The Lord Howe Rise is an underwater plateau

Plateau

In geology and earth science, a plateau , also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau...

 that extends from southwest of New Caledonia

New Caledonia

New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...

 to the Challenger Plateau

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 . The plateau originated in the Gondwanan breakup and is one of the five major submerged parts of Zealandia, a largely submerged continent....

, west of New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

. To its west is the Tasman Basin 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 1500 to 2500 metres under water. It is part of Zealandia

Zealandia (continent)

Zealandia , also known as Tasmantis or the New Zealand continent, is a nearly submerged continental fragment that sank after breaking away from Australia 60–85 million years ago, having separated from Antarctica between 85 and 130 million years ago...

, a much larger continent

Continent

A continent is one of several very large landmasses on Earth. They are generally identified by convention rather than any strict criteria, with seven regions commonly regarded as continents—they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...

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

Continental crust

The continental crust is the layer of igneous, sedimentary, and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called sial due to more felsic, or granitic, bulk composition, which lies in...

. It was rift

Rift

In geology, a rift or chasm is a place where the Earth's crust and lithosphere are being pulled apart and is an example of extensional tectonics....

ed away from Eastern Australia by a mid-ocean ridge

Mid-ocean ridge

A mid-ocean ridge is a general term for an underwater mountain system that consists of various mountain ranges , typically having a valley known as a rift running along its spine, formed by plate tectonics. This type of oceanic ridge is characteristic of what is known as an oceanic spreading...

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

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

.

Lord Howe Island

Lord Howe Island

Lord Howe Island is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, directly east of mainland Port Macquarie, and about from Norfolk Island. The island is about 11 km long and between 2.8 km and 0.6 km wide with an area of...

 and Ball's Pyramid

Ball's Pyramid

Ball's Pyramid is an erosional remnant of a shield volcano and caldera that formed about 7 million years ago. Ball's Pyramid is southeast of Lord Howe Island in the Pacific Ocean. It is high, while measuring only in length and across, making it the tallest volcanic stack in the world...

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

Further north is the Elizabeth

Elizabeth Reef

Elizabeth Reef is a coral reef in the Tasman Sea. The reef is separated by a deep oceanic pass, some 45 km wide, from nearby Middleton Reef, both of which are part of the underwater plateau known as the Lord Howe Rise. Elizabeth Reef is around 160 km from Lord Howe Island and...

 and Middleton

Middleton Reef

Middleton Reef is a coral reef in the Tasman Sea. It is separated by a deep oceanic pass some 45 km wide from nearby Elizabeth Reef, forming part of the Lord Howe Rise underwater plateau. Middleton Reef is around 220 km from Lord Howe Island and 555 km from the coast of New South...

 part of the Coral Sea Islands

Coral Sea Islands

The Coral Sea Islands Territory includes a group of small and mostly uninhabited tropical islands and reefs in the Coral Sea, northeast of Queensland, Australia. The only inhabited island is Willis Island...

, considered to be the most southern platform reefs on Earth.

The Lord Howe Rise contains a line of seamount

Seamount

A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface , and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of depth. They are defined by oceanographers as...

s called the Lord Howe seamount chain

Lord Howe seamount chain

The Lord Howe seamount chain is a Miocene seamount chain on northern Lord Howe Rise, Zealandia. The chain is defined by coral-capped guyots, extends to the north for 1000 km , most likely the result of the Indo-Australian Plate moving northward over a stationary hotspot....

 which formed during the Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

 period when this part of Zealandia existed over the Lord Howe hotspot.

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