The BGS Lexicon of Named Rock Units — Result Details

Ireleth Member

Computer Code: IRE Preferred Map Code: Ire
Status Code: Full
Age range: Cautleyan Stage (OU) — Cautleyan Stage (OU)
Lithological Description: Pale to dark grey, massive or thickly bedded limestone, commonly pervasively recrystallised with bedding planes which are either stylotitic or totally obscured; dolomitisation and haematite staining common in the south of the inlier with the limestone becoming cavernous and mottled brown in colour.
Definition of Lower Boundary: In Millom Park, it is a member within the Kirkley Bank Formation where it overlies volcaniclastic sandstone of the Low Scales Member; the base of the Ireleth Member is taken at the base of the limestone. Elsewhere the member overlies locally the Skiddaw Group and Borrowdale Volcanic Group.
Definition of Upper Boundary: Defined by the base of a sequence of calcareous siltstone within the main part of the Kirkley Bank Formation.
Thickness: Up to 30 m thick.
Geographical Limits: Restricted to the Millom Park and the Furness inliers, Cumbria.
Parent Unit: Kirkley Bank Formation (KKB)
Previous Name(s): High Haume Limestone (-1614)
Ireleth Limestone (-2866)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  High Haume Beacon Johnson et al., 2001. 
Reference(s):
Sedgwick A. 1846. On the classification of the fossiliferous slates of Cumberland, Westmoreland and Lancashire. Quarterly Journal of the Geological Society of London, Vol 2, 106 - 122. 
Kneller, B C, Scott R W, Soper N J, Johnson E W and Allen P M, 1994. Lithostratigraphy of the Windermere Supergroup, Northern England. Geological Journal, Vol. 29, 219-240. 
Rose, W C C. 1977. Geology and Hematite deposits of South Cumbria. Economic Memoir for 1:50,000 Sheet 58 and southern part of Sheet 48. Memoir of the geological Survey of Great Britain. 
Johnson, E W, Soper, N J, Burgess, I C, Ball, D F, Beddoe-Stephens, B, Carruthers, R M, Fortey, N J, Hirons, S, Merritt, J W, Millward, D, Roberts, B, Walker, A B and Young, B. 2001. Geology of the country around Ulverston. Memoir of the British Geological Survey, England and Wales, Sheet 48. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E048