The BGS Lexicon of Named Rock Units — Result Details

Culfargie Sand Member

Computer Code: CUSA Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Typically deltaic and estuarine, commonly very fine- to medium-grained, finely micaceous, mainly flat laminated grey sand with silt and some clay laminae. Scattered pebbles occur up to 2cm size along with rare pebble beds, and there are black sulphidic patches. Coarser deposits including much higher proportions of coarse sand and gravel beds are known in the western areas of occurrence.
Definition of Lower Boundary: Diachronous transitional base with, and passing laterally into, the Powgavie Clay (Forth Clay Formation), and also the Errol Clay Formation.
Definition of Upper Boundary: The Culfargie Sand Member has a complex upper boundary with multiple unconformities with younger strata including the Carey Silt Member, Kingston Sand Member and Carse of Gowrie Clay Member (Carse Clay Formation). Also is known at surface as the top deposit of later Devensian raised beach landforms.
Thickness: 35m known at Culfargie.
Geographical Limits: River Tay just northwest of Perth, River Earn from Dunning eastwards and adjacent to the Tay/Earn estuary.
Parent Unit: Forth Clay Formation (FOCL)
Previous Name(s): Culfargie Beds (-1466)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Huntingtower Borehole, BGS Ref NO02NE/14, from 9.5m down to 29.33m. Paterson et al., 1981. 
Type Section  Culfargie Borehole, BGS Ref NO11NE/2, from 11.2m to 46.2m depth; lower River Earn valley. Paterson et al., 1981. 
Reference(s):
Armstrong, M, Paterson, I B and Browne, M A E, 1985. Geology of the Perth and Dundee district. Memoir of the British Geological Survey, Sheets 48W, 48E and 49 (Scotland). 108pp. 
Paterson, I B, Armstrong, M and Browne, M A E. 1981. Quaternary estuarine deposits in the Tay-Earn area, Scotland. Report of the Institute of Geological Sciences, No.81/7. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S048 S048