The BGS Lexicon of Named Rock Units — Result Details

Rubha Dubh Ard Member

Computer Code: TCAR Preferred Map Code: notEntered
Status Code: Full
Age range: Tonian Period (AT) — Tonian Period (AT)
Lithological Description: Coarse, red sandstone with trough crossbedding at base, followed by medium-fine grey, tabular sandstone with ripple cross-lamination, and very thin grey, shaley siltstone units.
Definition of Lower Boundary: Unconformable upon Lewisian Gneiss (L) or overlying the Diabaig Formation (TCD) with a sharp contact.
Definition of Upper Boundary: Conformably overlain by the remainder of the Applecross Formation (TCA).
Thickness: c. 50-100 m.
Geographical Limits: NW Highlands: Assynt-Rubha Coigach area - Loch Broom.
Parent Unit: Applecross Formation (TCA)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Rubha Dubh Ard, 5 km SE of Achiltibuie, [NC 042 037 - NC 045 035]. 
Reference(s):
Stewart, A D. 2002. The later Proterozoic Torridonian rocks of Scotland: their sedimentology, geochemistry and origin. Geological Society Memoir. Vol. 24. (The Geological Society.) 
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. 
Nicholson, P G. 1993. A basin reappraisal of the Proterozoic Torridon Group, northwest Scotland. 183-202 in Tectonic Controls and Signatures in Sedimentary Successions. Frostick, L, and Steel, R (eds). Special Publication of the International Association of Sedimentologists, 20. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S101