The BGS Lexicon of Named Rock Units — Result Details
Llanbedrog Volcanic Group
Computer Code: | LIG | Preferred Map Code: | LVG |
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Status Code: | Full | ||
Age range: | Caradoc Series (O4) — Caradoc Series (O4) | ||
Lithological Description: | Basaltic trachyandesite-rhyodacite lavas and tuffs, with some ash flow tuffs and minor amounts of reworked sandstones, siltstones and conglomerates. | ||
Definition of Lower Boundary: | Underlain by sandstones and siltstones of the Dwyfach Formation. | ||
Definition of Upper Boundary: | Overlain by mudstones and slates of the Nod Glas Formation. | ||
Thickness: | From about 300 to about 1100m | ||
Geographical Limits: | Northwest Wales. | ||
Parent Unit: | Gwynedd Supergroup (GWYN) | ||
Previous Name(s): | Mynytho Volcanic Group
(MYV)
Mynytho Volcanic Group (MYV) Llanbedrog Igneous Group [Obsolete Name and Code: Use LIG] (-364) Llanbedrog Volcanic Series [Obsolete Name and Code: Use LIG] (-1658) Llanbedrog Ignimbrites [Obsolete Name and Code: Use LIG] (-4162) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Type Area | Around village of Llanbedrog, Llyn Peninsula. | ||
Reference(s): | |||
Young, T P, Gibbons, W and McCarroll, D. 2002. Geology of the country around Pwllheli. Memoir of the British Geological Survey, Sheet 134 (England and Wales). | |||
Williams, A and others, 1972. A correlation of Ordivician rocks in the British Isles. Geological Society of London Special Report No.3. | |||
Matley, C A, 1938. The geology of the country around Pwllheli, Llanbedrog and Madryn, southwest Carnarvonshire. Quarterly Journal of the Geological Society of London, Vol.94, 555-606. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
E134 |