Petrology of an unusual monomict ureilite, NWA1241
| Autor: | Yukio Ikeda |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Silicide
Ureilite formation Mineral Suessite Olivine Ecology Geochemistry Earth and Planetary Sciences(all) Monomict ureilites Ureilite Pyroxene Aquatic Science engineering.material Kamacite Meteorite Pigeonite engineering General Earth and Planetary Sciences Petrology Unusual ureilites Ecology Evolution Behavior and Systematics Geology |
| Zdroj: | Polar Science. 1:45-53 |
| ISSN: | 1873-9652 |
| DOI: | 10.1016/j.polar.2007.05.002 |
| Popis: | NWA1241 is an unusual monomict ureilite, consisting mainly of pigeonite, olivine, suessite, and carbonaceous materials. The modal ratio of pyroxene/(olivine + pyroxene) is higher than those of common monomict ureilites. Metallic phases in NWA1241 are mainly suessite, although metals in common ureilites are mainly kamacite. The high ratio of pyroxene to olivine and the abundant occurrence of suessite make the meteorite unusual. The suessite coexists with magnesian olivine and pyroxene in NWA1241, and this mineral assemblage indicates that the suessite was produced from FeO-bearing olivine and Ni-bearing kamacite at temperatures around 1500–1400K and oxygen fugacity of 10−18–10−20 bars. Most ureilites experienced two-stage reduction. Stage-I reduction was a smelting process in ureilite parent bodies (UPB's) to form the framework of monomict ureilites. Stage-II reduction took place after catastrophic destruction of the UPB's to eject many fragmental blocks into space, where suessite (NWA1241) or Si-bearing kamacite (common ureilites) were produced together with the formation of reversely zoned olivines. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect