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The Ordovician Orthoceratite Limestone and the Blommiga Bladet hardground complex at Horns Udde, Öland

Eriksson, Magnus (2010) In Dissertations in Geology at Lund University
Department of Geology
Abstract
Blommiga Bladet, Flowery Sheet in English, is an Early Ordovician (basal Dapingian) hardground complex
in the lowermost part of the Orthoceratite Limestone in southern Sweden. It formed in an epicontinental sea,
across Baltoscandia and has been described also from Russia as “Steklo”, from Estonia as “Pustakkith” and from
deep borings in Poland, thus covering an area exceeding 500,000 km². The Orthoceratite Limestone spans the
Floian, Dapingian and Darriwilian stages and records an extremely low net sedimentation rate (2mm/ka). Recurrent
periods of non-deposition allowed hardgrounds to form. These hardgrounds are numerous and probably represents a
significant portion of time in the Orthoceratite Limestone. The Blommiga Bladet... (More)
Blommiga Bladet, Flowery Sheet in English, is an Early Ordovician (basal Dapingian) hardground complex
in the lowermost part of the Orthoceratite Limestone in southern Sweden. It formed in an epicontinental sea,
across Baltoscandia and has been described also from Russia as “Steklo”, from Estonia as “Pustakkith” and from
deep borings in Poland, thus covering an area exceeding 500,000 km². The Orthoceratite Limestone spans the
Floian, Dapingian and Darriwilian stages and records an extremely low net sedimentation rate (2mm/ka). Recurrent
periods of non-deposition allowed hardgrounds to form. These hardgrounds are numerous and probably represents a
significant portion of time in the Orthoceratite Limestone. The Blommiga Bladet hardground complex displays distinct,
clear-cut and abraded hardground surfaces that slowly have been polished by calcareous particles swept
across the sea-floor by currents or waves, as well as a few more irregular omission surfaces that may represent
firmgrounds. The uppermost hardground surface was colonized by a borer belonging to the ichnospecies Gastrochaenolites
oelandicus. G. oelandicus borings cut trough indurated sediments and earlier omission surfaces, creating
a sac-like pit with a small aperture. Blommiga Bladet was mineralized by several ferruginous compounds in the
early diagenesis, making it skimmer in red, green and yellow. The cavities were subsequently filled with sediment.
In the Early and Middle Ordovician, Baltoscandia was mainly affected by eustasy and Blommiga Bladet probably
formed during a sea-level low-stand, when the sea-floor regionally was reworked by waves. (Less)
Abstract (Swedish)
Blommiga Bladet avser en serie hårdbottnar i den lägre delen av den ordoviciska Ortoceratitkalkstenen
i mellersta och södra Sverige. De bildades över ett 500,000 km² stort grundhav som täckte nuvarande
Sverige, Baltikum och västra Ryssland (Baltoscandia). Blommiga Bladet har blivit beskriven i bl.a. Ryssland som
”Steklo”, ”Pustakkith” i Estland och från djupa borrkärnor i Polen. Ortoceratitkalkstenen avsattes med en extremt
låg sedimentationshastighet (2mm/1000 år) under tidsåldrarna Floin, Dapingian och Darriwilian. Frekvent återkommande
perioder med sedimentationsavbrott tillät hårdbottnar att bildas. Det finns många sådana hårdbottnar i Ortoceratitkalkstenen
och de representerar troligtvis en stor del av avsättningstiden. Blommiga... (More)
Blommiga Bladet avser en serie hårdbottnar i den lägre delen av den ordoviciska Ortoceratitkalkstenen
i mellersta och södra Sverige. De bildades över ett 500,000 km² stort grundhav som täckte nuvarande
Sverige, Baltikum och västra Ryssland (Baltoscandia). Blommiga Bladet har blivit beskriven i bl.a. Ryssland som
”Steklo”, ”Pustakkith” i Estland och från djupa borrkärnor i Polen. Ortoceratitkalkstenen avsattes med en extremt
låg sedimentationshastighet (2mm/1000 år) under tidsåldrarna Floin, Dapingian och Darriwilian. Frekvent återkommande
perioder med sedimentationsavbrott tillät hårdbottnar att bildas. Det finns många sådana hårdbottnar i Ortoceratitkalkstenen
och de representerar troligtvis en stor del av avsättningstiden. Blommiga Bladet består av två distinkta,
klart markerade och abraderade plana ytor som långsamt blivit polerade av kalkpartiklar som svept fram
över ytan genom vågor och strömmar, samt ett fåtal ojämna omissionsytor som möjligen representerar en slags
halvhård botten (firmground). Den övre abraderade ytan har blivit genomborrad en okänd evertebrat
(Gastrochaenolites oelandicus ichnoart) som lämnade efter sig säckliknande borrhål. Innan borrhålen fylldes igen,
genom deras smala öppningar, mineraliserades troligtvis de olika lagren av diverse järnhaltiga föreningar. Dessa
föreningar gav Blommiga Bladet dess intensiva färger som skimrar i klarrött, grönt och gult. Stenbrottsarbetarna
ligger bakom dess något fantasifulla namn. Baltoscandia var, under tidig- och mellanordovicium, huvudsakligen
påverkat av globala havsnivåförändringar och Blommiga Bladet bildades troligen då havsnivån var så pass låg att
havsbottnen regionalt sett var omarbetad av vågor. (Less)
Please use this url to cite or link to this publication:
author
Eriksson, Magnus
supervisor
organization
alternative title
Den ordoviciska Ortoceratitkalkstenen och Blommiga Bladet vid Horns Udde, Öland
year
type
M2 - Bachelor Degree
subject
keywords
Orthoceratite Limestone, hardground, Lanna, Volkhov, Dapingian, Gastrochaenolites oelandicus, Blommiga Bladet, sea-level, Ortoceratitkalkstenen, hårdbotten, havsnivå
publication/series
Dissertations in Geology at Lund University
report number
262
language
English
id
2296603
date added to LUP
2012-01-18 15:10:26
date last changed
2012-01-18 15:10:26
@misc{2296603,
  abstract     = {{Blommiga Bladet, Flowery Sheet in English, is an Early Ordovician (basal Dapingian) hardground complex
in the lowermost part of the Orthoceratite Limestone in southern Sweden. It formed in an epicontinental sea,
across Baltoscandia and has been described also from Russia as “Steklo”, from Estonia as “Pustakkith” and from
deep borings in Poland, thus covering an area exceeding 500,000 km². The Orthoceratite Limestone spans the
Floian, Dapingian and Darriwilian stages and records an extremely low net sedimentation rate (2mm/ka). Recurrent
periods of non-deposition allowed hardgrounds to form. These hardgrounds are numerous and probably represents a
significant portion of time in the Orthoceratite Limestone. The Blommiga Bladet hardground complex displays distinct,
clear-cut and abraded hardground surfaces that slowly have been polished by calcareous particles swept
across the sea-floor by currents or waves, as well as a few more irregular omission surfaces that may represent
firmgrounds. The uppermost hardground surface was colonized by a borer belonging to the ichnospecies Gastrochaenolites
oelandicus. G. oelandicus borings cut trough indurated sediments and earlier omission surfaces, creating
a sac-like pit with a small aperture. Blommiga Bladet was mineralized by several ferruginous compounds in the
early diagenesis, making it skimmer in red, green and yellow. The cavities were subsequently filled with sediment.
In the Early and Middle Ordovician, Baltoscandia was mainly affected by eustasy and Blommiga Bladet probably
formed during a sea-level low-stand, when the sea-floor regionally was reworked by waves.}},
  author       = {{Eriksson, Magnus}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{Dissertations in Geology at Lund University}},
  title        = {{The Ordovician Orthoceratite Limestone and the Blommiga Bladet hardground complex at Horns Udde, Öland}},
  year         = {{2010}},
}