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Could a continent roughly the size of Europe, Africa and North-America combined be formed almost entirely due to volcanic action?

enter image description here Something with a similar formation to this.

From a chain of volcanoes the size of Yellowstone maybe? Sprouting over a platformy/plate thingy (can't remember how it's called right now) already in existence.

the volcanoes do not need to be active. Actually they need to be old enough to not be active.

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    $\begingroup$ Quick answer, no. $\endgroup$ – AngelPray Sep 24 '17 at 14:09
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    $\begingroup$ Continents are not formed by volcanic action. Basically, continents are areas of continental crust which are above sea level. (There are "submerged continents", areas of continental crust which are under the sea; see Zealandia.) Continental crust and oceanic crust are qualitatively different. Volcanoes do not enter the equation. $\endgroup$ – AlexP Sep 24 '17 at 14:23
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    $\begingroup$ Not related to the actual question, but I don't understand the letters at your graphic. If those are supposed to be compass directions, i.e. surrounding a south polar region, then this is not how east and west work. (All directions away from the south pole are north, east and west are ↻ and ↺.) $\endgroup$ – Paŭlo Ebermann Sep 24 '17 at 19:41
  • $\begingroup$ @PaŭloEbermann ? $\endgroup$ – shieldedtulip Sep 24 '17 at 19:47
  • $\begingroup$ @shieldedtulip East and West are relative. There is no east pole or west pole of the earth. There is no East side or West side of the earth. There is no eastern hemisphere or western hemisphere, the way there is a northern or southern hemisphere. If you are in China, east is still in the same direction it is if you are in America. So to say 'up' and 'down' on the map are 'north', but 'right' is east and 'left' is west, is interesting. $\endgroup$ – Justin Thyme Sep 24 '17 at 20:33
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Short answer no, long answer maybe you could create that much landmass but it probably wouldn't be contiguous, also the continent kind of has to be there already. Take a very large, shallow sea, thousands of square kilometers in all, add 2500 cubic kilometers of ash and debris (roughly what erupted from Yellowstone 2.1 million years ago) it's going to be a more or less circular distribution slightly distorted by prevailing winds and thickest in the centre. There would by definition have to be continental crust under the sea in the first place or it wouldn't be shallow enough for the ash and debris to raise the surface above sea level, a bit like New Zealand's underwater continent; the huge area of continental rock out to the East of the South Island.

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    $\begingroup$ That's what I am trying to ask about. I have an old continent, the center of it needs to have a crater or set of craters, need to be sort of rounded in shape (all the craters together). The continent does have quite a few volcanoes but not all of them are active. $\endgroup$ – shieldedtulip Sep 24 '17 at 15:22
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    $\begingroup$ @shieldedtulip The word you're looking for is Caldera, it's a perfectly reasonable set up. $\endgroup$ – Ash Sep 25 '17 at 10:09
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Yes. And yes, there is an example in our solar system. It actually exists. Except that there are currently no oceans. But when there were, it would have been.

It's on mars.

The highest point was built by repeated eruptions of Olympus Mons, the largest volcano in our solar system. Although Mars is a smaller planet than Earth, the heights and depths of these features are enormous in comparison.

A volcanic mountain over 13 miles high. Does that qualify?

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  • $\begingroup$ And note the impact crater - 'Hellas Impact Crater (also known as Hellas Planitia) is an enormous impact crater in the southern hemisphere of Mars. It is about 2,300 kilometers (1,400 miles) in diameter and about 9 kilometers (5 miles) deep. It is the largest impact crater on the planet. NASA Image.'.. Big enough? Put them together, and I think you have your world. $\endgroup$ – Justin Thyme Sep 24 '17 at 16:05
  • $\begingroup$ How could I have forgotten Mars? Thank you. Any volcano on an earth-like planet, with greater gravity than Mars, would cause a similar formation, right? It would depend on the severity of the vulcanism not gravity. $\endgroup$ – shieldedtulip Sep 24 '17 at 16:14
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    $\begingroup$ But Olympus Mons is as large as it is because of no crustal drift on Mars, it seems. $\endgroup$ – shieldedtulip Sep 24 '17 at 16:25
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    $\begingroup$ Mars does not currently have plate tectonics. There is just one massive plate encompassing all of Mars. That is, all of Mars is just one continent. Same with the Moon. $\endgroup$ – Justin Thyme Sep 24 '17 at 16:34
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    $\begingroup$ For counting as a continent, the height is not that important, more the area or diameter. Olympus Mons has a diameter of 600 km (i.e. an area of < 300 000 km², which is still quite small for a continent (for comparison, the Indian subcontinent has an area of 4.4 millions km², which is 15 times that). $\endgroup$ – Paŭlo Ebermann Sep 24 '17 at 19:51
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A single volcano would definitely not suffice to create a continent of such a size. You would require a ring or chains of volcanoes to create a larger structure; you may look for example at japan for comparison of creating a larger archipel in such a way. Volcanic eruption in itself would however not be enough to create a whole continent, in particular not of the size you want. Without plate tectonics and large land masses pushing up the continental surface from underneath the sea level, the formation of such a large continent is impossible. You can compare the 'super-continent' Pangaea from earth's own history.

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  • $\begingroup$ So, not one volcano but several. No problem, got enough of those on my planet. But wouldn't, over time, several volcanoes erupting at the same time create enough surface/land? Let's say they are lined up nicely, and some gather around the largest one, wouldn't that help create land? I know plate tectonics are needed, but volcanoes make landmasses faster, don't they? $\endgroup$ – shieldedtulip Sep 24 '17 at 14:33
  • $\begingroup$ @shieldedtulip: Volcanoes make tiny landmasses, if they make any durable landmass at all. Look at Hawaii; it's the best you can hope to get from volcanoes. If Hawaii looks like a continent to you, then fine. Not to mention that areas of widespread volcanism tend to appear at the boundary between two tectonic plates... $\endgroup$ – AlexP Sep 24 '17 at 14:37
  • $\begingroup$ @AlexP sorry, not trying to be argumentative, just trying to get away from having to fiddle too much with my world. Which I guess I'll have to do. I wasn't discounting plate tectonics, just need a different landmass formation which would allow me to have a large, very large crater at the center of my continent. Or maybe a collection of craters looking something like this i.pinimg.com/736x/ce/97/b1/… Only larger. $\endgroup$ – shieldedtulip Sep 24 '17 at 14:52
  • $\begingroup$ Yellowstone is a large crater... The largest in the world. Formations like the one in your picture are inherently unstable; volcanic craters look like that only when they are very very young. You cannot really have a very very large active crater, because for a significant length of time after a super-eruption nothing much lives on a very large area around... $\endgroup$ – AlexP Sep 24 '17 at 15:03
  • $\begingroup$ Venus doesn't seem to have plate tectonics (though admittedly we don't know all that much about its geology), but has continent-like areas ("terras") of high elevation: sos.noaa.gov/datasets/venus-topography $\endgroup$ – jamesqf Sep 24 '17 at 18:07
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technically all continents were formed by volcanic activity in the planet's early history, of course the term volcano does not mean much wehn the entire planets surface was lava. But I assume you are talking about in modern times, in which case the answer is not without killing every living thing on the planet. The best you can manage is something the size of the deccan traps but you are still talking about a mass extinction event.

Yellowstone is a hotspot induced composite volcano these can only occur on an existing continent otherwise you end up with something like Hawaii which you can see is not enough to produce a continent. Even with multiple eruptions the biggest you can get is something like the deccan traps or possibly Iceland or Japan. Volcanoes are rather tiny compared to the continents.

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  • $\begingroup$ I need an old old continent. not new one. Just a very large caldera type thing, old enough (volcano/volcanic chain) to not be active, surrounded by more old volcanoes, some active some not, and a very large landmass. Would something like this be possible? $\endgroup$ – shieldedtulip Sep 24 '17 at 15:04
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Yes. It is perfectly possible. I can name an example. The Tharsis Bulge, which is the is the size of North America. The Tharsis Bulge is one giant volcano, in fact. The world would need to have little to none tectonic activity, like Mars, but its volcanic activity could be crazy high. These would be the type of continents to form on Bathypelagic(normal earth ocean depth) Oceanic worlds, as no tectonic activity is why Bathypelagic Oceanic worlds exist.

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