The BGS Lexicon of Named Rock Units — Result Details

Upnor Formation

Computer Code: UPR Preferred Map Code: UPR
Status Code: Full
Age range: Paleocene Epoch (GP) — Paleocene Epoch (GP)
Lithological Description: The Upnor Formation is typically composed of variably but commonly abundant glauconitic fine- to coarse-grained sand with variable clay and silt content, and with beds, lenses and stringers of well-rounded, black flint gravel, and minor thin clays, commonly interbedded with glauconitic sand laminae and lenses. When fresh, the sands are dark grey-brown to dark green depending on proportion of glauconite grains which may be more than 25%. In south-east London there is a persistent pebble bed at the top. The sands weather pale grey-brown to yellow-brown but the glauconite remains dark green. In the central and northern London Basin pedogenic processes during deposition of the overlying Reading Formation modified the sands, resulting in development of carbonate concretions, clay enrichment and colour mottling that exceptionally extend through the formation. Oysters are common in unweathered sections.
Definition of Lower Boundary: In the eastern part of the London Basin, the Upnor Formation rests on silty fine-grained sand at a burrowed contact with the Thanet Formation, with burrows extending as much as 0.5m into the Thanet Formation, or on a channelled erosion surface (King in prep). The Upnor Formation is likely to be composed of medium to coarse-grained sand that is greener and commonly more gravelly than that of the Thanet Formation but in places has a confusingly similar lithology, especially where, as in the far east of the London Basin, bioturbation has produced a gradational juction (Ellison et al.,1994). According to Morton (1982), the top of the Thanet Formation has been leached during a period of exposure, probably with some erosion, prior to deposition of the Upnor Formation. In the west of the London Basin, to the west of the Thanet Formation outcrop and subcrop, the Upnor Formation rests on a burrowed contact with chalk and flints of the Chalk Group, commonly modified by karstic dissolution. In East Anglia, the Upnor Formation rests on a burrowed contact with the clay of the Ormesby Clay Member.
Definition of Upper Boundary: In general, marked by an upwards change from green glauconitic sand or sandy gravel to colour-mottled clays of the Reading Formation, or dark shelly clay or lignitic sand of the Woolwich Formation. Commonly however the Upnor Formation has been affected by contemporary pedogenic alteration associated with the mid-Lambeth Group Hiatus. Its original character may then be obscured and the contact with the overlying Reading Formation unclear. In north and east Kent, the Lambeth Group (including the top of the Upnor Formation) was eroded prior to deposition of the Harwich Formation (Oldhaven Member).
Thickness: Up to 15m in the east of the London Basin. Typically 5 to 8m in central London but locally as little as 2m, generally decreasing westwards to less than 2m.
Geographical Limits: The Upnor Formation occurs throughout most of the London and Hampshire basins but thins markedly to the west of London. It also occurs in north Essex and in Suffolk. In north Kent the top was removed by erosion prior to deposition of the Oldhaven Member.
Parent Unit: Lambeth Group (LMBE)
Previous Name(s): Bottom Bed (-5097)
Reading Bottom Bed [Obsolete Name And Code] (BBD)
Reading Formation Basement Bed (RFBB)
Woolwich Bottom Bed (-5099)
Hales Clay Member (HAC)
Alternative Name(s): none recorded or not applicable
Reference Section  Jubilee Extension Borehole 404T. BGS Registration No. TQ37NW/2118. Ellison et al., 1994. 
Type Section  Lower Upnor Pit, north of Chatham, north Kent. (Daley, 1999; Ellison et al., 1994; Kennedy and Sellwood, 1970). 
Reference Section  Charlton Pit (or Gilbert’s Pit), just south-west of Maryon Park, Charlton, London Borough of Greenwich. Daley, 1999; Ellison et al., 1994; Whitaker, 1889. 
Reference Section  BGS Crystal Palace Borehole (TQ37SW671), 141.95 to 145.10m depth. (Ellison et al., 2004, p.32) 
Reference Section  Staines 5 Borehole (TQ07SW156), 129.74 to 130.11m depth. (Ellison and Williamson, 1999, fig. 6). 
Reference Section  Old Cement Works, Harefield, London Borough of Hillingdon. Cooper, 1976; Daley, 1999; King, 1981, fig. 32). This locality exposes a thin development of the Upnor Formation in the west of the London Basin. 
Reference Section  Pincent’s Kiln, Theale, Berkshire. Crane and Goldring,1991; Daley, 1999. 
Knox, R W O. 1996. Tectonic controls on sequence development in the Palaeocene and earliest Eocene of southeast England: implications for North Sea stratigraphy. 209-230 in Sequence Stratigraphy in British Geology. Hesselbro, S P, and Parkinson, D N (editors). Geological Society of London Special Publication, No. 103. 
Morton, A C. 1982. The provenance and diagenesis of Palaeogene sandstones of southeast England as indicated by heavy mineral analysis. Proceedings of the Geologists’ Association, Vol. 93, 263-274. 
Hester, S W. 1965. Stratigraphy and palaeogeography of the Woolwich and Reading Beds. Bulletin of the Geological Survey of Great Britain No. 23, 117-137. 
King, C. in prep. A revised correlation of Palaeogene and Neogene deposits in the British Isles. Geological Society of London Special Report. 
Daley, B. 1999. London Basin: eastern localities, In: Daley, B., Balson, P. (Eds.), British Tertiary Stratigraphy. Geological Conservation Review Series 15, pp. 23-72. 
King, C. 1981. The stratigraphy of the London Clay and associated deposits. Tertiary Research Special Paper No.6. (Backhuys: Rotterdam). 
Whitaker, W., 1889. The geology of London and part of the Thames Valley (Explanation of Sheets 1, 2 and 7). Memoir of the Geological Survey of the United Kingdom Vol. 1. Descriptive geology. 
Kennedy, W.J., Sellwood, B.W., 1970. Ophiomorpha nodosa Lundgren, a marine indicator from the Sparnacian of south-east England. Proceedings of the Geologists' Association 81, 99-110. 
Edwards, R A and Freshney, E C. 1987. Lithostratigraphical classification of the Hampshire Basin Palaeogene Deposits (Reading Formation to Headon Formation) Tertiary Research, Vol.8, 43-73. 
Crane, P R and Goldring, R, 1991. The Reading Formation (late Palaeocene to early Eocene) at Cold Ash and Pincent's Kiln (Berkshire) in the western London Basin. Tertiary Research, Vol.12, 147-158. 
Aldiss, D.T., 2012. The stratigraphical framework for the Palaeogene successions of the London Basin, UK. British Geological Survey Open Report OR/12/004. Available from 
Ellison, R A and Williamson, I T. 1999. Geology of the Windsor and Bracknell district - a brief explanation of the geological map. Sheet Explanation of the British Geological Survey. 1:50 000 Sheet 269 Windsor (England and Wales). 
Ellison, R A, Knox R W O'B, Jolley, D W and King, C, 1994. A revision of the lithostratigraphical classification of the early Palaeogene strata of the London Basin and East Anglia. Proceedings of the Geologists' Association, Vol.105, 187-197. 
Ellison, R A, 1983. Facies distribution in the Woolwich and Reading Beds of the London Basin, England. Proceedings of the Geologists' Association, Vol. 94, 311-319. 
Ali, J R, and Jolley, D W. 1996. Chronostratigraphic framework for the Thanetian and lower Ypresian deposits of southern England. Geological Society, London, Special Publications, Vol. 101, 129-144. 
Barrow, G. 1919. Some future work for the Geologists' Association. Proceedings of the Geologists' Association, Vol. 30, 1-48, IN41-IN42. 
Cooper, J. 1976. Report of a field meeting to Harefield, Middlesex. Tertiary Research, Vol. 1, 31-36. 
Daley, B. 1999. London Basin: western localities. 73-84 in British Tertiary Stratigraphy. Daley, B, and Balson, P (editors). Geological Conservation Review Series, No. 15. 
Ellison, R A, Ali, J R, Hine, N M, and Jolley, D W. 1996. Recognition of Chron C25n in the upper Paleocene Upnor Formation of the London Basin, UK. Geological Society special publication., Vol. 101, 185-193. 
Gamble, H J. 1972. Field meeting to Boughton and Canterbury, Kent: Sunday, 11 July 1971. Proceedings of the Geologists' Association, Vol. 83, 471-478. 
Gurr, P R. 1962. A new fish fauna from the Woolwich Bottom Bed (Sparnacian) of Herne Bay, Kent. Proceedings of the Geologists' Association, Vol. 73, 419-447, IN418-IN419. 
Hepworth, J V. 1998. Aspects of the English silcretes and comparison with some Australian occurrences. Proceedings of the Geologists’ Association, Vol. 109, 271-288. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E256 E257 E268