Southwestern Pacific Basin

a submarine basin in the southwestern Pacific. It is bounded on the west by the Kermadec Trench, the Tonga Trench, and the New Zealand Plateau, on the north by the submarine bases of the mountain ranges that form the Cook and Tubuai islands, and on the east and south by the East Pacific and South Pacific rises.

Abyssal hills and rolling plains predominate in the basin. Isolated mountains are characteristic. Depths exceed 5,000 m, with a maximum of 6,250 m (6,098 m according to some sources) in the southern part. Sediments are primarily red clays and diatomaceous oozes.