Late-Holocene sea-level rise in northwest Ireland is thought to have comprised a high stand c. 5-6k year BP, but the evidence for raised shoreline features disappears as you move south through west Donegal. It is unclear where the hinge point lies, and in west Donegal, the evidence for any significant change in sea-level over the last 5k years is weak or non-existent. Coastal development here is likely sensitive to even small-scale sea-level change, but the relative importance of this in the context of the high energy, storm-dominated coastal climate of northwest Ireland is uncertain.
The focus of this PhD therefore is to unravel the relative importance of storminess, climate variability and sea-level change to coastal behaviour and sedimentary dynamics over the last few thousand years. The coast here is typified by small estuaries semi-enclosed by large dune systems at their mouths, meaning that there are plentiful sediments that can be investigated to explore coastal evolution at the century to millennia time scale. But initial work on this has shown that preservation of ecological proxies typically used to delimit water bodies with different environmental signatures and salinities is poor. This PhD therefore seeks to take a more integrated line, that includes contemporary evaluation of wetland micro-organisms across the coastal zone (marine, brackish and freshwater) to support a more targeted multifacted and multiproxy palaeo-environmental approach.
The key objectives are:
– undertake exploratory analyses of existing cores (saltmarsh/backbarrier) to evaluate the potential for multiproxy investigations
– acquire samples from across the coastal zone (fresh to sea water) to delineate the options for coastal environmental proxies on high energy coasts
– acquire further cores from key sites to extend the spatial context
– use a multiproxy approach to reconstruct coastal evolution and establish the relative roles of sea-level change and climate variability