Aran Volcanic Group
Geologic formation in Wales
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The Aran Volcanic Group is a geological group in Wales. It preserves fossils dated to the Ordovician period.[1] It is laterally equivalent with sedimentary rocks of the Ogwen Group, parts of which are interbedded with it.[2]
TypeGroup
Sub-unitsAran Fawddwy Formation, Benglog Formation, Brithion Formation, Craig Cau Formation, Craig y Ffynnon Formation, Cregennen Formation, Llyn y Gafr Volcanic Formation, Melau Formation, Offrwm Volcanic Formation, Pen-y-gadair Volcanic Formation, Pistyllion Formation, Rhiw Bach Volcanic Formation
UnderliesCeiswyn Formation
OverliesMawddach Group, Rhobell Volcanic Group
| Aran Volcanic Group | |
|---|---|
| Stratigraphic range: Ordovician | |
| |
| Type | Group |
| Sub-units | Aran Fawddwy Formation, Benglog Formation, Brithion Formation, Craig Cau Formation, Craig y Ffynnon Formation, Cregennen Formation, Llyn y Gafr Volcanic Formation, Melau Formation, Offrwm Volcanic Formation, Pen-y-gadair Volcanic Formation, Pistyllion Formation, Rhiw Bach Volcanic Formation |
| Underlies | Ceiswyn Formation |
| Overlies | Mawddach Group, Rhobell Volcanic Group |
| Thickness | up to 2.5 km |
| Lithology | |
| Primary | Basalt, Rhyolite, Volcaniclastics and Sedimentary rock |
| Location | |
| Country | Wales |
| Extent | Harlech Dome |
| Type section | |
| Named for | Aran mountain range |
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