Aran Volcanic Group

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Aran Volcanic Group
Stratigraphic range: Ordovician
Pillow lava Cadair Idris.jpg
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
Thicknessup 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]

See also

References

  1. British Geological Survey. "Aran Volcanic Group". BGS Lexicon of Named Rock Units. Retrieved 20 May 2025.
  2. Rushton, A.W.A.; Howells, M.F. (1999). "Stratigraphical framework for the Ordovician of Snowdonia and the Lleyn Peninsula" (PDF). British Geological Survey Research Report. Retrieved 21 May 2025.