The BGS Lexicon of Named Rock Units — Result Details

Arbuthnott-Garvock Group

Computer Code: ATGK Preferred Map Code: ATGK
Status Code: Full
Age range: Lochkovian Age (DO) — Pragian Age (DP)
Lithological Description: Sandstone predominates, interbedded with clast-supported conglomerate with well-rounded boulders, cobbles and pebbles predominantly of lava, psammite and quartzite in the northeast and adjacent to the Highland Boundary Fault. Siltstone and mudstone are interbedded with the sandstone, e.g. in the Dundee area and Strathallan. Piles of andesitic, basaltic and rhyolitic lavas, locally very thick, are interbedded with conglomerate and sandstone in many areas. Lenses and thicker formations of volcaniclastic sandstone are interbedded with conglomerate in the Stonehaven area and are associated with lavas elsewhere. Calcrete near top in many areas.
Definition of Lower Boundary: Diachronous, rising to higher levels towards the southwest. In the type area it lies at the top of the highest lava of the Crawton Volcanic Formation, where this is overlain by clast-supported conglomerate. Elsewhere its base is taken to lie at the eroded top of the Lintrathen Tuff Member or its presumed correlatives (cf. Paterson and Harris, 1969). Where these horizons are absent, on Sheets 66E and 67, the base has been taken at the base of the lowest of the series of andesitic lavas that characterise the lower part of the Group in this area.
Definition of Upper Boundary: At the base of bright red, massive poorly sorted siltstone and sandy siltstone of the Cromlix Mudstone Formation, overlying coarser-grained sandstone or conglomerate of the Arbuthnott-Garvock Group. Locally diachronous in areas adjacent to the Highland Boundary Fault where conglomerate interfingers with the Cromlix Mudstone Formation.
Thickness: Variable; 2400 to 3150m in the Stonehaven area. The sedimentary rocks thin to the southwest, but in the Stirling area the Ochil Volcanic Formation alone reaches 2400m.
Geographical Limits: Northern Midland Valley of Scotland, Arran to Stonehaven.
Parent Unit: Not Applicable (-)
Previous Name(s): Garvock Group [Obsolete Name And Code: See Arbuthnott-Garvock Group] (GKG)
Arbuthnott Group [Obsolete Name And Code: See Arbuthnott-Garvock Group] (ATG)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Banks of Allan Water between Bridge of Allan and Kinbuck. 
Reference Section  Valley of Bervie Water and unnamed tributary. 
Partial Type Section  Sea cliffs and foreshore, Crawton Bay to Whistleberry. 
Reference(s):
Carroll, S, 1994. Geology of the Stonehaven District. 1:10 000 Sheets NO88NW, NO88NE, NO88SW and NO88SE. British Geological Survey Technical Report WA/94/19. 
Campbell, R, 1913. The geology of south-eastern Kincardineshire. Transactions of the Royal Society of Edinburgh, Vol.48, pp.923-960. 
Armstrong, M, Paterson, I B and Browne, M A E, 1985. Geology of the Perth and Dundee district. Memoir of the British Geological Survey, Sheets 48W, 48E and 49 (Scotland). 108pp. 
Carroll, S, 1995. Geology of the Auchenblae District. British Geological Survey Technical Report. WA/95/80. 
Carroll, S, 1994. Geology of the Inverbervie and Catterline district, 1:10 000 sheets NO87NW, NO87NE and NO87SW. British Geological Survey, Technical Report, WA/94/20. 
Richardson, J B, Ford, J H and Parker, F, 1984. Miospores correlation and age of some Scottish Lower Old Red Sandstone sediments from the Strathmore region (Fife and Angus). Journal of Micropalaeontology, Vol.3, 109-124. 
Francis, E H, Forsyth, I H, Read, W A and Armstrong, M. 1970. The geology of the Stirling district. Memoir of the Geological Survey of Great Britain, Sheet 39 (Scotland). 
Carroll, S, 1995. Geology of the Laurencekirk District. British Geological Survey Technical Report No.WA/95/81. 
Allan, P A. 1940. The geology of the Highland Border from Glen Almond to Glen Artney. Transactions of the Royal Society of Edinburgh. Vol.60, p.185. 
Browne, M A E, Smith, R A and Aitken, A M. 2001. A lithostratigraphical framework for the Devonian (Old Red Sandstone) rocks of Scotland south of a line from Fort William to Aberdeen. Version 3. British Geological Survey Research Report RR/01/04. 
Paterson, I B and Harris, A L. 1969. Lower Old Red Sandstone ignimbrites from Dunkeld, Perthshire. Report of the Institute of Geological Sciences, No. 69/7. 
Westoll, T S. 1951. The vertebrate-bearing strata of Scotland. 18th International Geological Congress, London, 1948, Vol. 9, p. 5-21. 
Armstrong, M and Paterson, I B, 1970. The Lower Old Red Sandstone of the Strathmore Region. Report of the Institute of Geological Sciences No.70/12 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S067 S056 S012 S048 S048 S049 S056 S066 S040 S038 S045 S039 S039 S030 S040 S053 S054 S038 S022