Snowdon Volcanic Group
| Snowdon Volcanic Group | |
|---|---|
| Stratigraphic range: Caradoc Ordovician | |
Lower Rhyolitic Tuff Formation on the slopes of Y Lliwedd | |
| Type | Group |
| Sub-units | Upper Crafnant Volcanic Formation, Middle Crafnant Volcanic Formation, Lower Crafnant Volcanic Formation, Tal y Fan Volcanic Formation, Bedded Pyroclastic Formation, Lower Rhyolitic Tuff Formation |
| Underlies | Cadnant Shales Formation etc |
| Overlies | Cwm Eigiau Formation |
| Thickness | up to 1800 m |
| Lithology | |
| Primary | ash flow tuffs |
| Other | basalt, mudstones, siltstones, hyaloclastite |
| Location | |
| Region | northwest Wales |
| Country | Wales |
| Type section | |
| Named for | Snowdon |
The Snowdon Volcanic Group is an Ordovician lithostratigraphic group (a sequence of rock strata) in Snowdonia, north-west Wales. The name is derived from Snowdon, the highest peak in Wales where it outcrops. This assemblage of rocks has also been referred to as the Snowdon Volcanic Series.