The BGS Lexicon of Named Rock Units — Result Details

Upper Chalk Formation [Remains In Informal Use But Generally Regarded As Obsolete Onshore]

Computer Code: UCK Preferred Map Code: UCk
Status Code: Pending Upgrade
Age range: Turonian Age (KT) — Maastrichtian Age (KM)
Lithological Description: White chalks (microporous coccolithic limestone) with beds of flint, nodular chalks, hardgrounds and marl seams. NOTE: No type section has been established. See Chalk Rock for stratotypes of base of Upper Chalk.
Definition of Lower Boundary: At base of Chalk Rock, a hard basal unit. (Conventionally also taken at base of Holaster planus Zone).
Definition of Upper Boundary: In mainland Britain this is an unconformity overlain by post-Cretaceous formations.
Thickness: Up to 60m preserved in the Hitchin district, more than 300m in parts of Norfolk.
Geographical Limits: As used here: The Chilterns, extending to South Norfolk and Suffolk: ie area of "Anglo-Brabant Massif". Definition breaks down where Chalk Rock disappears. Approximates to the "Transitional Province" of Mortimore (1983).
Parent Unit: Chalk Group (CK)
Previous Name(s): Chalk, Undivided, Upper (Now Upper Chalk Formation) (-4948)
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
Jukes-Browne, A J and Hill, W. 1903 The Cretaceous Rocks of Britain, Vol.2. The Lower and Middle Chalk of England. Memoir of the Geological Survey of Great Britain. 
Mortimore, R N. 1983. The stratigraphy and sedimentation of the Turonian-Campanian in the Southern Province of England. Zitteliana, Vol.10, 27-41. 
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. 
Jukes-Browne, A J and Hill, W. 1904. The Cretaceous Rocks of Britain, Vol.3. The Upper Chalk of England. Memoir of the Geological Survey of Great Britain. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E220 E221 E222 E204 E205 E206 E238 E239 E240 E266 E282 E284 E298 E299 E327 E314 E283 E269 E237 E064 E065 E072 E147 E161 E160 E146 E159 E162 E132 E148 E300 E175 E188 E189 E190 E207 E223 E241 E253 E254 E255 E257 E258 E259 E268 E131 E267 E270 E271 E272 E273 E274 E281 E341 E342 E343