Great Scar Limestone Group

Great Scar Limestone Group
Stratigraphic range: Arundian-Brigantian
Type	Group
Unit of	Carboniferous Limestone Supergroup
Sub-units	See text
Underlies	Yoredale Group
Overlies	Ravenstonedale Group
Thickness	Up to 800 m (2,600 ft)
Lithology
Primary	Limestone
Other	Mudstone, siltstone, sandstone
Location
Region	England
Country	United Kingdom
Extent	Pennines to Isle of Man

The Great Scar Limestone Group is a lithostratigraphical term referring to a succession of generally fossiliferous rock strata which occur in the Pennines in northern England and in the Isle of Man within the Tournaisian and Visean stages of the Carboniferous Period.

It is contained within the Carboniferous Limestone Supergroup.[1]

Basinal successions

Stainmore Trough

The sequence in the Stainmore Trough is thus (youngest at top):

• Ashfell Sandstone (Arundian age)
• Breakyneck Scar Limestone (Arundian age)
• Red Hill Formation
• Brownber Formation (Chadian age)
• Scandal Beck Limestone (Chadian age)
• Coldbeck Limestone (Chadian age)

On the Alston Block corresponding to the North Pennines, the sequence contains the Melmerby Scar Limestone Formation.

Orton area

In the Orton area, the sequence is:

• Knipe Scar Limestone
• Potts Beck Limestone
• Ashfell Limestone
• Ashfell Sandstone
• Breakyneck Scar Limestone
• Brownber Formation
• Scandal Beck Limestone
• Coldbeck Limestone

Kendal, Skelsmergh and Deepslack outliers

In south Cumbria, the sequence is:[2]

• Urswick Limestone
• Park Limestone
• Dalton Formation (time-equivalent of Breakyneck Scar Limestone in Stainmore Trough) (Arundian age)

Isle of Man

On the Isle of Man, the following sequence is identified in the Castletown area:[3][4]

• Knockcrushen Formation (wackestones, packstones and mudstones; of Holkerian age)
• Derbyhaven Formation (packstones and mudstones with some mudstones and siltstones; of Arundian age)
  • Skillicore Member
  • Sandwick Member
  • Turkeyland Member

See also

• List of fossiliferous stratigraphic units in England

References

1. "Great Scar Limestone Group". The BGS Lexicon of Named Rock Units. British Geological Survey. Retrieved 27 July 2014.
2. 1:50,000 Geology Series England and Wales Sheet 28 Whitehaven Bedrock. British Geological Survey. 2004. ISBN 0751831603.
3. Stone, P; Millward, D; Young, B; Merritt, J W; Clarke, S M; McCormac, M; Lawrence, D J D (2010). British Regional Geology: Northern England. British Geological Survey, NERC. pp. 124–126. ISBN 9780852726525.
4. Isle of Man solid and drift geology 1:50,000 scale. British Geological Survey, NERC. 2001. ISBN 0751833266.