The BGS Lexicon of Named Rock Units — Result Details

Clogwyn Gottal Tuff

Computer Code: CWGOT Preferred Map Code: notEntered
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: Poorly sorted, heterolithic, felsic tuff with clasts of rhyolite, tuff and sedimentary rocks, interbedded with volcaniclastic sandstones and siltstones.
Definition of Lower Boundary: Conformably overlies silty mudstones of the Nant Ffrancon Subgroup.
Definition of Upper Boundary: Conformably overlain by sandstones of the Cwm Eigiau Formation.
Thickness: 15m
Geographical Limits: Central Snowdonia.
Parent Unit: Cwm Eigiau Formation (CEI)
Previous Name(s): none recorded or not applicable
Alternative Name(s): Capel Curig Volcanic Formation
Stratotypes:
Type Area  To the west of Dolwyddelan. Howells, M F and Smith, M. 1997. 
Reference(s):
Howells, M F and Smith, M. 1997. Geology of the country around Snowdon. Memoir of the British Geological Survey, Sheet 119 (England and Wales). (London: The Stationery Office). 104pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable