Mapping an Earthlike planet

[Akubra]

Hi Pixie and thanks a lot for the comments!

Now for your questions:

Daia Plate
Now that I look at it again, I realize that there is indeed something strange going on. Daia Plate is moving eastwards at 68 mm./year while West Nohhon Plate is moving to the southeast at exactly half that speed (34 mm./year). So if their common border has an angle of about 45° they should more or less slide along each other and create a transform fault instead of a subduction zone. On the other hand, I like that subduction zone, and I think it could work if I change their relative velocities: 58 for Daia (-10) and 44 for West Nohhon (+10). I don't think it would create problems with the surrounding plate borders. Do you?

Ghatia Plate
I don't quite understand why Ghatia Plate would have broken in two. Ranineo Plate is colliding with it (and moving over it) in a southwesterly direction at three times Ghatia's speed. Eneaga Plate does the same from the northwest, but moves beneath Ghatia instead of over it. So these two big plates add momentum to the southwestern movement of Ghatia. It in turn has room to follow in the wake of Taiunta because that plate moves faster than Ghatia. The only convergent boundary is with Ghaon Plate in the south. Could you maybe offer a little explanation why Ghatia would have split?

The lines
Yes I first drew the plates on an equirectangular projection, because that is what I have in Inkscape. As for the lines, I first drew coarse outlines of the plates' shapes. Then I drew some straight lines in different colours, lengths and directions (a sort of palette) and copy/pasted them where I wanted them on the map, roughly following the outlines. For the subduction zones I grouped a line and 2 triangles. Then I deleted the outlines. I have to admit that sometimes it was not obvious what type of boundary I should use, but I think I worked it out relatively well.

Glad you liked the colours and labels!

Well, I "stole" the idea of using relative velocity from the Wikipedia map...

Cheers - Akubra

[ascanius]

Huuraayy for nerds, we make the worlds go round.

I agree with Pixie. Awesome map.

[Akubra]

Huuraayy for nerds, we make the worlds go round.

We do indeed, ascanius, we do indeed

Cheers - Akubra

[groovey]

I share the enthusiasm for the tectonic map, it's awesome. I love how natural the shapes of the plates feel, and how neat and polished the whole thing is with all the information. That tectonic map of Earth you link as a reference is also my main reference map, but gee, I could never get mine to look so good as said map AND yours. It must have been a lot of work, but it paid off.

Potential silly question: how do you decide the speed of a plate? Kind of randomly depending on your needs or is it a mathematical matter?

[Triskelli]

One thing I'm always curious about is how artists go about deciding where extinct faultlines and associated ancient mountain ranges might belong, such as the Appalachians in America or the Ural mountains in Russia.

[Akubra]

Hey all, thanks a lot for the positive input! I didn't realize the map was that good Anyway, it feels good when something succeeds well. Now it's time to filter out the small (and maybe not so small) mistakes I made, and then start mapping the islands and the topography of the continents.

@groovey: Not a silly question at all! Indeed, I chose it rather randomly, and adapted it where it really created problems. So, nothing mathematical involved.

@Triskelli: Good question, I'd like to know that too, because right now I don't have a clue...

Cheers - Akubra

[Triskelli]

@Triskelli: Good question, I'd like to know that too, because right now I don't have a clue...

Well, after a little research, I suppose you could go about doing that by scattering a handful of cratons in the middle of the current plates and adding mountain ranges on trailing edges or where cratons might of collided in the past. Though considering the tectonics you've got set up the centers of most of the continents already have active plate boundaries in the middle I suppose this might set itself up as a number of island chains?

[Pixie]

This tectonics things is both absorbing and tiring, I wonder how long how many of us will keep digging for greater realism... Having said this, welcome to the pot, Triskelli, and thanks for the read you suggest about cratons - it took me to a few maps I didn't know, including this lovely detail of intra-plate rifting (the sort of thing that makes our work on plate movement more complex and at the same time less constrained).

Now, back into Akubra map.
Daia plate: Chanisi plate sinks under Daia plate and this one under West Nohhon. This gives the relative age of that oceanic crust, as it is always the oldest that gets underneath. So, Chanisi is the oldest and West Nohhon the youngest. But... Daia plate is being formed as the rift is active (west boundary), so it couldn't really be older than the West Nohhon oceanic bit. I guess it can be resolved in two ways - one, change the direction of the arrows, or make that part of the West Nohhon plate an extension of the continental crust (even if submerged). ... just some thoughts.

Ghatia plate: Oceanic crust subduction is a major pull force that makes plates move. Because there is subduction both at east and west borders, the plate would be stretched towards both sides, like a rubber band. If you want to keep that as it is, I'd reckon central Ghatia would be the very thinest crust, with volcanoes outcropping just because magma is so close to the surface and with lots (or at least a few) local north-south rifts, and, over a few millions, it will really rupture.

As always, feel free to ignore my "perfectionism", I know this is your creation, not mine.

[Akubra]

@Triskelli: Thanks for the link to the craton article. Fascinating stuff! I'm not yet sure I will delve very deep into it for the map, though. I would like to make some headway and if I linger too long in the tectonic phase, I'm afraid it will become rather tedious.

@Pixie: Thanks a lot for your explanations. I see what you mean about Ghatia plate, and I can follow your explanation on Daia plate up to a point (but that's not a problem, I'll try to read up on it). I will probably change something, but I haven't decided yet how I will make it work (well, at least try to).

In the meantime I started creating island arcs along the subduction zones. The first one is the longest one, starting at Yirral plate and going all the way to the top of Onuskia plate. As the planet Rautah has more or less the same size as Earth, this is one huge arc - I haven't measured it yet, but I suspect it to be over 5 times the length of the Indonesian islands. It does look a bit weird on the map, I'll admit that. I'll post an updated map when the outlines of these island arcs are ready.

Cheers - Akubra

[Akubra]

Well it's time for an update (even if it's Saturday evening )

What has happened? Well, here are two maps (one showing the islands in relation to the tectonic fault lines and one without the tectonic stuff)

1. I got rid of the subduction zone between Daia and West Nohhon plates and changed it to a divergent boundary with sufficient transform areas (I suppose it is safe to do so because Daia moves much faster than West Nohhon at a sufficiently wide angle). I also widened Daia and the southeastern part of West Nohhon, to bring the subduction zone northwest of Tabinoth closer to that continent, which I find visually more appealing.
2. I'm still wondering if I should do something about Ghatia plate. Ghatia's western fault line is not pulling it underneath Eneaga plate, but rather the opposite: Eneaga is pulled underneath Ghatia. So the pulling force is coming from the east, where Ghatia is going underneath Ranineo plate. For the moment I think I'll leave it as it is.
3. Then I started with the island arcs near the subduction zones.
   
   • There is one extremely long subduction zone starting at Yirral plate and going all the way to the north of Onuskia plate. I tried not to overdo it by placing a few long, thin islands along the fault line and filling some other areas with smaller islands. I think the result is still a bit weird, but maybe that's just because there is no such long arc on Earth, so I'm not used to seeing it.
   • I like the positions of the islands around Ranineo. They seem to flow quite nicely around the continent.
   • I chose to place two bigger islands north of Yirral, and again sprinkle them sparsely around Tabinoth.

So, what do you think? Does it have a sufficient level of realism? Is it visually appealing? Don't hold your horses!

Cheers - Akubra