OR/14/008 Obsolete lithostratigraphic terms and codes

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Aldiss, D T. 2014. The stratigraphical framework for the Palaeogene successions of the London Basin, UK. Nottingham, UK, British geological Survey. (OR/14/008)

This list is in alphabetical order of Lexicon Codes (The BGS Lexicon of named rock units). It is mainly restricted to unit names used on BGS maps and in other BGS publications, with entries in the BGS Lexicon.

Extant Lexicon code Obsolete Lexicon code Obsolete name Current name for equivalent or part-equivalent
BBD Reading Bottom Bed Upnor Formation
BGB Bagshot Beds Part of Bracklesham Group
BGBL Lower Bagshot Beds Near-equivalent to Bagshot Formation
BGBM Middle Bagshot Beds Near-equivalent to Windlesham Formation
BGBR Bagshot Beds and Bracklesham Beds (undifferentiated) Part of Bracklesham Group
BGBU Upper Bagshot Beds Camberley Sand Formation
BLB Blackheath Beds Blackheath Member
HAC Hales Clay Member Orwell Member (Harwich Formation) and Upnor Formation
LCBA London Clay Basement Bed Equivalent or part equivalent to Walton Member or Harwich Formation
LLTE Lower London Tertiaries Harwich Formation, Lambeth Group and Thanet Formation, undifferentiated
MCL Mottled Clay (Reading Formation) Reading Formation
OH Oldhaven Beds Oldhaven Member
RFBB Reading Formation Basement Bed Upnor Formation
TAB Thanet Sand Formation Thanet Formation
TS Thanet Sand Thanet Formation
WLOH Woolwich Beds – Oldhaven Beds Woolwich Formation and Harwich Formation undifferentiated
WRB Woolwich and Reading Beds Formation Woolwich Formation and Reading Formation undifferentiated
Blackwall Rock not known
Figure 1    Selected structures controlling the London Basin. This map shows the areas of the traditional English counties, prior to the formation of the modern Boroughs, Districts and Unitary Authorities, although it includes the area of the Greater London Authority.
Table 1    Chronostratigraphical subdivisions of the Cenozoic Era.
PERIOD EPOCH AGE/STAGE Age of base (Ma)
QUATERNARY Holocene
Pleistocene
2.59
NEOGENE Pliocene 5.33
Miocene 23.03
PALAEOGENE Late Oligocene Chattian 28.4
Early Rupelian 33.9
Late Eocene Priabonian 37.2
Mid Bartonian 40.4
Lutetian 48.6
Early Ypresian 55.8
Late Paleocene Thanetian 58.7
Selandian 61.1
Early Danian 65.5

From Ogg et al. (2008)[1], and from King (2006)[2] after Berggren et al. (1995)[3].
Age/Stage names for the Neogene and Quaternary have been omitted for simplicity.

Table 2    Stratigraphical hierarchy in the Palaeogene of the London Basin.
Group Formation Member Bed
Bracklesham Camberley Sand
Windlesham Stanners Hill Pebble
Bagshot Swinley Clay St Ann’s Hill Pebble
Thames London Clay Claygate
Sheppey
Aveley
Ockendon
Walton
Harwich Swanscombe
Oldhaven
Blackheath
Wrabness
Orwell
Lessness Shell
Harwich Stone Band
Suffolk Pebble
Lambeth Woolwich Woolwich Sands
Upper Shelly Clay
Striped Loams
Laminated Beds
Lower Shelly Clay
Shorne
Cobham Lignite
Reading Upper Mottled Clay
Lower Mottled Clay
Upnor
Montrose Thanet Reculver Sand
Pegwell Silt
Kentish Sands
Stourmouth Silt
Base Bed
Cliffs End Greensand Bullhead
Lista Ormesby Clay

Note that in normal usage, unit names are terminated by the rank term at the head of the column, other than those shown in italic script, which are informal.

Table 3    Subdivision of the Upper Palaeogene strata of the London Basin.
Warburton 1822[4] Prestwich 1847[5] Dewey and Bromehead 1915[6] King 1981[7] Bristow 1982[8] Curry 1992[9] Current BGS Framework
London Basin Hampshire Basin
Younger beds have been removed by erosion Barton Formation Bracklesham Group
Selsey Sand Formation
Bagshot Sand Upper Bagshot Sands Barton Beds Bagshot Formation Camberley Sand Formation Bracklesham Group
Middle Bagshot Sands Bracklesham Beds Middle Bagshot Beds

Middle unit

Lower unit
Windlesham Formation
Marsh Farm Formation
Earnley Sand Formation
Swinley Clay Member

Bagshot Formation
Wittering Formation
Lower Bagshot Sands Bagshot Beds Virginia Water Formation Bagshot Beds
London Clay Formation

Taken from a draft document prepared by R A Ellison and I T Williamson, BGS, in 1998.

References

  1. OGG, J G, OGG, G, and GRADSTEIN, F M. 2008. The concise geologic time scale. (Cambridge: Cambridge University Press.)
  2. KING, C. 2006. Paleogene and Neogene: uplift and a cooling climate. 395–427 in The geology of England and Wales. BRENCHLEY, P J, and RAWSON, P F (editors). (The Geological Society, London.)
  3. BERGGREN, W A, KENT, D V, SWISHER, C C, and AUBRY, M-P. 1995. A revised Cenozoic geochronology and chronostratigraphy. 129–212 in Geochronology, time scales and global stratigraphic correlation. BERGGREN, W A, KENT, D V, AUBRY, M-P, and HARDENBOL, J (editors). SEPM Special Publication, No. 54.
  4. WARBURTON, H. 1822. III.—On the Bagshot Sand. Transactions of the Geological Society of London, Vol. Series 2, Volume 1, 48–52.
  5. PRESTWICH, J. 1847. On the main points of structure and the probable age of the Bagshot Sands, and on their presumed equivalents in Hampshire and France. Quarterly Journal of the Geological Society, London, Vol. 3, 378–409.
  6. DEWEY, H, and BROMEHEAD, C E N. 1915. The geology of the country around Windsor and Chertsey. Memoir of the Geological Survey of Great Britain, Sheet 269 (England and Wales).
  7. KING, C. 1981. The stratigraphy of the London Clay and associated deposits. Tertiary Research Special Paper. No. 6. (Rotterdam: Dr W Backhuys.)
  8. BRISTOW, C R. 1982. The nomenclature of the Bagshot and the Claygate Beds of London and Essex. Tertiary Research, Vol. 4 (1), 7–8.
  9. CURRY, D. 1992. Tertiary. 389–411 in Geology of England and Wales. DUFF, P M D, and SMITH, A J (editors). (London: The Geological Society.)