The BGS Lexicon of Named Rock Units — Result Details

Macduff Formation

Computer Code: MCD Preferred Map Code: Mcd
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Metagreywacke: interbedded psammite and semipelite with subsidiary pelite. Contains major units of pebbly psammite, particularly in basal part (Knock Head Grit Member). Metamorphosed to slates, phyllites and mica-schists. Contains Boulder Bed at Macduff (glaciomarine diamicton). Minor calc-silicate pods. Contains andalusite, cordierite and locally staurolite porphyroblasts.
Definition of Lower Boundary: Change from calcareous semipelite to non-calcareous lithologies at top of Whitehills Grit Formation; commonly marked by change to locally coarsely gritty psammite of Knock Head Grit Member.
Definition of Upper Boundary: Not seen - highest beds are in centre of Turriff Syncline.
Thickness: Up to 5.5km, but could be less, as there is repetition by folding.
Geographical Limits: From Moray Firth coast [NJ 6514 6564-NJ 776 643], southwards to northern margin of Insch intrusion [NJ 650 325-NJ 725 305].
Parent Unit: Southern Highland Group (SOHI)
Previous Name(s): Boyndie Bay Group (-203)
Replaced By Macduff Formation (*259)
Macduff Slates (-1685)
Boyndie Bay Formation [Obsolete Name And Code: See MCD] (DCBD)
Macduff Slate [Obsolete Name And Code: Use MCD] (DCMS)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Coastal section from Craig Neen, Whitehills to Grip of Twinely (centre of Turriff Syncline). 
Reference(s):
Stephenson, D, et al. 1993. Stratigraphy and correlation of the Dalradian rocks of the East Grampian Project area. British Geological Survey Technical Report WA/93/91. 
Harris, A L, Haselock, P J, Kennedy, M J and Mendum, J R, 1994. The Dalradian Supergroup in Scotland, Shetland and Ireland. 33-53 in Gibbons, W E and Harris, A L (editors). A revised correlation of Precambrian rocks in the British Isles. Special Report of the Geological Society, London, No.22. 
Stephenson, D and Gould, D , 1995. British Regional Geology: the Grampian Highlands (4th edition). (London: HMSO for the British Geological Survey), 67-68. 
Read, H H, 1923. Geology of the country around Banff, Huntly and Turriff, Lower Banffshire and north-west Aberdeenshire. Memoir of the Geological Survey, Scotland Sheets 86 and 96 (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S096 S096 S086 S086 S087