The Thanet Formation is a

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...

found in the

London Basin The London Basin is an elongated, roughly triangular sedimentary basin approximately long which underlies London and a large area of south east England, south eastern East Anglia and the adjacent North Sea. The basin formed as a result of compr ...

of southeastern

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

.Thanet Formation
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org It is of early to mid-

Thanetian The Thanetian is, in the International Commission on Stratigraphy, ICS Geologic timescale, the latest age (geology), age or uppermost stage (stratigraphy), stratigraphic stage of the Paleocene epoch (geology), Epoch or series (stratigraphy), Serie ...

(late

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

) age and gave its name to that stratigraphic interval. It was previously known as the Thanet Beds, the Thanet Sands and the Thanet Sand Formation. It was named after the

Isle of Thanet The Isle of Thanet () is a peninsula forming the easternmost part of Kent, England. While in the past it was separated from the mainland by the Wantsum Channel, it is no longer an island. Archaeological remains testify to its settlement in a ...

. The type sections are

Herne Bay Herne Bay is a seaside town on the north coast of Kent in South East England. It is north of Canterbury and east of Whitstable. It neighbours the ancient villages of Herne, Kent, Herne and Reculver and is part of the City of Canterbury loca ...

Kent Kent is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Essex across the Thames Estuary to the north, the Strait of Dover to the south-east, East Sussex to the south-west, Surrey to the west, and Gr ...

for the upper part of the formation and Pegwell Bay for the lower part. It lies unconformably on the Late Cretaceous

Chalk Group The Chalk Group (often just called the Chalk) is the lithostratigraphic unit (a certain number of rock strata) which contains the Upper Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur ac ...

. It unconformably underlies the Lambeth Group, generally the Upnor Formation but in Essex it is the Reading Formation.

Distribution

The Thanet Formation is known at outcrop and in the subsurface over central and eastern parts of the London Basin. To the west it is missing, with the

Lambeth Group The Lambeth Group is a stratigraphic group, a set of geological rock strata in the London and Hampshire basins of southern England. It comprises a complex of vertically and laterally varying gravels, sands, silts and clays deposited between 56 ...

lying directly on the Chalk, and to the north it is replaced by the Ormesby Clay Member. It thins to the west and north of London. It reaches a maximum thickness of over 30 m in North Kent.

Lithology

The predominant

lithology The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lit ...

is very pale grey or buff fine-grained glauconitic sand. Particularly towards the base of the formation, the sand is interbedded with silts and clays. At the base of the formation a bed of flint pebbles is often developed with clasts up to cobble size in a matrix of glauconitic clayey sand. At Herne Bay the beds are divided as follows (top to bottom): * A layer of concretionary blocks (‘doggers') of calcareous indurated sandstone of 0.3 metre thickness * A pale grey sandstone with abundant shells 2.6 metre thickness * A layer of calcareous sandstone doggers, 0.3 metre thickness * A bedded, clayey buff sand with many shells, seen to 0.9 metre thickness

Depositional environment

The Thanet Formation was deposited in open marine conditions. The water depth was relatively shallow, above normal wave-base, in an inner or outer shelf setting.

Fossil content

The sequence is known for its rich fossil content, particularly molluscs and fish. The fauna give somewhat contradictory evidence of the climate, with molluscs of both cold and warm water type being found and tropical to sub-tropical fish recognised. Overall, a sub-tropical climate is indicated. The formation also has provided fossils of flora of '' Pinus macrocephalus'', '' Pinus prestwichi'', Palmae and '' Osmunda dowkeri''.

References

{{reflist Geologic formations of England Paleocene Series of Europe Paleogene England Sandstone formations Open marine deposits Fossiliferous stratigraphic units of Europe Paleontology in England Geology of London

Distribution

Lithology

Depositional environment

Fossil content

See also

References