The origin of the Brunflo fossil meteorite and extraterrestrial chromite in mid-Ordovician limestone from the Garde quarry (Jamtland, central Sweden)
(2009) In Meteoritics and Planetary Science 44(1). p.95-106- Abstract
- The Brunflo fossil meteorite was found in the 1950s in mid-Ordovician marine limestone in the Garde quarry in Jamtland. It originates from strata that are about 5 million years younger than similar limestone that more recently has yielded >50 fossil meteorites in the Thorsberg quarry at Kinnekulle, 600 km to the south. Based primarily on the low TiO2 content (about 1.8 wt%) of its relict chromite the Brunflo meteorite had been tentatively classified as an H chondrite. The meteorite hence appears to be an anomaly in relation to the Kinnekulle meteorites, in which chromite composition, chondrule mean diameter and oxygen isotopic composition all indicate an L-chondritic origin, reflecting an enhanced flux of meteorites to Earth following... (More)
- The Brunflo fossil meteorite was found in the 1950s in mid-Ordovician marine limestone in the Garde quarry in Jamtland. It originates from strata that are about 5 million years younger than similar limestone that more recently has yielded >50 fossil meteorites in the Thorsberg quarry at Kinnekulle, 600 km to the south. Based primarily on the low TiO2 content (about 1.8 wt%) of its relict chromite the Brunflo meteorite had been tentatively classified as an H chondrite. The meteorite hence appears to be an anomaly in relation to the Kinnekulle meteorites, in which chromite composition, chondrule mean diameter and oxygen isotopic composition all indicate an L-chondritic origin, reflecting an enhanced flux of meteorites to Earth following the disruption of the L chondrite parent body 470 Ma. New chondrule-size measurements for the Brunflo meteorite indicate that it too is an L chondrite, related to the same parent-body breakup. Chromite maximum diameters and well-defined chondrule structures further show that Brunflo belongs to the L4 or L5 type. Chromites in recently fallen L4 chondrites commonly have low TiO2 contents similar to the Brunflo chromites, adding support for Brunflo being an L4 chondrite. The limestone in the Circle quarry is relatively rich (about 0.45 grain kg(-1)) in sediment-dispersed extraterrestrial chromite grains (>63 mu m) with chemical composition similar to those in L chondrites and the limestone (1-3 grains kg(-1)) at Kinnekulle, suggesting that the enhanced flux of L chondrites prevailed, although somewhat diminished, at the time when the Brunflo meteorite fell. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1401770
- author
- Alwmark, Carl LU and Schmitz, Birger LU
- organization
- publishing date
- 2009
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Meteoritics and Planetary Science
- volume
- 44
- issue
- 1
- pages
- 95 - 106
- publisher
- Wiley-Blackwell
- external identifiers
-
- wos:000264476300008
- scopus:64549097249
- ISSN
- 1086-9379
- language
- English
- LU publication?
- yes
- id
- 5ef62210-5720-41d9-82b8-bcb27311fcda (old id 1401770)
- date added to LUP
- 2016-04-01 14:33:39
- date last changed
- 2022-03-22 00:45:33
@article{5ef62210-5720-41d9-82b8-bcb27311fcda,
abstract = {{The Brunflo fossil meteorite was found in the 1950s in mid-Ordovician marine limestone in the Garde quarry in Jamtland. It originates from strata that are about 5 million years younger than similar limestone that more recently has yielded >50 fossil meteorites in the Thorsberg quarry at Kinnekulle, 600 km to the south. Based primarily on the low TiO2 content (about 1.8 wt%) of its relict chromite the Brunflo meteorite had been tentatively classified as an H chondrite. The meteorite hence appears to be an anomaly in relation to the Kinnekulle meteorites, in which chromite composition, chondrule mean diameter and oxygen isotopic composition all indicate an L-chondritic origin, reflecting an enhanced flux of meteorites to Earth following the disruption of the L chondrite parent body 470 Ma. New chondrule-size measurements for the Brunflo meteorite indicate that it too is an L chondrite, related to the same parent-body breakup. Chromite maximum diameters and well-defined chondrule structures further show that Brunflo belongs to the L4 or L5 type. Chromites in recently fallen L4 chondrites commonly have low TiO2 contents similar to the Brunflo chromites, adding support for Brunflo being an L4 chondrite. The limestone in the Circle quarry is relatively rich (about 0.45 grain kg(-1)) in sediment-dispersed extraterrestrial chromite grains (>63 mu m) with chemical composition similar to those in L chondrites and the limestone (1-3 grains kg(-1)) at Kinnekulle, suggesting that the enhanced flux of L chondrites prevailed, although somewhat diminished, at the time when the Brunflo meteorite fell.}},
author = {{Alwmark, Carl and Schmitz, Birger}},
issn = {{1086-9379}},
language = {{eng}},
number = {{1}},
pages = {{95--106}},
publisher = {{Wiley-Blackwell}},
series = {{Meteoritics and Planetary Science}},
title = {{The origin of the Brunflo fossil meteorite and extraterrestrial chromite in mid-Ordovician limestone from the Garde quarry (Jamtland, central Sweden)}},
volume = {{44}},
year = {{2009}},
}