In Principio

[Corvus Marinus]

Map 01 Tectonic.png

Map 01 Continents.png

Map 01 Climate.png

Maps were a childhood passion of mine and perhaps the first element of my early attempts at creating fantasy worlds. I've been working on writing a novel or novel series set in this conworld for years. Recently I've tried to flesh out my world's geography and increase its realism, and I came up with this crudely-drawn outline of tectonics and landmasses on which I'd appreciate some comments, before I get any further.

These maps are intended to cover an essentially earthlike planet. They were created in Inkscape. The brown areas are major mountain ranges. The finished product will be a lot prettier, I hope, and include rivers and forests and islands and other details. I know the aspect ratio is probably not optimal, and I'll adjust that soon.

Virtually all the action of the novel takes place across the northern part of the major landmass. The protagonist starts in the northeastern area I've marked as "temperate," which I've characterized in the novel as rugged, grassy highlands, broadleaf forests in the north and some nut forests in the southwestern end, home to a pastoral, semi-nomadic people whose influences include the Scots, the Kyrgyz, the Buryats, and the Tuvans. The center of the north continent I wish to be steppe and desert, and in the west, also marked "temperate," I've envisioned a land hosting a waning empire a bit like Byzantium or Sassanid Persia, extremely fertile toward the coast and more arid in the interior, toward an ancient mountain range. I would prefer to modify the map to make these situations possible rather than vice-versa.

My starting idea for this map was a supercontinent breaking up. Rift valleys are forming and flooding while island chains are starting to appear at the antipodes. The big rose-colored plate is shifting east with a slight counterclockwise spin, while the movements of the smaller plates pull the supercontinent apart, as the continental blue north plate continues to drive up north and east. After I've finished working out the continents and tectonics I’ll concern myself more with the details of the climate.

I've never before cared about the lands beyond the purview of the novel, but a more top-down approach to worldbuilding seemed to be warranted. I've looked around at tutorials here and elsewhere. I'm an historian, not a geographer or geologist by any stretch of the imagination, so I don't trust myself not to notice glaring errors.

At each step above—does my logic appear sound? Any advice or recommendations would be helpful.

[Pixie]

Welcome to the grand (and tougher than usually one would imagine) endeavor of world creation.

Your logic appears sound and all, but there's one big/huge detail you should address right away and that's your understanding of tectonics. The plates your figured are just as fine as any others, but the nature of the plate borders is either unclear or wrong. Here's what I suggest - start by choosing a few of those junctions to be bottom of the ocean rifts or newly formed continental rifts. Now, any plate adjoining those junctions will move AWAY from that line. The whole plate. The whole plate (save slight bends) moves in the same direction.

I can see a huge rift in your map: on the western side of the pink plate and then joining with another rift that runs on the south margin of the gray-blue plate. Maybe you could try this... Once you do this, the parts of the world where the plates collide to form mountains appear effortlessly.

Climate will come at a later stage. Be patient.

And good luck, enjoy it!

[Corvus Marinus]

Okay. I'm not surprised I missed something in reading about tectonics, but I'm not entirely clear what the problem is you're pointing out. Do you think the motions improbably complex or confused? I was under the impression that most plates also have a bit of a rotation, so I incorporated that into the boundaries of most of the continental plates (which I should perhaps label for clarity of reference). Beyond that, I did not have clear reasons for the motion I assigned to each particular plate. I assumed that would ultimately be about as random as plate placement.

However, I think I understand the solution you propose, starting with strong divergent boundaries. I'll play with the map a bit more and post my results.

[Pixie]

I think it's more the improbable than the confusing. Only small plates have sizable rotation movements, and sometimes your arrows have 90º difference in direction.

Say, if rotation is the seasoning in tectonic movement, you exaggerated on the salt

Will wait for your version 2.0. From your msg, I bet you will be on the right track.

[Corvus Marinus]

Map 01 Tectonic.png

Better?

I've adjusted the motions of the plates…. Still not sure about some of the boundaries, especially on 1, 3, and 9. I've got a ring of divergent faults circling the globe and branching along the south border of 2. Something doesn't look right to me, but I'm not sure how to correct it.

[Hai-Etlik]

Really all plate movement is rotation. The difference is where the axis of rotation is relative to the centre of the plate. When the plate is "rotating" its axis of rotiation is near it. When it's "translating" the axis of rotation is far away.

To get tectonics right you really have to think in terms of being on a sphere. No map you can draw of an entire globe, or even an entire hemisphere can possibly preserve the direction of movement of tectonic plates so you really can't plan this out on a map. You really need a globe. A ball that you can draw on with a marker is the best way to accomplish this. Polystyrene craft balls are a possibility. Doing this in your head is REALLY hard and doing it with a map is just going to mislead you so get a ball, scribble on your ideas, figure out the converging, diverging, transverse faults, reshape the faults to fit what they are doing, (Transverse faults are circular arcs, usually very big ones that look like "straight lines" over the distance you see them, rift zones are usually arcs of great circles (the spherical equivalent of straight lines) broken up by transverse faults perpendicular to them, particularly along ocean floors. Subduction zones tend to bulge out toward the subducting plate, particularly if the overriding plate is oceanic, and continental convergent zones may retain the bulged arc from when the oceanic plate between them subducted away.

[Pixie]

Indeed, all plate movement is rotation. Particularly with the center of the planet as the reference - however, a lot of the movement seems translational if projected on the surface as if it was a flat surface.

Corvus, I think you are still a few iterations from finished and I would use Hai-Etlik advice of getting a spherical object to project your continent into. I know some oranges got stared at a lot when I was trying to envisage the tectonics for my con-planet.

Or, if oranges / polystyrene balls aren't readily available, download the program G.projector and upload your map into it, to get a grasp of how your drawings fit a globe. You'll be amazed at some results (especially a look at any of the poles directly from above - that's orthogonal projection). Try it

[Corvus Marinus]

Okay, I took your advice, and it's all been quite helpful. No oranges or balls happened to be handy, so I used G.projector. I adjusted some problematically-shaped plates and got a general sense of proper relative direction. I also studied this diagram for some time: File:Tectonic plates boundaries detailed-en.svg - Wikipedia, the free encyclopedia

I came up with this. Red arrows show plate motion and the other arrows show boundaries (purple: divergent, blue: convergent, green: transform). Am I getting closer?

Map 01 Tectonic C.png

[Pixie]

Using g.projector will surely put you closer, but I think you may have been a little hasty in calling this. There's a lot of issues, which seem to originate in not taking enough time to glue all bits and pieces together... here's some:

- plate 9 has no movement. It is also just a bundle of convergent boundaries, it should have a divergent one which would then fuel its movement.
- plate 1 is nearly the same. It has far too many convergent boundaries.
- plate 12 has a divergent boundary, but it is not consistent with its movement.
- same goes for plate 8 on its western side.
- with the current movement direction of plates 1 and 2, the boundary between then should be divergent, at least at its northern end. (this would create a nice little triangular plate, being pushed southwards by 6 (subduction) and forming on the its southern side as magma rises to cover the gap left by the splitting of plates 1 and 2)
- plate 13 moving southwards creates a divergent boundary with plate 4, not a convergent one

On the plus side (don't want you to quit, after all)
- I like what you did with plates 2/3/4/5
- I like that you scrapped most of the boundaries that ran all the way to the pole (a common beginners mistake)
- you have microplates, that's a useful instrument to accomodate the tricky details in the end
- you are rightfuly using a very good image of Earth's tectonics as a model (I use that same image a lot)

Here's what I suggest:
Retrace your boundaries as your create the next version - start with oceanic divergent (which will be long curves, with almost no angles).
Plates which are mainly oceanic, formed on those boundaries, will move directly away from it.
The rest needs to fit this. Always. Oceanic crust creation IS the source of nearly all movement.

(If I sound like a teacher setting homework or a mr-know-it-all and in any way annoying you, please just say. This is me enjoying being able to help, that's all)

[Corvus Marinus]

Oh no, you're not annoying me at all. I'm glad you enjoy being able to help, as I don't wish to be a nuisance with my questions and generally low level of comprehension.

I figured most of the movement in a supercontinent breaking up would come from rifting continental plates rather than oceanic crust creation. I do see what you mean about plate 9, though; it occurred to me afterward that I should have added a strong divergent boundary on that side of the ocean. Would you recommend that I change the motion of plates 1 and 11 and make the 1/9 and 11/9 boundaries divergent? That would give me an extensive length for oceanic crust creation, whose shape I would modify.

The convergent boundary at 1 and 2 was suggested to me by the way the map looked in G.Projector; but that angle is a bit difficult to read one way or another. Based on the general motion of the plates, I see that divergent is more logical.

As far as the north boundary of plate 12, the idea was that 4 was moving faster than 12 and subducting it… unless the relative motion of 4 and 12 would actually take them away from one another. The 14/12 boundary would then also be divergent.

I'll do some redrawing and get back to you.