1. School of Natural and Built Environment, Queen's University Belfast, Stranmillis Road, Belfast BT9 5AG, UK
2. British Geological Survey, The Lyell Building, Research Avenue South, Edinburgh EH14 4AP, UK
3. School of Geosciences, University of Aberdeen, Meston Building, King's College, Aberdeen AB24 3UF, UK
4. Geological Survey of Northern Ireland, Dundonald House, Upper Newtownards Road, Belfast BT4 3SB, UK