The BGS Lexicon of Named Rock Units — Result Details

Corbar Grit

Computer Code: COG Preferred Map Code: CoG
Status Code: Full
Age range: Marsdenian Substage (CZ) — Marsdenian Substage (CZ)
Lithological Description: Sandstone, fine-grained, flaggy, feldspathic, with subordinate mudstone, in up to 4 turbiditic cycles.
Definition of Lower Boundary: The base of the unit is poorly defined. In the field and on stratigraphic logs, the lower boundary is taken at the base of the first sandstone within a sandstone-dominated unit overlying a mudstone-dominated part of the Millstone Grit Group, overlying an unnamed sandstone within the latter; where this is absent the unit is the first sandstone-dominated unit above the mudstone-dominated part of the Millstone Grit Group overlying limestones of the Monsal Dale Limestone Formation.
Definition of Upper Boundary: The upper boundary is taken at the base of a mudstone-dominated succession of the Millstone Grit Group above sandstones of the Corbar Grit.
Thickness: 200m
Geographical Limits: Longclough (Cheshire) [SJ 987 737], Whitehills [SJ 973 728] (Cheshire); Edgemoor (Derbyshire) [SK 0343 7345].
Parent Unit: Millstone Grit Group [See Also MIGR] (MG)
Previous Name(s): Ashover Grit (ASG)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Disused quarry at Corbar Hill (Buxton, Derbyshire) exposes 20.28m (no further details available) (Aitkenhead et al., 1985). 
Type Section  Edgemoor (Derbyshire); natural section exposes 33.53 m (no further details available) (Aitkenhead et al., 1985). 
Reference Section  A stream section at Kirby Clough (Derbyshire) exposes 3 thin sandstone units from the Corbar Grit (no further details available) (Stevenson and Gaunt, 1971). 
Reference(s):
Aitkenhead, N, Chisholm, J I and Stevenson, I P. 1985. Geology of the country around Buxton, Leek and Bakewell. Memoir of the British Geological Survey, England and Wales Sheet 111. 
Jones, C M, 1980. Deltaic sedimentation in the Roaches Grit and associated sediments (Namurian R2b) in the south-west Pennines. Proceedings of the Yorkshire Geological Society Vol.43, Pt.1, 39-67. 
Smith, E G, Rhys, G H and Eden, R A. 1967. Geology of the country around Chesterfield, Matlock, and Mansfield. Memoir of the Geological Survey of Great Britain. England and Wales Sheet 112. 
Stevenson, I P and Gaunt, G D, 1971. Geology of the country around Chapel-en-le-Frith. Memoir of the Geological Survey of Great Britain, England and Wales, Sheet 99. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E099 E111