| Computer Code: |
LMBT |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Thanetian Age (GT)
— Ypresian Age (GY) |
| Lithological Description: |
The Lambeth Formation is represented by a poorly known and variable succession of brown, yellow, grey and red mudstones with locally developed sandstones. The mudstones and claystones appear to represent interbedded or colour-mottled lithologies, and are typically soft and poorly bedded. The sandstones are mostly non-glauconitic, medium to fine grained but locally with flint pebbles. In some sections these display blocky wireline-log character, but locally in the thicker successions of quadrants 48, 49, 50 and 53, they display upward-coarsening cycles. In some sections a thin unit of glauconitic sandstone is present near the base. |
| Definition of Lower Boundary: |
The base of the Lambeth Formation is defined by a downward change from sandstone or yellow, brown or red-brown mudstone to green grey or grey mudstone of the Lista Formation. It commonly lies beneath a thin low-gamma or high-velocity mudstone unit (e.g. 49/1-3), which passes locally into sandstone. It is also commonly identified by a downward change to relatively high and consistent resistivity values. |
| Definition of Upper Boundary: |
The top of the Lambeth Formation is defined by a downward change from grey mudstone (Sele unit 3) to sandstone or brown or yellow mudstone, and is marked by a downward decrease in gamma-ray values. |
| Thickness: |
The thickness is generally between 10 and 30 m, but reaches c. 45 m in well 44/11-3. |
| Geographical Limits: |
The Lambeth Formation is present over much of the Paleogene subcrop. |
| Parent Unit: |
Moray Group (MORA)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
North Sea well 49/15- 1: 875-908.5 m (2870-2980 ft) (Lott and Knox, 1994). |
| Reference(s): |
| Lott, G K and Knox, R W O'B. 1994. 7. Post-Triassic of the Southern North Sea. In: Knox, R W O'B and Cordey, W G (eds.) Lithostratigraphic nomenclature of the UK North Sea. British Geological Survey, Nottingham. |
| Waters, C N, Smith, K, Hopson, P M, Wilson, D, Bridge, D M, Carney, J N, Cooper, A H, Crofts, R G, Ellison, R A, Mathers, S J, Moorlock, B S P, Scrivener, R C, McMillan, A A, Ambrose, K, Barclay, W J, and Barron, A J M. 2007. Stratigraphical Chart of the United Kingdom: Southern Britain. British Geological Survey, 1 poster. |
| 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. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
