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| Mortimer, Nick; Campbell, Hamish J.; Tulloch, Andy J.; King, Peter R.; Stagpoole, Vaughan M.; Wood, Ray A.; Rattenbury, Mark S.; Sutherland, Rupert; Adams, Chris J.; Collot, Julien; Seton, Maria. |
| A 4.9 Mkm2 region of the southwest Pacific Ocean is made up of continental crust. The region has elevated bathymetry relative to surrounding oceanic crust, diverse and silica-rich rocks, and relatively thick and low-velocity crustal structure. Its isolation from Australia and large area support its definition as a continent— Zealandia. Zealandia was formerly part of Gondwana. Today it is 94% submerged, mainly as a result of widespread Late Cretaceous crustal thinning preceding supercontinent breakup and consequent isostatic balance. The identification of Zealandia as a geological continent, rather than a collection of continental islands, fragments, and slices, more correctly represents the geology of this part of Earth. Zealandia provides a fresh context... |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00489/60035/63303.pdf |
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| Patriat, Martin; Collot, Julien; Etienne, Samuel; Poli, Sara; Clerc, Camille; Mortimer, Nick; Pattier, France; Juan, Caroline; Roest, Walter. |
| One of the largest ophiolitic peridotite masses in the world covers a quarter of the island of Grande Terre, New Caledonia. The Peridotite Nappe was obducted during the Eocene, is weakly deformed and corresponds to the highest of a structurally simple pile of thrust nappes. We present new marine seismic data that allows us to track the offshore continuation of the Peridotite Nappe along‐strike for a distance of more than 500 km south of New Caledonia, and to image its pre‐, syn‐ and post‐obduction sedimentary records. Offshore, the Peridotite Nappe underlies a c. 150‐km wide and 2 km‐deep basin. Flat‐topped horsts of peridotite are clearly bounded by major normal faults; in contrast faults are obscure onland. To the east, the Peridotite Nappe roots along... |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00431/54242/55568.pdf |
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| Mortimer, Nick; Patriat, Martin. |
| VESPA was a successful 25 day research cruise on R/V l'Atalante that took place in May and June 2015. The main aim was to acquire new rock samples from extinct volcanoes on the Norfolk, Loyalty and Three Kings ridges, which connect New Caledonia and New Zealand. This was in order to test various hypotheses of Late Cretaceous-Miocene SW Pacific tectonic development relating to (i) nature and duration of magmatism on the ridges; (ii) timing of subduction initiation east of northern Zealandia; (iii) postulated subduction polarity changes. A total of 3400 km of 'sismique rapide' shallow reflection seismic data were acquired and processed onboard. The seismic lines provided a very useful structural-stratigraphic framework for the rock dredging. Combined with... |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00343/45408/44923.pdf |
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| Sutherland, Rupert; Collot, Julien; Lafoy, Yves; Logan, Graham A.; Hackney, Ron; Stagpoole, Vaughan; Uruski, Chris; Hashimoto, Takehiko; Higgins, Karen; Herzer, Richard H.; Wood, Ray; Mortimer, Nick; Rollet, Nadege. |
| We use seismic reflection and rock sample data to propose that the first-order physiography of New Caledonia Trough and Norfolk Ridge formed in Eocene and Oligocene time and was associated with the onset of subduction and back-arc spreading at the Australia-Pacific plate boundary. Our tectonic model involves an initial Cretaceous rift that is strongly modified by Cenozoic subduction initiation. Hence, we are able to explain (1) complex sedimentary basins of inferred Mesozoic age; (2) a prominent unconformity and onlap surface of middle Eocene to early Miocene age at the base of flat-lying sediments beneath the axis of New Caledonia Trough; (3) gently dipping, variable thickness, and locally deformed Late Cretaceous strata along the margins of the trough;... |
| Tipo: Text |
Palavras-chave: Norfolk ridge system; Back arc extension; New zealand region; South fiji basin; Sw pacific; Northland plateau; Tasman sea; Seismic stratigraphy; Geodynamic ecolution; Tectonic evolution. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00001/11271/9283.pdf |
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