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Comparing wild 2 particles to chondrites and idps
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Weisberg, Michael Simon, Steven Graham Sr., Giles Ishii, Hope Velbel, Michael Rietmeijer Sr., Frans Nakamura-Messenger, Keiko Grossman, Lawrence Nakamura, Tomoki Matrajt, Graciela Tomioka, Naotaka Mikouchi, Takashi Zolensky, Michael Stroud, Rhonda Kearsley, Anton Langenhorst, Falko Ohnishi, Ichiro Leroux Sr., Hugues Ohsumi, Kazumasa Stephan Sr., Thomas Tomeoka, Kazushige Brownlee, Don Zega Sr., Thomas Joswiak, David Krot, Alexander |
| Copyright Year | 2008 |
| Description | We compare the observed composition ranges of olivine, pyroxene and Fe-Ni sulfides in Wild 2 grains, comparing these with chondritic IDPs and chondrite classes to explore whether these data suggest affinities to known hydrous materials in particular. Wild 2 olivine has an extremely wide composition range, from Fo4-100 with a pronounced frequency peak at Fo99. The composition range displayed by the low-calcium pyroxene is also very extensive, from En52 to En100, with a significant frequency peak centered at En95. These ranges are as broad or broader than those reported for any other extraterrestrial material. Wild 2 Fe-Ni sulfides mainly have compositions close to that of FeS, with less than 2 atom % Ni - to date, only two pentlandite grains have been found among the Wild-grains suggesting that this mineral is not abundant. The complete lack of compositions between FeS and pentlandite (with intermediate solid solution compositions) suggests (but does not require) that FeS and pentlandite condensed as crystalline species, i.e. did not form as amorphous phases, which later became annealed. While we have not yet observed any direct evidence of water-bearing minerals, the presence of Ni-bearing sulfides, and magnesium-dominated olivine and low-Ca pyroxene does not rule out their presence at low abundance. We do conclude that modern major and minor element compositions of chondrite matrix and IDPs are needed. |
| File Size | 5933569 |
| Page Count | 24 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20080013409 |
| Archival Resource Key | ark:/13960/t5m956c62 |
| Language | English |
| Publisher Date | 2008-01-01 |
| Access Restriction | Open |
| Subject Keyword | Olivine Scanning Electron Microscopy Pyroxenes Calcium Mineralogy Iron Particles Wild 2 Comet Aerogels Sulfides Transmission Electron Microscopy Solid Solutions Chondrites Nickel Interplanetary Dust Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
