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32-516: The trough is 2,300 km (1,400 mi) long and at ocean depths between 1.0 and 3.5 km (0.62 and 2.17 mi) orientated initially under the southern Coral Sea northeast to southwest similar to the alignment of Grande Terre but at the southern end of Grande Terre strikes north–south. At about 33°S the strike turns south-west towards northern Taranaki. These have been termed the northern (18–23°S), central (23–33°S) and southern (33–37°S) sectors. The northern and central portions are often termed

64-638: A Paleocene fully oceanic environment by 63.5 – 56 million years ago. Water depths vary from 3 to 1.8 km (1.9 to 1.1 mi). An area studied in detail of the Lord Howe raise western edge has volcanic seamounts and a canynon entering the basin. The Taranaki Basin southern termination of the New Caledonia Trough is in shallow water. Its eastern limit has long been defined by the Taranaki boundary fault system. Due to oil exploration studies

96-537: A failed rift compared to the eastern opening of the Tasman Sea from the Australian plate that started about this time. Plate modelling in a New Zealand reference frame is currently consistent with North Zealandia containing the proto-New Caledonia Trough rotating from an initial southeast to northeast orientation near New Zealand 43.79 million years ago to an east–west orientation by 26.55 million years ago with

128-707: A line joining the east extremities of Elizabeth Reef and South East Rock ( 31°47′S 159°18′E  /  31.783°S 159.300°E  / -31.783; 159.300 ) then to the southward along this line to the South East Rock [an outlier of Lord Howe Island ]. On the Northeast From the South East Rock to the north point of Three Kings Islands ( 34°10′S 172°10′E  /  34.167°S 172.167°E  / -34.167; 172.167 ), thence to North Cape in New Zealand. On

160-597: A number of midsea island groups, quite apart from coastal islands located near the Australian and New Zealand mainlands: The East Australian Current that commences its flow southwards in the tropics of the Coral Sea, near the eastern coast of Australia is the most energetic circulation feature in the south western Pacific Ocean and is a primary means of heat transport from the tropics to the middle latitudes between Australia and New Zealand. The East Australian Current

192-537: Is a geological concept that did not exist before 1995 when the subducted slab capture hypothesis was first applied to the breakup of east Gondwana . The full submergence had taken place by 63.5 – 56 million years ago. The timings and drivers of the formation of the trough have accordingly become the subject of research orientated to test this hypothesis and the Zealandia concept but the more recent tectonics could be explained in more than one way. The New Caledonia Trough

224-680: Is a return of the westward-flowing Pacific Equatorial Current (Pacific South Equatorial Current ). At the juncture between the Tasman and Coral seas while the East Australian Current continues south in the western Tasman a branch flows east called the Tasman Front towards the north of New Zealand with most continuing eastward above New Zealand into the South Pacific Ocean. It transpires that while predominantly

256-631: Is less steep than a trench , a trough can be a narrow basin or a geologic rift . These features often form at the rim of tectonic plates . There are various oceanic troughs on the ocean floors. This geomorphology article is a stub . You can help Misplaced Pages by expanding it . Tasman Sea 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

288-511: Is now usually thought to have been initiated by the Late Cretaceous but it still may be Jurassic in initial rifting. There is evidence from studies of its northern aspects that it may have had a two-stage process with more recent Eocene to Oligocene formation timings. Its basement rock is now assumed to have continental characteristics with a thin continental crust of about 10 km (6.2 mi) thickness along its whole length. In

320-623: Is the Fairway Ridge which contain seamounts that start at depths just below sea level at the Lansdowne Bank , but towards the south the ridge structures are 2.9 km (1.8 mi) deep where the adjacent Fairway Basin to the ridges east joins the New Caledonia Basin at its widest. The western margin of the northern sector is initially the northeastern ridge that projects under the Coral Sea from Grande Terre towards

352-600: The 148th meridian to Flinders Island ; beyond this island a line running to the eastward of the Vansittart Shoals to [Cape] Barren Island , and from Cape Barren (the easternmost point of [Cape] Barren Island) to Eddystone Point (41°S) in Tasmania, thence along the east coast to South East Cape , the southern point of Tasmania. On the North The parallel of 30°S from the Australian coast eastward as far as

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384-719: The East On the Southeast A line running from South West Cape , Stewart Island, through the Snares (48°S, 166°30'E) to North West Cape, Auckland Island ( 50°30′S 166°10′E  /  50.500°S 166.167°E  / -50.500; 166.167 ), through this island to its southern point. On the South A line joining the southern point of Auckland Island ( 50°55′S 166°0′E  /  50.917°S 166.000°E  / -50.917; 166.000 ) to South East Cape,

416-413: The New Caledonia Basin. It extends from 20°0′0″S 162°30′0″E  /  20.00000°S 162.50000°E  / -20.00000; 162.50000 to 37°27′0″S 172°4′59.9″E  /  37.45000°S 172.083306°E  / -37.45000; 172.083306 A clear distinction between the trough and its constituent basins was only defined in 2012. The eastern boundary of the northern sector

448-745: The South Island by the shapes of the Lord Howe Rise and southern east coast of the North island continues to the south. The East Australian Current south of Tasmania also is diverted west in the Subtropical Front which collides with the western moving Subantarctic front of the Antarctic Circumpolar Current . The East Australian Current sheds eddies on its way south that move south-westward with some known as

480-644: The Tasman Leakage making it as far westward as the Indian Ocean. A deep-sea research ship, the RV Tangaroa , explored the sea and found 500 species of fish and 1300 species of invertebrates. The tooth of a megalodon , an extinct shark, was also found by researchers. In 1876, the first telegraph cable connecting Australia and New Zealand was laid in the Tasman Sea. The telegraph cable

512-529: The Tasman Sea is comparable to referring to the North Atlantic Ocean as "the Pond". The south of the sea is passed over by depressions going from west to east. The northern limit of these westerly winds is near to 40°S . During the southern winter, from April to October, the northern branch of these winds from the west changes its direction toward the north and goes up against trade winds . Hence,

544-518: The eastern margin of Gondwana in the period from 260 to 110 million years ago. From about 110 to 100 million years ago this convergent regime changed to being extensional and intracontinental rifting became established along much of the eastern Gondwana margin, at which time Zealandia began to separate from Gondwana. By the Late Cretaceous (83.5 million years ago) the New Caledonia Trough was established as an extension basin but can be regarded as

576-466: The extension of the trough towards the Aotea Basin. A common consensus stratigraphy exists as first defined here. The findings are related to a 0.594 km (0.369 mi) core. It is based on the three regional tectonic phases of Zealandia and is: Aotea Basin (deepwater Taranaki Basin) sampling has shown a transition at 68 – 66 million years ago (Late Cretaceous) from sediments from land plants to

608-480: The geological history of the Taranaki Basin out to the deep water Taranaki Basin has been well mapped from 98 million years ago to 57 million years ago. 29°27′32.5″S 166°33′12″E  /  29.459028°S 166.55333°E  / -29.459028; 166.55333 Trough (geology) In geology, a trough is a linear structural depression that extends laterally over a distance. Although it

640-547: The geology of the trough relies on studies of adjacent structures and the basins adjacent and within the trough. The recent tectonics have been modelled at both the New Caledonian and New Zealand ends of the trough and will be commented on first, before consideration of the geology known of the relevant basins and the consensus stratigraphy. There is general agreement on the main tectonic phases, but not on finer details. Pacific basin subducting slab dipped southwest beneath

672-707: The location of westerly wind stress is a factor in how far north the formation of the Tasman Front occurs, so is the presence of the New Zealand land mass, as the top of New Zealand defines the furtherest south that the Tasman Front can be split off by the westerly winds. A boundary current called the East Auckland Current goes down the west coast of the North Island and further south the East Cape Current, that has been diverted towards

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704-687: The north d'Entrecasteaux Ridge , then the island of Grande Terre, followed by the northern portion of the Norfolk Ridge . The eastern margin of the central sector is the Lord Howe Rise , and the distal southern sector the Challenger Plateau . The western margin of the central sector continues to be the Norfolk Ridge until the West Norfolk Ridge strikes off it at about 31°S. The Fairway Basin opens at its south into

736-461: The north to 2.2 km (1.4 mi) in the south since the Eocene (33.9 million years ago). This basins stratigraphy west of New Caledonia is consistent with foreland loading and tilting associated with Eocene and younger southwest verging thrusts along its eastern margin. Its deepest portion is 3.5 km (2.2 mi) off Grande Terre. A core sample at a depth of 3.196 km (1.986 mi) from

768-447: The present northwest to southeast orientation established by 10 million years ago continuing to today's orientation. During this period the evidence is that the trough was contained on no more than two blocks with any block rotation occurring in the region of the central sector and southern sectors mentioned above. The tectonic component of the subsidence of the trough has been estimated to vary between more than 1.1 km (0.68 mi) in

800-436: The region southwest of New Caledonia, the New Caledonia Trough has a crustal thickness of between 6 and 8 km (3.7 and 5.0 mi). and a total depth from sea floor bottom to Moho of 15–17 km (9.3–10.6 mi). There is generally along the full trough up to 10 km (6.2 mi) of sediments above the basement, but post-Eocene layers are more typically about 1.5 km (0.93 mi) thick. Current understanding of

832-460: The sea is made up of globigerina ooze. A small zone of pteropod ooze is found to the south of New Caledonia and to the southern extent of 30°S , siliceous ooze can be found. The International Hydrographic Organization defines the limits of the Tasman Sea as: On the West A line from Gabo Island (near Cape Howe , 37°30'S) to the northeast point of East Sister Island (148°E), thence along

864-434: The sea receives frequent winds from the southwest during this period. In the Australian summer (from November to March), the southern branch of the trade winds goes up against west winds and produces further wind activity in the area. The Tasman Sea is 2,250 km (1,400 mi) wide and has an area of 2,300,000 km (890,000 sq mi). The maximum depth of the sea is 5,943 m (19,498 ft). The base of

896-505: The southern central New Caledonia Trough had the RU1 regional Eocene-Oligocene hiatus layer at 0.389 km (0.242 mi) deep in the sediments. Another core sample to 0.85 km (0.53 mi) Eocene sediments exists from the middle central New Caledonia Trough. The Fairway Basin which is separated from the New Caledonia Basin by the Fairway Ridge for its full length, is up to 2 km (1.2 mi) deep and joins up at its southern end with

928-420: The southern point of Tasmania. The Tasman Sea's midocean ridge developed between 85 and 55 million years ago as Australia and Zealandia broke apart during the breakup of supercontinent Gondwana . It lies roughly midway between the continental margins of Australia and Zealandia. Much of Zealandia is submerged, so the ridge runs much closer to the Australian coast than New Zealand's. The Tasman Sea features

960-617: The trough and this section has been called the Fairway-Aotea Basin. The southern sector contains the Aotea Basin and then the Taranaki Basin. The New Caledonia Trough has also been called the Norfolk Island Trough and the Norfolk Trough. The trough is between 200 and 300 km (120 and 190 mi) wide, and traverses a number of sedimentary basins within the submerged continent of Zealandia. This

992-572: Was made obsolete in 1963 when the Commonwealth Pacific Cable , New Zealand's first international telephone cable, was completed. Moncrieff and Hood were the first to attempt a trans-Tasman crossing by plane in January 1928. The aviators were never seen or heard of again. The first successful flight over the sea was accomplished by Charles Kingsford Smith and Charles Ulm later that year. The first person to row solo across

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1024-600: 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. The Tasman Sea is informally referred to in both Australian and New Zealand English as the Ditch ; for example, " crossing the Ditch " means travelling to Australia from New Zealand, or vice versa. The diminutive term "the Ditch" used for

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