Benue Trough the Central African Shear Zone and for the volcanic island of St. Helena in the Atlantic ocean. Three periods of magmatic activity (volcanic action) have been identified, 147–106 Ma, 97–81 Ma and 68–49 Ma. The first is prominent in the north of the trough, and contemporary with magmatism in Brazil, probably occurring during a period of crustal extension before the Atlantic started to open. The second is found only in the south of the trough, and may belong to a period when the extension of the Atlantic had slowed down, ending with a period of compression. The third and last
Rockall to claim sovereignty for itself. The UK does not make a claim to extended EEZ based on Rockall, as it has ratified the United Nations Convention on the Law of the Sea (UNCLOS); this says that "rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf". However, such features are entitled to a territorial sea extending 12 nautical miles. With effect from 31 March 2014, the UK and Ireland published EEZ limits which resolved any disputes over the extent of their respective EEZs. In response to a Freedom of