Petrographic classification of middle ordovician fossil meteorites from Sweden
(2007) In Meteoritics and Planetary Science 42(10). p.1781-1789- Abstract
- The maximum diameter of chromite (FeCr2O4) grains within L chondrites reflects the petrographic type of the sample. On the basis of our measurements of nine recent L chondrites, L3 chromite D-mac = 34-50 mu m, L4 = 87-150 mu m, L5 = 76-158 mu m, and L6 = 253-638 mu m. This variation reflects the crystallization of the chromite grains during parent body thermal metamorphism.We use this calibration to classify six fossil meteorites from the Middle Ordovician in Sweden as type 3 (or 4) to 6. The high flux of L chondrites at 470 Ma contained a range of petrographic types and may have had a higher proportion of lower petrographic type meteorites than are found in recent L chondrite falls. The fossil meteorites have in places preserved... (More)
- The maximum diameter of chromite (FeCr2O4) grains within L chondrites reflects the petrographic type of the sample. On the basis of our measurements of nine recent L chondrites, L3 chromite D-mac = 34-50 mu m, L4 = 87-150 mu m, L5 = 76-158 mu m, and L6 = 253-638 mu m. This variation reflects the crystallization of the chromite grains during parent body thermal metamorphism.We use this calibration to classify six fossil meteorites from the Middle Ordovician in Sweden as type 3 (or 4) to 6. The high flux of L chondrites at 470 Ma contained a range of petrographic types and may have had a higher proportion of lower petrographic type meteorites than are found in recent L chondrite falls. The fossil meteorites have in places preserved recognizable chondrule textures, including porphyritic olivine, barred olivine, and radiating pyroxene. A large relict clast and fusion crust have also been tentatively identified in one fossil meteorite. Apart from chromite, all of the original meteorite minerals have been replaced by carbonate (and sheet silicate and sulfate) during diagenesis within the limestone host. The preservation of chondrule definition has allowed us to measure the mean diameters of relict chondrules. The range (0.4-0.6 mm) is consistent with measurements made in the same way on recent L chondrites. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1407597
- author
- Bridges, J. C. ; Schmitz, Birger LU ; Hutchison, R. ; Greenwood, R. C. ; Tassinari, M and Franch, I. A.
- organization
- publishing date
- 2007
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Meteoritics and Planetary Science
- volume
- 42
- issue
- 10
- pages
- 1781 - 1789
- publisher
- Wiley-Blackwell
- external identifiers
-
- wos:000252529700007
- scopus:38949120516
- ISSN
- 1086-9379
- DOI
- 10.1111/j.1945-5100.2007.tb00537.x
- language
- English
- LU publication?
- yes
- id
- 5a5c8ea5-6058-46d4-b1b5-9a2281ef5412 (old id 1407597)
- date added to LUP
- 2016-04-01 16:16:06
- date last changed
- 2022-02-27 20:03:34
@article{5a5c8ea5-6058-46d4-b1b5-9a2281ef5412,
abstract = {{The maximum diameter of chromite (FeCr2O4) grains within L chondrites reflects the petrographic type of the sample. On the basis of our measurements of nine recent L chondrites, L3 chromite D-mac = 34-50 mu m, L4 = 87-150 mu m, L5 = 76-158 mu m, and L6 = 253-638 mu m. This variation reflects the crystallization of the chromite grains during parent body thermal metamorphism.We use this calibration to classify six fossil meteorites from the Middle Ordovician in Sweden as type 3 (or 4) to 6. The high flux of L chondrites at 470 Ma contained a range of petrographic types and may have had a higher proportion of lower petrographic type meteorites than are found in recent L chondrite falls. The fossil meteorites have in places preserved recognizable chondrule textures, including porphyritic olivine, barred olivine, and radiating pyroxene. A large relict clast and fusion crust have also been tentatively identified in one fossil meteorite. Apart from chromite, all of the original meteorite minerals have been replaced by carbonate (and sheet silicate and sulfate) during diagenesis within the limestone host. The preservation of chondrule definition has allowed us to measure the mean diameters of relict chondrules. The range (0.4-0.6 mm) is consistent with measurements made in the same way on recent L chondrites.}},
author = {{Bridges, J. C. and Schmitz, Birger and Hutchison, R. and Greenwood, R. C. and Tassinari, M and Franch, I. A.}},
issn = {{1086-9379}},
language = {{eng}},
number = {{10}},
pages = {{1781--1789}},
publisher = {{Wiley-Blackwell}},
series = {{Meteoritics and Planetary Science}},
title = {{Petrographic classification of middle ordovician fossil meteorites from Sweden}},
url = {{http://dx.doi.org/10.1111/j.1945-5100.2007.tb00537.x}},
doi = {{10.1111/j.1945-5100.2007.tb00537.x}},
volume = {{42}},
year = {{2007}},
}