The BGS Lexicon of Named Rock Units — Result Details

Athais Till Formation

Computer Code: ATTI Preferred Map Code: ATH
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Stoney clayey sand diamicton, matrix-supported, moderate brown to yellowish brown, extremely compact, containing clasts of Devonian sandstone and siltstone, with some psammite, granite and schist. Many clasts are weathered, with orange weathering rinds. Mainly massive lodgement till, but contains lenses of stratified gravelly sandy diamicton and bedded sandy gravel. Locally includes a bed of glacitectonite at the base (Allt Odhar site).
Definition of Lower Boundary: Sharp, undulating or planar, glacitectonic, unconformable contact with white, sandy, organic deposits of the Dalcharn Palaeosol Formation, compressed peat of the Allt Odhar Peat Formation, or bedrock.
Definition of Upper Boundary: Either a gradational contact with dark yellowish brown to olive grey stony sandy clay diamicton of the overlying Beinn an Uain Till Formation or a sharp, glacitectonic, boundary with some wedge structures filled by that till.
Thickness: 10m
Geographical Limits: Sheet 84W (Fortrose), SE of Inverness.
Parent Unit: Inverness Glacigenic Subgroup (INVG)
Previous Name(s): Moy Paraglacial Complex Member (-658)
Moy Lower Till Member (-3181)
Dalcharn Lower Till Formation (-1318)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Exposed towards the top of a river cliff of the Allt Odhar, immediately upstream of its confluence with the Caochan nan Suidheig, Moy Estate, 16km southeast of Inverness. The Allt Odhar Interstadial site. Walker, M J C and 6 others. 1992. 
Reference Section  30m-high river cliff sections of the Allt Dearg, 6km southwest of Cawdor, Nairnshire. The Dalcharn Interglacial site. Walker, M J C and 6 others. 1992. 
Reference(s):
Walker, M J and 6 others. 1992. Allt Odhar and Dalcharn: two pre-Late Devensian (Late Weichselian) sites in northern Scotland. Journal of the Quaternary Science, Vol.7, 69-86. 
Sutherland D G and Gordon, J E. (editors). 1993. The Quaternary of Scotland. Geological Conservation Review Series: 6. London: Chapman and Hall. 
Fletcher, T P et al. 1996. Geology of the Fortrose and eastern Inverness district. Memoir of the British Geological Survey, Sheet 84W (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S084