The BGS Lexicon of Named Rock Units — Result Details

Barra Formation

Computer Code: BARA Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Marine Isotope Stage 3 (QMIS003) — Marine Isotope Stage 2 (QMIS002)
Lithological Description: Dark grey clay, very soft-very firm, silty and gritty with scattered pebbles.
Definition of Lower Boundary: Base lies on major erosion surface or associated Hebrides Formation overlain by Jura Formation or crops out.
Definition of Upper Boundary: Not defined.
Thickness: 66 metres in Borehole 78/2. Reaches maximum of 130 metres in western part of the sea of the Hebrides.
Geographical Limits: Not defined.
Parent Unit: Eilean Siar Glacigenic Group (EISR)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
Reference(s):
Fyfe, J A, Long, D, and Evans, D. 1993. United Kingdom offshore regional report: the geology of the Malin-Hebrides sea area. (London: HMSO for the British Geological Survey.) 
Davies, H C, Dobson, M R, and Whittington, R J. 1984. A revised seismic stratigraphy for the Quaternary deposits on the inner continental shelf west of Scotland between 55° 30’ N and 57° 30’ N. Boreas, Vol. 13, 49-66. 
Stoker, M S, Balson, P S, Long, D, and Tappin, D R. 2011. An overview of the lithostratigraphical framework for the Quaternary deposits on the United Kingdom continental shelf. British Geological Survey Research Report, RR/11/03. 48pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable