copyright |
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