The BGS Lexicon of Named Rock Units — Result Details

Sutherland Group

Computer Code: SUTH Preferred Map Code: SUTH
Status Code: Full
Age range: Hettangian Age (JH) — Tithonian Age (JI)
Lithological Description: Sequence of predominantly mudstone, siltstone and sandstone, with common shelly fauna at many levels, variously calcareous, carbonaceous, bituminous, with thin sandy limestone beds, ironstone beds, thin coal seams, a basal conglomerate and boulder beds towards the top.
Definition of Lower Boundary: Unconformity: nodular carbonate rock of the Stotfield Cherty Rock Formation (Triassic) overlain by interbedded conglomerate and sandstone of the Dunrobin Pier Conglomerate Member of the Dunrobin Bay Formation.
Definition of Upper Boundary: Top of the interbedded boulder beds, sandstone and mudstone beds of the Helmsdale Boulder Beds Formation, not at outcrop onshore. Overlying bedrock formation is unknown.
Thickness: At least 1400m.
Geographical Limits: Coastal strips of Moray Firth, north-east Scotland, from Golspie to Helmsdale, near Balintore, near Lossiemouth. Correlates offshore in the Inner Moray Firth with the combined Dunrobin Bay and Fladen groups and the Heather and Kimmeridge Clay formations (Hudson and Trewin, 2002, fig. 11.7).
Parent Unit: Not Applicable (-)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Coastal section, at high water mark from Dunrobin Pier 2km east-north-east of Golspie to Ord Point 4km east-north-east of Helmsdale, a distance of 27km. Exposes highly discontinuous section including incomplete Dunrobin Bay, Brora Coal, Strathsteven Mudstone, Clynekirkton Sandstone, Kintradwell Boulder Beds, Allt na Cuile Sandstone and Helmsdale Boulder Beds formations. Sykes, 1975; Hurst, 1981; Batten et al., 1986; Wright and Cox, 2001. 
Reference Section  Lossiemouth No.4 Borehole (NJ26NW4) from 12.8m to 82.3m (terminal depth). Sequence of sandstone and mudstone, calcareous in part, thought to be all Sinemurian. Berridge and Ivimey-Cook, 1967. 
Reference(s):
Andrews, I J, Long, D, Richards, P C, Thomson, A R, Brown, S, Chesher, J A, and Mccormac, M. 1990. The geology of the Moray Firth. British Geological Survey United Kingdom offshore regional report (London). 
Berridge, N G, and Ivimey-Cook, H C. 1967. The geology of a Geological Survey borehole at Lossiemouth, Morayshire. Bulletin of the Geological Survey of Great Britain, Vol. 27, 155-169. 
Hudson, J D, and Trewin, N H. 2002. Jurassic. 323-350 in The geology of Scotland. Trewin, N H (editor). (London: Geological Society of London.) 
Simms, M J, Chidlaw, N, Morton, N, and Page, K N. 2004. British Lower Jurassic Stratigraphy. Geological Conservation Review Series. No. 30. (Peterborough: Joint Nature Conservation Committee/Chapman and Hall.) 
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.) 
Barron, A J M, Lott, G K, and Riding, J B. 2012. Stratigraphical framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf. British Geological Survey Research Report RR/11/06. 
Hurst, A R. 1981. Mid Jurassic stratigraphy and facies at Brora, Sutherland. Scottish Journal of Geology, Vol. 17, p. 169 - 177. 
Batten, D J, Trewin, N H and Tudhope, A W, 1986. The Triassic-Jurassic junction at Golspie, Inner Moray Firth Basin. Scottish Journal of Geology, Vol.22, part 1, 85-98. 
British Geological Survey. 1999. Golspie. Scotland Provisional Sheet 103W. Solid and Drift. 1:50 000. 
Wright, J K, and Cox, B M. 2001. British Upper Jurassic Stratigraphy (Oxfordian to Kimmeridgian). Geological Conservation Review Series. No. 21. (Peterborough: Joint Nature Conservation Committee/Chapman and Hall.) 
British Geological Survey, 1998. Helmsdale. Scotland Sheet 103E. Solid and Drift. 1:50 000 Geology Series. British Geological Survey, Keyworth, Nottingham. 
Lee, G.W., 1925. Mesozoic rocks of East Sutherland and Ross, In: Read, H.H., Ross, G., Phemister, J. (Eds.), The geology of the country around Golspie, Sutherlandshire. Memoir of the Geological Survey, pp. 65-114. 
Neves, R and Selley, R C. 1975. A review of the Jurassic rocks in north-east Scotland. In: Finstead, K.G. & Selley, R.C. (eds) Proceedings of the Jurassic Northern North Sea Symposium, Stavanger 28-30 September 1975, 5/1-5/21. 
Sykes, R M. 1975. The stratigraphy of the Callovian and Oxfordian stages (Middle-Upper Jurassic) in northern Scotland. Scottish Journal of Geology, Vol.11, 51-78. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S094 S094 S095