The BGS Lexicon of Named Rock Units — Result Details

Ferriby Chalk Formation

Computer Code: FYCK Preferred Map Code: FyCk
Status Code: Full
Age range: Cenomanian Age (KE) — Cenomanian Age (KE)
Lithological Description: Grey, soft, marly, flint-free chalk, typically weathering buff in exposures; locally includes pinkish bands; some harder, gritty, shell-debris-rich beds, and thin discrete marl seams.
Definition of Lower Boundary: The lower boundary is placed at an erosion surface, locally developed on a hardground, overlain by nodular chalk (lowest Cenomanian) of the Paradoxica (or Sponge) Bed or, in the Cleveland Basin, the flaser-bedded white chalks with red or purple marls of the Crowe's Shoot Member (Gaunt et al., 1992; Mitchell, 1995).
Definition of Upper Boundary: The upper boundary is an uneven erosion surface, that may be stained with iron minerals and glauconite, at the top of a succession of marly chalk (Ferriby Formation) and a little way above the so called Upper Pink Band (of bed status). This surface is succeeded by a thin unit of marls and marly chalks (the Plenus Marls Member, Welton Formation), which generally forms a topographical slack at outcrop. This facilitates the mapping of the top of Ferriby Formation, which is also readily recognised from geophysical log signature in boreholes.
Thickness: The formation is typically about 20 to 25m thick throughout the southern part of the region. It thins to 10 to 15m over the Market Weighton High (Jeans, 1973) and its extension to Hornsea. It thickens immediately at the margin of the Cleveland Basin to the north, being 33 to 35m thick on the coast at Speeton (Wright, 1963; Jeans, 1980), and possibly 50m or more in boreholes inland near Fordon.
Geographical Limits: Throughout the Yorkshire and Lincolnshire Wolds, and superficial deposit-covered area to southeast, from Speeton Cliffs south to the Skegness area on the Lincolnshire coast.
Parent Unit: Grey Chalk Subgroup (GYCK)
Previous Name(s): Chalk Without Flints (-903)
Ferriby Formation (-4663)
Lower Chalk (-4056)
Alternative Name(s): Grey Chalk Subgroup
Stratotypes:
Type Section  South Ferriby Quarry, Lincolnshire. The full succession was visible and taken as the standard for the Humberside region at this quarry. See Gaunt et al. (1992). 
Type Area  Humberside area of North Lincolnshire and East Riding of Yorkshire. See Gaunt et al. (1992). 
Reference Section  Speeton Cliffs. The full succession is visible at various exposures within the landslid cliffs. See Wright (1963); Mitchell (1992). 
Reference(s):
Rawson, P F. 1992. Cretaceous, 355-388 in Duff, P McL D and Smith, A J (editors), Geology of England and Wales. (London: Geological Society.) 
Sumbler, M G. 1996. The stratigraphy of the Chalk Group in Yorkshire, Humberside and Lincolnshire. British Geological Survey Technical Report WA/96/26C. 
Hopson, P M. 2005. A stratigraphical framework for the Upper Cretaceous Chalk of England and Scotland, with statements on the Chalk of Northern Ireland and the UK Offshore Sector. British Geological Survey Research Report RR/05/01 102pp. ISBN 0 852725175 
Wood, C J and Smith, E G. 1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. Proceedings of the Yorkshire Geological Society, Vol. 42, 263-287. 
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. 
Sumbler, M G. 1999. The stratigraphy of the Chalk Group in Yorkshire and Lincolnshire. British Geological Survey Technical Report WA/99/02. 
Whitham, F. 1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. Proceedings of the Yorkshire Geological Society, Vol.48, 227-254. 
Mitchell, S F. 1995. Lithostratigraphy and biostratigraphy of the Hunstanton Formation (Red Chalk, Cretaceous) succession at Speeton, North Yorkshire, England. Proceedings of the Yorkshire Geological Society, Vol.50, 285-303. 
Wright, C W. 1963. Itinery IX. Reighton Gap to Speeton Cliffs. 30-33 in Hester, S W (editor), Geology of the Yorkshire Coast. Geologists' Association Guide, No.34 (first edition). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E103 E104 E115 E116 E054 E055 E064 E065 E072 E073 E080 E081 E089 E090 E091