The BGS Lexicon of Named Rock Units — Result Details

Etive Formation

Computer Code: ETVE Preferred Map Code: notEntered
Status Code: Full, pending ratification
Age range: Aalenian Age (JA) — Bajocian Age (JB)
Lithological Description: Brown to grey, massive, fine- to medium-grained, cross-bedded sandstones. Upward coarsening (e.g. 3/3-3 and 211/27-10) and upward fining (211/18a-21) sections occur. Thin coal seams occur locally.
Definition of Lower Boundary: The lower boundary is placed at a down-section change from less micaceous and/or coarser sandstones to finer, more micaceous, sandstones (Rannoch Formation). A down-section increase in gamma values and increase in velocity occurs at the boundary.
Definition of Upper Boundary: The Etive/Ness boundary is an erosion surface. In the type section it is placed at the base of the lowest significant mudstone or coal seam, and significant down-section decrease in gamma values. In north-eastern East Shetland Basin sandstones of the Ness or Tarbert formations overlie without a distinctive argillaceous interval and the boundary is difficult to define on wireline logs. Locally the upper boundary is placed at a downward change from siltstones and mudstones (Heather Formation) to sandstones.
Thickness: Up to 40 m.
Geographical Limits: East Shetland Basin, north of about 60 deg. 30 min. North, eastwards into the Viking Graben. North Sea quadrants 2, 3, 210, 211.
Parent Unit: Brent Group (BRNT)
Previous Name(s): Etive Sub-Unit (-5190)
Massive Sand Bed (-5191)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  North Sea Well 211/29-3 between 2772 and 2783 m below KB (Deegan and Scull, 1977). 
Reference Section  North Sea Well 211/18a-21 between 3455.5 m and 3503 m below KB (Richards et al., 1993). 
Reference Section  North Sea Well 211/19-6 between 3240 and 3271.5 m (Richards et al., 1993). 
Reference Section  North Sea Well 211/27-10 between 3583 and 3597.5 m (Richards et al., 1993). 
Reference Section  North Sea Well 3/3-3 between 3198 and 3212.5 m below KB (Richards et al., 1993). 
Reference(s):
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. 
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, 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] viii + 219 pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable