Geologists Seamounts

Geologists Seamounts (alternatively were named South West Hawaii Group^[2]) are a cluster of seamounts in the Pacific Ocean, located mainly 100 miles (160 km) south of Oahu, Hawaii^[3] and 100–200 kilometres (62–124 mi)^[4] south-west from Big Island (Hawaiʻi).^[5] Clockwise from north they are named Perret, Jaggar, McCall, Pensacola, Daly, Swordfish, Cross, Washington and Ellis.^[6] The Kauluakalana seamount to the north of Oahu on the far side of the Hawaiian chain to the other seamounts of the cluster, and south-east of the Musicians Seamounts has reason to be regarded as part of the Geologists Seamounts,^[7] but would not so be grouped logically by the former name for the cluster.

Geologists Seamounts
Bathymetric map of the south-west Geologists Seamounts
North Pacific Ocean
Location
Location	North Pacific Ocean
Coordinates	18°40′N 157°40′W[1]
Geology
Age of rock	Cretaceous

Geology

The seamounts developed during the Cretaceous,^[8] about 80 million years ago, and there is no geological relationship to the neighbouring Hawaiian Islands.^[4] There is about contemporaneous timing with the formation of the Musicians Seamounts to the north-west of Oahu and Hawaiʻi, from the limited sampling and analysis to date.^[9] Ages that have been obtained include 80.5 Ma for Kauluakalana, 84.5 Ma for Cross and 82.7 Ma for McCall.^[7] Rocks dredged from the seamounts include iron-manganese crusts, carbonates and basalts.^[10]

Ecology

Corals and sponges have been recorded at the south-western Swordfish Seamount at a depth of 1,071 m (3,514 ft) with plexauridae, alcyonacea, and coralliidae corals.^[11] The deeper coral community on Ellis Seamount at a depth of 2,135 m (7,005 ft) was less diverse with bamboo corals dominant.^[11]