The Thames Group is an Eocene lithostratigraphic group (a sequence of rock strata) which is widespread in southeast England, especially in the Hampshire Basin from Dorset through Hampshire to West Sussex and in the Isle of Wight and in the London Basin from Berkshire east through northern Hampshire, Surrey and Greater London to Essex and north Kent. It is encountered in older literature as the London Clay Group.[1]

Thames Group
Stratigraphic range: Eocene
London Clay Formation exposed at the base of the cliffs at Walton-on-the-Naze
TypeGroup
Sub-unitsHarwich Formation, London Clay Formation
UnderliesBracklesham Group
OverliesOldhaven Formation or Lambeth Group
Thicknessc110 - 115m in Hampshire Basin
Lithology
Primarymudstone
Othersilty clay, sandy silt, sandy clayey silt
Location
CountryEngland
ExtentHampshire Basin, London Basin
Type section
Named forRiver Thames

Stratigraphy

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The London Clay Formation is the uppermost sub-unit of the Group. It is overlain by the lowermost units of the Bracklesham Group; these being the Bagshot Formation in the London Basin, and the Poole and Wittering formations in the Hampshire basin and English Channel. Beneath the London Clay is the Harwich Formation which itself overlies Lambeth Group strata, these being rocks of the Thanet Formation in the London Basin.[2]

References

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  1. ^ http://www.bgs.ac.uk/Lexicon/lexicon.cfm?pub=THAM (BGS on-line lexicon of rock units)
  2. ^ "BGS Lexicon of Named Rock Units - Result Details".