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Palaeoenvironmental significance of cool- water microbialites in the Darriwilian ( Middle Ordovician) of Sweden

Lindskog, Anders LU (2014) In Lethaia 47(2). p.187-204
Abstract
Well-developed oncoids and centimetre-sized stromatolites are reported for the first time from the Darriwilian (Middle Ordovician) cool-water orthoceratite limestone' at Kinnekulle, Vastergotland, Sweden. The characteristics and stratigraphical distribution of these microbialites show an apparent relationship to fluctuations in relative sea level. The most abundant and well-developed oncoids occur in stratigraphical intervals that are characterized by notable sea-level lowstands. Stromatolites, which share many compositional characteristics with the oncoids, are essentially confined to a single bed associated with an especially prominent lowstand. Stromatolite-like lamination also occurs in the uppermost part of the studied succession, but... (More)
Well-developed oncoids and centimetre-sized stromatolites are reported for the first time from the Darriwilian (Middle Ordovician) cool-water orthoceratite limestone' at Kinnekulle, Vastergotland, Sweden. The characteristics and stratigraphical distribution of these microbialites show an apparent relationship to fluctuations in relative sea level. The most abundant and well-developed oncoids occur in stratigraphical intervals that are characterized by notable sea-level lowstands. Stromatolites, which share many compositional characteristics with the oncoids, are essentially confined to a single bed associated with an especially prominent lowstand. Stromatolite-like lamination also occurs in the uppermost part of the studied succession, but this feature may be of abiogenic origin. The microbialites appear to be originally calcareous, but synsedimentary iron- and/or phosphate-enriched laminae are conspicuous, and secondary substitution by coarse calcite and barite is common. Iron staining is most prominent in poorly preserved specimens. Diagenesis has occluded the identity of the producers of these microbialites, but characteristics of associated endolithic borings suggest that they were formed in photic waters. The laminated fabrics of the documented microbialites record a depositional environment sensitive to high-frequency environmental change. Most significantly, the microbialites have provided important information about the depositional environment of their enigmatic host limestone, and the collective observations challenge the notion that the studied strata were deposited in a deep shelf to basinal environment - rather, it appears that they are to a large extent, shallow-water deposits, formed in waters only a few tens of metres deep. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Eendolithic borings, Holen Limestone, Kinnekulle, Middle Ordovician, oncoids, orthoceratite limestone, stromatolites
in
Lethaia
volume
47
issue
2
pages
187 - 204
publisher
Taylor & Francis
external identifiers
  • wos:000332776400005
  • scopus:84896085473
ISSN
0024-1164
DOI
10.1111/let.12050
language
English
LU publication?
yes
id
7fad7713-5576-4032-8e15-8658d9c51f1f (old id 4410954)
date added to LUP
2014-04-29 11:22:49
date last changed
2017-10-08 03:59:34
@article{7fad7713-5576-4032-8e15-8658d9c51f1f,
  abstract     = {Well-developed oncoids and centimetre-sized stromatolites are reported for the first time from the Darriwilian (Middle Ordovician) cool-water orthoceratite limestone' at Kinnekulle, Vastergotland, Sweden. The characteristics and stratigraphical distribution of these microbialites show an apparent relationship to fluctuations in relative sea level. The most abundant and well-developed oncoids occur in stratigraphical intervals that are characterized by notable sea-level lowstands. Stromatolites, which share many compositional characteristics with the oncoids, are essentially confined to a single bed associated with an especially prominent lowstand. Stromatolite-like lamination also occurs in the uppermost part of the studied succession, but this feature may be of abiogenic origin. The microbialites appear to be originally calcareous, but synsedimentary iron- and/or phosphate-enriched laminae are conspicuous, and secondary substitution by coarse calcite and barite is common. Iron staining is most prominent in poorly preserved specimens. Diagenesis has occluded the identity of the producers of these microbialites, but characteristics of associated endolithic borings suggest that they were formed in photic waters. The laminated fabrics of the documented microbialites record a depositional environment sensitive to high-frequency environmental change. Most significantly, the microbialites have provided important information about the depositional environment of their enigmatic host limestone, and the collective observations challenge the notion that the studied strata were deposited in a deep shelf to basinal environment - rather, it appears that they are to a large extent, shallow-water deposits, formed in waters only a few tens of metres deep.},
  author       = {Lindskog, Anders},
  issn         = {0024-1164},
  keyword      = {Eendolithic borings,Holen Limestone,Kinnekulle,Middle Ordovician,oncoids,orthoceratite limestone,stromatolites},
  language     = {eng},
  number       = {2},
  pages        = {187--204},
  publisher    = {Taylor & Francis},
  series       = {Lethaia},
  title        = {Palaeoenvironmental significance of cool- water microbialites in the Darriwilian ( Middle Ordovician) of Sweden},
  url          = {http://dx.doi.org/10.1111/let.12050},
  volume       = {47},
  year         = {2014},
}