The BGS Lexicon of Named Rock Units — Result Details
Statfjord Formation
Computer Code: | STAT | Preferred Map Code: | notEntered |
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Status Code: | Full | ||
Age range: | Rhaetian Age (TR) — Sinemurian Age (JS) | ||
Lithological Description: | The formation comprises interbedded sandstones, siltstones, mudstones and occasional minor coals. In the East Shetland Basin, sandstones are pale grey to white, fine- to very coarse-grained, sometimes pebbly, micaceous, variably kaolinitic and sometimes cross-bedded. Siltstones and mudstones are grey, green, reddish-brown, occasionally red, micaceous and sometimes carbonaceous. Coal seams up to 3.5 m thick occur locally. In the Beryl Embayment sandstone beds usually have sharp bases and frequently form upward fining cycles. Cross-bedding and ripple-lamination are present. Carbonized wood is present. Thin sandstones, which are interbedded with siltstones, mudstones and coal, show parallel to sub-parallel laminations, ripple laminations and water escape structures. The associated mudstones are mid-grey, generally blocky and massive (but occasionally fissile). | ||
Definition of Lower Boundary: | The lower boundary is defined by a downward change from mainly pale grey, white and green coloured, mainly arenaceous deposits to predominantly red argillaceous facies (Cormorant Formation). A down-section increase in gamma values may occur. | ||
Definition of Upper Boundary: | Defined by a downward change from sandstones (Nansen Formation) to interbedded sandstones, mudstones and minor coals, associated with a down-section increase in gamma values and a more erratic gamma-ray log response. | ||
Thickness: | East Shetland Basin: up to more than 300 m. Beryl Embayment: up to c. 80 m. | ||
Geographical Limits: | East Shetland Basin, Beryl Embayment and Viking Graben. North Sea quadrants 3, 9 and 211. | ||
Parent Unit: | Banks Group (BAKS) | ||
Previous Name(s): | Eriksson Member
(-5204)
Eriksson Formation (-5203) Lower Beryl Sandstone 1 (-5205) Lower Formation (-5206) Nansen Member (-5195) Raude Member (-5207) Scott Formation (-5208) Statfjord Sand Formation (-5209) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Type Section | Norwegian Sector North Sea well N33/12-2 between 2719 and 2951 m below KB (Deegan and Scull, 1977; revised by Richards et al., 1993). | ||
Reference Section | North Sea well 211/24- 1 between 3158.5 and 3434 m (Richards et al., 1993). | ||
Reference Section | North Sea well 3/15- 2 between 3645.5 and 3997 m (Richards et al., 1993). | ||
Reference Section | North Sea well 9/13- 19 between 3842 and 3910.5 m (Richards et al., 1993). | ||
Reference(s): | |||
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.) | |||
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. | |||
Richards, P C, Lott, G K, Johnson, H, Knox, R W O'B. and Riding, J B. 1993. 3. Jurassic 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. | |||
Bowen, J M. 1975. The Brent Oil-Field. In: Woodland, A W (ed.) Petroleum and the contineental shelf of North-West Europe, 353-361. [Heyden & Son, London] | |||
Richards, P C. 1991. The evolution of Lower Jurassic coastal plain and fan delta sediments in the Beryl Embayment, North Sea. Journal of the Geological Society, London, 148, 1037-1047. | |||
Richards, P C. 1989. Lower and Middle Jurassic sedimentology of the Beryl Embayment, and implications for the evolution of the northern North Sea. Unpublished Ph.D. thesis, University of Strathclyde. | |||
Richards, P C. 1990. The early to mid-Jurassic evolution of the northern North Sea. In: Hardman, R F P and Brooks, J (eds.) Tectonic events responsible for Britain's oil and gas reserves. Special Publication of the Geological Society, London, No.55, 191-205. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
none recorded or not applicable |