The Mid-Pacific Mountains (MPM) is a large oceanic plateau located in the central North Pacific Ocean or south of the
Hawaiian–Emperor seamount chain
The Hawaiian–Emperor seamount chain is a mostly undersea mountain range in the Pacific Ocean that reaches above sea level in Hawaii. It is composed of the Hawaiian ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, ...
. Of volcanic origin and Mesozoic in age, it is located on the oldest part of the Pacific Plate and rises up to ( Darwin Rise) above the surrounding ocean floor and is covered with several layers of thick sedimentary sequences that differ from those of other plateaux in the North Pacific. About 50 seamounts are distributed over the MPM. Some of the highest points in the range are above sea level which include
Wake Island
Wake Island ( mh, Ānen Kio, translation=island of the kio flower; also known as Wake Atoll) is a coral atoll in the western Pacific Ocean in the northeastern area of the Micronesia subregion, east of Guam, west of Honolulu, southeast of T ...
and
Marcus Island
, also known as Marcus Island, is an isolated Japanese coral atoll in the northwestern Pacific Ocean, located some southeast of Tokyo and east of the closest Japanese island, South Iwo Jima of the Ogasawara Islands, and nearly on a straight l ...
.
The ocean floor of the MPM dates back to the Jurassic-Cretaceous, some of the oldest
oceanic crust
Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic ...
on Earth.
The MPM is a range of
guyot
In marine geology, a guyot (pronounced ), also known as a tablemount, is an isolated underwater volcanic mountain (seamount) with a flat top more than below the surface of the sea. The diameters of these flat summits can exceed .hotspot that uplifted the ocean floor of the still young Pacific Plate. Reefs developed on the subsiding islands and renewed volcanism in the Late Cretaceous helped maintain some of eastern islands but inevitably the guyots sank to their present depth.
It has been proposed that the MPM has crossed over several hotspots, and the MPM guyots are indeed older on the western MPM than the eastern part, but the guyots do not form chains that can be traced to any known hotspots. The MPM, nevertheless, must have originated over the South Pacific Superswell. Among the guyots in the Mid-Pacific Mountains are
Allison Guyot
Allison Guyot (formerly known as Navoceano Guyot) is a tablemount (guyot) in the underwater Mid-Pacific Mountains of the Pacific Ocean. It is a trapezoidal flat mountain rising 1,500 metres above the seafloor to a depth of less than 1,500 m, wi ...
Easter hotspot
The Easter hotspot is a volcanic hotspot located in the southeastern Pacific Ocean. The hotspot created the Sala y Gómez Ridge which includes Easter Island, Salas y Gómez Island and the Pukao Seamount which is at the ridge's young western ed ...
chain, a lineament that includes the Line Islands and
Tuamotu
The Tuamotu Archipelago or the Tuamotu Islands (french: Îles Tuamotu, officially ) are a French Polynesian chain of just under 80 islands and atolls in the southern Pacific Ocean. They constitute the largest chain of atolls in the world, extendin ...
archipelago, begins near the eastern part of the MPM. The formation of the MPM thus probably occurred at the Pacific-Farallon Ridge and the Easter hotspot, or where the Easter Microplate is now located.