The Emerald Fracture Zone () is an undersea fracture zone running the distance from the southwest corner of the

Campbell Plateau 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 ...

to the northern tip of

Iselin Bank Iselin Bank () is a submarine bank in the Ross Sea The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its n ...

. The name was proposed by Dr. Steven C. Cande of the Scripps Institution of Oceanography for the vessel ''Emerald'', which traversed this region in 1821, and was approved by the

Advisory Committee for Undersea Features The United States Board on Geographic Names (BGN) is a federal body operating under the United States Secretary of the Interior. The purpose of the board is to establish and maintain uniform usage of geographic names throughout the federal govern ...

in June 1997. The Emerald Basin to its north west was named from the same source.NOAA gazetteer:Emerald
/ref> Some have restricted the name to the southern east west orientated transform fault zone but the north south orientated faults that define the eastern boundary of the Emerald Basin are generally included in the literature.

Geology

The latest reinterpretation of the ocean floor geology of the region based on magnetic data assigns the area of the fault zone to oceanic crust of

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

age and so would distinguish other north south fault zones in the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

oceanic crust to the south east of the Campbell Plateau. The fracture zone is related to the Hjort Trench that represents the southern end of the

Australian Plate The Australian Plate is a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately when India broke ...

and Pacific Plate convergence, contains the

Macquarie Triple Junction The Macquarie Triple Junction is a geologically active tectonic boundary located at at which the Indo-Australian Plate, Pacific Plate, and Antarctic Plate collide and interact. The term Triple Junction is given to particular tectonic boundaries ...

at its south western margin and mainly acts as a leaky transform fault zone between the

Antarctic Plate The Antarctic Plate is a tectonic plate containing the continent of Antarctica, the Kerguelen Plateau, and some remote islands in the Southern Ocean and other surrounding oceans. After breakup from Gondwana (the southern part of the superconti ...

and Pacific Plate. It has only moderate current seismic activity. An example was the event of 9 June 2023.

Tectonics

The clockwise rotation of the Pacific Plate and

between 12 and 10 million years ago resulted in fragmentation of the long-offset Emerald transform fault and its replacement over less than 2 million years with closely spaced, highly variable transform offsets that were joined by short ridge segments. There was asymmetrical spreading rates in the area of the leaky transform fault zone near the Macquarie Triple Junction.

References

Geology of the Southern Ocean Ross Dependency {{marine-geo-stub

Geology

Tectonics

See Also

References