The BGS Lexicon of Named Rock Units — Result Details

Pitlurg Calcareous Flag Formation

Computer Code: PCFL Preferred Map Code: SYMB
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Calcareous, banded psammite and semipelite, grey and pale green, normally flaggy. Some beds of impure metalimestone locally.
Definition of Lower Boundary: At incoming of calcareous (greenish, tremolite-bearing) psammites and semipelites above the non-calcareous Findlater Flag Formation.
Definition of Upper Boundary: Below graphitic pelites with beds of pure metalimestone comprising the Mortlach Graphitic Schist Formation.
Thickness: >50 - 1200m (based on outcrop width and average dip). Real thickness is probably closer to lower estimate, owing to prevalent open folds.
Geographical Limits: Ardonald Anticline, from Blackhillock and Alehousehillock, in the Cairnie area, SW to Achmore, Glen Rinnes. And around Keith from Drummuir to Ardrone (Sheets 85E and 86W). Above Keith Shear Zone - equivalent stratigraphically to Cairnfield Calcareous Formation below the Keith Shear Zone.
Parent Unit: Lochaber Subgroup (DALO)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Section  Burn at Davidston from 150m NW of Hillend to 500m N of Bridge at Blairmoon. 
Reference Section  Den of Pitlurg 
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. 
Stephenson, D, 1993. Amphiboles from Dalradian Metasedimentary Rocks of NE Scotland: Environmental Inferences and Distinction from Amphiboles of Meta-Igneous Amphibolites. Mineralogy and Petrology, Volume 49, 45-62. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S086 S085