The BGS Lexicon of Named Rock Units — Result Details

Fresgoe Sandstone Member

Computer Code: FGSA Preferred Map Code: notEntered
Status Code: Full
Age range: Eifelian Age (DI) — Eifelian Age (DI)
Lithological Description: A thickly bedded, cross-stratified, pale grey to pale yellow, medium-grained sandstone. The unit represents the first thick sandstone in a generally more thinly-bedded sequence. It is consequently a mappable unit. It is a notable reflector in seismic sections and a marker horizon in borehole cores, marking the top of the Bighouse Formation in the Dounreay area.
Definition of Lower Boundary: Overlies a thinly interbedded, sandstone-dominated rhythmic sequence of sandstones, siltstones and laminated carbonate mudstones (fish beds) of the Bighouse Formation.
Definition of Upper Boundary: The base of the overlying Sandside Bay Formation, which displays a cyclic depositional sequence dominated by sandstones, with thicker well-developed carbonate laminated mudstones (fish beds).
Thickness: 32m
Geographical Limits: Onshore and immediate offshore of the Dounreay area, Caithness, northern Scotland.
Parent Unit: Bighouse Formation (BIGH)
Previous Name(s): Fresgoe Sandstone (-907)
Fresgeo Sandstone [Unit Name And Code Obsolete: Use FGSA] (FRSB)
Fresgoe Sandstone Bed (-246)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Sea cliff beneath carpark, 70m southsouthwest of Fresgoe Harbour, on the western side of Sandside Bay, 1.3km northwest of Reay village, Caithness. Mendum, 1991. 
Reference Section  Sea cliff, 550m west of Isauld House, on the eastern side of Sandside Bay, about 900m north of Reay village, Caithness. Mendum, 1991. 
Reference(s):
Auton, C A. 2003. The Quaternary and Devonian geology of Scotland Sheet 115E (Reay). British Geological Survey Commissioned Report CR/03/030 for UKAEA. 78pp. 
British Geological Survey. (In preparation, to be published in 2005). Bedrock geology. Scotland Special Sheet (Dounreay).1:25 000. 
British Geological Survey. 2003. Bedrock and superficial deposits. Scotland Sheet 115E (Reay).1:50 000. 
Fletcher, T P and Key, R M. 1991. Solid geology of the Dounreay District. British Geological Survey Technical Report WA/91/35C. 
Mendum, J R. 1991. Geology of NC 96SW. BGS Report. HI/JRM/91/1 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S115