ABSTRACT

The Caherbla Group (Devonian) in the Dingle Peninsula of southwest Ireland is a consanguineous association of alluvial fan, aeolian and fluviatile lithofacies. These sediments accumulated in an elongate trough adjacent to a source ridge composed largely of high-grade metamorphic rocks. Two laterally equivalent, inter-fingering formations are recognized. The Inch Conglomerate Formation is an alluvial fan deposit containing blocks of schist and gneiss up to 75 70 60 cm in size in a sparse red sandy matrix. It fines north-westwards away from the proposed source area. The Kilmurry Formation is composed very largely of aeolian sandstones with large-scale dune cross-stratification. Thes aeolian sandstones are interbedded with and largely laterally equivalent to the fan breccio-conglomerates of the Inch Conglomerate Formation. The dune fields developed between the fans and on their lower slopes. Interbedded with these dune units are lenticular sequences of fluviatile sandstones and mudstones representing the channel fill of impermanent rivers impounded by dune sands and engulfed by them during dry periods.