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. In southwest Northants and north Oxfordshire only the upper part of the Formation is represented, by largely argillaceous strata, and the lower part is replaced by the Horsehay Sand, Chipping Norton Limestone, Sharp's Hill and Taynton Limestone formations.
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: The Cherwell Valley, around Northbrook [SP 49 22], where the reduced Formation passes westward into the Hampen Formation, (Horton et al., 1987, fig.8), northeast 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)
Alternative Name(s): none recorded or not applicable
Type Section  Ketton Quarry. 
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). 
Type Area  East Midlands including Rutland, from Wellingborough to Grantham. 
Reference Section  Ardley Railway Cutting. 
Reference Section  Cranford St John Quarry, near Kettering. 
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.) 
Bradshaw,M J. 1978. A facies analysis of the Bathonian of eastern England. Unpublished PhD thesis, University of Oxford. 
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. 
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.) 
Cox, B M and Sumbler, M G. 2002. British Middle Jurassic stratigraphy. Geological Conservation Review Series, Vol.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). 
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). 
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