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Mikael Calner

Mikael Calner

Professor

Mikael Calner

A new upper Middle Ordovician-Lower Silurian drillcore standard succession from Borenshult in Ostergotland, southern Sweden: 1. Stratigraphical review with regional comparisons

Författare

  • Stig M. Bergstroem
  • Mikael Calner
  • Oliver Lehnert
  • Amir Noor

Summary, in English

A recent drilling at Borenshult near Motala resulted in discovery of the stratigraphically most complete succession through the upper Darriwilian-Rhuddanian interval known in Ostergotland. The approximately 70m long drillcore succession is subdivided into eight formations, the oldest being the late Darriwilian Furudal Limestone and the youngest being the Rhuddanian Motala Formation. Conodonts are used for a detailed biostratigraphic classification of the Borenshult drillcore into three subzones of the Pygodus serra Zone, two subzones of the Pygodus anserinus Zone, and three subzones of the Amorphognathus tvaerensis Zone. The base of the Amorphognathus superbus Zone is taken to be similar to 10m above the Kinnekulle K-bentonite, that of the Amorphognathus ordovicicus just below the Fjacka Shale, and that of the Ozarkodina hassi Zone at the base of the Middle Member of the Loka Formation. Because of its unique lithology and paleontology and its wide geographic occurrence, this member is formally named herein the Skultorp Member. The previously uncertain stratigraphical position of the internationally known "Borenshult fauna" is shown to correlate with the Skultorp Member. A regional comparison of the Borenshult drillcore succession shows it to be most similar to coeval successions in Vastergotland and Dalarna but there are some significant regional differences. The average rate of net rock accumulation during late Darriwilian and Sandbian time is calculated to be similar to 3-4 mm/ka.

Avdelning/ar

  • Berggrundsgeologi

Publiceringsår

2011

Språk

Engelska

Sidor

149-171

Publikation/Tidskrift/Serie

GFF

Volym

133

Issue

3-4

Dokumenttyp

Artikel i tidskrift

Förlag

Taylor & Francis

Ämne

  • Geology

Nyckelord

  • Middle and Upper Ordovician
  • Rhuddanian
  • stratigraphy
  • conodont
  • biostratigraphy
  • Borenshult fauna
  • Sweden

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 2000-0863