The BGS Lexicon of Named Rock Units — Result Details

Portskerra Psammite Formation

Computer Code: PORK Preferred Map Code: notEntered
Status Code: Full
Age range: Tonian Period (AT) — Tonian Period (AT)
Lithological Description: Psammite and minor semipelite, gneissose, migmatitic. Local calc-silicate bands and rare quartzite.
Definition of Lower Boundary: Upon the Loch Coire Formation (LOCE), but contact is strongly sheared.
Definition of Upper Boundary: Not exposed; cut by the Strath Halladale Granite.
Thickness: none recorded or not applicable
Geographical Limits: Northern Highlands: East Sutherland and Caithness. Restricted to the Swordly Nappe.
Parent Unit: Loch Eil Group (LEIL)
Previous Name(s): Portskerra Formation [Obsolete Name and Code: Use PORK] (-3622)
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
Holdsworth, R E, Strachan, R A and Harris, A L, 1994. Precambrian rocks in northern Scotland east of the Moine Thrust: The Moine Supergroup in Gibbons, W and Harris, A L (editors). A revised correlation of Precambrian rocks in the British Isles. Special Report of the Geological Society, No.22. 
British Geological Survey. 2003. Bedrock and superficial deposits. Scotland Sheet 115E (Reay). 1:50 000. 
Krabbendam, M. 2021. A stratigraphic framework for the early Neoproterozoic successions of the Northern Highlands of Scotland. UK Stratigraphic Framework Series. British Geological Survey Open Report, OR/21/072. 86pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S109 S109 S115 S115