Oceanic trench the level of the surrounding oceanic floor. The greatest ocean depth measured is in the Challenger Deep of the Mariana Trench, at a depth of below sea level. Oceanic lithosphere moves into trenches at a global rate of about 3 km/yr. There are approximately of convergent plate margins, mostly around the Pacific Ocean—the reason for the reference “Pacific-type” margin—but they are also in the eastern Indian Ocean, with relatively short convergent margin segments in the Atlantic Ocean and in the Mediterranean Sea. Globally, there are over 50 major ocean trenches covering an area of 1.9 million km or about 0.5%
Mariana Trench poles than at the equator. As a result, parts of the Arctic Ocean seabed are at least closer to the Earth's centre than the Challenger Deep seafloor. In 2009, the Marianas Trench was established as a United States National Monument. Xenophyophores have been found in the trench by Scripps Institution of Oceanography researchers at a record depth of below the sea surface. On 17 March 2013, researchers from the Scottish Association for Marine Science reported data that suggested microbial life forms thrive within the trench. The Mariana Trench is named for the nearby Mariana Islands (in turn named Las Marianas