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Re:Africa 'witnessing birth of a new ocean' (2010) by btilly on Wednesday January 11, 2017 @07:13PM (#13378739)
The Earth has a continental drift cycle where we form a supercontinent, which changes the circulation pattern, the supercontinent breaks up, the pieces drift around the world, and then recombine into a supercontinent again.

The last supercontinent was Pangea Asia, Europe and Africa are what is left and they are continuing to break up. The next one will meet where the Pacific plate now is.

So this starts as a rift, then a valley, then an inlet, then that will widen into an ocean, and then the barriers between oceans will disappear.

So yes, this will be a sea before it is an ocean. But it is also correct to talk about it as the birth of a new ocean. (The Red Sea is also on its way to being an ocean. It is just farther along. And the Atlantic is farther along still.)

Re:Africa 'witnessing birth of a new ocean' (2010) by hyperpallium on Wednesday January 11, 2017 @09:07PM (#13379303)
Is there evidence for continent/ocean placement affecting convection currents in the mantle (and thus plate movements)?

Is there evidence for any changes in convection currents?

i.e. what do we have to go on, besides back-extrapolation of observed drift (happening today, and in "recent" geologic past, e.g. reversal of magnetized direction)?

Why should the continents recombine into a supercontinent, rather that drift arbitrarily? Is the idea that, sooner or later, a traffic jam will occur, where first two bang into each other and can't move, creating a larger obstacle, which another then collides with... but since there's some process for a supercontinent to separate, what's the neccessity for this process to not tear apart the collided continents before a full supercontinent is formed?

Re:Africa 'witnessing birth of a new ocean' (2010) by samplatt on Wednesday January 11, 2017 @08:16PM (#13379094)
Isn't it a bit early to be calling it a cycle? I mean, we've not even completed one full iteration yet.

Unless I'm wrong, and the tectonic plates existed and were moving long before the oceans did?

Re:Africa 'witnessing birth of a new ocean' (2010) by bcraven on Thursday January 12, 2017 @04:48AM (#13381074)
No we have plenty of evidence of previous cycles. It's called the Wilson Cycle:

http://csmres.jmu.edu/geollab/Fichter/Wilson/Wilson.html

For further reading I can recommend 'Supercontinent' by Ted Nield.

Re:Africa 'witnessing birth of a new ocean' (2010) by Tushon on Wednesday January 11, 2017 @08:37PM (#13379179)
One full iteration of continent formation and breaking up?

https://en.wikipedia.org/wiki/List_of_supercontinents#Prehis...

Seems to indicate otherwise, but I'm certainly no expert on geology or whatever sub-specialization is concerned with plate tectonics and history of them.

Re:Africa 'witnessing birth of a new ocean' (2010) by sjwright on Thursday January 12, 2017 @01:55AM (#13380321)
By that logic, it's a bit early to conclude that Pluto orbits the sun. We haven't even seen it go half way around yet.
Re:Africa 'witnessing birth of a new ocean' (2010) by FreeFull on Wednesday January 11, 2017 @08:35PM (#13379171)
The cycle has already completed many times. At all points there were oceans somewhere, it's not like the water materialised out of nowhere recently.