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
Bounty Trough the South Island's coast. It covers an area of approximately . Much of The Bounty Trough lies at depths of , and it marks an indentation in the "coastline" of the largely submerged continent of Zealandia. A curious feature of the Bounty Trough is that it marks the continuation of several main river features in the South Island – the "Otago Fan Complex". This is a distinct series of channels existing in the base of the trough which is an extension of the Clutha and Waitaki River systems. Both these rivers, especially the Clutha, are noted for their fast flow.