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
Okinawa Trough extends to China-Ryukyu Border Trough naturally, which has been over 200 nautical miles away from the mainland baseline of Chinese territorial waters. According to UNCLOS, any country claiming continental shelves beyond 200 nm shall provide relevant scientific evidence to CLCS. To collect solid data, China deployed 14 scientific survey ships, covering an area of 250,000 square kilometers. Okinawa Trough The (also called , literally China-Ryukyu Border Trough ) is a seabed feature of the East China Sea. It is an active, initial back-arc rifting basin which has formed behind the Ryukyu arc-trench system in the West Pacific. It developed where