The BGS Lexicon of Named Rock Units — Result Details

Concretionary Limestone Member

Computer Code: CNCL Preferred Map Code: CNCL
Status Code: Full
Age range: Guadalupian Epoch (PUG) — Lopingian Epoch (PUL)
Lithological Description: Lithologically varied dolostone with calcite concretions formed by a variety of primary and secondary sedimentary processes. Interpreted as the basin slope deposit of the Roker Formation (see Smith, 1994, fig.46 on page 94).
Definition of Lower Boundary: Gradational, by interdigitation with the underlying Hartlepool Anhydrite Formation.
Definition of Upper Boundary: Base of the overlying Forden Evaporite Formation, marked by the incoming of anhydrite and halite.
Thickness: Up to a maximum of about 95 - 100m.
Geographical Limits: Durham Province, onshore and offshore outcrops, of the English Zechstein Group: County Durham, Tyne and Wear, Cleveland and northernmost North Yorkshire.
Parent Unit: Roker Formation (ROD)
Previous Name(s): Upper Magnesian Limestone (Durham) [Obsolete Name And Code: See SHE, CNCL, ROD] (UML)
Upper Magnesian Limestone (-2105)
Concretionary Limestone Formation (-149)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Fulwell Hill quarries, Sunderland. Smith, 1994. 
Type Area  Coastal cliffs from South Shields, via Sunderland, to a point 3km. north of Seaham Harbour. Smith, 1994. 
Reference(s):
Smith, D B and Francis, E A. 1967. Geology of the country between Durham and West Hartlepool. Memoir of the Geological Survey of Great Britain, Sheet 27 (England and Wales). 
Smith, D B. 1985. Zechstein reefs and associated facies. E1 to E23 in The Role of Evaporites in Hydrocarbon Exploration. Taylor, J C M (ed.), London: JAPEC Course Notes, No. 39. 
Smith, D B, 1994. Geology of the country around Sunderland. Memoir of the British Geological Survey, Sheet 21, (England and Wales). 
Smith, D B. 1971. The stratigraphy of the Upper Magnesian Limestone in Durham - a revision based on the Institute's Seaham Borehole. Report of the Institute of Geological Sciences, No.71/3. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E021 E027