The BGS Lexicon of Named Rock Units — Result Details

Kyle Group

Computer Code: KYLE Preferred Map Code: notEntered
Status Code: Full, pending ratification
Age range: Givetian Age (DV) — Frasnian Age (DR)
Lithological Description: The Kyle Group is characterized by white, buff, brownish grey, or pink limestones and thin grey shales, with an overlying, more variable unit of marine, lagoonal, and basin-marginal sabkha facies. The limestones of the basal unit are generally argillaceous, with a thin basal mudflake conglomerate in the Auk Field. Their texture varies between cryptocrystalline, microcrystalline, and coarsely crystalline. They contain both tabulate and rugose corals in the Argyll Field (Pennington 1975), and have also yielded ostracods, brachiopods, bivalves, gastropods, and crinoids. In well 38/3-1, the interbedded shales contain ostracods and a sparse brachiopod fauna that includes lingulids and strophomenids. In well 38/3-1, the limestones are overlain by dark grey mudstones containing brachiopods and veins of dolomite. In different sections in the Auk-Argyll area, equivalent sediments include microcrystalline dolomite (e.g. 30/25a-2), reddish brown or grey calcareous mudstone with thin limestone and dolomite beds (e.g. 30/16-5), or interbedded sandy siltstone, shale, anhydrite and dolomite (e.g. 30/24-3).
Definition of Lower Boundary: An angular unconformity separates Kyle Group limestones from underlying reddened Lower Paleozoic turbidites and shales in well 30/16-5. The base of the limestones has not been penetrated elsewhere. However, they probably rest on Lower Paleozoic basement at 38/3-1, as Lower Devonian strata are unknown in the Central North Sea south of the offshore continuation of the Southern Uplands Fault (Gatliff et al., in press).
Definition of Upper Boundary: In and around the Auk Field, the Kyle Group underlies Lower Permian sandstones, beneath the regional base-Permian unconformity. In well 38/3-1 and in the Argyll Field, the Kyle Group is conformably overlain by the Upper Old Red Group, the boundary being taken at the transition from marine or lagoonal to continental red-bed facies. At 38/3-1, the boundary is marked by a downward change from sandstones, conglomerates and minor volcanics to marine mudstones, but does not generate a significant wireline-log break.
Thickness: 177 m thick in well 38/3-1; 130 m thick in the Argyll Field.
Geographical Limits: The Kyle Group has been proved in five wells along the western flank of the south Central Graben.
Parent Unit: Not Applicable (-)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  North sea well 38/3-1: 3611-3798 m TD (11848-12460 ft TD) below KB. 
Reference Section  North sea well 30/16-5: 2580.5-2707 m (8466-8882 ft). 
Reference Section  North sea well 30/24-3: 2950.5-3085 m TD (9680-10122 ft TD). 
Reference Section  North Sea well 30/25a-2: 2846-2974 m TD (9337-9758 ft TD). 
Reference(s):
Cameron, T D J. 1993. 4 Triassic and Permian 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. 
Gatliff, R W, Richards, P C, Smith, K, Graham, C C, McCormac, M, Smith, N J P, Long, D, Cameron, T D J, Evans, D, Stevenson, A G, Bulat, J, and Ritchie, J D. 1994. United Kingdom offshore regional report: the geology of the central North Sea. (London: HMSO for the British Geological Survey.) 
Pennington, I J. 1975. The geology of the Argyll Field. In: Woodland, A W (ed.) Petroleum and the continental shelf of north-west Europe, 285-291. Applied Science Publishers, London. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable