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 "Two Royal Marines and a civilian naturalist, led by Royal Navy officer Lieutenant Commander Desmond Scott, raised a Union flag on the island and cemented a plaque into the rock". Prior to this the island was legally "terra nullius". In 1972, the British Island of Rockall Act formally annexed Rockall to the United Kingdom. The UK considers the island administratively part of the Isle of Harris and, under the Scottish Adjacent Waters Boundaries Order 1999 a large sea area around it was declared to be under the jurisdiction of Scots law. A navigational beacon was installed on the island in