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Shocked chromites in fossil L chondrites : A Raman spectroscopy and transmission electron microscopy study

Rout, Surya S.; Heck, Philipp R.; Zaluzec, Nestor J.; Ishii, Takayuki; Wen, Jianguo; Miller, Dean J. and Schmitz, Birger LU (2017) In Meteoritics and Planetary Science
Abstract

Chromites from Middle Ordovician fossil L chondrites and from matrix and shock-melt veins in Catherwood, Tenham, and Coorara L chondrites were studied using Raman spectroscopy and TEM. Raman spectra of chromites from fossil L chondrites showed similarities with chromites from matrix and shock-melt veins in the studied L chondrite falls and finds. Chromites from shock-melt veins of L chondrites show polycrystallinity, while the chromite grains in fossil L chondrites are single crystals. In addition, chromites from shock-melt veins in the studied L chondrites have high densities of planar fractures within the subgrains and many subgrains show intergrowths of chromite and xieite. Matrix chromite of Tenham has similar dislocation densities... (More)

Chromites from Middle Ordovician fossil L chondrites and from matrix and shock-melt veins in Catherwood, Tenham, and Coorara L chondrites were studied using Raman spectroscopy and TEM. Raman spectra of chromites from fossil L chondrites showed similarities with chromites from matrix and shock-melt veins in the studied L chondrite falls and finds. Chromites from shock-melt veins of L chondrites show polycrystallinity, while the chromite grains in fossil L chondrites are single crystals. In addition, chromites from shock-melt veins in the studied L chondrites have high densities of planar fractures within the subgrains and many subgrains show intergrowths of chromite and xieite. Matrix chromite of Tenham has similar dislocation densities and planar fractures as a chromite from the fossil meteorite Golvsten 001 and higher dislocation densities than in chromite from the fossil meteorite Sextummen 003. Using this observation and knowing that the matrix of Tenham experienced 20-22 GPa and <1000° C, an upper limit for the P,T conditions of chromite from Golvsten 001 and Sextummen 003 can be estimated to be 20-22 GPa and 1000° C (shock stage S3-S6) and 20 GPa and 1000° C (S3-S5), respectively, and we conclude that the studied fossil meteorite chromites are from matrix.

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organization
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Contribution to journal
publication status
in press
subject
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Meteoritics and Planetary Science
publisher
Wiley-Blackwell
external identifiers
  • scopus:85018950766
ISSN
1086-9379
DOI
10.1111/maps.12887
language
English
LU publication?
yes
id
6ac9a0af-d695-403e-8910-09eb33c958db
date added to LUP
2017-06-07 14:36:33
date last changed
2017-06-07 14:36:33
@article{6ac9a0af-d695-403e-8910-09eb33c958db,
  abstract     = {<p>Chromites from Middle Ordovician fossil L chondrites and from matrix and shock-melt veins in Catherwood, Tenham, and Coorara L chondrites were studied using Raman spectroscopy and TEM. Raman spectra of chromites from fossil L chondrites showed similarities with chromites from matrix and shock-melt veins in the studied L chondrite falls and finds. Chromites from shock-melt veins of L chondrites show polycrystallinity, while the chromite grains in fossil L chondrites are single crystals. In addition, chromites from shock-melt veins in the studied L chondrites have high densities of planar fractures within the subgrains and many subgrains show intergrowths of chromite and xieite. Matrix chromite of Tenham has similar dislocation densities and planar fractures as a chromite from the fossil meteorite Golvsten 001 and higher dislocation densities than in chromite from the fossil meteorite Sextummen 003. Using this observation and knowing that the matrix of Tenham experienced 20-22 GPa and &lt;1000° C, an upper limit for the P,T conditions of chromite from Golvsten 001 and Sextummen 003 can be estimated to be 20-22 GPa and 1000° C (shock stage S3-S6) and 20 GPa and 1000° C (S3-S5), respectively, and we conclude that the studied fossil meteorite chromites are from matrix.</p>},
  author       = {Rout, Surya S. and Heck, Philipp R. and Zaluzec, Nestor J. and Ishii, Takayuki and Wen, Jianguo and Miller, Dean J. and Schmitz, Birger},
  issn         = {1086-9379},
  language     = {eng},
  publisher    = {Wiley-Blackwell},
  series       = {Meteoritics and Planetary Science},
  title        = {Shocked chromites in fossil L chondrites : A Raman spectroscopy and transmission electron microscopy study},
  url          = {http://dx.doi.org/10.1111/maps.12887},
  year         = {2017},
}