The BGS Lexicon of Named Rock Units — Result Details

Portsoy Group [Obsolete Name And Code: See CAPT And PTSL]

Computer Code: DBPB Preferred Map Code: notEntered
Status Code: Index Level
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Dark grey graphite-schist and kyanite-schist, staurolite-schist, mica-schist, coarse-grained limestone and quartzite as well as tremolite-limestone. (Correlative of Portsoy Group = Carbonaceous Group).
Definition of Lower Boundary: Drawn at base of staurolite schist of Portsoy Group where it rests conformably on quartzite and quartzose, mica-schist of the Durn Hill Quartzite.
Definition of Upper Boundary: Drawn at unconformable upward change from schists of the Portsoy Group to biotite gneiss of the Cowhythe Gneiss.
Thickness: 1400m approx.
Geographical Limits: Grampian, Scotland.
Parent Unit: Not Entered (?)
Previous Name(s): Carbonaceous Group (-848)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Portsoy, Grampian, Scotland. 
Reference(s):
Read, H H, 1921. The Banffshire Coast section of the Highland Schists. Summary of Progress of the Geological Survey of Great Britain for 1920, p.70. 
Brown, P E, Caledonian and Earlier Magmatism. "In" Craig, G Y, 1983. Geology of Scotland. 176-177. 
Fettes, D J, Lesley, A G, Stephenson, D and Kimbell, S F, 1991. Disruption of Dalradian stratigarphy along the Portsey Lineament from new geological and magnetic surveys. Scottish Journal of Geology, Vol.27, 57-73. 
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). 
Harris, A L and others, 1973. A correlation of the Pre-Cambrian rocks in the British Isles. Geological Society of London Special Report No 6. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable