The BGS Lexicon of Named Rock Units — Result Details

Garth Tuff Member

Computer Code: GT Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Soudleyan Substage (OY) — Soudleyan Substage (OY)
Lithological Description: White weathering, primary felsic ash-flow tuff.
Definition of Lower Boundary: Highly discordant on mudstones of the Nant Ffrancon Subgroup.
Definition of Upper Boundary: Conformably overlain by silty mudstones and fine grained sandstones of the Capel Curig Volcanic Formation.
Thickness: 40m
Geographical Limits: Not specified.
Parent Unit: Capel Curig Volcanic Formation (CCV)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
none recorded or not applicable
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:
E120