The BGS Lexicon of Named Rock Units — Result Details

Crosskirk Bay Formation

Computer Code: CKBA Preferred Map Code: notEntered
Status Code: Full
Age range: Givetian Age (DV) — Givetian Age (DV)
Lithological Description: Sandstone-dominated rhythmic cycles of interbedded sandstone, siltstone and calcareous laminite limestone.
Definition of Lower Boundary: Base of lowest medium-grained sandstone unit overlying siltstone-dominated cyclic sequence of the Dounreay Shore Formation.
Definition of Upper Boundary: Highest unit in local stratigraphy. Top not seen.
Thickness: More than 290m
Geographical Limits: Onshore and immediately offshore of the Dounreay area, Caithness, Northern Scotland.
Parent Unit: Caithness Flagstone Group (CNFL)
Previous Name(s): Achreamie Sandstone Formation [Obsolete Name and Code: Use CKBA] (-3301)
Crosskirk Flagstone Formation [Obsolete Name and Code: Use CKBA] (-3302)
Buldoo Flagstone Formation [Obsolete Name and Code: Use CKBA] (-1432)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Brims Ness coastal section, c. 7.5 km northwest of Thurso, northeast Caithness, Highland Region. 
Partial Type Section  Coastal section from Lower Dounreay (southeast end of Dounreay Nuclear Establishment) to Crosskirk Bay, northeast Caithness. 
Reference(s):
British Geological Survey. (In preparation, to be published in 2005). Bedrock geology. Scotland Special Sheet (Dounreay).1:25 000. 
Fletcher, T P and Key, R M. 1991. Solid geology of the Dounreay District. British Geological Survey Technical Report WA/91/35C. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable