East Pacific Basin

an ocean basin occupying the northeastern part of the Pacific Ocean. Covering approximately 32.5 million sq km, the East Pacific Basin is bounded in the north by the Aleutian Trench and in the southeast by the Albatross Cordillera and the East Pacific Rise. It is bounded in the southwest by the Tuamotu Ridge and in the west by a series of ridges, including the Northwest Christmas Island Ridge, the Hawaiian Ridge, and the Emperor Seamount Chain. Predominant depths are 5,000–5,500 m and the maximum depth is 6,528 m, in the Chinook Fracture Trench.

The northern part of the basin is occupied by a flat abyssal plain with numerous seamounts, including guyots, and mountains rising above sea level, including Revillagigedo and Clipperton islands and the Marquesas Islands. The rest of the basin is covered with rolling abyssal plains, ranges, and depressions. Most of the depressions are related to latitudinal fracture zones that dissect the basin floor. The zones include the Mendocino Seascarp and the Pioneer, Murray, Clarion, and Clipperton fracture zones. The most common type of sediment is abyssal red clay. Terrigenous and organogenic diatomaceous silts are common in the north and organogenic foraminiferal and radiolarian oozes are common in the south.