The BGS Lexicon of Named Rock Units — Result Details

Iubhair Beag Calcareous Formation

Computer Code: IBGC Preferred Map Code: IB
Status Code: Full
Age range: Neoproterozoic Era (AZ) — Neoproterozoic Era (AZ)
Lithological Description: Tremolite-rich calc-silicate schist with layering produced by variations in mica content. Minor semipelite.
Definition of Lower Boundary: Where tremolite schist becomes dominant overlying the magnetite-semipelite of the underlying Sron Garbh Formation. Rapid transition.
Definition of Upper Boundary: At the top of the highest tremolite schist unit - overlain by semipelites of the Coire Cheap Formation.
Thickness: c. 60m at most. More typically 10m
Geographical Limits: Ardverikie Forest between An Lairig [NN 50 77] and the Allt Mhainisteir [NN 53 86]. Sheet 63E [Dalwhinnie].
Parent Unit: Appin Group (APP)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  NE steep rocky shoulder of Sron Garbh. 
Type Area  Southeast flank of Geal Charn, between Coire an Iubhair Beag and 500m NE of Loch A'Bhealaich Leambain. 
Reference(s):
Robertson, S and Mendum, J R, in press. Lithostratigraphy of the Grampian and Appin Groups in the Dalwhinnie district, sheet 63E, Scotland. British Geological Survey Technical Report. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S063