The Tasmantid Seamount Chain is a 2,000 km (1,200 mi) long chain of seamounts in the South Pacific Ocean. The chain consists of over 16 extinct volcanic peaks, many rising more than 4,000 m (13,000 ft) from the seabed. It 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.
Like its neighbour, the Tasmantid Seamount Chain has resulted from the Indo-Australian Plate moving northward over a stationary hotspot. It ranges in age from 40 to 6 million years old. Alternative names for the Tasmantid Seamount Chain include the Tasmantid Seamounts, Tasman Seamounts, Tasman Seamount Chain and the Tasmantide Volcanoes.
The Tasmantid Seamount Chain includes the following:
Banc Capel is a guyot, or flat-topped underwater volcano, in the Coral Sea.Bollons Seamount
Bollons Seamount is a seamount just east of the international date line, a few hundred miles off the coast of New Zealand. It represents a continental fragment that was separated from Zealandia by rifting.
The seamount was involved in a 2002 survey and collection project defined to find the edge of New Zealand's continental shelf. The Bollons Seamount has been shown to be a site of extensive Cretaceous-era rifting in the area towards the southern Chatham Rise between 83.7 and 78.5 MYA.Magnetic anomalies from the seamount indicate that it was the site of highly irregular activity, with differences in the rifting there being up to 100 km (62 mi). A 50 km (31 mi) gap near the seamount, known as the Ballons gap, is interpreted as being due to excess volcanism from the seafloor spreading process. A ridge just south of the seamount, the Antipodes Fracture Zone, is interpreted as having been built by a combination of compression and volcanic activity associated with the triple-junction Bellingshausen-Marie Byrd Land plate boundary nearby.Bounty Trough
The Bounty Trough is a major submerged feature, a bathymetric depression, of the oceanography of the southwest Pacific Ocean. It is located off the east coast of New Zealand's South Island. It is named after the Bounty Islands near the Eastern end of the trough. The islands in turn, named after HMS Bounty.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 500 km (310 mi) and an area of about 280,000 km2 (110,000 sq mi). The water depth over the plateau varies between 500 m (1,600 ft) to 1,500 m (4,900 ft) and is covered by up to 3,500 m (11,500 ft) of sedimentary rocks of Upper Cretaceous to recent in age. The plateau originated in the Gondwanan breakup and is one of the five major submerged parts of Zealandia, a largely submerged continent.Coral Sea Marine Park
The Coral Sea Marine Park (previously known as the Coral Sea Commonwealth Marine Reserve) is an Australian marine park located in the Coral Sea off the coast of Queensland. The marine park covers an area of 989,836 km2 (382,178 sq mi) and is assigned IUCN category IV. It is Australia's largest single marine park and is one of the world's largest protected areas.The Coral Sea Marine Park lies directly adjacent to and east of the Great Barrier Reef Marine Park.Great South Basin
The Great South Basin is an area of mainly sea to the south of the South Island of New Zealand.
Starting in the 1960s, the area was explored and drilled for oil deposits by various, mostly international minerals companies — including Hunt Oil — but by 1984 all of these companies had left empty-handed.With advances in seismic surveying and drilling technology, hopes have been raised once again for a potential oil strike. Since 2006, new tenders for drilling rights have been issued.In 2010, Exxon Mobil and Todd Energy relinquished their exploration rights, citing technical difficulties and the harshness of the environment. Royal Dutch Shell subsequently purchased a stake in a joint venture headed by OMV New Zealand, with drilling announced at the start of 2014.Anadarko Petroleum made a test drilling in the area in early 2014, without success. Schlumberger subsequently made a drilling attempt in the same areas later in the year.Healy (volcano)
Healy is a submarine volcano located among New Zealand's Kermadec Islands. Its last major eruption took place around 1360, creating a large caldera.
The volcano's name originates from the British-Australian explorer and navigator Captain Jake Healy who first wrote about the volcano in his journal after noticing Volcanic glass in the water while he was fishing.Hikurangi Plateau
The Hikurangi Plateau is an oceanic plateau in the South Pacific Ocean east of the North Island of New Zealand. It is part of a large igneous province (LIP) together with Manihiki and Ontong Java, now located 3,000 km (1,900 mi) and 3,500 km (2,200 mi) north of Hikurangi respectively. Mount Hikurangi, in Māori mythology the first part of North Island to emerge from the ocean, gave its name to the plateau.Hikurangi Trench
The Hikurangi Trench, also called the Hikurangi Trough, is an oceanic trench in the bed of the Pacific Ocean off the east coast of the North Island of New Zealand, lying between the southern end of the Cook Strait and the Chatham Rise. It is the southward continuation of the much deeper Kermadec Trench. It lies in the Hikurangi Margin subduction zone, which is the southern extension of the Kermadec-Tonga subduction zone. The Hikurangi Margin is the subduction zone where the thick oceanic Hikurangi Plateau is subducting beneath continental crust of the Indo-Australian Plate. By contrast, the Kermadec and Tonga trenches represent the parts of the subduction zone where oceanic crust of the Pacific Plate is subducting beneath oceanic crust of the Indo-Australian Plate.
Although shallower than the trenches north of it, the Hikurangi Trench reaches depths of 3,000 metres as close as 80 kilometres from shore. Its maximum depth is about 3,750 metres (12,300 ft).At the southern end of the trench, off the coast of the Marlborough region, the seabed rises sharply, and because of the prevailing winds and tides in this area, many deep water species are found close to the shore. This food source attracts the whales for which the town of Kaikoura is famous.
The plate boundary continues inland along the Marlborough Fault System, linking through to the Alpine Fault. Here the plates converge much more obliquely, exhibiting transpression instead of subduction.Kenn Plateau
The Kenn Plateau is a large piece of submerged continental crust off northeastern Australia that rifted from northeastern Australia about 63-52 mya, along with other nearby parts of the Zealandia continent.Louisiade Plateau
The Louisiade Plateau is a poorly studied oceanic plateau in the northern Coral Sea of the South Pacific Ocean. It has been described as a continental fragment that rifted away from the northwestern continental margin of Australia but its position at the northern end of the Tasmantid Seamount Chain also suggests that the Louisiade Plateau might be a large igneous province formed by the arrival of the Tasmantid hotspot.Maari oil field
The Maari oilfield is an oil reservoir located 80 kilometres (50 mi) off the coast of South Taranaki, New Zealand. Maari is the second largest crude oil field in New Zealand with total reserves of 49 million barrels (7.8×10^6 m3). Production of oil began in February 2009, and the field is expected to have a productive life of 10 to 15 years. The lead partner for the field is OMV New Zealand (69%), with other parties Horizon Oil (26%) and Cue Taranaki (5%).Macquarie Fault Zone
The Macquarie Fault Zone is a major right lateral-moving transform fault along the seafloor of the south Pacific Ocean which runs from New Zealand southwestward to the Macquarie Triple Junction. It is also the tectonic plate boundary between the Indo-Australian Plate to the northwest and the Pacific Plate to the southeast.
The Macquarie Fault Zone includes a component of convergence which increases as it approaches the South Island of New Zealand. Many researchers conclude that the fault zone here is an incipient subduction zone, with oblique motion corresponding to the transition from lateral (strike-slip) motion. In the area known as the Puysegur Trench, the Indo-Australian Plate appears to be starting to sink beneath the Pacific Plate, the reverse of what is occurring off of New Zealand's North Island (see Kermadec-Tonga Subduction Zone).
A major geographic feature which runs along the Macquarie Fault Zone is known as the Macquarie Ridge. This ridge represents both the different relative heights of the abutting plates as well as the component of compression between the plates. The namesake Macquarie Island, named after Lachlan Macquarie lies atop a segment of the Macquarie Ridge.
The Macquarie Fault Zone merges into the Alpine Fault which cuts across the continental crust of New Zealand's South Island.Norfolk Ridge
The Norfolk Ridge is a long submarine ridge running between New Caledonia and New Zealand, about 1300 km off the east-coast of Australia.
It is part of a complex region of ridges between the crust of the Pacific Basin and the continental crust of Australia. Little is known about the Norfolk Ridge; however, it generally lies about 2000 m below sea level and consists of Late Cretaceous continental crust. It is part of Zealandia, a submerged continent that sank 60-85 million years ago.Pohokura field
The Pohokura field is an oil and gas field located 4 km offshore of north Taranaki in New Zealand, in approximately 30 m of water. The field was discovered in 2000 by Fletcher Challenge and has ultimate recoverable reserves (1P) of 1,227 Bcf (1435 PJ) of gas and 61 mmbbls of oil and condensate.The field has 6 offshore and 3 onshore wells, with the production station located on shore, adjacent to the Motunui methanol plant. The production station is unmanned, and is operated from a control room in New Plymouth. The first commercial production was in September 2006.
In 2009, Pohokura was the largest gas-producing field in New Zealand, producing 42% of total production.Pohokura is owned by OMV (74%) and Todd Energy (26%), and is operated by OMV.Puysegur Trench
The 6,300-metre (20,700 ft) deep Puysegur Trench is a deep cleft in the floor of the south Tasman Sea formed by the subduction of the Indo-Australian Plate under the Pacific Plate to the south of New Zealand. Immediately to its east lies a ridge, a northern extension of the Macquarie Ridge, which separates the Puysegur Trench from the Solander Trough. To the west is the expanse of the Tasman Basin, which stretches most of the distance to Australia. To the north of the trench lies the Fiordland Basin, which can be considered an extension of the trench. The Puysegur Trench mirrors the Kermadec Trench and Tonga Trench north of New Zealand.
The Puysegur Trench stretches for over 800 kilometres south from the southwesternmost point of the South Island's coast, its southernmost extent being 400 kilometres due west of the Auckland Islands. It is named after Puysegur Point.Tasman Seamounts
Tasman Seamounts may refer to:
Tasmantid Seamount ChainTasmantid hotspot
The Tasmantid hotspot is a volcanic hotspot located in the South Pacific Ocean. Due to plate tectonics the hotspot was under different parts of the seabed in the past. It was initially centered under what is now the southern Coral Sea 60 million years ago where the first Tasmantid volcano was created. As the Indo-Australian Plate continued to drift northwards the hotspot was positioned in the northern Tasman Sea 20 million years ago, eventually reaching its current location east of Tasmania in response to ongoing northward plate motion.The northward movement of the Indo-Australian Plate over the last 60 million years coupled with volcanism of the Tasmantid hotspot has resulted in a north-south line of submarine volcanoes called the Tasmantid Seamount Chain. This includes over 10 seamounts, the youngest of which is the seven million year old Gascoyne Seamount. The Tasmantid hotspot is now 400 km (250 mi) south of Gascoyne Seamount and is defined by a prominent zone of seismic activity.The Tasmantid hotspot may have created the Louisiade Plateau, a supposed large igneous province at the northern end of the Tasmantid Seamount Chain.Wanganui Basin
The Wanganui Basin (also spelled Whanganui Basin) is an onshore-offshore basin on the North Island of New Zealand. The basin provides an important stratigraphic and palaeontological record for the late Neogene marine environment of New Zealand.