Bagshot Formation (London Basin), Wittering Formation and Poole Formation (Hampshire Basin and English Channel)
Overlies
Harwich Formation
Thickness
up to 150 m
Location
Region
southern England
Geological map of the London Basin; the London Clay is marked in dark brown.
Eroding London Clay cliffs at The Naze in EssexOxshott Heath, where the overlying sand and the London Clay layers are exposed as a sand escarpment, rising approximately 25 metres (82 feet)
The London Clay Formation is a marine geological formation of Ypresian (early Eocene Epoch, c. 54-50 million years ago)[1] age which crops out in the southeast of England. The London Clay is well known for its fossil content. The fossils from the lower Eocene rocks indicate a moderately warm climate, the tropical or subtropical flora. Though sea levels changed during the deposition of the clay, the habitat was generally a lush forest – perhaps like in Indonesia or East Africa today – bordering a warm, shallow ocean.
The London Clay is a stiff bluish clay which becomes brown when weathered and oxidized. Nodular lumps of pyrite are frequently found in the clay layers. Pyrite was produced by microbial activity (sulfate reducing bacteria) during clay sedimentation. Once clay is exposed to atmospheric oxygen, framboidal pyrite with a great specific surface is rapidly oxidized. Pyrite oxidation produces insoluble brown iron oxyhydroxide (FeOOH) and sulfuric acid leading to the formation of relatively soluble gypsum (CaSO4·2H2O, calcium sulfate dihydrate). This latter is more soluble and mobile than iron oxides and can further recrystallize to form larger crystals sometimes called selenite (coming from the moon, but not related to selenium, although the etymology is the same), or "waterstones".
Large septarian concretions, produced by microbial activity (oxidation of organic matter) in the ancient seafloor during clay early diagenesis, are also common. These have been used in the past for making cement. They were once dug for this purpose at Sheppey, near Sittingbourne, and at Harwich, and also dredged, off the Hampshire coast. The clay is still used commercially for making bricks, tiles, and coarse pottery in places such as Michelmersh in Hampshire.
^ abFriedman, Matt; Beckett, Hermione T.; Close, Roger A.; Johanson, Zerina (2016). "The English Chalk and London Clay: two remarkable British bony fish Lagerstätten". Geological Society, London, Special Publications. 430 (1): 165–200. doi:10.1144/SP430.18. ISSN 0305-8719.
The LondonClay Formation is a marine geological formation of Ypresian (early Eocene Epoch, c. 54-50 million years ago) age which crops out in the southeast...
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, Al2Si2O5(OH)4). Most...
prehistoric and extant species whose fossils have been found in the LondonClay, which underlies large areas of southeast England. Plant fossils, especially...
directory) List of dinosaur-bearing rock formations Kimmeridge ClayLondonClay Weald Clay "Oxford Clay Formation". The BGS Lexicon of Named Rock Units. British...
(about 60 cm in length) perissodactyl ungulates that was found in the LondonClay formation. This small, fox-sized animal is (for some scientists) considered...
Nicholas Anthony Phillip Clay (18 September 1946 – 25 May 2000) was an English actor. Clay was born in Streatham, London on 18 September 1946, the son...
Barnaby Clay (born 15 May 1973) is a British film and music video director. Clay graduated London International Film School in 1996, directing the school's...
Kentish mainland. Sheppey, like much of north Kent, is largely formed from LondonClay and is a plentiful source of fossils. The Mount near Minster rises to...
called Suffolk. The Suffolk coastline is a complex habitat, formed by Londonclay and crag underlain by chalk and therefore susceptible to erosion. It...
Tertiary rocks younger than the LondonClay, surrounded by former routes of the Thames where much younger deposits overlie the clay. Smaller outliers of such...
Fire clay is a range of refractory clays used in the manufacture of ceramics, especially fire brick. The United States Environmental Protection Agency...
Stamford Hill is formed on a widening bed of LondonClay. Brickearth deposits are within tongues of clay extending beneath Clapton Common, Stamford Hill...
Cenozoic rocks made up of the Paleocene age Reading beds and Eocene age LondonClay that occupies the remaining southern part. On the northern boundary and...
"Diagenesis of mudrocks and concretions from the LondonClay Formation in the London Basin". Clay Minerals. 29 (4): 693–707. Bibcode:1994ClMin..29..693H...
Chiltern Hills and the younger Palaeocene, Reading Beds and Eocene, LondonClay which occupy the remaining southern part. The eastern half of the county...
be excavated to expose the brickearth (which was found overlying the Londonclay subsoil), which was then turned into bricks on the site by moulding and...
Weald Clay or the Weald Clay Formation is a Lower Cretaceous sedimentary rock unit underlying areas of South East England, between the North and South...
line where the permeable chalk of the North Downs meets the impermeable LondonClay. Several tributaries of the Hogsmill River rise in the town and in the...
Brea Tar Pits, California, United States List of fossil species in the LondonClay, England List of White Sea biota species by phylum, Russia Paleobiota...
London, running from Hampstead to Highgate, which rests on a band of LondonClay. The heath is rambling and hilly, embracing ponds, recent and ancient...
Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2Si2O5(OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline...
increasing number worked in the brick industry that exploited the local LondonClay. In the early 18th century nonconformist preacher Samuel Chandler was...
Henry Clay Sr. (April 12, 1777 – June 29, 1852) was an American lawyer and statesman who represented Kentucky in both the U.S. Senate and House of Representatives...
of sands and clays of shallow-water origin, some being fresh-water, some marine. They belong to the upper Eocene formation of the London and Hampshire...
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