The BGS Lexicon of Named Rock Units — Result Details

Sgaorishal Member

Computer Code: SGAOR Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Triassic Period (T) — Triassic Period (T)
Lithological Description: Cross-stratified conglomerates, containing cornstone, quartzite and Torridonian sandstone clasts predominate. Channels, cross-bedding and a high degree of sediment sorting indicate that fluvial deposition was likely, indicating a gradual transition to the marine conditions of the overlying Allt Dubh Member. Clasts reach a maximum size of 150mm. Not shown on 50K maps.
Definition of Lower Boundary: Cross-stratified conglomerate mark the base of the Member, above poorly-sorted conglomerates of the A'Mharagach Member.
Definition of Upper Boundary: Below marine fossil-rich sandstone beds of the Allt Dubh Member.
Thickness: 9m
Geographical Limits: Sea of the Hebrides Basin/Isle of Rum.
Parent Unit: Monadh Dubh Sandstone Formation (MODS)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Reference Section  A'Mharagach, northwest Rum. Emeleus, 1997. 
Emeleus, C H. 1997. Geology of Rum and the adjacent islands. Memoir (sheet) of the Geological Survey of Great Britain (Scotland) (60). (The Stationery Office for the British Geological Survey.) 171pp. 
Steel, R J. 1974. New Red Sandstone piedmont and floodplain sedimentation in the Hebridean province, Scotland. Journal of Sedimentary Petrology, Vol.44, 336-357. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: