[WIP] Building a world from tectonics onward

[MrBragg]

Alright, so I've been working on developing a tectonic model for my world for a while now and think I finally have a rough draft that isn't too embarrassing to show. My goal is to get something that plausibly follows the "rules of tectonics" that I can then use as a base for determining geography, climates, etc. The model is probably a bit on the simple side right now, and the coasts here are still a very rough draft (plus this resolution made blobs out of my island arcs...), but at this stage I think the plate motions and interactions make sense; the colors follow the standard scheme--blue = subduction, red = divergent, green = transform, pink = convergent (orange is for old / failed rifts). The plates are named after departed cabinet secretaries since finding proper names is another project and, like their namesakes, any of these current plates could come and go without warning

With Plate Labels
draftTectonics_1_names.png

Without Plate Labels
draftTectonics_1.png

I'd be really curious to hear if anyone has any comments / critiques on this tectonic model before I move on to refining the coasts and/or trying to add some more "interesting" tectonic regions and/or beginning to get started on working out everything needed for climates. Thanks in advance!

[CTA]

I'm no expert (trying to build a tectonics map of my own), but this looks super cool! I do have a question about the Kelly plate. I would assume you would have more divergence on the border with the Sessions plate, since it's directly opposite the direction of subduction, than on the border with the Pruitt plate. What is your rationale here?

[MrBragg]

Thanks!

Kelly's motion is a bit hard to depict on a static equirectangular projection like this, so here's an animation of the motion in orthographic from 16 Ma - present (teal = Kelly, orange = Pruitt, purple = Sessions). You're completely right that there's greater spreading between Kelly and Sessions than Kelly and Pruitt; there's actually a bit of a rotational component to the motion between Kelly and Pruitt, which, combined with being relatively close to the pole, makes the motion a little weird looking in equirectangular. Hopefully that helps to clear up!

southerOcean.gif

[Tiluchi]

This all looks excellent! If I had one small critique, it's that the subductive margin on the southern Tillerson Plate looks quite irregular, in a way that's difficult to find on Earth. With irregular plate boundaries like that I'd expect to see more offshore volcanic arcs and back-arc basins, as is the case with the western edge of the Pacific Plate or the Mediterranean Sea between the Eurasian and African Plates.

The subductive margin wrapping tightly around 3/4 of the Comey Plate also makes me a bit uncomfortable, and my sense is that the slab pull from all that subduction would make the continent rift apart in the middle. But I'm far from an expert and it looks like you've put quite a bit of work into GPlates so I'd believe you if you said it's plausible with the tectonic history and all

[MrBragg]

Hey Tiluchi, your previous tectonics projects were a big inspiration for me, so I'm glad you're here so I can say thanks!

Totally valid critiques, too. The subductive margin on the southern margin of Tillerson is quite irregular--it's also quite an oblique margin--so I think you're entirely right about this being a good place for some nice back-arc basins. Adding these in is now on the to-do list.

But I'm far from an expert and it looks like you've put quite a bit of work into GPlates so I'd believe you if you said it's plausible with the tectonic history and all

Believing me is likely a mistake My thought with Comey was that this scenario of being almost surrounded by subduction would be similar to Laurasia before the breakup of Pangea, where the reconstructions I've seen have subduction on most of its sides. Obviously it did eventually break up, but the reconstructions have the encircling subduction persisting for quite a while. The current Sunda plate is also bounded on 3 sides by subduction, so I thought such an arrangement could be stable for at least a little while. You have a lot more experience here than I do, so I'm very much open to being convinced otherwise.

[MrBragg]

Small edit adding the back-arc basins suggested by Tiluchi and also beginning to very roughly sketch in where some mountains should be based on current and past tectonics (+ some really old mountains where things were otherwise boring).

plates_take2.png

[MrBragg]

I decided to take a stab at doing some ocean currents, and this is what I managed to come up with. A few of the more horizontally-flowing currents I wasn't quite sure how to color, so I largely left them as neutral (black), which might not be how to properly handle them. In any case, if anyone has any feedback I'd be happy to hear it

currents.png

[MrBragg]

Apologies for the thread spam, this is probably (hopefully!) the last one for a while. Anyway, here's an attempt at pressures and winds for Jan and July. There are quite a few places where I'm not sure if I'm doing things correctly, so please don't be shy with comments / criticism!

Jan
pressure_winds_jan.png

July
pressure_winds_july.png

[Naima]

Old post ... delete plz.

[MrBragg]

Congratz on finishing the topograhy, MrBragg! I think you must be the first one to have finished a planetary-scale elevation map built with this kind of technique and detail (makes me think I should get off my lazy arse and get some progress done on my own project).

Thanks, Charerg! I guess being stubborn does actually have some advantages Would also love to see your latest map since it was one of the big inspirations for me.

1, I've done some tests lately with exoplasim runs starting with 1 meter of initial global glacial cover; it takes a bit longer for the climate to settle out, at least 50 years whereas they usually are mostly settled within 20 years otherwise, but the resulting glacial cover is a lot more accurate, as well as the global average temperature. it does make some mid-latitude areas even colder than they should be, though.

So I tried this at T42 and starting with glaciers did converge to a marginally cooler overall temperature at 300 ppm CO2 (22.4 C vs 22.9 C). Starting with <=200 ppm CO2 resulted in a snowball, though, so the hysteresis caused by starting with glaciers may constrain the accessible final temperatures somewhat.

On a somewhat related note, @worldbuilding pasta, do you have any experience running resolutions >T85? For giggles I tried everything larger and each and every one immediately crashed before the model even got going, even when using an identical input from T85 (only resolution and sra inputs changed) that worked fine.