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 exp ...

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 compre ...

of southeastern

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

.Thanet Formation
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.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), E ...

) 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 anc ...

. The

type section A stratotype or type section in geology is the physical location or outcrop of a particular reference exposure of a stratigraphic sequence or stratigraphic boundary. If the stratigraphic unit is layered, it is called a stratotype, whereas the stan ...

s 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 and Reculver and is part of the City of Canterbury local government ...

Kent Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...

for the upper part of the formation and

Pegwell Bay Pegwell Bay is a shallow inlet in the English Channel coast astride the estuary of the River Stour north of Sandwich Bay, between Ramsgate and Sandwich in Kent. Part of the bay is a nature reserve, with seashore habitats including mudflats and ...

for the lower part. It lies

unconformably An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

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 acr ...

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

Reading Formation The Reading Formation is a geologic formation in southern England. It dates to the Paleocene period, and is part of the Lambeth Group. It overlies the London Basin and is below the Harwich Formation. The formation is composed of "a series of lent ...

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 56-55 ...

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 Glauconite is an iron potassium phyllosilicate ( mica group) mineral of characteristic green color which is very friable and has very low weathering resistance. It crystallizes with a monoclinic geometry. Its name is derived from the Greek () m ...

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 Cobble may refer to: * Cobble (geology), a designation of particle size for sediment or clastic rock * Cobblestone, partially rounded rocks used for road paving * Hammerstone, a prehistoric stone tool * Tyringham Cobble, a nature reserve in Tyr ...

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 Shelf ( : shelves) may refer to: * Shelf (storage), a flat horizontal surface used for display and storage Geology * Continental shelf, the extended perimeter of a continent, usually covered by shallow seas * Ice shelf, a thick platform of ice f ...

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 A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...

'', ''

Pinus prestwichi A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...

'',

Palmae The Arecaceae is a family of perennial flowering plants in the monocot order Arecales. Their growth form can be climbers, shrubs, tree-like and stemless plants, all commonly known as palms. Those having a tree-like form are called palm trees ...

and ''

Osmunda dowkeri ''Osmunda'' is a genus of primarily temperate-zone ferns of family Osmundaceae. Five to ten species have been listed for this genus. Description Completely dimorphic fronds or pinnae (hemidimorphic), green photosynthetic sterile fronds, and n ...

''.

Distribution

Lithology

Depositional environment

Fossil content

See also