The Northampton Sand Formation, sometimes called the Northamptonshire Sand, is a Middle

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

geological formation which is placed within the Inferior Oolite Group. It was formerly worked extensively in

Northamptonshire Northamptonshire ( ; abbreviated Northants.) is a Ceremonial counties of England, ceremonial county in the East Midlands of England. It is bordered by Leicestershire, Rutland and Lincolnshire to the north, Cambridgeshire to the east, Bedfordshi ...

for its

ironstone Ironstone is a sedimentary rock, either deposited directly as a ferruginous sediment or created by chemical replacement, that contains a substantial proportion of an iron ore compound from which iron (Fe) can be smelted commercially. Not to be c ...

. The Northampton Sand Formation constitutes the lowest part of the Inferior Oolite Group and lies on the upper Lias clay. It attains a maximum thickness of up to to the north and west of

Northampton Northampton ( ) is a town and civil parish in Northamptonshire, England. It is the county town of Northamptonshire and the administrative centre of the Unitary authorities of England, unitary authority of West Northamptonshire. The town is sit ...

where it lies in a subterranean basin. In the south, it fades out around Towcester. Northward from the edge of the basin in the upper Lias, under Northampton, it lies progressively lower beneath the

Lincolnshire limestones. A little to the north of

Corby Glen Corby Glen, formerly just Corby, is a village and civil parish in the South Kesteven district of Lincolnshire, England. It is approximately south-east of Grantham and north west of Bourne. In 2011 it had a population of 1,017. History The ...

() it is at about from the surface. It fades out under north

Lincolnshire Lincolnshire (), abbreviated ''Lincs'', is a Ceremonial counties of England, ceremonial county in the East Midlands and Yorkshire and the Humber regions of England. It is bordered by the East Riding of Yorkshire across the Humber estuary to th ...

as the strata rise towards the Market Weighton Axis. The formation to dates to the Aalenian, and predominantly consists of sandy

, which when freshly exposed is greenish-grey in colour, which weathers to limonitic brown

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

. It formed in an extensive, shallow sea on the northwestern margin of the London-Brabant Massif.

Dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

.Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press . pp. 517-607. A species of

horseshoe crab Horseshoe crabs are arthropods of the family Limulidae and the only surviving xiphosurans. Despite their name, they are not true crabs or even crustaceans; they are chelicerates, more closely related to arachnids like spiders, ticks, and scor ...

, '' Mesolimulus woodwardi'' has been described from the formation. The formation is a significant emitter of

radon Radon is a chemical element; it has symbol Rn and atomic number 86. It is a radioactive noble gas and is colorless and odorless. Of the three naturally occurring radon isotopes, only Rn has a sufficiently long half-life (3.825 days) for it to b ...

gas.

Commercial exploitation

There is a description of the twentieth century exploitation of the Northampton Sand for iron-smelting in the

Wellingborough Wellingborough ( ) is a market town in the North Northamptonshire, Unitary Authority area, England, from London and from Northampton, north of the River Nene. Originally named "Wendelingburgh" (the stronghold of Wændel's people), the Anglo ...

article.

References

Bibliography

*Kent, P. & Gaunt, G.D. ''British Regional Geology Eastern England to The Wash'' (1980) *Hains, B.A. & Horton, A. ''British Regional Geology Central England'' (1969) *British Geological Survey ''1:50 000 Series. Stamford. Sheet 157'' Solid & Drift Edition (1978) Aalenian Stage Jurassic System of Europe {{UK-geologic-formation-stub

Commercial exploitation

See also

References

Bibliography