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
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. 
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: