The BGS Lexicon of Named Rock Units — Result Details

Allt Na H-Airbhe Member

Computer Code: ANHA Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Probably overcompacted diamicton and sandy gravel in mid-loch region, including possible glacitectonised silt and clay. Probable debris-flow diamictons in deeper water.
Definition of Lower Boundary: Unconformable glacitectonic boundary with (parent) Assynt Glacigenic Formation below.
Definition of Upper Boundary: Unconformably overlain by Summer Isles Formation in outer loch. Locally downlapped by Ullapool Gravel Formation in mid-loch region; otherwise exposed or covered by Holocene lag.
Thickness: Up to 12m.
Geographical Limits: Mid- to outer Loch Broom (between Corry Point and middle of outer loch). Possibly including coastal fringes, e.g. Newton Loggie.
Parent Unit: Assynt Glacigenic Formation (ASGL)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  General seabed area between Corry Point and Ullapool Point, Loch Broom. Stoker, M.S., Bradwell, T., Howe, J.A., Wilkinson, I.P. & McIntyre, K. 2009. Lateglacial ice-cap dynamics in NW Scotland: evidence from the fjords of the Summer Isles region. Quaternary Science Reviews, 28, 31613184. (See Figure 13). 
Reference(s):
Stoker, M S and Bradwell, T. In press. Quaternary geology of the Summer Isles region - a brief explanation of the marine environment map. Sheet Explanation of the British Geological Survey. 1:50 000 Special Sheet Summer Isles (Scotland). 
Bradwell, T and Stoker, M S. 2010. Quaternary Lithostratigraphy of the NW Highlands. In: Lukas, S. & Bradwell, T. (eds), The Quaternary of Western Sutherland and adjacent areas. (London: Quaternary Research Association), 29-37. 
Stoker, M S, Bradwell, T, Howe, J A, Wilkinson, I P & McIntyre, K. 2009. Lateglacial ice-cap dynamics in NW Scotland: evidence from the fjords of the Summer Isles region. Quaternary Science Reviews, 28, 3161-3184. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable