| タイトル | Asteroidal Differentiation Processes Deduced from Ultramafic Achondrite Ureilite Meteorites |
| 本文（外部サイト） | http://hdl.handle.net/2060/20060056235 |
| 著者（英） | Franchi, Ian; Mittlefehldt, David W.; Romanek, Christopher S.; Downes, Hilary; Hudson, Pierre |
| 著者所属（英） | NASA Johnson Space Center |
| 発行日 | 2006-01-01 |
| 言語 | eng |
| 内容記述 | Ureilites are the second largest achondrite group. They are ultramafic achondrites that have experienced igneous processing whilst retaining some degree of nebula-derived chemical heterogeneity. They differ from other achondrites in that they contain abundant carbon and their oxygen isotope compositions are very heterogeneous and similar to those of the carbonaceous chondrite anhydrous mineral line. Their carbonaceous nature and some compositional characteristics indicative of nebular origin suggest that they are primitive materials that form a link between nebular processes and early periods of planetesimal accretion. However, despite numerous studies, the exact origin of ureilites remains unclear. Current opinion is that they represent the residual mantle of an asteroid that underwent silicate and Fe-Ni-S partial melting and melt removal. Recent studies of short-lived chronometers indicate that the parent asteroid of the ureilites differentiated very early in the history of the Solar System. Therefore, they contain important information about processes that formed small rocky planetesimals in the early Solar System. In effect, they form a bridge between nebula processes and differentiation in small planetesimals prior to accretion into larger planets and so a correct interpretation of ureilite petrogenesis is essential for understanding this critical step. |
| NASA分類 | Lunar and Planetary Science and Exploration |
| 権利 | Copyright, Distribution as joint owner in the copyright |
