The BGS Lexicon of Named Rock Units — Result Details

Mynydd-Rhiw Rhyolitic Tuff Member

Computer Code: MRRT Preferred Map Code: MRT
Status Code: Full
Age range: Abereiddian Stage (O2) — Abereiddian Stage (O2)
Lithological Description: Fine-grained, purple weathering, welded rhyolitic tuff.
Definition of Lower Boundary: Overlies mudstones and siltstones with coarse sandstone interbeds.
Definition of Upper Boundary: Overlain by mudstones and siltstones with coarse sandstone interbeds.
Thickness: none recorded or not applicable
Geographical Limits: Pwllheli district, northwest Wales.
Parent Unit: Trygarn Formation (TGN)
Previous Name(s): Mynydd Rhiw Rhyolitic Tuff Member (-2329)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Displaced blocks around Mynydd Rhiw to Ty'n-y-mynydd. 
Reference(s):
Fitch, F J, 1967. Ignimbrite volcanism in North Wales. Bulletin Volcanologique, 30, 199-219 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E134