The BGS Lexicon of Named Rock Units — Result Details

St Sunday Crag Tuff Member

Computer Code: SSC Preferred Map Code: SSC
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Dacitic ignimbrite in the form of lapilli-tuff, mostly with a eutaxitic foliation due to welding, and with bedded tuffs at the base and top (some with accretionary lapilli, top only) which represent pyroclastic fall and surge deposits.
Definition of Lower Boundary: Basal bedded tuffs are conformable on sandstone of the Deepdale Sandstone Formation.
Definition of Upper Boundary: Bedded tuffs are overlain by andesite - probably a sill.
Thickness: Typically 45-55m
Geographical Limits: St Sunday Crag, Bannerside, Gavel Pike, Lord's Seat, Coldcove and adjacent to Trough Head, all in northeastern Lake District, Cumbria.
Parent Unit: Deepdale Sandstone Formation (DPD)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Reference Section  Crags on south side of Lord's Seat, Deepdale (north side). 
Reference Section  Top of crags that form St Sunday Crag. Crags are north facing and lie between Grisedale (north) and Deepdale (south). 
Woodhall, D G, 1998. The geology of the Wythburn, Thirlmere and Fairfield areas of the north-east Lake District. British Geological Survey Technical Report WA/98/07. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: