Hydrodynamics and cold-water coral facies distribution related to recent sedimentary processes at Galway Mound west of Ireland

Cold-water coral carbonate mound development is the result of complex and interactive hydrographical, biological and geological processes that can result in morphostructures several hundred meters high. The case study presented here investigates one of these large mounds – Galway Mound – in the eastern Porcupine Seabight to build an understanding of mound forming processes and the driving factors. For the first time, bottom current data have been recorded at six locations over a mound thus allowing an interpretation of the local flow field to be made. In addition to the overall flow pattern in the Porcupine Seabight, the recorded data display distinct diurnal tides. Comparison of the local flow field, coral facies distributions, current induced seabed features and grain size distributions over the Galway Mound highlights a correlation between the abundance of living corals with areas of enhanced bottom currents. However, the interplay of contour currents, tidal currents and the local topography further influences the coral facies and results in a distinct asymmetry in the coral facies distribution at Galway Mound. By baffling sediment, the corals also affect sedimentation on the mound.