The BGS Lexicon of Named Rock Units — Result Details

Rutland Formation

Computer Code: RLD Preferred Map Code: Rld
Status Code: Full
Age range: Bajocian Age (JB) — Bathonian Age (JN)
Lithological Description: Interpreted as a succession of up to seven shallowing upward, essentially delta-type rhythms, comprising ideally of a grey marine mudstone passing up into non-marine mudstone and siltstone, with a greenish-grey rootlet bed at the top. The basal beds comprise mainly fluviatile and lacustrine sandstones, designated the Stamford Member in the south, passing north in central Lincolnshire into the Thorncroft Sand Member. Subordinate sandstone beds occur higher in the sequence locally, as well as typically shelly and shell-detrital marine limestones and calcareous mudstones, notably in the mid part, the Wellingborough Limestone Member, in Northamptonshire. The Wellingborough Limestone thins and loses its character northwards such that it is not recognisable in Rutland, where the formation above the Stamford Member is called the Castle Member (Hudson and Clements, 2007). This is approximately equivalent to the ‘Priestland Clay Member’ (Gaunt et al., 1992) of central Lincolnshire to east Yorkshire.
Definition of Lower Boundary: Generally a sharp unconformable boundary of sandy beds of the Stamford or Thorncroft Sand members overlying: in Lincolnshire, Rutland and north Northants, limestones of the Lincolnshire Limestone Formation, commonly marked by the "Ironstone Junction Bed"; or in mid Northants, north Buckinghamshire and Bedfordshire, by ironstone or ferruginous sandstone of the Northampton Sand Formation, or mudstones of the Lias Group; and across the London Platform subcrop by Palaeozoic strata. In the southwest, the lower boundary is an upwards gradation from limestones of the Taynton Limestone Formation to mudstone of the reduced Rutland Formation (see Lithological Description).
Definition of Upper Boundary: A gradational boundary from argillaceous beds of the Rutland Formation into limestones of the Blisworth Limestone Formation or, in the southwest on Sheets 218,219,236,237, into limestones of the White Limestone Formation.
Thickness: Typically from about 8 to 12m, and up to about 15m thick, measured as about 12m at the type section, and, where reduced in the southwest, typically from 2m to 4m thick.
Geographical Limits: In south-west Northamptonshire and north Oxfordshire, the lower part is replaced by the Horsehay Sand, Chipping Norton Limestone, Sharp’s Hill, and Taynton Limestone formations and only the upper part of the formation is represented, by largely argillaceous strata, and passes westward into the Hampen Formation (Horton et al., 1987, fig. 8). From here, at the Cherwell Valley, around Northbrook [SP 49 22], Oxfordshire, the formation’s outcrop extends north-east and north, to the Market Weighton High around North Newbald [SE 91 37], where the unit is overstepped by Cretaceous rocks.
Parent Unit: Great Oolite Group (GOG)
Previous Name(s): Glentham Formation (GLF)
Upper Estuarine "Series" [Obsolete Name And Code: Use RLD] (UE)
Upper Estuarine Series (-697)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Thompson's Quarry, Wilsford Heath, near Ancaster, (especially upper part of formation) (Richardson, 1939). 
Reference Section  Gregory's Quarry, Wilsford Heath, near Ancaster (especially the lower part of the formation). 
Reference Section  Ardley Railway Cutting. Arkell et al., 1933; Cox, B M, and Sumbler, M G. 2002. 
Type Section  Ketton Quarry, Rutland, exposes the full thickness of the formation in typical facies, 11.7 to 12.8 m thick, including the Stamford Member, and six rhythms above, resting on the Lincolnshire Limestone Formation, and overlain by the Blisworth Limestone Formation (Aslin, 233-237 in Torrens, 1968; Cox and Sumbler, 2002; Hudson and Clements, 2007) 
Type Area  East Midlands including Rutland, from Wellingborough to Grantham. 
Reference Section  Cranford St John Quarry, near Kettering. Bradshaw, 1978; Cox, B M, and Sumbler, M G. 2002. 
Reference(s):
Aslin, C J. 1968. 233-237 in Torrens, H S. 1968. The Great Oolite Series. 227-263 in Sylvester-Bradley, P C and Ford, T D (editors), The geology of the East Midlands. (Leicester: Leicester University Press.) 
Torrens, H S. 1968. The Great Oolite Series. 227-263 in Sylvester-Bradley, P C and Ford, T D (editors), The geology of the East Midlands. (Leicester: Leicester University Press.) 
Arkell, W J, Richardson, L and Pringle, J, 1933. The Lower Oolites exposed in the Ardley-Fritwell railway cuttings, between Bicester and Banbury, Oxford. Proceedings of the Geologists' Association, Vol.44, 340-354. 
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. 
Barron, A J M, Lott, G K, and Riding, J B. 2012. Stratigraphical framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf. British Geological Survey Research Report RR/11/06. 
Hudson, J D and Clements, R G. 2007. The Middle Jurassic Succession at Ketton, Rutland. Proceedings of the Geologists' Association, Vol 118, 239-264. 
RICHARDSON, L. 1939. Weekend field meeting in the Stamford district. Proceedings of the Geologists' Association, Vol. 50, 29-45. 
Judd, J W. 1875. The geology of Rutland and parts of Lincoln, Leicester, Northampton, Huntingdon and Cambridge. Memoir of the Geological Survey of Great Britain (Old Series sheet 64). 
Horton, A, Sumbler, M G, Cox, B M and Ambrose, K, 1995. Geology of the country around Thame. Memoir of the British Geological Survey, Sheet 237 (England and Wales). 
Bradshaw, M J. 1978. A facies analysis of the Bathonian of eastern England. (University of Oxford: Unpublished PhD thesis.) 
Cox, B M and Sumbler, M G. 2002. British Middle Jurassic Stratigraphy. Geological Conservation Review Series No.26. [Peterborough: Joint Nature Conservation Committee.] 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E102 E103 E114 E115 E127 E128 E143 E144 E157 E158 E159 E170 E171 E172 E175 E185 E186 E188 E189 E202 E203 E218 E219 E220 E237 E072 E080 E089