| Computer Code: |
KYRE |
Preferred Map Code: |
notEntered |
| Status Code: |
Full |
| Age range: |
Turonian Age (KT)
— Campanian Age (KC) |
| Lithological Description: |
The Kyrre Formation typically comprises a thick, monotonous sequence of mudstones with sporadic limestone stringers. The mudstones are grey, silty, slightly calcareous and occasionally pyritic, glauconitic and micaceous. The limestones are off-white to pale brown, argillaceous, chalky and locally dolomitic. |
| Definition of Lower Boundary: |
The base of the Kyrre Formation is normally marked by a downward change from mudstones to argillaceous chalky limestones and interbedded mudstones of the Macbeth Formation. It is marked on wireline logs by a downward decrease in gamma values and an increase in velocity. Locally, the basal sediments of the Kyrre Formation display a progressive downward decrease in gamma values and an increase in velocity (e.g. 3/10b-1), which is similar to the log signatures displayed by the basal Flounder and Mackerel formations. On intrabasinal highs, the Kyrre Formation locally rests unconformably on pre-Cretaceous rocks. In the South Viking Graben, the Kyrre Formation locally rests on the Herring Formation (e.g. 16/3-1). |
| Definition of Upper Boundary: |
The top of the Kyrre Formation is usually marked by a downward change from pale grey and commonly red-brown calcareous mudstones and argillaceous chalky limestones of the Jorsalfare Formation (unit J1) to darker grey mudstones. It is marked on wireline logs by a downward increase in gamma values and a decrease in velocity. |
| Thickness: |
The Kyrre Formation reaches a thickness of about 1100 m. Seismic data suggest that it thins by onlap over contemporaneous highs, but condensed basal sections may also occur (Johnson et al., 1993). |
| Geographical Limits: |
The Kyrre Formation is widely distributed across the Viking Graben, Beryl Embayment and East Shetland Basin, covering intrabasinal highs. |
| Parent Unit: |
Shetland Group (STLN)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
Norwegian Sector North Sea well N25/1-1 (Isaksen and Tonstad, 1989, p.29, fig.33): 2997-3582 m (9832.5-11752 ft) below KB. |
| Reference Section |
North Sea well 3/29- 1: 2925-3603 m (9596-11821 ft) (Johnson and Lott, 1993). |
| Reference Section |
North Sea well 3/10b- 1: 2528-3586 m (8294-11765 ft) (Johnson and Lott, 1993). |
| Reference(s): |
| Johnson, H and Lott, G K. 1993. 2. Cretaceous of the Central and Northern 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, Gillespie, M R, Smith, K, Auton, C A, Floyd, J D, Leslie, A G, Millward, D, Mitchell, W I, McMillan, A A, Stone, P, Barron, A J M, Dean, M T, Hopson, P M, Krabbendam, M, Browne, M A E, Stephenson, D, Akhurst, M C, and Barnes, R P. 2007. Stratigraphical Chart of the United Kingdom: Northern Britain. (British Geological Survey.) |
| Abbotts, I L (ed.) 1991. United Kingdom oil and gas fields 25 years commemorative volume. Geological Society, London, Memoir No. 14. |
| Deegan, C E and Scull, B J. 1977. A standard lithostratigraphic nomenclature for the Central and Northern North Sea. Report of the Institute of Geological Sciences, 77/25; NPD Bulletin No.1. |
| Isaksen, D and Tonstad, K. 1989. A revised Cretaceous and Tertiary lithostratigraphic nomenclature for the Norwegian North Sea. NPD-Bulletin No.5 |
| Johnson, H, Richards, P C, Long, D, and Graham, C C. 1993. United Kingdom offshore regional report: the geology of the northern North Sea. (London: HMSO for the British Geological Survey.) |
| King, C, Bailey, H W, Burton, C A, and King, A D. 1989. Cretaceous of the North Sea. In: Jenkins, D G and Murray, J W (eds) Stratigraphical atlas of fossil foraminifera, 372-417. Ellis Horwood Limited, Chichester, for the British Micropalaeontological Society. |
| Ritchie, J D, Gatliff, R W and Riding, J, 1996. 1. Pre - Tertiary lithostratigraphy. In: Stratigraphic Nomenclature of the UK North West Margin. British Geological Survey, Nottingham. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
