Gascoyne Seamount, also called Gascoyne Guyot or Gascoyne Tablemount, is a

guyot In marine geology, a guyot (), also called 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 . Guyots are most commonly fo ...

in the

Tasman Sea The Tasman Sea is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer Abel Janszoon Tasman, who in 1642 wa ...

of the

South Pacific Ocean South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both west and east. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

Geography

Located east of the Australian coastal town of Bermagui, Gascoyne Seamount is the southernmost and youngest significant

seamount A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly a ...

of the Tasmantid Seamount Chain. This is an underwater mountain range extending some to the north. The Tasmantid Seamount Chain has resulted from the Indo-Australian Plate moving northward over a stationary hotspot.

Geology

The seamount is about 7 million years old. It incorporates a tropical to subtropical, very shallow water

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

algal Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular microalgae, s ...

/encrusting foraminiferid biota, suggesting deposition in water deep. Age diagnostic forms have not been recovered. Gascoyne Seamount is named after HMAS ''Gascoyne'', one of two ships in the

Royal Australian Navy The Royal Australian Navy (RAN) is the navy, naval branch of the Australian Defence Force (ADF). The professional head of the RAN is Chief of Navy (Australia), Chief of Navy (CN) Vice admiral (Australia), Vice Admiral Mark Hammond (admiral), Ma ...

assigned to Australian programs in the International Indian Ocean Expedition, which took place from 1960 to 1965.

References

{{reflist Seamounts of the Tasman Sea Guyots Hotspot volcanoes Polygenetic volcanoes Miocene volcanoes Volcanoes of the Tasman Sea Seamounts of the Pacific Ocean