The BGS Lexicon of Named Rock Units — Result Details

Beinn Iadain Mudstone Formation

Computer Code: BIAD Preferred Map Code: notEntered
Status Code: Full
Age range: Late Cretaceous Epoch (KU) — Paleocene Epoch (GP)
Lithological Description: Mudstone and siltstone, shaly and micaceous, red to purplish in colour but bleached white in places. Considered to be "argillised ash" by Mortimore et al., (2001). Organic-rich and sandy in lower part.
Definition of Lower Boundary: The lower boundary is unconformable above an erosive contact with underlying conglomerates of the Clach Alasdair Conglomerate Member.
Definition of Upper Boundary: The upper boundary is disconformable at a sharp contact beneath Paleocene lavas.
Thickness: Some 2.5m at Allt na Teangaidh on Mull, about 1.9m at Feorlin tributary section [NM 5317 2225], 0.92 m at the type site on Beinn Iadain.
Geographical Limits: Known from Morvern and the island of Mull.
Parent Unit: Inner Hebrides Group (IHEB)
Previous Name(s): Upper Estuarine Series (-697)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Allt na Teangaidh on Mull. See Mortimore et al. (2001, 448-451). 
Type Section  Beinn Iadain Section A of Braley (1990) in Morvern. See also Mortimore et al. (2001, 462-469). 
Reference(s):
Mortimore, R N, Wood, C J and Gallois, R W, 2001. British Upper Cretaceous Stratigraphy. Geological Conservation Review Series. No. 23. (Peterborough: Joint Nature Conservation Committee.) 
Braley, S M. 1990. The Sedimentology, Palaeoecology and Stratigraphy of Cretaceous Rocks in N.W. Scotland. Unpublished PhD Thesis CNAA, Polytechnic SouthWest (now University), Plymouth. 
Hopson, P M. 2005. A stratigraphical framework for the Upper Cretaceous Chalk of England and Scotland, with statements on the Chalk of Northern Ireland and the UK Offshore Sector. British Geological Survey Research Report RR/05/01 102pp. ISBN 0 852725175 
Lowden, B, Braley, S, Hurst, A and Lewis, J, 1992. Sedimentological studies of the Cretaceous Lochaline Sandstone, NW Scotland. 159-162 in Parnell, J (editor), Basins on the Atlantic Seaboard: Petroleum Geology, Sedimentology and Basin Evolution. Geological Society of London Special Publication, No.62. 
Waters, C N, Gillespie, M R, Smith, K, Auton, C A, Floyd, J D, Leslie, A G, Millward, D, Mitchell, W I, McMillan, A A, Stone, P, Barron, A J M, Dean, M T, Hopson, P M, Krabbendam, M, Browne, M A E, Stephenson, D, Akhurst, M C, and Barnes, R P. 2007. Stratigraphical Chart of the United Kingdom: Northern Britain. (British Geological Survey.) 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable