Deep oceanic basin in the southwestern Pacific Ocean
Fiji
Lau Basin
Tonga- Kermadec Ridge
Lau- Colville Ridge
Tonga Trench
Kermadec Trench
Osbourn Trough
Louisville
Seamount
Chain
Hikurangi
Trough
Wish- bone scarp
New Zealand
The major geological relationships of the Osbourn Trough. It defines with the Louisville Ridge intersection the Tonga Trench (violet) to the north and the Kermadec Trench (violet) to the south. Blue represents ocean depths of a kilometer or so and brown shades are shallower. Land is shown in dark green. The black line delineates the continent of Zealandia.
The Osbourn Trough, is a 900 km (560 mi)-long[1] extinct mid-ocean ridge, that may have stopped spreading as recently as 79 million years ago.[2] It is a west-to-east oriented sea floor feature, located to the east of the present Tonga-Kermadec Ridge where the present Pacific Plate is under going subduction under a micro-plate of the Australian Plate. The Osbourn Trough is key to understanding the postulated breakup mechanism of the historic massive Ontong Java-Manihiki-Hikurangi large igneous province (LIP),[1] as it has been shown to be the spreading centre that lead to the separation of the Manihiki Plateau to its north and the Hikurangi Plateau to its south close to New Zealand.[3]
^ abWorthington et al. 2006, Abstract
^van de Lagemaat et al. 2023, Section 5.1. Dating the end of convergence across the Gondwana margins
^Downey et al. 2007, Sections: Abstract, Conclusion
Trench Kermadec Trench OsbournTrough Louisville Seamount Chain Hikurangi Trough Wish- bone scarp New Zealand The OsbournTrough, is a 900 km (560 mi)-long...
block. Spreading along the Pacific-Phoenix ridge ended 83 Ma at the OsbournTrough at the Tonga-Kermadec Trench. During the Permian, atolls developed near...
Hekinian; Peter Stoffers; Thomas Kuhn; Folkmar Hauff (30 May 2006). "OsbournTrough: Structure, geochemistry and implications of a mid-Cretaceous paleospreading...
scarp Tonga Trench OsbournTrough Kermadec Trench Hikurangi Plateau Chatham Rise The oldest volcanic rocks of the chain come from Osbourn Seamount at 78...
margin, the Manihiki Scarp, and separated Manihiki and Hikurangi. The OsbournTrough is an abandoned spreading centre between Manihiki and Hikurangi. In...
current best fit Pacific Plate reference frame tectonics model where the OsbournTrough is modelled as a spreading centre between the Manihiki Plate and the...
Louisville Ridge – A chain of over 70 seamounts in the Southwest Pacific Ocean Osbourn Seamount – The westernmost and oldest non-subducted seamount of the Louisville...
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