The BGS Lexicon of Named Rock Units — Result Details

Cracoe Limestone Formation

Computer Code: CCOE Preferred Map Code: notEntered
Status Code: Full
Age range: Holkerian Substage (CQ) — Brigantian Substage (CX)
Lithological Description: Medium and medium-pale grey limestones ranging from organic boundstones to packstones and wackestones with a variable grainsize depending on the bioclastic components.
Definition of Lower Boundary: The lower boundary has not been proved, but it is likely to comprise reef limestones of the Cracoe Limestone Formation resting upon the bedded, medium to medium-dark grey limestone of the Scaleber Quarry Limestone Member.
Definition of Upper Boundary: The upper boundary is a marked unconformity, with the reef limestones of the Cracoe Limestone Formation overlain by dark grey mudstones of the Bowland Shale Formation.
Thickness: Total thickness not proved, but in excess of 100m at the type locality.
Geographical Limits: South of the Middle Craven Fault, occurring in a roughly west-east tract extending 20km east from Settle [SD83 63] to Burnsall [SE 01 61]. The apron reef has become dislocated into fault slices along the Craven Fault System. The formation passes northwards into the Cove Limestone and Gordale Limestone members and probably also the Lower Hawes Limestone (Alston Formation).
Parent Unit: Great Scar Limestone Group (GSCL)
Previous Name(s): Marginal Reef Limestones (-3909)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Swinden Quarry, near Cracoe, North Yorkshire. Zones of megabrecciation and neptunean dykes (crinoid and mudstone filled) are present within the Formation. Pre-reef and post reef limestones are present in the quarry, although the contacts with the reef limestones are faulted. 
Reference(s):
Arthurton, R S, Johnson, E W and Mundy, D J C. 1988. Geology of the country around Settle. Memoir of the British Geological Survey, Sheet 60 (England and Wales). 
Mundy, D J C. 2000. Field meeting to the Craven Reef Belt: Settle and Cracoe, Sunday 23rd July 2000. [Calgary: Talisman Energy Inc.] 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E060