The Lord Howe Rise is a deep sea

plateau In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides ha ...

which extends from south west of

New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...

to the

Challenger Plateau The Challenger Plateau is a large submarine plateau west of New Zealand and south of the Lord Howe Rise. It has an approximate diameter of and an area of about . The water depth over the plateau varies between to and is covered by up to of se ...

, west of

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

in the south west of the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

. To its west is the

Tasman Basin Tasman most often refers to Abel Tasman (1603–1659), Dutch explorer. Tasman may also refer to: Animals and plants * Tasman booby * Tasman flax-lily * Tasman parakeet (disambiguation) * Tasman starling * Tasman whale People * Tasman ( ...

and to the east is the New Caledonia Basin. Lord Howe Rise has a total area of about 1,500,000 square km, and generally lies about 750 to 1,200 metres under water. It is part of Zealandia, a much larger

continent A continent is any of several large landmasses. Generally identified by convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continents. Ordered from largest in area to smallest, these seven ...

that is now mostly submerged, and so is composed of continental crust.

Formation

The Lord Howe Rise was formed by seafloor spreading which also resulted in the creation of the Tasman Sea. It was rifted away from Eastern Australia by a

mid-ocean ridge A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a diverge ...

that was active from 80 to 60 million years ago, and now lies 800 kilometres offshore from

mainland Australia Mainland Australia is the main landmass of the Australian continent, excluding the Aru Islands, New Guinea, Tasmania, and other Australian offshore islands. The landmass also constitutes the mainland of the territory governed by the Commonwealt ...

. The Lord Howe Rise contains a line of

seamount A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abru ...

s called the

Lord Howe Seamount Chain The Lord Howe Seamount Chain formed during the Miocene. It features many coral-capped guyots and is one of the two parallel seamount chains alongside the east coast of Australia; the Lord Howe and Tasmantid seamount chains both run north-south t ...

which formed during the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

period when this part of Zealandia existed over the Lord Howe hotspot. Lord Howe was the last volcano to erupt on the rise.

Islands, reefs and seamounts

Lord Howe Island Lord Howe Island (; formerly Lord Howe's Island) is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies directly east of mainland P ...

and

Ball's Pyramid Ball's Pyramid is an erosional remnant of a shield volcano and caldera lying southeast of Lord Howe Island in the Pacific Ocean. It is high, while measuring in length and only across, making it the tallest volcanic stack in the world. Bal ...

cap a seamount towards the central east of the rise in an area known as the Lord Howe platform. The

extends northwards along the rise. The seamounts provide habitat to a diverse range of marine species which attracts commercial fishers, but cover a very small area, less than 1% of the total area of Lord Howe Rise. Further north is the Elizabeth and Middleton part of the

Coral Sea Islands The Coral Sea Islands Territory is an external territory of Australia which comprises a group of small and mostly uninhabited tropical islands and reefs in the Coral Sea, northeast of Queensland, Australia. The only inhabited island is W ...

, which together with reefs around

are the most southern coral reefs on Earth.

Environment

The

seabed The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

on the rise is mostly sandy mud with some volcanic outcrops, gravel and boulders. The doubleheader fish, '' Coris bulbifrons'', is endemic to reefs on the Lord Howe Rise and the West Norfolk Rise.

Resources

Much of the basin remains unexplored in relation to oil and gas reserves.

References

{{coord, 28, S, 161, E, display=title Plateaus of Oceania Underwater ridges of the Pacific Ocean Zealandia Tasman Sea

Formation

Islands, reefs and seamounts

Environment

Resources

See also

References