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 Mya. The J ...

geological

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

which is placed within the

Inferior Oolite Group The Inferior Oolite is a sequence of Jurassic age sedimentary rocks in Europe. It was deposited during the Middle Jurassic.Weishampel, David B; et al. (2004). "Dinosaur distribution (Middle Jurassic, Europe)." In: Weishampel, David B.; Dodson, Pet ...

. It was formerly worked extensively in

Northamptonshire Northamptonshire (; abbreviated Northants.) is a county in the East Midlands of England. In 2015, it had a population of 723,000. The county is administered by two unitary authorities: North Northamptonshire and West Northamptonshire. It is ...

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 con ...

. The Northampton Sand Formation constitutes the lowest part of the

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 market town and civil parish in the East Midlands of England, on the River Nene, north-west of London and south-east of Birmingham. The county town of Northamptonshire, Northampton is one of the largest towns in England; ...

where it lies in a subterranean basin. In the south, it fades out around

Towcester Towcester ( ) is an affluent market town in Northamptonshire, England. It currently lies in West Northamptonshire but was the former administrative headquarters of the South Northamptonshire district council. Towcester is one of the oldest ...

. Northward from the edge of the basin in the upper Lias, under Northampton, it lies progressively lower beneath the

Lincolnshire limestone The Lincolnshire Limestone Formation is a geological formation in England, part of the Inferior Oolite Group of the (Bajocian) Middle Jurassic strata of eastern England. It was formed around 165 million years ago, in a shallow, warm sea on the ma ...

s. A little to the north of

Corby Glen Corby Glen is a village and civil parish in the South Kesteven district of Lincolnshire, England. It is approximately south-east of the market town of Grantham and 8 miles (13 km) north west of Bourne. History The Church of England paris ...

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

Lincolnshire Lincolnshire (abbreviated Lincs.) is a county in the East Midlands of England, with a long coastline on the North Sea to the east. It borders Norfolk to the south-east, Cambridgeshire to the south, Rutland to the south-west, Leicestershire ...

as the strata rise towards the

Market Weighton Axis The Market Weighton Axis is a geological feature which forms the south-eastern part of Yorkshire, England. The feature goes under a number of names such as 'block' or 'area' while the name of the town, Market Weighton is retained. 'Block' seems to ...

. The formation to dates to the

Aalenian The Aalenian () is a subdivision of the Middle Jurassic Epoch/Series of the geologic timescale that extends from about 174.1 Ma to about 170.3 Ma (million years ago). It was preceded by the Toarcian and succeeded by the Bajocian. Stratigraphic ...

, and predominantly consists of sandy

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

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

. It formed in an extensive, shallow sea on the northwestern margin of the

London-Brabant Massif The London-Brabant Massif or London-Brabant Platform is, in the tectonic structure of Europe, a structural high or massif that stretches from the Rhineland in western Germany across northern Belgium (in the province of Brabant) and the North Sea t ...

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

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

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

.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 marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are chelicerates, most closely related to arachn ...

, '' Mesolimulus woodwardi'' has been described from the formation.

Commercial exploitation

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

Wellingborough Wellingborough ( ) is a large market and commuter town in the unitary authority area of North Northamptonshire in the ceremonial county of Northamptonshire, England, 65 miles from London and from Northampton on the north side of the River Nen ...

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