The BGS Lexicon of Named Rock Units — Result Details

Basal Quartzite Member

Computer Code: BAQ Preferred Map Code: FBQ
Status Code: Full
Age range: Comley Series (EC) — Comley Series (EC)
Lithological Description: Quartzite and quartz arenite with a thin basal conglomerate. the name Basal Quartzite Member is more accurate and up-to-date than the existing name of False-Bedded Quartzite Member, which is a term no longer used by many experts in this sequence, or in most recent literature. The latter name is also geologically misleading, although it does have a long history of use.
Definition of Lower Boundary: Defined where a thin conglomerate at the base of the Basal Quartzite Member lies above an angular unconformity and oversteps both the Lewisian Complex and the Torridon Group.
Definition of Upper Boundary: Conformable and gradational boundary with the overlying Pipe Rock Member.
Thickness: 75-125m
Geographical Limits: The Eriboll Formation (including the Basal Quartzite Member) forms a narrow belt, extending along the northwestern side of Scotland from the Durness-Eriboll area, through Assynt, Dundonnell, Kinlochewe and Kishorn, to Skye.
Parent Unit: Eriboll Formation (ERSA)
Previous Name(s): False Bedded Quartzite, Lower Quartzite (-3814)
False-Bedded Quartzite Formation (-3815)
False-Bedded Quartzite Member (*613)
False Bedded Grit (-38)
Basal Quartzite (-668)
Cross-Bedded Quartzite (-669)
False-Bedded Quartzite Member [Obsolete Name And Code: Use BAQ] (FBQ)
Alternative Name(s): False-Bedded Quartzite Member
Stratotypes:
Reference Section  Skiag Bridge by Loch Assynt displays a good reference section, showing gradational boundary with the overlying Pipe Rock Member. Peach, et al., 1907; Johnson and Parsons, 2000. 
Reference Section  Eastern slopes of ridge separating the Kyle of Durness from Loch Eriboll, Durness area, north coast of Scotland. Grid reference provided refers to location where basal conglomerate is well exposed. Peach et al., 1907. 
Reference(s):
Peach, B N, Home, J, Gunn, W, Clough, C T and Hinxman, L W, 1907. The Geological Structure of the northwest Highlands of Scotland. Memoir of the Geological Survey of Great Britain. 
Johnson, M R W and Parsons I. 2000. Macgregor and Phemister's geological excursion guide to the Assynt district of Scotland. (Edinburgh Geological Society.) 
Prigmore, J K and Rushton, A W A. 1999. Scotland: Cambrian and Ordovician of the Hebridean Terrane. 295-315 in British Cambrian to Ordovician Stratigraphy. Rushton, A W A, Owen, A W, Owens, R M and Prigmore, J K (editors). Geological Conservation Review Series. (Joint Nature Conservation Committee.) 
Park, E G, Stewart, A D and Wright, D T. 2002. The Hebredean Terrane. 45-80 in the Geology of Scotland. Trewin, N H (Editor). (The Geological Society, London.) 
Phemister, J. 1948. British Regional Geology: Scotland: the Northern Highlands (2nd edition) (Edinburgh: HSMO for the Geological Survey and Museum.) 
Johnston, G S and Mykura, W. 1989. British regional geology: the Northern Highlands (4th edition) (London: HMSO for the British Geological Survey.) 
Cowie, J W. 1974. The Cambrian of Spitsbergen and Scotland. 123-155 in Cambrian of the British Isles, Norden and Spitsbergen, Holland, C H (editor). Lower Palaeozoic Rocks of the World, Vol. 2. (John Wiley and Sons.) 
Lapworth, C. 1883. The secret of the Highlands. Geolgical Magazine, Decade 2, Vol. 10, 120-128, 193-199, 337-344. 
Wright, D T and Knight, I. 1995. A revised chronostratigraphy for the lower Durness Group. Scottish Journal of Geology, Vol. 31, 11-22. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S071 S114 S081 S082 S092 S102 S108 S101 S107