Rates, patterns and processes of rock breakdown on the coast of Ireland

Ph.D Student: Niamh Cullen

Supervisor: Dr Mary Bourke

Funding:

• Trinity College Dublin, Trinity Award
• British Society for Geomorphology Postgraduate research grants
• FP7 Marie Curie

Research abstract:

Rock coasts are exposed to numerous marine and sub aerial processes that result in unique geomorphic responses. Weathering and erosion processes (together referred to as rock breakdown) cause surface rocks to disintegrate. Weathering alone can play an important role in the recession of rocky coasts since many physical and chemical processes are facilitated by frequent tidal wetting and drying cycles and the presence of salts. Erosion by waves, particularly during storms, causes significant recession ‘events’. My research will examine how both weathering and erosion processes contribute to threshold changes in rock coast systems.

Increases in temperature and the frequency of intense precipitation and storm events, predicted by climate change models, will affect rates of rock breakdown. Rising sea level and increasing storm intensity are expected to increase erosion. Our poor understanding of individual rock breakdown mechanisms at coastal locations and their relationship to environmental controls thwart attempts to quantify or predict the effects of climate change. In addition, complex interactions between processes operating on rock coasts occur across a variety of spatial and temporal scales leading to a non-linear response. This makes predictions regarding the impacts of climate change on rock coasts problematic.

This research will determine recent and present day rates of erosion and examine the relationship between environmental controls and the rock breakdown processes.

Traditionally, cliffs and their associated platforms have been studied as separate entities. This research will examine these two components as a single connected system. This research will measure rock breakdown processes across a range of spatial scales and monitor system feedbacks. This proposed work will provide empirical data on current rates and styles of rock breakdown on Ireland’s coastline. This will permit a more robust assessment of the potential impacts of climate change either by extreme storm events and/or more gradual rock breakdown processes.