The basement geology of continental margins of western Ireland is important to aid the understanding of the opening of the Atlantic Ocean and the development of the ensialic basins that are aligned in an NS orientation along the Irish continental shelf.

A geological map has been produced to highlight the the relationship between Irish onshore and offshore geology; terrain analysis of the onshore Irish geology, and projecting the onshore geology of Ireland and Newfoundland at a terrain level to reconstruct pre-Atlantic ocean opening geological map of the continental shelf. Integration of geophysical, borehole and seismic data into the offsore database has produced a geological and tectonic map of the basement of the western Irish continental shelf, using data available in the public domain and mapping the extension of the onshore basement geology and tectonic linears into the western offshore region.