The BGS Lexicon of Named Rock Units — Result Details

Kirton Cementstone Beds (Knoll-Reef)

Computer Code: KCMK Preferred Map Code: K
Status Code: Index Level
Age range: Bajocian Age (JB) — Bajocian Age (JB)
Lithological Description: Limestone (calcilutite and wackestone), commonly accummulated around a framework of corals, bivalves and other organisms, forming localised lenticular bodies typically less than 100m in lateral extent ("knoll-reef").
Definition of Lower Boundary: Conformable contact between the underlying mudstones of the Kirton Cementstone or peloidal and ooidal wackestones and packstones of the Scawby Limestone and coralliferous limestone of the knoll-reef.
Definition of Upper Boundary: Conformable contact between coralliferous limestone of the knoll-reef and overlying mudstones of the Kirton Cementstone.
Thickness: 0 to 5m
Geographical Limits: BGS 1:50 000 sheets 89, 102 and 114; North Lincolnshire, Lincoln to the Humber,
Parent Unit: Kirton Cementstone Beds (KCM)
Previous Name(s): Coral Knoll (In Kirton Cementstones) (-3492)
Coralline Knolls Of Patch-Reef Type (-340)
Alternative Name(s): none recorded or not applicable
Reference Section  Greetwell Quarry on eastern outskirts of Lincoln. Knoll reef up to 5m thick and 75m across within Kirton Cementstone Beds seen in eastern face. Cox and Sumbler, 2002. 295-297. 
Cox, B M and Sumbler, M G. 2002. British Middle Jurassic Stratigraphy. Geological Conservation Review Series No.26. [Peterborough: Joint Nature Conservation Committee.] 
Gaunt, G D, Fletcher, T P and Wood, C J. 1992. Geology of the country around Kingston upon Hull and Brigg. Memoir of the British Geological Survey, sheets 80 and 89 (England and Wales). 172pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable