Melanesian Basin
Melanesian Basin
a basin in the western Pacific Ocean. It is bounded on the north by the swell and mountain ridges of the Marshall Islands, on the east by the mountain ridge of the Gilbert and Ellice islands, and on the south by the east Melanesian island arc. The basin is an oval extending in a northwesterly direction for approximately 2,600 km. It has a width of 1,600 km and an average depth of 3,000 m to 5,400 m, descending to 5,634 m. In the center of the basin there are underwater plateaus at depths of about 3,500 m. Several mountain peaks rise above sea level, forming the islands of Nauru, Ocean, Kusaie, and Pingelap. The basin is covered with calcareous sediments and red ooze; near the islands there are coral sands.