Rockall Basin

The Rockall Porcupine Margin in the Atlantic Ocean is a region of the Irish–Scottish margin of the north-east Atlantic continental margin of Europe. It consists of the Rockall Plateau, the Rockall Trough, the Rockall-Hatton Basin and the Porcupine Seabight and banks.

The Rockall Trough (Scottish Gaelic: Clais Sgeir Rocail) is a deep-water bathymetric feature to the northwest of Scotland and Ireland, running roughly from southwest to northeast, flanked on the north by the Rockall Plateau and to the south by the Porcupine Seabight. At the northern end, the channel is bounded by the Wyville-Thomson Ridge, named after Charles Wyville Thomson, professor of zoology at the University of Edinburgh and driving force behind the Challenger Expedition. At the southern end, the trough opens into the Porcupine abyssal plain. The Rockall Basin (also known as the Hatton Rockall Basin) is a large (approximately 800 by 150 kilometres (500 by 90 mi)) sedimentary basin that lies beneath the trough. Both are named after Rockall, a rocky islet lying 301.4 km (187.3 mi) west of St Kilda.

The Rockall Plateau consists of a number of fishing banks: the most important being the Rockall Bank and Hatton Bank, together with adjacent smaller banks and seamounts. From north to south these are Bill Bailey’s Bank, Lousy Bank, Rosemary Bank, George Bligh Bank, Anton Dohrn Seamount, and the Hebrides Terrace Seamount. Other features of the Rockall Plateau have been officially named after features of Middle-earth in the fiction of J. R. R. Tolkien, e.g. Eriador Seamount, Rohan Seamount, Gondor Seamount, Fangorn Bank, Edoras Bank, Lorien Knoll, Isengard Ridge.

In February 2000, the RRS Discovery, a British oceanographic research vessel sailing in the Rockall Trough encountered the largest waves ever recorded by scientific instruments in the open ocean, with a SWH of 18.5 metres (61 ft) and individual waves up to 29.1 metres (95 ft).