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The Österplana Fossil Meteorites and… What Else? Terrestrial Cr-Spinels and Zircons in the Ordovician Limestones of the Thorsberg Quarry (Sweden)

Lenaz, Davide ; Velicogna, Matteo ; Petrelli, Maurizio and Schmitz, Birger LU (2022) In Geosciences (Switzerland) 12(2).
Abstract

In the Ordovician limestone of the Thorsberg quarry (South Sweden), about 130 meteorites have been found. Among the extraterrestrial material, several terrestrial Cr-spinels and zircons have been found too. In particular, in the interval 416–447 cm above the Arkeologen bed, terrestrial Cr-spinels, compositionally different from previous studied Cr-spinels of the same sequence, are present. Previous studies on zircon provided depositional ages that range from 464.22 ± 0.37 Ma to 465.01 ± 0.26 Ma. The trace element content of zircons suggests different possible source rocks. In fact, zircons from the oldest ash layer resemble those from dolerite, while those in the youngest layers are similar to zircons commonly found in granitoids, with... (More)

In the Ordovician limestone of the Thorsberg quarry (South Sweden), about 130 meteorites have been found. Among the extraterrestrial material, several terrestrial Cr-spinels and zircons have been found too. In particular, in the interval 416–447 cm above the Arkeologen bed, terrestrial Cr-spinels, compositionally different from previous studied Cr-spinels of the same sequence, are present. Previous studies on zircon provided depositional ages that range from 464.22 ± 0.37 Ma to 465.01 ± 0.26 Ma. The trace element content of zircons suggests different possible source rocks. In fact, zircons from the oldest ash layer resemble those from dolerite, while those in the youngest layers are similar to zircons commonly found in granitoids, with more than 65% wt. SiO2 . The chemistry of Cr-spinels suggests a strong alteration, so that it is difficult to assign them to a specific area, however they recall the chemistry of altered spinels from ophiolitic occurrences (among other possibilities). The geological setting of the Laurentia and Baltica areas, including the description of basalts to rhyolite association and the presence of ophiolitic slices, makes us confident about the derivation of these zircons and Cr-spinels from those areas.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Baltica, Cr-spinel, Laurentia, Ordovician, Sweden, Zircon
in
Geosciences (Switzerland)
volume
12
issue
2
article number
54
publisher
MDPI AG
external identifiers
  • scopus:85124139806
ISSN
2076-3263
DOI
10.3390/geosciences12020054
language
English
LU publication?
yes
id
88e7e145-b88d-47d3-b045-d1bbb54a90f9
date added to LUP
2022-05-16 14:43:40
date last changed
2022-05-16 14:43:40
@article{88e7e145-b88d-47d3-b045-d1bbb54a90f9,
  abstract     = {{<p>In the Ordovician limestone of the Thorsberg quarry (South Sweden), about 130 meteorites have been found. Among the extraterrestrial material, several terrestrial Cr-spinels and zircons have been found too. In particular, in the interval 416–447 cm above the Arkeologen bed, terrestrial Cr-spinels, compositionally different from previous studied Cr-spinels of the same sequence, are present. Previous studies on zircon provided depositional ages that range from 464.22 ± 0.37 Ma to 465.01 ± 0.26 Ma. The trace element content of zircons suggests different possible source rocks. In fact, zircons from the oldest ash layer resemble those from dolerite, while those in the youngest layers are similar to zircons commonly found in granitoids, with more than 65% wt. SiO<sub>2</sub> . The chemistry of Cr-spinels suggests a strong alteration, so that it is difficult to assign them to a specific area, however they recall the chemistry of altered spinels from ophiolitic occurrences (among other possibilities). The geological setting of the Laurentia and Baltica areas, including the description of basalts to rhyolite association and the presence of ophiolitic slices, makes us confident about the derivation of these zircons and Cr-spinels from those areas.</p>}},
  author       = {{Lenaz, Davide and Velicogna, Matteo and Petrelli, Maurizio and Schmitz, Birger}},
  issn         = {{2076-3263}},
  keywords     = {{Baltica; Cr-spinel; Laurentia; Ordovician; Sweden; Zircon}},
  language     = {{eng}},
  month        = {{02}},
  number       = {{2}},
  publisher    = {{MDPI AG}},
  series       = {{Geosciences (Switzerland)}},
  title        = {{The Österplana Fossil Meteorites and… What Else? Terrestrial Cr-Spinels and Zircons in the Ordovician Limestones of the Thorsberg Quarry (Sweden)}},
  url          = {{http://dx.doi.org/10.3390/geosciences12020054}},
  doi          = {{10.3390/geosciences12020054}},
  volume       = {{12}},
  year         = {{2022}},
}