The stratigraphy and sedimentology of the Ordovician Partry Group, southeastern Murrisk, Ireland

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Abstract
The uppermost part of the Ordovician succession in southeastern Murrisk, western Ireland, consists of coarse‐grained sedimentary rocks and tuffs, the Partry Group, hitherto subdivided into the Mweelrea Formation, unconformably overlain by the Maumtrasna Formation. The age of the lower part of the succession is late Llanvirn whilst that of the upper part is unknown. Evidence is presented to show that the two formations are lateral equivalents. Consequently the Mweelrea Formation is redefined and the Maumtrasna Formation becomes redundant. The revision of the stratigraphy enables a coherent sedimentological model for the group to be proposed. The sediments of the Mweelrea Formation were deposited on alluvial fans and distally‐equivalent alluvial plains and delta fans. The direction of sediment transport was towards the north and northwest.