An Early Ordovician age for the Annascaul Formation of the SE Dingle Peninsula, SW Ireland

The phyllitic mudrocks, quartz wacke sandstones and melange units of the An nascaul Formation in the SE Dingle Peninsula, SW Ireland have been previous ly assumed to be Silurian in age, similar to overlying fossiliferous Wenloc k rocks of the Ballynane Member. The contact between the Ballynane Member a nd the underlying Annascaul beds is either faulted or unconformable, and th e Annascaul mudrocks contain two or more cleavages not present in the Silur ian Ballynane and younger strata. The Ballynane Member is therefore differe ntiated from the Annascaul Formation by upgrading the proven Wenlock Ballyn ane beds to formational status. Grey and black mudrocks in the Annascaul Fo rmation have yielded diagnostic palynomorph assemblages indicative of an Ea rly Ordovician age. The Annascaul Formation invites comparison with similar Early Ordovician rocks, south of the putative trace of the Iapetus Suture, in SE and eastern ireland, in the English Lake District, and in central Ne wfoundland.