Coldbeck Limestone Formation
Coldbeck Limestone Formation is part of the Great Scar Limestone Group
The name is derived from Coldbeck, Ravenstonedale, Westmorland.
See Mitchell (1978); Dunham and Wilson (1985). The formation comprises dark grey, fine-grained, well bedded limestones with mudstone partings, and flaggy dolostones characterised by an abundance of algal macrostructures including stromatolites and oncolites.
The formation was deposited in a carbonate-dominated, nearshore to peritidal, restricted marine environment.
Lower and upper boundaries
The lower boundary is at the base of the ‘Spongiostroma Band’ of Turner (1950), which overlies the thick-bedded, porcellanous limestones and thin-bedded dolostones in the upper part of the Stone Gill Limestone Formation, Ravenstonedale Group (Figure 9, Column 16).
The upper boundary of the Coldbeck Limestone Formation is at the top of the Algal Nodular Beds. These conformably underlie the dark grey limestone of the Scandal Beck Limestone Formation.
Some 52 m of strata are visible in a continuous section in Stone Gill, Ravenstonedale, but Turner (1950, p. 30) estimated that a further 31 m are cut out by faulting. The formation is about 50 m thick at Gaisgill, but thins westward from here.
Distribution and regional correlation
Ravenstonedale, Cumbria and the Stainmore Trough.
Age and biostratigraphical characterisation
Early Chadian. There are at least three algal bands within the formation.
- Mitchell, M.1978.Dinantian.168–177 in The geology of the Lake District. Moseley, F (editor).Occasional Publication of the Yorkshire Geological Society, No. 3.
- Dunham, K C, and Wilson, A A.1985.Geology of the Northern Pennine Orefield: Volume 2, Stainmore to Craven.Economic Memoir of the British Geological Survey, Sheets 40, 41 and 50, parts 31, 32, 51, 60 and 61(England and Wales).
- Taylor, B J, Burgess, I C, Land, D H, Mills, D A C, Smith, D B, and Warren, P T.1971.British regional geology: northern England (4th edition). (London: HMSO for Institute of Geological Sciences.)
- Turner, J S.1950.Notes on the Carboniferous Limestone of Ravenstonedale, Westmorland.Transactions of the Leeds Geological Association, Vol. 6, 124–134.