Aggregate potential of Irish south coast offshore palaeovalleys

Abstract

The southern shelf of offshore Ireland possesses many developed marine based resources such as hydrocarbons and commercial fisheries. Increasing knowledge of the seabed and the processes that cause large scale variation to the morphology and sedimentology is crucial in determining marine aggregate resource potential on the south coast. Qualitative data was processed using a multiproxy geophysical and sedimentological approach, creating detailed seabed maps using bathymetric data supported by ground truthing sedimentsamples. Surficial sediment deposits display a close fit to industry standard aggregates but considerable temporal variance at depth from vibrocore analysis shows variable marine reworking over time. Marine processes off the south coast diminish the aggregate quality of reworked fluvio-glacial deposits as evidence of increased marine reworking causes the replacement of favorable coarse-grained deposits with shell fragments. The southern shelf, at depth shows potential for marine aggregate exploration but variance within the extractable near surface deposits deems it too variable and accurate prediction of areas with high aggregate yield is diminished.