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Tom Mazanec
2019-Jan-07, 11:53 AM
Dougal Dixon's After Man has some 50 Million AD volcanic islands that allow interesting species to evolve.
The Islands of Batavia (pp 108-109) form in the Pacific when a new hotspot appears. The bats have greatly evolved, so they must have been there a long time. Where do hotspots originate? Could a new one appear in the near future, or are they primordial features of the planet?
The Islands of Pacaus (pp 110-111) are said to be 40 million years old, so appear about ten million years from now. They formed several thousand kilometers east of Australia by friction between the northward-moving Australian plate and the westward-moving Pacific plate. Is this the correct way such plates interact?
How plausible are Dixon's volcanoes?

Eclogite
2019-Jan-07, 12:34 PM
Dougal Dixon's After Man has some 50 Million AD volcanic islands that allow interesting species to evolve.
The Islands of Batavia (pp 108-109) form in the Pacific when a new hotspot appears. The bats have greatly evolved, so they must have been there a long time. Where do hotspots originate? Could a new one appear in the near future, or are they primordial features of the planet?
This has been a subject of some debate and my comments here may not accurately reflect the current consensus.

Many hotspots (some investigators say all hotspots) originate close to the core-mantle boundary. They are generally long lasting (many tens of millions of years), but new ones can arise from time to time.


The Islands of Pacaus (pp 110-111) are said to be 40 million years old, so appear about ten million years from now. They formed several thousand kilometers east of Australia by friction between the northward-moving Australian plate and the westward-moving Pacific plate. Is this the correct way such plates interact?
How plausible are Dixon's volcanoes?Friction has very little to do with the volcanic activity. Rather partial melting is promoted in the athenosphere as water (and other volatiles) are introduced from the descending oceanic plate at subduction zones.

Without seeing Dixon's detailed proposals it is impossible to know if he has presented a plausible arrangement. That said, it shouldn't be a difficult task, so - unless he is incompetent -he probably has it right.

Roger E. Moore
2019-Jan-07, 04:18 PM
It is my understanding that aside from hotspots generating new volcanos, superplumes from the mantle can create massive igneous provinces virtually anywhere, though more likely near the equator. We should count ourselves lucky for not having such a thing at present, as this type of event seems to provoke mass extinctions.

Swift
2019-Jan-07, 10:25 PM
I don't know the relative numbers, but I suspect that more volcanoes form at plate boundaries than at mid-plate hotspots, and so it would seem more likely that future volcanoes would form along them than at new hotspots.

Even if no new hotspots appear, in 50 million years the current ones (if still active) will form new islands. Hawaii's hotspot is moving 5 to 10 centimeters per year (LINK (https://en.wikipedia.org/wiki/Hawaii_hotspot)); that's 5000 miles in 50 million years (if I did my math right). There could be a lot of new islands by then.

Swift
2019-Jan-07, 10:29 PM
Here is one model (http://www.scotese.com/future.htm) of the world 50 million years in the future, given current movements of the plates.


If we continue present-day plate motions the Atlantic will widen, Africa will collide with Europe closing the Mediterranean, Australia will collide with S.E. Asia, and California will slide northward up the coast to Alaska.
I would think all of these changes will be a much greater driver of evolution than the formation of a few new volcanic islands.

Spacedude
2019-Jan-08, 04:11 AM
A nuke should do it, gun powder works too, but you have to journey to the center of the earth to set it off ;-)

eta --- oops. wrong volcano thread

Squink
2019-Jan-08, 07:13 AM
I don't know the relative numbers, but I suspect that more volcanoes form at plate boundaries than at mid-plate hotspots Basin and range topography far from plate edges produces a lot of volcanoes too.

Tom Mazanec
2019-Jan-08, 12:31 PM
Here is one model (http://www.scotese.com/future.htm) of the world 50 million years in the future, given current movements of the plates.


I would think all of these changes will be a much greater driver of evolution than the formation of a few new volcanic islands.

Actually, in the book they are.
He has "Lemuria" (East Africa) split off, but that map does not.
Predicting plate tectonics is like predicting the weather, I guess.

Roger E. Moore
2019-Jan-08, 02:57 PM
Actually, in the book they are.
He has "Lemuria" (East Africa) split off, but that map does not.
Predicting plate tectonics is like predicting the weather, I guess.

When it comes to publishing, there are two issues when drawing out a map of what the world will look like in XX million years. The first and obvious issue is the actual science behind plate movements, which directions and how fast and all that.

The second is copyright. You do not want YOUR map of Earth in 50 million years to be like anyone else's, because all published maps are copyrighted. Think of it as a cottage industry, like coming up with everyone who shot JFK: your theory, to be marketable, must be unique and copyrightable or else you: 1) won't earn anything from it, and 2) might have pay royalties to someone else if you use their concept without permission, just because it looked right to you.

When you draw out the placement of continents on the Earth, you realize you have a lot of wiggle room in which to place them. Continents can be thought of as moving like hurricane: they have pathways increasingly subject to random movement, so they could move in a vaguely western or southern or whatever direction, but you aren't going to know the exact location. This helps copyright. This is why there are many different versions of what the "next" proposed supercontinent will look like in 200 million years. "Mega-Pangaea" is marketable science. You come up with a good version, make sure it is not like anyone else's, then copyright it and publish it. Maybe you can get a TV series based on it, who knows.

I mean, Dixon's gotten book deals and TV deals and everything. Marketable science.

PaleoMap Project is the same way: http://www.scotese.com/license.htm

dgavin
2019-Jan-12, 07:15 AM
There does seem to be some indication that some hot spots, are generated when a plate, or part of one, has completely subducted and starts to fall towards the core inside the mantle. The Yellowstone, Newberry, Long valley hot spots all seem to share an origin about 17mil years ago, just a few million years after part of the Fallon (now called Juan de Fuca) plate broke off and slide into the mantle.