Looking for advice on tectonics (early WIP)

[MrBragg]

Apologies in advance for what may very well be a crime against geology, but I was hoping I might be able to get some feedback from you all on my first stab at breaking up a supercontinent. Basically, what I've done so far is determine a rough idea of where I want my present-day continents to be and what those continents could look like and then tried to reconstruct how they could have gotten there by breaking up an ancient supercontinent. After a lot of fiddling around in gplates, the following image sequence is what I've managed to come up with. The initial supercontinent is this:

img6.png

Firstly, the supercontinent fragments into two pieces, a southern conglomerate and a northern one, the southern one heading vaguely southeast and the northern one taking a trip over the north pole.

img4.png

The next event to happen is the orange subcontinent breaks off a la India and starts cruising north / northeast.

img3.png

Sometime later, green continent separates from its mates and starts heading south-ish, while at the same time the gray contient breaks off and heads toward the south pole.

img2.png

Near the present day (in relative terms), pink-yellow separates from red-blue while orange approaches green.

img1.png

Finally, today, red-blue have just rifted apart while orange is plowing into green and shoving up some impressive mountains.

img0.png

Try to ignore the fact that some of the continents have color segments that don't ever do anything (looking at you pink-yellow and teal-purple), those are artifacts of when I was overly ambitious and planned to have even more fragments floating around.

So yeah, I have no idea how plausible any of this is, which is where I can hopefully solicit your comments / advice / scolding. Geology is very much not my science, and I'm very open to the likely major reworks I'm going to need--both in terms of plate movements and coast positions / shapes--so don't hold back

[Eowyn Cwper]

Hello!

I'm not an expert in geology either, but indeed, your continents should deform! You would not only expect them to move, but also rifts and faults to open and close (look up this one and that one), seas to empty and disappear, coasts to erode and coastlines to evolve over time. It might be interesting/helpful to make a seismic map along with this one.

Volcanoes would also play their part in designing islands (look up hot spots – no, not those ones, these ones :D).

Surely people will help more down below but I was thinking it good to mention these things! ^^

[MrBragg]

Thanks for the reply! Yeah, my goal is to eventually model in hot spots and island arcs and nascent rifts and all that fun stuff, but at this point I mostly want to figure out all the places my model of continental drift is wrong so I can fix those before diving into the smaller details.

On the bright side, I did finally figure out how to turn this into an animation, so hopefully this is more clear than my previous descriptions:

drift.gif

[Eowyn Cwper]

I don't see how you could explain how the “à la India” bit detaches from the rest, it seems a bit counterintuitive. I'm also not sure about that green part suddenly going backwards but if you can justify it by a paper of some sort it's fine! Again, I'm no specialist on the matter. ^^ I really hope you'll get more answers.

[Charerg]

First off, the whole sequence looks really good and I think it could be plausible at least for the most part. So give yourself a big pat in the back, as you've already made it further than most cartographers on the tectonic front (I guess I might add that the vast majority of cartographer's are not insane enough to bother with the whole hassle of building up tectonics for their conworlds, but anyway).

At this point the key question is how much time and effort are you willing/motivated to invest into the tectonics? You certainly have the basics covered: you have a plausible model of a supercontinent breaking apart. Of course you could go deeper, and start modelling the formation of oceanic crust as the pieces split apart (which would likely also mean changes to the movements, since modelling the crust formation quickly reveals flaws in the continental drift), and consider the forces responsible for the movements themselves (say, create a scenario that places "India" under slab pull, explaining why it collides with the green continent). There are a lot of possibilities with tectonics, and it can be a fairly long process to build up the tectonic model if you want to dive really deep into the rabbit hole (probably involving several iterations of the tectonic model itself).

[MrBragg]

Thanks for the kind words Insane as it may sound, I actually am interested in diving deeper into the tectonics to get the underlying processes at least close to correct (I'm a scientist by day, so spending lots of time on tiny minutiae doesn't really phase me, plus this is interesting stuff to learn about!). I've read enough to at least be superficially familiar with concepts like slab pull / ridge push and how oceanic crust is formed at spreading centers, but that's about as far as I get before I stop really being able to translate concepts into the effects they'd have on a tectonic model, which why I decided to turn to the experienced folks here before beating my head into my desk. So yeah, I fully expect having to go through a few iterations--even starting from near-scratch if necessary--in order to get things ~right, so any advice / guidance / resources would be greatly appreciated!

[Charerg]

I see, so as it seems that you've chosen the hardcore tectonics nutjob road (despite all the voices of sanity arguing against it ), here are some resources you'll probably find helpful (some of which you may already be familiar with):

• First off, there is the GPlates tutorial I wrote a while back. Not a resource for plate tectonics per se, but it contains a number of methods and advice in using some of the more advanced features of the program.
• Then there's C. R. Scoteses Atlas of Plate Tectonics, well worth the read
• Mr. Scotese also has a youtube channel with many useful videos
• And then there's Earthbyte, another useful channel
• Finally, here's a link to a paper detailing the Seton et al. plate tectonic reconstruction, which will likely be an informative (if long) read
• Also, since you have a bit of scientific background and might have easy access to online libraries like science direct, here's a link to another paper detailing the Matthews et al. plate tectonic reconstruction (this one I haven't read personally)

I think those should probably get you started.

[Eowyn Cwper]

Artifexian is having a series on GPlates these days, amongst other things as far as I can tell.

https://www.youtube.com/channel/UCeh...TBJDXMNZeWSUVA

[MrBragg]

Thanks! This is precisely the kind of info I was looking for. I'll chew on these for a while and hopefully come back with a more fleshed-out model of what's going on (you've been warned... ).