The Tasman Sea is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about 2,000 km (1,200 mi) across and about 2,800 km (1,700 mi) from north to south. The sea was named after the Dutch explorer Abel Janszoon Tasman, who in 1642 was the first known person to cross it. British explorer Lieutenant James Cook later extensively navigated the Tasman Sea in the 1770s during his three voyages of exploration.
In marine geology, a guyot, also called a tablemount, is an isolated underwater volcanic mountain (seamount) with a flat top more than 200 m (660 ft) below the surface of the sea. The diameters of these flat summits can exceed 10 km (6 mi). Guyots are most commonly found in the Pacific Ocean, but they have been identified in all the oceans except the Arctic Ocean. They are analogous to tables on land.
A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface, and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to 1,000–4,000 m (3,300–13,100 ft) in height. They are defined by oceanographers as independent features that rise to at least 1,000 m (3,281 ft) above the seafloor, characteristically of conical form. The peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea. During their evolution over geologic time, the largest seamounts may reach the sea surface where wave action erodes the summit to form a flat surface. After they have subsided and sunk below the sea surface, such flat-top seamounts are called "guyots" or "tablemounts".
The Coral Sea is a marginal sea of the South Pacific off the northeast coast of Australia, and classified as an interim Australian bioregion. The Coral Sea extends 2,000 kilometres (1,200 mi) down the Australian northeast coast. Most of it is protected by the French Natural Park of the Coral Sea and the Australian Coral Sea Marine Park. The sea was the location for the Battle of the Coral Sea, a major confrontation during World War II between the navies of the Empire of Japan, and the United States and Australia.
The South Tasman Rise is an area of seafloor that lies 550 km south of Hobart, Tasmania in the Southern Ocean where water depths are about 1,500 metres. The South Tasman Rise is also known as the Tasmania Ridge or South Tasmania Ridge. The South Tasman Rise is a sunken landbridge that used to connect Tasmania to Antarctica.
The Campbell Plateau is a large oceanic plateau south of New Zealand and the Chatham Rise. It originated in the Gondwanan breakup and is part of Zealandia, a largely submerged continent. The above sea level parts of the plateau — the Bounty Islands, Antipodes Islands, Auckland Islands and Campbell Island — form part of the New Zealand Subantarctic Islands which were declared a World Heritage Site in 1998. Large parts of the Campbell Plateau lie less than 1000 m below sea level. It rises to 500 m at the Pukaki Rise and emerges above sea level at the Auckland and Campbell Islands.
The Norfolk Ridge is a long submarine ridge running between New Caledonia and New Zealand, about 1,300 km (810 mi) off the east-coast of Australia.
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 through parts of the Coral Sea and Tasman Sea. These chains have longitudes of approximately 159°E and 156°E respectively.
Lansdowne Bank, sometimes called Landsdowne Bank, is an extensive submerged bank located between the main island of New Caledonia and the Chesterfield Islands, in the easternmost part of the Coral Sea. It covers an area of 4,300 km2 (1,660 sq mi), making it one of the largest banks of the world, has general depths of 60 to 80 metres (197–262 ft), and a largely sandy bottom. Two reefs mark the shallowest spots of the bank, but they are still submerged at low tide.
The following outline is provided as an overview of and introduction to Oceanography.
Zealandia, also known as Te Riu-a-Māui (Māori) or Tasmantis, is an almost entirely submerged mass of continental crust in Oceania that subsided after breaking away from Gondwana 83–79 million years ago. It has been described variously as a submerged continent, continental fragment, and microcontinent. The name and concept for Zealandia was proposed by Bruce Luyendyk in 1995, and satellite imagery shows it to be almost the size of Australia. A 2021 study suggests Zealandia is over a billion years old, about twice as old as geologists previously thought.
The East Tasman Plateau is a submerged microcontinent south east of Tasmania. Its area is 50,000 square kilometres (19,000 sq mi), and it is mostly from 2,500 to 3,000 metres deep. It is a circular piece of continental rocks surrounded by oceanic crust. Volcanism occurred there 36 million years ago. The East Tasman Plateau is separated from the island of Tasmania by 100 kilometres (62 mi) of deeper water, and the East Tasman Saddle is a higher ridge connecting the plateau to the Freycinet Peninsula region of the Tasmanian East Coast. This ridge runs north west from the plateau. South-west of the plateau is the L'Atalante Depression. The East Tasman Plateau represents a continental fragment.
The Pacific Ocean evolved in the Mesozoic from the Panthalassic Ocean, which had formed when Rodinia rifted apart around 750 Ma. The first ocean floor which is part of the current Pacific plate began 160 Ma to the west of the central Pacific and subsequently developed into the largest oceanic plate on Earth.
The Norfolk Marine Park is an Australian marine park located in the waters immediately offshore of Norfolk Island, an external territory of Australia. The marine park extends 700 km (430 mi) in a north–south direction and covers an area of 188,444 km2 (72,759 sq mi). The park is assigned IUCN category IV and is one of 8 parks managed under the Temperate East Marine Parks Network.
The Lord Howe Marine Park is an Australian marine park located about 550 km (340 mi) offshore of New South Wales, near Lord Howe Island. The marine park covers an area of 110,126 km2 (42,520 sq mi), encompassing the smaller Lord Howe Island Marine Park, and is assigned IUCN category IV. It is one of 8 parks managed under the Temperate East Marine Parks Network.
Joseph Gilbert Seamount is a large seamount in the Tasman Sea located 450 km (280 mi) west of the South Island of New Zealand at the southern edge of the Lord Howe Rise. It has an elongated northwest–southeast trend, covering an area of about 11,500 km2 (4,400 sq mi) and rising to 2,400 m (7,900 ft) below sea level.
The geology of New Caledonia includes all major rock types, which here range in age from ~290 million years old (Ma) to recent. Their formation is driven by alternate plate collisions and rifting. The mantle-derived Eocene Peridotite Nappe is the most significant and widespread unit. The igneous unit consists of ore-rich ultramafic rocks thrust onto the main island. Mining of valuable metals from this unit has been an economical pillar of New Caledonia for more than a century.
The Lord Howe Seamount Chain of which Gifford Guyot is an eruptive centre, and part of a pair of coral-capped guyots, formed during the Miocene. The Gifford Marine Park is co-located off the Queensland coast near Brisbane.
Zealandia is an area of mostly submerged continental crust that contains New Zealand and New Caledonia.
The Three Kings Ridge, sometimes known as Three Kings Rise and more rarely at its southern end as the Three Kings Bank is a deep sea westward facing volcanic arc of Zealandia continental crust extending from 55 kilometres (34 mi) northwest of Cape Reinga / Te Rerenga Wairua, New Zealand on a line bisecting New Caledonia and Fiji in the South Pacific Ocean. Its southern portion contains the Manawatāwhi / Three Kings Islands which have biological significance as they are host to unique species and important marine ecosystems.
