Aran Volcanic Group | |
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Stratigraphic range: Ordovician | |
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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 |
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]