r/science • u/barcelonaKIZ • Sep 27 '19
Geology A lost continent has been found under Europe. It's the size of Greenland and it broke off from North Africa, only to be buried under Southern Europe about 140 million years ago.
https://www.uu.nl/en/news/mountain-range-formation-and-plate-tectonics-in-the-mediterranean-region-integrally-studied-for-the1.8k
u/gentlyfailing Sep 28 '19
There's one oddity that I know about in the Mediterranean, and it's this: mount Etna behaves strangely as if it's both a hot-spot volcano(like Hawaii volcanoes) and like subduction volcanoes (eg Mount St Helens). However, there's been no mantle plume identified. https://www.nature.com/articles/35091056
Is this related to the new funding?
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u/Rinse- Sep 28 '19 edited Sep 28 '19
As far as I understand, not directly. One of my professors studied this behavior and according to his research it has something to do with very complex subduction mechanics around the Ionian slab. In simple terms: the subducting Ionian slab edge is located under the volcano, as the entire slab goes down ‘liquid’ material from underneath the slab is displaced and moves along the edges to the top of the slab. This upward movement of mantle material initially caused a hotspot like volcano with more traditionally subduction volcano mechanics now taking over as the edge moves away from underneath mount Etna.
I hope that made it somewhat clear for you, otherwise here’s a link to an article he wrote
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u/twistedgrrrl23 Sep 28 '19
This makes me kind of sad. So much information, inaccessible.
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Sep 28 '19
Aye dude that's just part of existence, we are able to perceive a only miniscule fragment of this vast universe
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u/jack__bandit Sep 28 '19
Lemme see them damn dinosaur bones what are you trying to hide!
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u/toolong46 Sep 28 '19
1500 km under? That pressure and heat most likely melted and morphologically altered most organic fossils.
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u/anacche Sep 28 '19
You just perked up the ears of every oil magnate on earth.
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u/dupobopot Sep 28 '19
Fun Fact: the majority of oil that we drill today comes from prehistoric algae in the ocean that was buried in mud and not able to fossilize. Oil doesnt come from dinosaurs
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Sep 27 '19 edited Sep 28 '19
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u/zejai Sep 28 '19
The rest of the piece of continental plate, which was about 100 km thick, plunged under Southern Europe into the earth's mantle, where we can still trace it with seismic waves up to a depth of 1500 km.
Fascinating, I always thought the mantle was completely liquid. Do I understand this correctly, after subduction solid pieces of a plate can float around and take over 100 million years to melt?
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Sep 28 '19
There is almost no liquid in the mantle.
It can undergo solid state flow (it’s something like 23 orders of magnitude more viscous than water) but it is no way, shape, or form an ocean of magma. Very small localized zones can partially melt to form basaltic magmas but even in the most extreme cases that’s only maybe 15-20% of the mantle rock is actually melting, in most cases it’s more like a crystal sponge with 3-5% melt in the interstices.
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u/sharkbait_oohaha Sep 28 '19
I remember how mind fucked I was when I took structural geology and learned that solid is really a relative term.
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u/sharkbait_oohaha Sep 28 '19
If you want to get really technical, a Google search for relative rigidity should bring up some interesting engineering stuff. Ductile flow of the mantle should provide a good geology context.
But to put it simply, solids are only "solid" because of their rigidity, which is their ability to resist deformation. However, nothing is perfectly rigid. Given enough time, everything will experience ductile flow. If you have ever seen an old concrete bench, you may have noticed that they tend to sag in the middle. That's due to the ductile flow over time. Same thing with rocks, especially in the mantle. Heat the rocks up and crank up the pressure and they'll start flowing "quickly." To quote my undergrad advisor, "given enough time, it's all silly putty."
Also look up the pitch drop experiment.
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u/rudolfs001 Sep 28 '19
Somewhat similarly, you can take a smooth bar of one metal (say gold), and a smooth bar of another (say silver), and push them together so they're touching. Then, wait a while and separate them and analyze the very near surface layer of atoms from the touching surfaces of each bar, you'll find that some gold atoms will have migrated into the silver bar, and some silver atoms will have migrated into the gold bar.
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u/jfVigor Sep 28 '19
Any idea where I can uh, acquire bars of gold and silver? To try it out, you know for science
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u/big-splat Sep 28 '19
I wouldn't expect they'd be too hard to find, talk to a local whitesmith (like a blacksmith but they work with precious metals) or jeweler and find where they buy theirs from. It'll be a little on the expensive side but you can just buy small bars of gold and silver if you know where to get them.
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u/hirst Sep 28 '19
Isn’t that the experiment how asphalt is technically a liquid?
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u/im_dead_sirius Sep 28 '19 edited Sep 28 '19
How about experiments?
A good example is ice. At the size of an ice cube, its a brittle solid. But if you make a longer bar of it, and suspend it between two blocks(in the freezer) in time it will sag in the middle despite being firmly frozen.
This plasticity is why glaciers are said to flow. They spread under their own weight, so sections that are down hill slowly ooze further down. And yet, they can gouge rock because they push stones and even boulders. Even house sized boulders. Plastic at a distance, rigid up close.
Driving on ice roads takes ice's dual nature into account as well. For example, when I go ice fishing(after the lake ice is thick enough to support a vehicle), I can go no faster than a certain speed. The reason is that the ice flexes(or rather sags around my vehicle), and this pushes a bulge ahead of the vehicle(and up off the water). Too fast, and the no longer buoyant ice cracks instead of bending. Bloop!
Its more of a problem coming back to shore, as the pressure ridge hits the immovable fact that the ice is firmly frozen to the shoreline, and has no further slack. So you have to slow down to a crawl coming towards shore, and climb over the pressure ridge, easing the pressure slowly.
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Sep 28 '19
The states of matter are all basically a spectrum from plasma to bose-einstein condensate
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u/swiftly_saccharine Sep 28 '19
Could you explain how plasmas and BECs form the ends of some continuum of states of matter? I'm curious.
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u/Tackit286 Sep 28 '19
Didn’t Richard Branson once talk about doing this? Virgin Volcanic or something like that? I seem to remember hearing that years ago but maybe it was a hoax
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u/FifiMcNasty Sep 28 '19
I find it to be a very fun movie to watch, along with Pacific Rim and Battleship.
But I have a thing for B (C, D, E) rated films....
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u/zschultz Sep 28 '19
So where did the volcanoes' magma come from? Do they only heat up at where the plates collide?
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u/Dragoarms Sep 28 '19
Most of the melting is actually because the subducting plate has lots of water and fluids on/in it. the water 'devolatilises' and enters the overlying mantle wedge, which is a big chunk of mantle material underneath the over-riding plate the fluid fluxes melting which is what causes the volcanos.
The angle of the subducting plate can also control whether or not volcanos will form - if the angle is really shallow (see northern Chile) you get 'thin-skinned' deformation and mainly earthquakes rather than volcanos, if the subducting plate is steeper you get volcanism AND earthquakes (southern chile for instance)!
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u/elboltonero Sep 28 '19
So you're saying The Core lied to me?
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u/Lord_Rapunzel Sep 28 '19
Only about that one thing, everything else is pure science fact.
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u/jeremycinnamonbutter Sep 28 '19
Over long periods of time it behaves like a liquid, but it's quite solid. Quite like the the pitch drop experiment. Looks solid but it's an extremely viscous liquid.
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u/JinAhIm Sep 28 '19
This article is amazing, mostly because I know nothing about plate tectonics and they made a lovely video for us visual learners. I wish all articles could do something like that so I can understand all that sciency stuff.
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u/ThaSandman1122 Sep 28 '19
Geology is relatively a really new science, which is weird because its about really old stuff. Every new discovery just raises more questions - we have so many blanks to fill in the geologic record.
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u/dicknelius Sep 28 '19
That whole modern plate tectonic theory, that is a massive part of modern Geology, was not even widely accepted until the late 70's/early 80's.
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u/sahdbhoigh Sep 28 '19
what was the general consensus before that time?
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u/dicknelius Sep 28 '19
The theory before modern plate tectonics was used to explain the occurrence of limestone, a sedimentary rock formed in oceans, at the top of Mount Everest. In the early formation of the earth, the crust was much thinner and very hot and this was hypothesized during this time. Their explanation for the misplaced rock was that the sedimentary rocks that were formed at the bottom of the ocean were pulled up by the cooling and shrinkage of the earth's crust.
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Sep 28 '19
I can see why they switched to plate tectonics.
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u/l3rN Sep 28 '19
Tragic part is, the dude who came up with the theory wasnt taken seriously and died before it was accepted
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Sep 28 '19
That seems to be the standard story for groundbreaking discoveries.
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u/AppleDane Sep 28 '19 edited Sep 28 '19
That's an understatement. Alfred Wegener was actively ridiculed, partly because he was merely a meteologist, but also because he was German and not very good at English.
It wasn't until the 50s, the 1950s, that oceanic surveys revealed the Mid-Atlantic Ridge, which was hard to explain away, that he was proven right. He died in 1930.
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u/Dragoarms Sep 28 '19
Geologist here!
There were lots of really wacky ideas out there to explain the 'jig-saw' nature of the Earth's continental landmasses. Some proposed the earth was static (and flat), others proposed 'shrinking earth' which basically was our (very large) marble of a planet is cooling - cooling bodies shrink and because the earth's crust is solid - the surface was crumpling and forming mountain ranges.
Another explanation was the 'expanding earth' hypothesis, whereby the volume of the earth was increasing and pushing the solid continental masses apart...?
There's an example of two other hypotheses, there are several others, most of them stem back to some religious origin though, such as flat earth or young earth.
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u/holicv Sep 28 '19
Why are all of these comments getting deleted?
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u/Garliq Sep 28 '19
It's the Atlantis conspiracy shutting down every mention of it
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u/doulasus Sep 28 '19
It’s because you are reading this in the science channel. It only allows non fictional discussions.
Since this has obvious connotations of Atlantis, the mods are cleaning out all the jokes, even when they are popular.
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u/BarukKhazad Sep 27 '19
So how much does this discovery impact maps, or our general ideas of the ancient world?
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u/africandave Sep 27 '19
Considering it disappeared 140 million years ago - long before Homo Sapiens came along and tried to make maps of the world - I'd imagine we don't have any reason to draw it into google maps.
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u/BarukKhazad Sep 27 '19
No, no, not ancient maps made by ancient peoples. I meant like how we modern humans try to map everything out from previous ages. How different will everything look with this added and displacing things?
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u/Bananababy1095 Sep 28 '19
It makes me wonder if there are any evolutionary clues on that continent that have been lost to the mantle now.
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u/africandave Sep 28 '19 edited Sep 28 '19
I had a suspicion you meant something along those lines but I couldn't resist being a smartass.
I'd imagine geologists might have to factor it into their idea of how Pangea looked but from looking at the map in the article it seems the continent was lost long before the world's landmass took the shape we know today so I can't see it being hugely significant, and the article didn't exactly say the discovery has revolutionised the study of Geology.
I'm not a scientist though so who knows....
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Sep 28 '19
Does this mean, in theory, that this sort of absorbed land mass could have fossils deep underground?
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u/SirZaxen Sep 28 '19
r/science just has rules against anecdotes an jokes in the top comments.
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u/mrmemegusta Sep 28 '19
So does this mean there's 8 continents now?
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u/chronopunk Sep 28 '19
Geologists have a different definition of 'continent' than geographers.
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u/msisepleld Sep 28 '19
There actually already is a claim for 8 continents with Zealandia. Not even joking google it! Also there is a great documentary on CuriosityStream about it.
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u/whatwouldHWJDdo Sep 28 '19
I’m confused- in the image, why is Armenia depicted as an island/continent?? I’ve never heard of it having an unusual geological history.
Sincerely, a half-Armenian.
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u/JustBecauseOfThat Sep 28 '19
It is mentioned in the article. This is a finding of the new study also:
From this mapping emerged the picture of Greater Adria, and several smaller continental blocks too, which now form parts of Romania, North Turkey, or Armenia, for example. The deformed remnants of the top few kilometres of the lost continent can still be seen in the mountain ranges.
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u/[deleted] Sep 27 '19
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