The BGS Lexicon of Named Rock Units — Result Details

Lledr Valley Tuffs

Computer Code: LVT Preferred Map Code: LVT
Status Code: Full
Age range: Soudleyan Substage (OY) — Soudleyan Substage (OY)
Lithological Description: Ash-flow tuffs, welded.
Definition of Lower Boundary: Local members within Capel Curig Volcanic Formation.
Definition of Upper Boundary: Not defined.
Thickness: none recorded or not applicable
Geographical Limits: Northern and central Snowdonia.
Parent Unit: Capel Curig Volcanic Formation (CCV)
Previous Name(s): Garth Tuff [Obsolete Name and Code: Use LVT] (-3544)
Alternative Name(s): Garth Tuff
Stratotypes:
Type Area  About anticline in the Lledr Valley. 
Reference(s):
Howells, M F, Francis, E H, Leveridge, B E and Evans, C D R, 1978. Classical areas of British Geology. Capel Curig and Betws-y-Coed. Description of 1:25 000 Sheet SH75. London: HMSO for Institute of Geological Sciences. 
Rushton, A W A and Howells, M F. 1998. Stratigraphical framework for the Ordovician of Snowdonia and the Lleyn Peninsula. British Geological Survey Research Report, RR/99/08. 
Howells, M F, Reedman, A J and Campbell, S D G, 1991. Ordovician (Caradoc) marginal basin volcanism in Snowdonia (north-west Wales). (London: HMSO for the British Geological Survey). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E119