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Palaeokarst evidence for widespread regression and subaerial exposure in the middle Katian (Upper Ordovician) of Baltoscandia: significance for global climate.

Calner, Mikael LU ; Lehnert, Oliver and Nõlvak, Jaak (2010) In Palaeogeography, Palaeoclimatology, Palaeoecology 296(3-4). p.235-247
Abstract
We report on widespread and contemporary palaeokarst in the middle Katian (Upper Ordovician) of Sweden,

Estonia and Latvia, the first major palaeokarst horizon to be reported from the Ordovician of Baltoscandia. The

solution features occurwithin a fewmetres of thick zone of limestone immediately belowthe widespread Fjäcka

Shale and are related to an unconformity with preserved palaeorelief in the Slandrom Limestone in Sweden and

the time-equivalent Saunja Formation in Estonia and Latvia. Facies evidence for a karst origin comes fromseveral

outcrops and core sections and includes 1) frequent karren-likemorphologies interpreted as ‘Swiss-cheese’ karst

[sensu Baceta et al., 2001], 2) local... (More)
We report on widespread and contemporary palaeokarst in the middle Katian (Upper Ordovician) of Sweden,

Estonia and Latvia, the first major palaeokarst horizon to be reported from the Ordovician of Baltoscandia. The

solution features occurwithin a fewmetres of thick zone of limestone immediately belowthe widespread Fjäcka

Shale and are related to an unconformity with preserved palaeorelief in the Slandrom Limestone in Sweden and

the time-equivalent Saunja Formation in Estonia and Latvia. Facies evidence for a karst origin comes fromseveral

outcrops and core sections and includes 1) frequent karren-likemorphologies interpreted as ‘Swiss-cheese’ karst

[sensu Baceta et al., 2001], 2) local occurrences of solution/collapse breccia, 3) presence of bladed pseudospar

crystals in solution cavities, and 4) carbon isotope values indicating meteoric influence to the succession. These

findings are herein put in context with previously reported, large-scale erosional channels that may cut down

several tens of metres below the Fjäcka Shale in the subsurface Baltic Sea area, and with regional, anomalous

thickness variations in the Slandrom Limestone and Saunja Formation, all together forming strong support for

regional exposure of the Baltoscandian continent in the middle Katian. High-resolution stable isotopic data show

that the regression and lowstand of sea-level overlap with theWaynesville carbon isotope excursion. It resulted

in basin-wide cessation of carbonate production near the Amorphognathus superbus and A. ordovicicus conodont

zonal boundary. The contemporary development of palaeokarst in different confacies belts of the basin suggests

that this was an extraordinary sea-level lowstand, herein interpreted as reflecting a middle Katian glaciation. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Palaeogeography, Palaeoclimatology, Palaeoecology
volume
296
issue
3-4
pages
235 - 247
publisher
Elsevier
external identifiers
  • wos:000283020700003
  • scopus:77956922931
ISSN
1872-616X
DOI
10.1016/j.palaeo.2009.11.028
language
English
LU publication?
yes
id
f39ffd5b-60c6-4c9d-a0c1-82f1d72f12e6 (old id 1730817)
date added to LUP
2010-11-29 08:04:46
date last changed
2018-06-17 03:05:28
@article{f39ffd5b-60c6-4c9d-a0c1-82f1d72f12e6,
  abstract     = {We report on widespread and contemporary palaeokarst in the middle Katian (Upper Ordovician) of Sweden,<br/><br>
Estonia and Latvia, the first major palaeokarst horizon to be reported from the Ordovician of Baltoscandia. The<br/><br>
solution features occurwithin a fewmetres of thick zone of limestone immediately belowthe widespread Fjäcka<br/><br>
Shale and are related to an unconformity with preserved palaeorelief in the Slandrom Limestone in Sweden and<br/><br>
the time-equivalent Saunja Formation in Estonia and Latvia. Facies evidence for a karst origin comes fromseveral<br/><br>
outcrops and core sections and includes 1) frequent karren-likemorphologies interpreted as ‘Swiss-cheese’ karst<br/><br>
[sensu Baceta et al., 2001], 2) local occurrences of solution/collapse breccia, 3) presence of bladed pseudospar<br/><br>
crystals in solution cavities, and 4) carbon isotope values indicating meteoric influence to the succession. These<br/><br>
findings are herein put in context with previously reported, large-scale erosional channels that may cut down<br/><br>
several tens of metres below the Fjäcka Shale in the subsurface Baltic Sea area, and with regional, anomalous<br/><br>
thickness variations in the Slandrom Limestone and Saunja Formation, all together forming strong support for<br/><br>
regional exposure of the Baltoscandian continent in the middle Katian. High-resolution stable isotopic data show<br/><br>
that the regression and lowstand of sea-level overlap with theWaynesville carbon isotope excursion. It resulted<br/><br>
in basin-wide cessation of carbonate production near the Amorphognathus superbus and A. ordovicicus conodont<br/><br>
zonal boundary. The contemporary development of palaeokarst in different confacies belts of the basin suggests<br/><br>
that this was an extraordinary sea-level lowstand, herein interpreted as reflecting a middle Katian glaciation.},
  author       = {Calner, Mikael and Lehnert, Oliver and Nõlvak, Jaak},
  issn         = {1872-616X},
  language     = {eng},
  number       = {3-4},
  pages        = {235--247},
  publisher    = {Elsevier},
  series       = {Palaeogeography, Palaeoclimatology, Palaeoecology},
  title        = {Palaeokarst evidence for widespread regression and subaerial exposure in the middle Katian (Upper Ordovician) of Baltoscandia: significance for global climate.},
  url          = {http://dx.doi.org/10.1016/j.palaeo.2009.11.028},
  volume       = {296},
  year         = {2010},
}