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