[WIP] Building a world from tectonics onward

[Tiluchi]

Ah, nothing like the rabbithole of plate tectonics, where you can always make things more complicated!

It's always tough to suss things out without playing around on GPlates myself, but I think my instinct here would be to have the southern A/B margin as more or less a transform boundary, and have it running northwest to southeast, somewhat parallel to the direction of microcontinent B. The other option might be to have something like what you have at 150 Ma, with the subductive margin extending southwards beyond the continent; this is perfectly normal in plate tectonics as far as I know, though I might expect the subduction zone to keep moving to the west as there's no continental margin to stop it; this is more or less what happened with the Scotia Plate, and I think maybe the Greater and Lesser Antilles.

But these are all just guesses and I'm by no means an expert- getting a realistic tectonic history is a cycle of constant frustration for me, even though I find myself steadily happier with my results as I go on...

[MrBragg]

getting a realistic tectonic history is a cycle of constant frustration for me, even though I find myself steadily happier with my results as I go on...

One of the truest things I've read in a long time

@Charerg, yep, we're definitely on the same page, you just said it better than me!

Appreciate both of your feedback! I actually tweaked things a bit and made a smaller Cimmeria-like block break off first rather than the bigger microcontinent; "Cimmeria" now collides with the northern continent before the cycle more or less repeats itself with the ridge subducting and then the rift jumping south and breaking off the microcontinent later (it will still eventually hit the north).



I've also followed the evolution a bit farther in time to the next big event happening in this region, which is a microcontinent-arc collision that happens around 100 Mya on the southwestern flank of the northern supercontinent (A). Given that the oceanic crust to the east of that arc is quite old, I have the subduction polarity reversing, placing A under slab pull and thus initiates breakup of the northern supercontinent. This part is more of a reach, but it also seemed reasonable that, which this change in direction of A, the subduction zone to the east of A might extend itself around to the west, consuming that old oceanic crust from both sides.