Clackmannan Group

Clackmannan Group
Stratigraphic range: Carboniferous
Type Group
Sub-units Lower Limestone Formation, Limestone Coal Formation, Upper Limestone Formation, Passage Formation
Underlies Coal Measures Group
Overlies Strathclyde Group
Lithology
Primary sandstones, mudstones
Other limestones, siltstones, ironstones, coal, seatrocks, fireclay
Location
Region Central Lowlands of Scotland
Country Scotland
Type section
Named for Clackmannan (town)

The Clackmannan Group is the name given to a suite of rocks of late Dinantian and Namurian age laid down during the Carboniferous period in the Midland Valley of Scotland.[1]

The Group comprises a lower unit of coarse sandstones, siltstones, mudstone, and limestones with thin coals and ironstones known as the Lower Limestone Formation, an overlying sequence of similar rocks known as the Limestone Coal Formation, then an Upper Limestone Formation and at its top the sandstones of the Passage Formation. This last formation also includes fireclays, siltstones, mudstones, ironstones, coal and seatrocks.

The Clackmannan Group conformably overlays the rocks of the Strathclyde Group and underlays the Coal Measures, this latter boundary also being conformable. [2][3]

Remains of the prehistoric shark †Cladodus elegans Newberry & Worthen, 1870 (braincase and a tooth) have been found in the Lower Limestone formation.[4]

References

  1. ↑ "Clackmannan Group". The BGS Lexicon of Named Rock Units. British Geological Society. Retrieved 27 February 2014.
  2. ↑ British Geological Survey Research Report RR/07/01: Lithostratigraphical framework for Carboniferous successions of Great Britain (Onshore) Waters, C.N. et al 2007
  3. ↑ British Geological Survey 1:50,0000 scale geological map sheet (Scotland) 23W Hamilton
  4. ↑ The Braincase and Jaws of Cladodus from the Lower Carboniferous of Scotland. Michal Ginter and John G. Maisey, Palaeontology, March 2007, Volume 50, Issue 2, pages 305–322, doi:10.1111/j.1475-4983.2006.00633.x
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