Is Zealandia Earth's 8th Continent?

how many continents does the earth have some might think this is an easy question but it might not be as simple as you think if you ask an American like me you'll probably get the answer of seven North America South America Europe Africa Asia and Australia oh yeah and Antarctica but ask a person from South America and they might say six America which is just one continent Europe Africa Asia Australia oh yeah and Antarctica then someone who knows a lot about geography might tell you that nothing really divides Europe and Asia so there are only five continents America not mine but Eurasia Africa Australia oh yeah and Antarctica and technically before the Suez Canal was Doug Africa and Eurasia were connected by land as well so some people like to say that there are only four continents America afro-eurasia Australia oh yeah and Antarctica but then there are some who would argue that all of these have still left out a continent the eighth continent the continent of Zealandia within the Pacific Ocean lies a scrap of continental crust that has raised more than one kilometer higher than the surrounding oceanic crust and is geologically distinct from any and all surrounding bodies completely separated from Australia by the Quito trough it's nearly five million square kilometres an area which means it's nearly two times larger than Greenland and nearly two thirds the size of its neighbor Australia and while that might look like it's covered in water well it is but it's not made of oceanic crust it's made up of continental crust - the same thing you and I are sitting on right now the only problem is that today out of those five million square kilometres of continental crust 94% of it lies beneath sea level and only the continents highest mountains remain above the ocean which formed the islands of New Zealand and New Caledonia in all there's only around 350,000 square kilometers of Zealandia above sea level today that's less area than the US state of Montana but it wasn't always this way for millions of years Earth's land surface was split between two major land masses Gondwana and Laurasia the fragments of the greater Pangaea Zealandia was part of Gondwana and made up roughly 5% of the super in total land area then has Gondwana began to break apart to become modern-day South America Africa India and Australia oh yeah and Antarctica Zealandia split away as well but as these continents moved apart some of them like South America and Africa were pushed against themselves so they became more narrow but also taller then the opposite happened for the other landmasses so Antarctica and Zealandia were stretched longer making them thinner kinda like stretching a rubber band because it was made thinner than the rest of the continents as the Landy afloat slower in the Earth's molten mantle just beneath modern sea levels but this means there was a time around 180 million years ago just when Gondwana was beginning to break apart that Zealandia was in its full form and proper height above the oceans 55 million years after it split from Australia however Zealandia had become almost completely submerged because of this a lot of people dismissed Zealandia as a true continent despite it being a huge piece of continental crust so let's take a look at what the criteria is in order to be considered a continent and see if Zealandia qualifies while it might seem easiest to look at tectonic plates of the earth to decide our continents and oceans a second look reveals this to not be very helpful at all some plates contain large portions of both land and ocean like the South American plate which is over 50% submerged and also there are a number of smaller plates that none of us would consider to be full continents like the Caribbean Nazca or Juan de Fuca plate so we need to look somewhere else to find what a continent truly is the idea for Zealandia was first introduced in 1995 by Bruce Lyon Dyck and was expanded upon by Nick Mortimer and his team of researchers in a paper titled Zealandia Earth's hidden continent which was going to be the name of this video until I decided to try to be a little more original than that but in this paper the basic outline of what constitutes a continent is given first is that a continent must have an elevation above that of the ocean floor surrounding it a quick look at any ocean floor elevation map will show Zealandia shape rising more than a kilometer over the surrounding ocean so on that point Zealandia gets an e-zpass second is more a geological rule saying the crust of the continent must contain a wide range of igneous sedimentary and Men morphic Rock this is to keep Islands and oceanic plates out of the running things like volcanic islands are basically all igneous rock and ocean crusts are usually mostly basalt another igneous rock so they're both disqualified rock samples from the sunken continent revealed plenty of variation in rock types so Zealandia gets another pass third the continent must be thicker and less dense than oceanic crust and therefore have a lower seismic velocity as we've seen while the crust making up Zealandia is thinner than other continents it's still noticeably thicker than the surrounding post annika crust because of its geological makeup we just talked about it's also less dense than oceanic crust so again pass the fourth and last criteria is the continent must have a well-defined extent that is large enough to qualify it as a continent rather than a micro continent or continental fragment an example of a micro continent would be the island of Madagascar off the coast of Africa still very large but not quite large enough and this is where I run into a little trouble because well what exactly qualifies as continent size well let's take a look Australia is the smallest quote/unquote official continent at seven million six hundred ninety-two thousand square kilometers so any and all land masses bigger would definitely be a continent then the biggest island would be Greenland at two million one hundred and sixty six thousand square kilometers anything smaller would definitely not be a continent but rather another Island but Zealandia falls somewhere in the middle bigger than the biggest island but smaller than the smallest continent this sets up an interesting question does a landmass only have to be bigger than Greenland to be a continent or greater than or equal to Australia to be a continent bigger than two million square kilometers or bigger than eight we've never needed a more exact definition because no land masses between these two sizes exist today although in prehistoric times the earth was littered with them like India and Arabia Nick Mortimer's paper offers 1 million square kilometers as a possible cutoff which would also qualify Greenland as its own continent so I don't like it plus this number is rather arbitrary with essentially zero geological basis why 1 million 1,000,001 why not 999 thousand and so on even more people dismiss this claim however based on the sole fact that while yes the entire shelf comes in at nearly 5 million square kilometers most definitions of continent includes something along the lines of massive expanse of land of which is the land iya has very little but the proponents of Zealandia argue that if we studied earth and its continents like we do for other planets ignoring surface liquid Zealandia status as a bonafide continent would become apparent because it's still so much higher than the surrounding ocean crust I think the overarching issue is that we don't really have a good definition of what makes a continent a continent and this is because well they're kind of made up we invented the idea long ago when earth was just land and sea with nothing in between but now we have zeal and zeal and Zealandia boom got it and that's why no one today can agree on what exactly a continent is or even how many of them we have so what do you think should Zealandia be considered earth's eighth continent and exactly how many continents do you think there are let me know in the comments and if you liked this video and want to see more hey how about liking and subscribing to this channel I'll be back next week with another video thanks [Music]

Channel: Atlas Pro

Views: 1,033,464

Rating: 4.8310161 out of 5

Keywords: education, geography, science, Zealandia, New Zealand, Zeeland, Zeelandia, Australia, pacific ocean, plate tectonics, pacific, lost continent, lost city, atlantis, zelandia, tasmantis, tazmantis, tasmania, new zealandia, geology, continent, contenent, zealandis, new continent, atlas pro

Id: _qepWb_NVj4

Length: 7min 40sec (460 seconds)

Published: Wed Aug 01 2018

Reddit Comments

[u/Below_The_Roots]

I consider it a part of the Australian continent, as Greenland is part of the North American continent. The Havre Trough isn't enough of a separation in its northern area to properly separate the land masses, just as the Davis Straight/Bafins Bay aren't enough to separate Greenland. Same tectonic plate, same continent. In the (geologic) future, Zealandia will likely become it's own continent, and if/when it does I support the name Tazmantis. As far as North and South America, yeah two. The real are they separate continents question is North America and Eurasia, not a lot of oceanic crust in the Bering Sea. Geologically they were separate but now aren't. Long answer short: Geographically, which considers both physiographic and cultural elements and doesn't really give a rat's ass about that bathymetry or rock composition, there are 7; South America, Europe, Asia, Africa, Australia, and Antarctica. A good case can be made for six, and I tend to lean this way. Geologically it is much more useful to talk about tectonic plates, but for the sake of argument, there are 5 "continents"; North America-Eurasia, South America, Africa, Australia, and Antarctica

[u/caelankelley]

Okay so I'm posting this because i'm curious what the Geology community thinks. I posted this video in r/geography and the answer I got was a resounding NO, but then I posted it in r/newzealand and got a resounding IT'S A SCIENTIFIC FACT. So now I've been made curious, what do geologists think of Zealandia? Yea or Nay?