Shock melting of ordinary chondrite powders and implications for asteroidal regoliths

— A series of 59 impacts in the laboratory reduced a coherent 460 g piece of the L6 ordinary chondrite ALH 85017 to a coarse‐grained “regolith.” We then subjected the 125–250 μm fines from this sample to reverberation shock stresses of 14.5–67 GPa in order to delineate the melting behavior of porous...

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Bibliographic Details
Published in:Meteoritics & planetary science 2005-10, Vol.40 (9-10), p.1329-1346
Main Authors: Hörz, Friedrich, Cintala, Mark J., See, Thomas H., Le, Loan
Format: Article
Language:English
Subjects:
Asteroids
Chondrites
Droplets
Iron
Melting
Melts
Meteorites
Meteors & meteorites
Reduction
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Summary:— A series of 59 impacts in the laboratory reduced a coherent 460 g piece of the L6 ordinary chondrite ALH 85017 to a coarse‐grained “regolith.” We then subjected the 125–250 μm fines from this sample to reverberation shock stresses of 14.5–67 GPa in order to delineate the melting behavior of porous, unconsolidated, chondritic asteroid surfaces during meteorite impact. The initial pore space (40–50%) was completely closed at 14.5 GPa and a dense aggregate of interlocking grains resulted. Grain‐boundary melting commenced at 80 GPa, which is associated with impact velocities >8 km/sec. The Fe‐Ni and troilite clasts of the original meteorite melted with particular ease, forming immiscible melts that are finely disseminated throughout the silicate glass. These metal droplets are highly variable in size, extending to
ISSN:1086-9379
1945-5100
DOI:10.1111/j.1945-5100.2005.tb00404.x