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 from 26 May 1985 to 4 July 1985 to affirm the UK's claim to the islet. In 1997, the environmentalist organisation Greenpeace occupied the islet for a short time, calling it Waveland, to protest against oil exploration. Greenpeace declared the island to be a "new Global State" (in this case qualifying it as a micronation) and offered citizenship to anyone willing to take their pledge of allegiance. The British Government's response was to state that "anyone is free to go there" and otherwise ignore them. During his one night on Rockall, Greenpeace protester and Guardian journalist John Vidal unscrewed the