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Megascopic processes reflected in the microscopic realm : sedimentary and biotic dynamics of the Middle Ordovician “orthoceratite limestone” at Kinnekulle, Sweden

Lindskog, Anders LU and Eriksson, Mats E. LU (2017) In GFF
Abstract

The Middle Ordovician (Dapingian–middle Darriwilian) “orthoceratite limestone” is documented in its traditional type area at Kinnekulle in the province of Västergötland in southern Sweden. Detailed field studies combined with systematic qualitative and quantitative analyses of carbonate microfacies at high stratigraphic resolution show that this suite of cool-water carbonate rocks is more variable than is suggested by its overall homogeneous macroscopic appearance. Long-term changes in carbonate textures and fossil grain assemblages, together with pervasive rhythmic/cyclic patterns, suggest a strong influence from sea level on microfacies characteristics. Assessment of the results in light of regional facies patterns indicates that the... (More)

The Middle Ordovician (Dapingian–middle Darriwilian) “orthoceratite limestone” is documented in its traditional type area at Kinnekulle in the province of Västergötland in southern Sweden. Detailed field studies combined with systematic qualitative and quantitative analyses of carbonate microfacies at high stratigraphic resolution show that this suite of cool-water carbonate rocks is more variable than is suggested by its overall homogeneous macroscopic appearance. Long-term changes in carbonate textures and fossil grain assemblages, together with pervasive rhythmic/cyclic patterns, suggest a strong influence from sea level on microfacies characteristics. Assessment of the results in light of regional facies patterns indicates that the cool-water “orthoceratite limestone” behaved much like “model” siliciclastic sedimentary systems, in that carbonate texture varied with depositional depth as particle size of siliclastics does. Carbonate texture thus appears to reflect absolute depth well, whereas grain assemblages record high-frequency cycles of changes in both sea level and substrate conditions. A relative sea level curve compiled from the collective data shows excellent agreement with previously published curves based on different proxies. The most important factor for the long-term establishment and regional dominance of the “orthoceratite limestone” throughout much of the Early and Middle Ordovician appears to have been a limited terrigenous sediment input to the Baltoscandian paleobasin. Hence, much of the regional facies zonation may reflect distance from weathering sources rather than bathymetric conditions.

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author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Carbonate sedimentology, cool-water carbonates, lower Paleozoic, microfacies, paleoecology, sea level
in
GFF
pages
21 pages
publisher
Geological Society of Sweden
external identifiers
  • scopus:85014472577
  • wos:000413398600001
ISSN
1103-5897
DOI
10.1080/11035897.2017.1291538
language
English
LU publication?
yes
id
537dac50-17c5-4dd6-80b6-467bef542f30
date added to LUP
2017-03-15 07:52:59
date last changed
2018-01-16 13:24:49
@article{537dac50-17c5-4dd6-80b6-467bef542f30,
  abstract     = {<p>The Middle Ordovician (Dapingian–middle Darriwilian) “orthoceratite limestone” is documented in its traditional type area at Kinnekulle in the province of Västergötland in southern Sweden. Detailed field studies combined with systematic qualitative and quantitative analyses of carbonate microfacies at high stratigraphic resolution show that this suite of cool-water carbonate rocks is more variable than is suggested by its overall homogeneous macroscopic appearance. Long-term changes in carbonate textures and fossil grain assemblages, together with pervasive rhythmic/cyclic patterns, suggest a strong influence from sea level on microfacies characteristics. Assessment of the results in light of regional facies patterns indicates that the cool-water “orthoceratite limestone” behaved much like “model” siliciclastic sedimentary systems, in that carbonate texture varied with depositional depth as particle size of siliclastics does. Carbonate texture thus appears to reflect absolute depth well, whereas grain assemblages record high-frequency cycles of changes in both sea level and substrate conditions. A relative sea level curve compiled from the collective data shows excellent agreement with previously published curves based on different proxies. The most important factor for the long-term establishment and regional dominance of the “orthoceratite limestone” throughout much of the Early and Middle Ordovician appears to have been a limited terrigenous sediment input to the Baltoscandian paleobasin. Hence, much of the regional facies zonation may reflect distance from weathering sources rather than bathymetric conditions.</p>},
  author       = {Lindskog, Anders and Eriksson, Mats E.},
  issn         = {1103-5897},
  keyword      = {Carbonate sedimentology,cool-water carbonates,lower Paleozoic,microfacies,paleoecology,sea level},
  language     = {eng},
  month        = {02},
  pages        = {21},
  publisher    = {Geological Society of Sweden},
  series       = {GFF},
  title        = {Megascopic processes reflected in the microscopic realm : sedimentary and biotic dynamics of the Middle Ordovician “orthoceratite limestone” at Kinnekulle, Sweden},
  url          = {http://dx.doi.org/10.1080/11035897.2017.1291538},
  year         = {2017},
}