Rockall part of the deeply eroded Rockall Igneous Centre that was formed as part of the North Atlantic Igneous Province, approximately 55 million years ago, when the ancient continent of Laurasia was split apart by plate tectonics. Greenland and Europe separated and the northeast Atlantic Ocean was formed between them, eventually leaving Rockall as an isolated islet. The RV "Celtic Explorer" surveyed the Rockall Bank in 2003. The Irish Light Vessel "Granuaile" (the same name as the steamer on the RIA 1896 botany survey) was chartered by the Geological Survey of Ireland, on behalf of the Department of Communications, Marine and
Rockall 17.15 m (56.27 ft). It is often washed over by large storm waves, particularly in winter. There is a small ledge of , known as Hall's Ledge, from the summit on the rock's western face. It is the only named geographical location on the rock. The nearest point on land from Rockall is 301.3 km, or 162.7 nmi, east at the uninhabited Scottish island of Soay in the St Kilda archipelago. The nearest inhabited area lies 303.2 km, or 163.7 nmi, east at Hirta, the largest island in the St. Kilda group, which is populated intermittently at a single military