Skomer Volcanic Group

Group
Stratigraphic range: Silurian
Type	Group
Underlies	upper Llandovery shales and sandstone
Overlies	Ordovician rocks
Thickness	about 1000m
Lithology
Primary	lava flows
Other	breccias, conglomerates, quartzitess, clay rocks
Location
Region	West Wales
Country	Wales
Extent	Skomer and adjacent parts of mainland Wales
Type section
Named for	Skomer island

The Skomer Volcanic Group is a Silurian lithostratigraphic group (a sequence of rock strata) in Pembrokeshire, Wales. The name is derived from the island of Skomer off the west coast of Pembrokeshire. It was traditionally known as the Skomer Volcanic Series. The rocks are exposed across the island of Skomer and along the northern half of the nearby Marloes peninsula as far east as St Ishmaels. ^{[1] [2]}

Lithology and stratigraphy

The Group comprises around 1000m thickness of lava flows and associated strata including felsite, albite-trachyte, keratophyre etc laid down during the Silurian Period. ^[3]

References

1. British Geological Survey 1:50,000 scale geological map (England & Wales) sheet 226/227 Milford
2. Ziegler, A. M.; McKerrow, W. S.; Burne, R. V.; Baker, P. E. (1969-01-01). "Correlation and environmental setting of the Skomer Volcanic Group, Pembrokeshire" . Proceedings of the Geologists' Association. 80 (4): 409–439. doi:10.1016/S0016-7878(69)80031-3. ISSN   0016-7878.
3. https://webapps.bgs.ac.uk/Lexicon/lexicon.cfm?pub=SVG (BGS on-line lexicon of rock units)