The BGS Lexicon of Named Rock Units — Result Details
Wentlooge Member
| Computer Code: | WLLEV | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Holocene Epoch (QH) — Holocene Epoch (QH) | ||
| Lithological Description: | Soft to very soft, blue-grey clay, with scattered diffuse silt laminae and peats. A basal gravel and diachronous basal peat are commonly present. | ||
| Definition of Lower Boundary: | In the type area it lies unconformably on bedrock, fluvioglacial sand and gravel of Welsh Ice origin, and locally on Brecknockshire Formation. | ||
| Definition of Upper Boundary: | Generally the ground surface; locally overlain by deposits of the Severn and Avon Catchments Subgroup. | ||
| Thickness: | Generally 9 to 12 m, though locally more in the region of buried channels. 15 m proved in borehole [ST58NW/2] at Sudbrook. | ||
| Geographical Limits: | Northern shore of the Severn Estuary between Cardiff and Gloucester. Includes Wentlooge Level, Caldicote Level, New Grounds and Minsterworth Ham, as well as tidal banks north of the main channel. | ||
| Parent Unit: | Gwent Levels Formation (GLEV) | ||
| Previous Name(s): | Tidal flat deposits
(TFD)
Awre Formation [Obsolete Name and Code: Use WLLEV] (-1920) Gwynllwg Formation [Obsolete Name and Code: Use WLLEV] (-1921) Tidal flat deposits (TFD) Estuarine Alluvium [Obsolete Name And Code: Use TFD] (ESAL) Rumney Formation (-612) Wentlooge Formation (-613) Northwick Formation [Obsolete Name and Code: Use WLLEV] (-3133) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Coastal plain between Cardiff and Newport on the Wentlooge Level. Tidal flat deposits formed during the post-Devensian global sea-level rise. Allen, 1987. | ||
| Reference(s): | |||
| McMillan, A A, Hamblin, R J O, and Merritt, J W. 2011. A lithostratigraphical framework for onshore Quaternary and Neogene (Tertiary) superficial deposits of Great Britain and the Isle of Man. British Geological Survey Research Report, RR/10/03. 343pp. | |||
| Allen, J R L. 1987. Late Flandrian shoreline oscillations in the Severn Estuary: the Rumney Formation at its typesite (Cardiff area). Philosophical Transactions of the Royal Society of London, B315, 157-174. | |||
| Waters, R A and Lawrence, D J D. 1987. Geology of the South Wales Coalfield - Part III: the country around Cardiff. Memoir of the British Geological Survey, Sheet 263. (England and Wales). | |||
| Bowen, D Q. 1999. Wales. Chapter 7 in A revised correlation of Quaternary deposits in the British Isles. Bowen, D Q (editor). Geological Society of London Special Report, No. 23. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E233 E234 E249 E250 E263 | |||