| Computer Code: |
LSCL |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Ypresian Age (GY)
— Ypresian Age (GY) |
| Lithological Description: |
The Lower Shelly Clay consists almost entirely of a low-diversity fauna of fossil shells (of types indicating brackish water deposition) in dark grey, dark brown or black organic clay. The shell debris is concentrated into distinct beds or drifts (coquinas), which in some cases have been cemented to form limestones. The basal part is locally a shelly, clayey sand.
The Lower Shelly Clay represents deposition in marginal marine lagoons. In the far west, this environment occurred during a very brief interval, but in the east of the London Basin lagoonal conditions persisted for longer, depositing the lower part of the Woolwich Formation. However, in the east the depositional conditions also varied in time and space, resulting in the different lithologies of the lower Woolwich Formation.
Early Eocene (earliest Ypresian). |
| Definition of Lower Boundary: |
The base of the Lower Shelly Clay is a sharply-defined contact on the Lower Mottled Clay or, passing eastwards, locally on the Shorne Member or on the Upnor Formation. In the London area, the basal Woolwich Formation rests on a burrowed omission surface at the top of a pedogenically-altered interval within the Lower Mottled Clay and, in places, the Upnor Formation. This omission surface corresponds to the mid-Lambeth Group Hiatus of Page and Skipper (2000). |
| Definition of Upper Boundary: |
The top of the Lower Shelly Clay is generally a sharply conformable boundary with the Laminated Beds, or locally in south London with the Upper Shelly Clay. |
| Thickness: |
Up to 6 m. |
| Geographical Limits: |
The Lower Shelly Clay occurs in London (east of a line through Euston, Marylebone and Chelsea) eastwards to south-west Essex and north-west Kent (Ellison et al., 2004, fig. 17).
There is a small development of this facies within the Lambeth Group near Guildford, which is otherwise locally dominated by the Reading Formation (Curry, 1958, p. 78; Ellison et al., 2002) and in the outliers at Newhaven, East Sussex, in the easternmost part of the Hampshire Basin (Bone, 1976; Dupuis and Gruas-Cavagnetto, 1985; Skipper, 1999). |
| Parent Unit: |
Woolwich Formation (WL)
|
| Previous Name(s): |
Woolwich Shell Bed(s) [Obsolete Name and Code: Use LSCL, UPSCL]
(-5087)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
The stratotype section is in the Charlton Pit (or Gilbert's Pit), just south-west of Maryon Park, Charlton, London Borough of Greenwich (Daley, 1999; Ellison et al., 1994; Hooker, 2010; Whitaker, 1889). |
| Reference Section |
BGS Crystal Palace Borehole (TQ37SW 671) 136.42 to 138.00 m depth (Ellison et al., 2004, p. 32). |
| Reference Section |
The Lower Upnor Pit (Daley, 1999; Ellison et al., 1994; Kennedy and Sellwood, 1970). |
| Reference Section |
Cliff sections west of Newhaven, East Sussex (Dupuis and Gruas-Cavagnetto, 1985). |
| Reference(s): |
| Bone, D A. 1976. The Tertiary deposits at Newhaven, Sussex. Tertiary Research 1, 47-49. |
| Daley, B. 1999. London Basin: eastern localities, In: Daley, B, Balson, P (Eds.), British Tertiary Stratigraphy. Geological Conservation Review Series 15, pp. 23-72. |
| Dupuis, C., Gruas-Cavagnetto, C., 1985. The Woolwich Beds and the London Clay of Newhaven (East Sussex): new palynological and stratigraphical data. The London Naturalist 75, 27-39. |
| 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. |
| Stamp, L.D., Priest, S., 1920. The geology of the Swanscombe Eocene outlier, Kent, and report of excursion: Saturday, 24th April, 1920. Proceedings of the Geologists' Association 31, 187-199, IN183. |
| 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. |
| 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. |
| Curry, D. 1958. Part 3a XII Palaeogene. Lexique Stratigraphique International. Whittard, W F, and Simpson, S (editors). Vol. 1 Europe (Paris: Centre Nationale de la Research Scientifique.) |
| Page, D P, and Skipper, J A E. 2000. Lithological characteristics of the Lambeth Group. Ground Engineering, Vol. 33, 38-43. |
| 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, Williamson, I T and Humpage, A J. 2002. Geology of the Guildford district - a brief explanation of the geological map. Sheet explanation of the British Geological Survey. 1:50 000 Sheet 285 Guildford (England and Wales). |
| Hooker, J J. 2010. The mammal faunas of the early Eocene Blackheath Formation of Abbey Wood, London. Monograph of the Palaeontographical Society, London, 164, 1-162. |
| Skipper, J A. 1999. The stratigraphy of the Lambeth Group (Paleocene) of South East England. PhD thesis, Imperial College, London. |
| Ellison, R A, Woods, M A, Allen, D J, Forster, A, Pharaoh, T C and King, C. 2004. Geology of London. Memoir of the British Geological Survey, Sheets 256 (North London), 257 (Romford), 270 (South London), 271 (Dartford) (England and Wales). |
| Aldiss, D T. 2014. The stratigraphical framework for the Palaeogene successions of the London Basin, UK. British Geological Survey Open Report OR/14/008. 95 pp. |
| 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. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
