Geology of Cambridgeshire

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This article describes the geology of the ceremonial county of Cambridgeshire. It thus includes the present City of Peterborough and the historic county of Huntingdonshire which was brought into the county in 1974.

The geology of Cambridgeshire in eastern England largely consists of unconsolidated Quaternary sediments such as marine and estuarine alluvium and peat overlying deeply buried Jurassic and Cretaceous age sedimentary rocks. [1]

England Country in north-west Europe, part of the United Kingdom

England is a country that is part of the United Kingdom. It shares land borders with Wales to the west and Scotland to the north. The Irish Sea lies west of England and the Celtic Sea to the southwest. England is separated from continental Europe by the North Sea to the east and the English Channel to the south. The country covers five-eighths of the island of Great Britain, which lies in the North Atlantic, and includes over 100 smaller islands, such as the Isles of Scilly and the Isle of Wight.

Quaternary is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.588 ± 0.005 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene and the Holocene. The informal term "Late Quaternary" refers to the past 0.5–1.0 million years.

Alluvium Loose soil or sediment that is eroded and redeposited in a non-marine setting

Alluvium is loose, unconsolidated soil or sediment that has been eroded, reshaped by water in some form, and redeposited in a non-marine setting. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel. When this loose alluvial material is deposited or cemented into a lithological unit, or lithified, it is called an alluvial deposit.

Contents

Jurassic

Limestones, mudstones and sandstones of the Inferior Oolite Group and Great Oolite Group dating from the early to mid Jurassic Period are present at depth beneath western Cambridgeshire. The later Kellaways and Oxford Clay formations and Ampthill Clay formations all assigned to the Ancholme Group of middle to late Jurassic times underlie much of central Cambridgeshire.

Limestone Sedimentary rocks made of calcium carbonate

Limestone is a carbonate sedimentary rock that is often composed of the skeletal fragments of marine organisms such as coral, foraminifera, and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). A closely related rock is dolomite, which contains a high percentage of the mineral dolomite, CaMg(CO3)2. In old USGS publications, dolomite was referred to as magnesian limestone, a term now reserved for magnesium-deficient dolomites or magnesium-rich limestones.

Mudstone Fine grained sedimentary rock whose original constituents were clays or muds

Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.063 millimetres (0.0025 in) with individual grains too small to be distinguished without a microscope. With increased pressure over time, the platy clay minerals may become aligned, with the appearance of fissility or parallel layering. This finely bedded material that splits readily into thin layers is called shale, as distinct from mudstone. The lack of fissility or layering in mudstone may be due to either original texture or the disruption of layering by burrowing organisms in the sediment prior to lithification. Mud rocks such as mudstone and shale account for some 65% of all sedimentary rocks. Mudstone looks like hardened clay and, depending upon the circumstances under which it was formed, it may show cracks or fissures, like a sun-baked clay deposit.

Sandstone A clastic sedimentary rock composed mostly of sand-sized particles

Sandstone is a clastic sedimentary rock composed mainly of sand-sized mineral particles or rock fragments.

Cretaceous

Cretaceous rocks come to the surface in the east of the county and beneath Cambridge itself including the lower and upper Greensand, the Gault Formation and lastly the Chalk Group, youngest element of the local bedrock.

The Cretaceous is a geologic period and system that spans from the end of the Jurassic Period 145 million years ago (mya) to the beginning of the Paleogene Period 66 mya. It is the last period of the Mesozoic Era, and the longest period of the Phanerozoic Eon. The Cretaceous Period is usually abbreviated K, for its German translation Kreide.

Cambridge City and non-metropolitan district in England

Cambridge is a university city and the county town of Cambridgeshire, England, on the River Cam approximately 50 miles (80 km) north of London. At the United Kingdom Census 2011, its population was 123,867 including 24,506 students. Cambridge became an important trading centre during the Roman and Viking ages, and there is archaeological evidence of settlement in the area as early as the Bronze Age. The first town charters were granted in the 12th century, although modern city status was not officially conferred until 1951.

Gault

The Gault Formation is a geological formation of stiff blue clay deposited in a calm, fairly deep-water marine environment during the Lower Cretaceous Period. It is well exposed in the coastal cliffs at Copt Point in Folkestone, Kent, England, where it overlays the Lower Greensand formation, and underlies the Upper Greensand Formation. These represent different facies, with the sandier parts probably being deposited close to the shore and the clay in quieter water further from the source of sediment; both are believed to be shallow-water deposits.

Quaternary

Extensive areas of older glacial till are mapped across parts of the southwest of the county, notably between Peterborough and Royston, south of Newmarket and in isolated patches around March and Ely. [2]

Peterborough City and unitary authority in England

Peterborough, United kingdom is a cathedral city in Cambridgeshire, England, with a population of 196,640 in 2015. Historically part of Northamptonshire, it is 76 miles (122 km) north of London, on the River Nene which flows into the North Sea 30 miles (48 km) to the north-east. The railway station is an important stop on the East Coast Main Line between London and Edinburgh. The city is also 70 miles (110 km) east of Birmingham, 38 miles (61 km) east of Leicester, 81 miles (130 km) south of Kingston upon Hull and 65 miles (105 km) west of Norwich.

Royston, Hertfordshire town in Hertfordshire, England

Royston is a town and civil parish in the District of North Hertfordshire and county of Hertfordshire in England.

Newmarket, Suffolk Market town in Suffolk, England

Newmarket is a market town in the English county of Suffolk, approximately 65 miles north of London. It is generally considered the birthplace and global centre of thoroughbred horse racing and a potential World Heritage Site. It is a major local business cluster, with annual investment rivalling that of the Cambridge Science Park, the other major cluster in the region. It is the largest racehorse training centre in Britain, the largest racehorse breeding centre in the country, home to most major British horseracing institutions, and a key global centre for horse health. Two Classic races, and an additional three British Champions Series races are held at Newmarket every year. The town has had close royal connections since the time of James I, who built a palace there, and was also a base for Charles I, Charles II, and most monarchs since. The current monarch, Queen Elizabeth II, visits the town often to see her horses in training.

See also

Further reading

Related Research Articles

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Inferior Oolite

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The geology of Northumberland in northeast England includes a mix of sedimentary, intrusive and extrusive igneous rocks from the Palaeozoic and Cenozoic eras. Devonian age volcanic rocks and a granite pluton form the Cheviot massif. The geology of the rest of the county is characterised largely by a thick sequence of sedimentary rocks of Carboniferous age. These are intruded by both Permian and Palaeogene dykes and sills and the whole is overlain by unconsolidated sediments from the last ice age and the post-glacial period. The Whin Sill makes a significant impact on Northumberland's character and the former working of the Northumberland Coalfield significantly influenced the development of the county's economy. The county's geology contributes to a series of significant landscape features around which the Northumberland National Park was designated.

This article describes the geology of the Broads, an area of East Anglia in eastern England characterised by rivers, marshes and shallow lakes (‘broads’). The Broads is designated as a protected landscape with ‘status equivalent to a national park’.

This article describes the geology of the New Forest, a national park in Hampshire, in southern England.

References

  1. ↑ British Geological Survey 1:625,000 scale geological map Bedrock Geology UK South 5th Edn. NERC 2007
  2. ↑ British Geological Survey 1:625,000 scale geological map Quaternary Map of the United Kingdom South 1st Edn. 1977
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