The BGS Lexicon of Named Rock Units — Result Details

Northampton Sand Formation

Computer Code: NS Preferred Map Code: NS
Status Code: Full
Age range: Aalenian Age (JA) — Aalenian Age (JA)
Lithological Description: Sandy, berthierine-ooidal and sideritic ironstone, greenish grey where fresh, weathering to brown limonitic sandstone, typically displaying a box-stone structure. The basal part, is commonly muddy and less ferruginous. The uppermost beds are generally more or less ferruginous sandstone. The unit includes lenses of mudstone and limestone in places, and contains a fairly abundant marine fauna of bivalves, brachiopods and ammonites, which are not generally evident in weathered sections.
Definition of Lower Boundary: A sharp, unconformable contact of sandy, berthierine-ooidal and sideritic ironstone overlying mudstones of the Whitby Mudstone Formation (Lias Group), commonly marked by a pebble bed containing phosphatic nodules and derived fossils from the underlying Whitby Mudstone.
Definition of Upper Boundary: Generally a sharp erosional, or in some places apparently transitional boundary, from sandy, berthierine-ooidal and sideritic ironstone with, to the north of the Kettering-Peterborough area, a generally less ferruginous sandstone, siltstone or mudstone of the Grantham Formation, which in some places contains pebbles of reworked Northampton Sand, or to the South of Kettering-Peterborough, a sharp erosional contact with essentially non-ferruginous interpreted non-marine sandstone, siltstone or mudstone of the Stamford Member of the Rutland Formation or in the Brackley district the equivalent Horsehay Sand Formation.
Thickness: Up to about 21m thick (Thompson, 1921, and Hollingworth and Taylor,1951), typically in the range from 4m to 8m.
Geographical Limits: North Lincolnshire from just south of the Humber, where the unit is apparently overstepped by the Grantham Formation (according to Gaunt et al.,1992), to the Chipping Norton area, where it passes laterally into the 'Scissum Beds' of Horton et al.,1987, now known as the Leckhampton Member of the Birdlip Limestone Formation. East and south-eastwards from the outcrop, the Northampton Sand is overstepped by the Grantham Formation in the north (e.g. west of Peterborough [TL09]), and the Rutland Formation in the south (e.g. east of Northampton [SP 85 60]).
Parent Unit: Inferior Oolite Group (INO)
Previous Name(s): Dogger (-208)
Ironstone Beds (-4227)
Ironstone Series (*57)
Northampton Ironstone Beds (-4228)
Northampton Ironstone Series (-1093)
Northampton Sand (-2343)
Northampton Sand (Lower Part) (-1732)
Northampton Sand Ironstone (-1094)
Variable Beds Of Northampton Sand (-2961)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Duston Top Pit. Sharp,1870; Thompson 1921; also known as 'Old Duston Stone Pit' acccording to Richardson, 1926. formerly exposed about 2.9m of ‘Northampton Ironstone’ (base not seen), overlain by about 8.7m of ‘Variable Beds’, total about 11.6m of Northampton Sand Formation, overlain by ‘Lower Estuarine White Sands’ (Stamford Member, Rutland Formation). There may be an extant face here. 
Type Area  Northampton area. Sharp,1970. 
Reference(s):
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. 
Arkell W J, 1933. The Jurassic System in Great Britain [Oxford: Clarendon Press.] 
Woodward, H B, 1894. The Jurassic Rocks of Britain, Vol.4. The Lower Oolitic Rocks of England (Yorkshire excepted). Memoir of the Geological Survey of the United Kingdom. 
Hollingworth, S E and Taylor, J H, 1951. The Northampton Sand Ironstone, Stratigraphy, Structure and Reserves. Memoir of the Geological Survey of Great Britain. 
Aveline, W T and Trench, R. 1860.The geology of part of Northamptonshire (Old Series One-Inch Sheet 53SE). 
Bradshaw, M J. 1978. A facies analysis of the Bathonian of eastern England. (University of Oxford: Unpublished PhD thesis.) 
Horton, A, Poole, E G, Williams, B J, Illing, V C and Hobson, G D. 1987. Geology of the country around Chipping Norton. Memoir of the British Geological Survey, Sheet 218 (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). 
Thompson, B. 1910. Northamptonshire (including contiguous parts of Rutland and Warwickshire. p.450-487 in Geology in the Field. Monckton, H W and Herries, R (editors). (London:Stanford.) 
Thompson, B. 1921. The Northampton Sand of Northamptonshire: Part 1. Journal of the Northampton Natural History Society, Vol. 21, p.25-38. 
Thompson, B. 1928. The Northampton Sand of Northamptonshire. Reprints from the Journal of the Northampton Natural History Society, 1921 to 1928. (London: Dulau and Co.) 
Richardson, L.1926. Certain Jurassic (Aalenian-Vesulian) strata of the Duston area, Northamptonshire. Proceedings of the Cotteswold Naturalists' Field Club, Vol.22, p. 137-152. 
Hollingworth, S E, and Taylor, J H. 1946. An Outline of the Geology of the Kettering District. Proceedings of the Geologists' Association, Vol. LVII, 204-233. 
Lamplugh, G W, Wedd, C B, and Pringle, J. 1920. Bedded iron ores of the Lias, Oolites and later formations in England. Special Reports on the Mineral Resources of Great Britain, Vol. XII. Memoir of the Geological Survey of Great Britain. 
Kent, P E. 1968. Fossiliferous Dogger in north Lincolnshire. Transactions of the Lincolnshire Naturalists' Union, Vol. 17, 28-29. 
Sharp, S. 1870. The Oolites of Northamptonshire, Part 1. Quarterly Journal of the Geological Society of London, Vol. 26, 354-391. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E102 E103 E114 E115 E127 E128 E142 E143 E144 E157 E158 E170 E171 E184 E185 E186 E201 E202 E218 E219 E080 E089