The BGS Lexicon of Named Rock Units — Result Details

Skomer Volcanic Group

Computer Code: SVG Preferred Map Code: notEntered
Status Code: Full
Age range: Aeronian Age (SA) — Aeronian Age (SA)
Lithological Description: Subaerial lava flows with breccias, conglomerates, quartzites and red clayrocks. Mafic to felsic, including felsite, albite-trachyte, keratophyre, skomerite, marloesite, mugearite and olivine basalt.
Definition of Lower Boundary: Drawn at the base of the Skomer Volcanic Group (which is never seen) where it unconformably overlies Ordovician rocks.
Definition of Upper Boundary: Drawn at the conformable upward passage of the Skomer Volcanic Group where it is unconformably overlain by upper Llandovery shales and sandstone.
Thickness: 1000 metres approx.
Geographical Limits: Skomer Island off the Pembrokeshire coast.
Parent Unit: Not Applicable (-)
Previous Name(s): Skomer Volcanic Series (-3703)
Conglomerate "Series" [Obsolete Name And Code: Use SVG] (CGT)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Skomer Island 
Reference(s):
Thomas, H H. 1911. The Skomer Volcanic Series, Pembrokeshire. Quarterly Journal of the Geological Society of London, Vol.67, p.211. 
Cantrill, T C and others, 1916. South Wales Coalfield, part XII, Milford. Memoir of the Geological Survey of Great Britain. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable