| Computer Code: |
LMPL |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Turonian Age (KT)
— Coniacian Age (KO) |
| Lithological Description: |
The Lamplugh Formation consists of chalky limestones which are typically white to grey, soft to moderately hard, commonly argillaceous and characteristically chert-bearing. The presence of chert (flint) bands throughout the unit is a characteristic feature. |
| Definition of Lower Boundary: |
The lower boundary of the Lamplugh Formation is characterized by a downward change from moderately hard, chalky limestones to the harder, clean, micritic limestones of the Herring Formation. There is a corresponding downhole decrease in gamma ray and increase in sonic velocity responses. |
| Definition of Upper Boundary: |
The upper boundary of the Lamplugh Formation is marked by a downward change from the chalky limestones of the Jukes Formation into harder, more argillaceous chalks. It is marked by a sharp downward increase in velocity accompanied in some sections by a slight increase in gamma-ray values e.g. 49/24-1. In some wells the mid-part of the Lamplugh Formation is particularly argillaceous (e.g. well 42/29-C01; 53/4-2) giving the log profiles a 'waisted' appearence. |
| Thickness: |
The Lamplugh Formation ranges up to 200 m (e.g. well 49/25-1). |
| Geographical Limits: |
The Lamplugh Formation is widely distributed throughout the Southern North Sea Basin but may vary in thickness due to intra-basinal tectonic controls and post-Cretaceous erosion. |
| Parent Unit: |
Chalk Group (CK)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
North Sea well 49/24- 1: 1060-1242 m (3478-4075 ft) (Lott and Knox, 1994). |
| Reference Section |
North Sea well 38/24- 1: 1585.5-1670.5 m (5202-5481 ft) (Lott and Knox, 1994). |
| Reference Section |
North Sea well 49/05- 1: 1679.5-1987 m (5510-6519 ft) (Lott and Knox, 1994). |
| Reference(s): |
| NAM and RGD (Nederlandse Ardolie Maatschappij and Rijks Geologische Dienst) 1980. Stratigraphic nomenclature of the Netherlands. Transactions of the Royal Dutch Geological and Mining Society of Delft. |
| Whitham, F. 1991. The stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham formations north of the Humber, north-east England. Proceedings of the Yorkshire Geological Society, Vol.48, 227-254. |
| Wood, C J and Smith, E G. 1978. Lithostratigraphical classification of the Chalk in North Yorkshire, Humberside and Lincolnshire. Proceedings of the Yorkshire Geological Society, Vol. 42, 263-287. |
| 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. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
