The BGS Lexicon of Named Rock Units — Result Details

Gwern Feifod Tuff Member

Computer Code: GFT Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Costonian Substage (OO) — Harnagian Substage (OG)
Lithological Description: Coarse- to fine-grained welded felsic crystal lapilli tuff.
Definition of Lower Boundary: Conformably overlies the felsic Gwern Feifod Lava Member [Llangynog Formation].
Definition of Upper Boundary: Conformably and gradationally overlain by volcaniclastic mudstones of the main part of the Llangynog Formation.
Thickness: About 10m
Geographical Limits: none recorded or not applicable
Parent Unit: Llangynog Formation (LGF)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
none recorded or not applicable
Wedd, C B, Smith, B, King, W B R and Wray, D A. 1929. Geology of the country around Oswestry. Memoir of the Geological Survey of Great Britain, Sheet 137. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E136 E137