Modelling the Development of Rocky Shoreline Profiles along the Northern Coast of IrelandEmail: robin.edwards@tcd.ie
AbstractA mathema�cal wave-erosion model is used to simulate postglacial shoreline profiles along the rocky, high energy coast of the north of Ireland. The wave erosion model is driven by a suite of rela�ve sea-level (RSL) curves for the last 16,000 years produced from four glacial rebound models. Mul�ple runs are performed with different ini�al shore profiles and rock resistances to inves�gate shoreline evolu�on and the significance of inherited morphology on the resultant profile shape. The simulated profiles are then compared with mapped profiles from three areas of the north of Ireland with different lithological and hydrographic proper�es.Modelled profiles generally replicate the overall mean shoreline gradients observed across the region when rock resistance is rela�vely high and erosion rates correspondingly low. In these profiles, breaks in mean slope are observed at depths comparable to the RSL minima in several of the RSL scenarios (at c. -10m, -15m and -20m for North Antrim, Derry and Donegal respec�vely). At Portrush and Portballintrae (Derry), profiles may be influenced by structural controls rela�ng to the underlying basalt surface and the removal of overlying glaciogenic sediments.All RSL scenarios replicate the observed eastward increase in cliff-pla�orm junc�on height, reflec�ng the differen�al glacioisosta�c rebound experienced along the coast. However, the precise eleva�on at which the simulated cliff base occurs is sensi�ve to the choice of RSL scenario, sugges�ng that this parameter may prove useful in evalua�ng glacial rebound model performance. Several of the RSL scenarios generate raised shore pla�orms or terraces in North Antrim and Derry at heights comparable to raised shoreline features reported in the literature. However, no single curve or combina�on of parameters is capable of genera�ng the range of pla�orm and terrace features observed in the bathymetric and topographic data. These misfits are consistent with the idea that many rock pla�orm or terrace features are inherited from an earlier phase or phases of RSL.Keywords: wave erosion, model, rela�ve sea level, rock coast, shore pla�orms, marine terraces, IrelandAbbrevia�ons: Rela�ve Sea Level (RSL); Joint Irish Bathymetric Survey (JIBS); Digital Eleva�on Model (DEM); mean high water spring �de (MHWS), mean high water neap �de (MHWN), mid-�de (MT), mean low water neap �de (MLWN), and mean low water spring �de (MLWS); Ordnance Datum Malin Head (OD) This is the author's final copy of a published manuscript made available via Trinity's Access to Research Archive (TARA). This item is protected by original copyright. For full details visit the TARA website at www.tara.tcd.ie Author's Final Copy Available via Trinity College Dublin's Open Access Repository (www.tara.tcd.ie) 2
Introduc�onThe high energy, wave dominated coastline of the north of Ireland comprises rocky cliffs and shore pla�orms, commonly associated with g...