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Topic: Zealandia: Earth’s Hidden Continent (Read 236 times) previous topic - next topic

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  • osmanthus
  • Administrator
  • Fingerer of piglets
Zealandia: Earth’s Hidden Continent
Nice little paper just out on GSA. Very easy reading, and very interesting.

Zealandia: Earth's Hidden Continent

Quote from: Abstract
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 in which to investigate processes of continental rifting, thinning, and breakup.
The paper goes into why they've decided it's a genuine continent, and they appear to have a very good case. Check it out. :)
Truth is out of style

Re: Zealandia: Earth’s Hidden Continent
Reply #1
Cool. Bookmarked for later.

Re: Zealandia: Earth’s Hidden Continent
Reply #2
I thought Australia was Earth's hidden continent.

  • osmanthus
  • Administrator
  • Fingerer of piglets
Re: Zealandia: Earth’s Hidden Continent
Reply #3
This one is even sneakier.
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  • MikeS
Re: Zealandia: Earth’s Hidden Continent
Reply #4
This will just inflate the ego of kiwis.

  • osmanthus
  • Administrator
  • Fingerer of piglets
Re: Zealandia: Earth’s Hidden Continent
Reply #5
They do seem to be quite pleased with themselves at the moment, judging by a few comments I've seen around the traps. :grin:
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  • nostrum
  • easily led
Re: Zealandia: Earth’s Hidden Continent
Reply #6
is this like Pluto all over again

  • MSG
Re: Zealandia: Earth’s Hidden Continent
Reply #7
Nice little paper just out on GSA. Very easy reading, and very interesting.

Zealandia: Earth's Hidden Continent

Quote from: Abstract
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 in which to investigate processes of continental rifting, thinning, and breakup.
As I commented when this was first reported a year or two back - only 6% to go
braying among the ruins

  • osmanthus
  • Administrator
  • Fingerer of piglets
Re: Zealandia: Earth’s Hidden Continent
Reply #8
is this like Pluto all over again
Sort of, but the other way around. I can see people having great fun arguing this both ways for ages. In terms of the geology the paper makes a very good case.
Truth is out of style

  • osmanthus
  • Administrator
  • Fingerer of piglets
Re: Zealandia: Earth’s Hidden Continent
Reply #9
Nice little paper just out on GSA. Very easy reading, and very interesting.

Zealandia: Earth's Hidden Continent

Quote from: Abstract
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 in which to investigate processes of continental rifting, thinning, and breakup.
As I commented when this was first reported a year or two back - only 6% to go
Then we can put them on our rugby team, and be invincible.
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  • MSG
Re: Zealandia: Earth’s Hidden Continent
Reply #10
Why would you bother
braying among the ruins

  • osmanthus
  • Administrator
  • Fingerer of piglets
Re: Zealandia: Earth’s Hidden Continent
Reply #11
Some people are into rugby, and the Kiwis love it when they beat us, so making them join our team would be the ultimate humiliation.
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  • F X
  • The one and only
Re: Zealandia: Earth’s Hidden Continent
Reply #12
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

  • osmanthus
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  • Fingerer of piglets
Re: Zealandia: Earth’s Hidden Continent
Reply #13
Truth is out of style

  • osmanthus
  • Administrator
  • Fingerer of piglets
Re: Zealandia: Earth’s Hidden Continent
Reply #14
And first suggested in 1995.
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  • Martin.au
  • Thingyologist
Re: Zealandia: Earth’s Hidden Continent
Reply #15
Waits for New Zealand to claim Norfolk and Lord Howe islands. :)
"That which can be asserted with evidence can also be dismissed without evidence." (Dave Hawkins)

  • MSG
Re: Zealandia: Earth’s Hidden Continent
Reply #16
Norfolk Island is a part of New Zealand in biodiversity terms
braying among the ruins

  • osmanthus
  • Administrator
  • Fingerer of piglets
Re: Zealandia: Earth’s Hidden Continent
Reply #17
Hey there's some weird shit going on here. Check the picture.



So the edges of Orstrylya and Kiwilantis are almost touching at the Cato Trough. Yet further south there is a huge gap, getting on for around 1500 km down near Tassie. And originally the two were attached to each other down the Oz east coast.

So the gap is genuine sea floor basalt, which had to come out of a hole in the ground, which implies an active plate boundary, which aint there any more.

Not only that, but when it was spreading it obviously didn't spread at the Cato Trough. That bit stayed put and the rest scarpered. Which means Kiwilantis has either been sheared diagonally, or rotated a heck of a lot relative to Hansonistan, or both. All of this happening before the current Australian/Pacific plate boundary showed up sometime in the Cenozoic.
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  • Martin.au
  • Thingyologist
Re: Zealandia: Earth’s Hidden Continent
Reply #18
This may help
Quote
The edges of Australia and Zealandia continental crust approach to within 25 km across the Cato Trough (Fig. 2). The Cato Trough is 3600 m deep and floored by oceanic crust (Gaina et al., 1998; Exon et al., 2006). The Australian and Zealandian COBs here coincide with, and have been created by, the Cato Fracture Zone along which there has been ~150 km of dextral strike slip movement, linking Paleogene spreading centers in the Tasman and Coral seas (Fig. 2; Gaina et al., 1998). This spatial and tectonic separation, along with intervening oceanic crust, means that the Zealandia continental crust is physically separate from that of Australia. If the Cato Trough did not exist, then the content of this paper would be describing the scientific advance that the Australian continent was 4.9 Mkm2 larger than previously thought.
"That which can be asserted with evidence can also be dismissed without evidence." (Dave Hawkins)

  • MikeS
Re: Zealandia: Earth’s Hidden Continent
Reply #19
Hey there's some weird shit going on here. Check the picture.

Spoiler (click to show/hide)
So the gap is genuine sea floor basalt, which had to come out of a hole in the ground, which implies an active plate boundary, which aint there any more.

Not only that, but when it was spreading it obviously didn't spread at the Cato Trough. That bit stayed put and the rest scarpered. Which means Kiwilantis has either been sheared diagonally, or rotated a heck of a lot relative to Hansonistan, or both. All of this happening before the current Australian/Pacific plate boundary showed up sometime in the Cenozoic.
The paper proposes a spreading center in that specific area between Ozzy and Kiwi.



Quote
The edges of Australia and Zealandia continental crust approach to within 25 km across the Cato Trough (Fig. 2). The Cato Trough is 3600 m deep and floored by oceanic crust (Gaina et al., 1998; Exon et al., 2006). The Australian and Zealandian COBs here coincide with, and have been created by, the Cato Fracture Zone along which there has been ~150 km of dextral strike slip movement, linking Paleogene spreading centers in the Tasman and Coral seas (Fig. 2; Gaina et al., 1998). This spatial and tectonic separation, along with intervening oceanic crust, means that the Zealandia continental crust is physically separate from that of Australia. If the Cato Trough did not exist, then the content of this paper would be describing the scientific advance that the Australian continent was 4.9 Mkm2 larger than previously thought.

Paleogene was 65mm to 25mm years ago.  So the spread center was probably inactivated and locked together by the increasing impact of the Pacific plate.

  • MikeS
Re: Zealandia: Earth’s Hidden Continent
Reply #20
Also, the Kiwi continent was basically part of the continental shelf of Australia/Antarctica during the Jurrasic.



ETA: So New Zealand was the result of the Pacific Plate eventually striking this continental body.  Similar to an island arc event without the slipping/sliding of the island chain.
  • Last Edit: September 28, 2017, 06:26:44 AM by MikeS

  • Martin.au
  • Thingyologist
Re: Zealandia: Earth’s Hidden Continent
Reply #21
Splitters!!!
"That which can be asserted with evidence can also be dismissed without evidence." (Dave Hawkins)

  • osmanthus
  • Administrator
  • Fingerer of piglets
Re: Zealandia: Earth’s Hidden Continent
Reply #22
Yes I get all of that. It's just odd that things effectively stayed locked at Cato, apart from a tiny bit of movement, while carrying on like a headless chook everywhere else.
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