The BGS Lexicon of Named Rock Units — Result Details

Ailnack Phyllite And Limestone Formation

Computer Code: APAL Preferred Map Code: SYMB
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Semipelites with subsidiary psammites, generally phyllitic, more calcareous in its upper part. Distinctive white limestone bands typically. Also grey finely crystalline limestones and calc-silicate bands. In Glenlivet-Glen Suie area divided into three members.
Definition of Lower Boundary: At upper limit of quartzite of the Corryhabbie Quartzite Formation and at lowest occurrence of white limestone or semipelite.
Definition of Upper Boundary: Rapid gradation from calcareous semipelite and limestone to graphitic pelite/semipelite of Clashnoir Semipelite Formation.
Thickness: 40 - 600m.
Geographical Limits: Extends from Muckle Allt Venney (Glen Markie) southwest to Glenfiddich, Upper Glenlivet and Glen Suie to the Kylnadrochit-Fodderletter area (Strathavon), Water of Ailnack section and Glen Avon (Burn of Little Fergie to Foal's Crag) and Glen Builg. Southern limit - Loch Builg.
Parent Unit: Ballachulish Subgroup (DABH)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Section  Central section of water of Ailnack gorge around junction with Allt Dearcaige. 
Reference Section  Tor of Suie area, Glen Suie. 
Memoir of the British Geological Survey, Sheet 75, in preparation. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S075 S086