Help with tectonics

Hi ^_^ I've been lurking for a while and now I'm starting my very first mapping project. It's in the beginning stages and I only have drafts of the continents and approximations of mountains. The map is of a fantasy world, and even though it has a lot of magic and unbelievable events in its history I sort of became obsessed with doing the physical geography of it right. I studied different articles on it for a while, but in the end I think I need some advice.

The red are the tectonic plates, the blue is the tectonic movements, and the green are the mountains. The brown triangles are places where I intend to place islands.

My question are:

1. Do the continents look good? When I came up with the shapes I sort of went with what seemed aesthetically pleasing, but do they actually look like continents and not like random black blobs?

2. Do the tectonics make sense?

3. Did I miss any mountains? Did I put mountains where the shouldn't be any?

4. Does the island placement make sense? I sort of spaced by the time the articles I read started on volcanic island formation o_O

I would appreciate every bit of advice. I know I'm stressing over things that most people won't care about when they look at the map, but for some reason it's become very important for me to get it right. :?:

\\ tectonic map edited according to suggestions \\

Well, I've seen IANAL (I am not a lawyer) put in a message, so I write this with the IANAG (I am not a geologist) disclaimer.

Your continents look pretty neat. However, would any two of them easily fit together? From your numbered map, it appears that some might, but I would make the continental drift (actually former continental fit) more explicit. The fit does not have to be perfect (there are all those eons of erosion and earthquakes after all) but it should be roughly there. Its a bit hard to tell with some of your continents, you might want to think of streamlining and simplifying their shapes just a tad.

As for the plates themselves, other than making your world more realistic, why do you want to have them? If this world is a world for a roleplaying campaign or story you are writing, I wouldn't stress over the tectonic plates too much. Somehow I just can't see one of the Fellowship of the Ring saying "Ssh, we have to be careful, we're nearing a subduction zone" ;)

That being said, If you are going to have the plates, streamline and alter the plate boundaries so it doesn't look like so much that you drew circles around your continents and left the remainder as huge "superplates".

Using the earth as a guide (http://www.physicalgeography.net/fun...als/10i_2.html), I would move some of the boundaries of your plates far out into the ocean (like the North American Plate is in the Atlantic). Also, don't be afraid to have plate boundaries right on the edge of your continents. Take a look at the eastern boundaries of the Pacific, Juan De Fuca, Cocos, and Nazca plates, they are right on the edge of North and South America (which may explain why you have such high mountains in those areas).

Another feature you've noted missing is volcanically formed islands on or near the plate boundaries. Try putting them near where you have 3 or 4 plates bumping into each other or two plates that due to the overall plate configuration are not able to slide past each other successfully or easily. Both areas tend to be volcanically active and remained "locked" enough that undersea volcanic activity over time is able to build up to the point of breaking the surface.

Also, try using the search feature with the term "tectonic plates" here on the guild. This subject has been covered before and you will find additional advice scattered in those old threads.

Good luck Laime and keep mapping.

thebax2k
Thanks for your advice ^_^ I sort of mashed the continent parts together in PS and they kind of made sense. I utilized India-like continent part a lot (a piece breaking off from one plate to drift into another), so I guess on the first glance it does look like they don't fit. I tried to fix the 'drawing the circles around continents' problem, it does look sort of better now.

I looked for places to draw islands - they are marked with brown triangles now. Does that make sense?

Sadly, it din't occur to me to do a forum search, which I guess speaks volumes about my IQ ^_^. I'll search the guild and hopefully understand half of the things people write.

As for why I need that headache at all, I just feel better prepared. For me it's like building a house - if the foundation isn't there, it's hard to do much else. When I'm finished with tectonics, I'll be doing winds and climate, and then I'll pull out my history and anthropology books... I'm pretty obsessive about stuff like that ^_^

I can certainly understand building something from the ground (er tectonic plates) up ;)

Your second map looks better than the first. I would fiddle with the directions of the plates a bit though and have more plates in collision. For instance, you've got a massive mountain chain in the west of plate 9, yet plate 6 and plate 9 appear to both be heading "north" (or at least "up"). You are not going to get massive Himalaya type mountains (maybe I'm misinterpreting your mountain depictions, but it sure looks Himalaya like) unless you have two plates that are pushing/colliding against each other (which is what the Indian plate has been doing to the Asian plate for the last several million years).

Your triangles are fine as temporary markers for where you wish to place your islands. Not every plate collision will have islands, but there were a few areas that did not have islands that had me scratching my head a bit (such as the boundary at 9, 14, and 16 and the boundary between 2 and 17 which are pressing against each other). As for island size, you can make them any size you want, but I would have very large islands (New Zealand, Iceland, Japan sized) on or near the boundaries of 3 or more plates.

Keep working at it Laime, you have the fundamentals of a great map here.

I can't help you with the tectonics (I largely ignore them on my maps), but you have the makings of a nice map here, some great land shapes to start with.

Having trod the tectonics road before, in my own map, I think that generally yours currently looks pretty good. Projection-wise, though, it looks a bit odd. You've got a squarish sort of map projection here, which means if this were to be put in a standard Mercator-ish projection (2-to-1 aspect ratio) this would experience a lot of stretching. Either that or the plates along the west and east edges have a lot of empty material missing.

So, if you continue down this road, I'd take that into consideration. Additionally, I'd take into consideration now (before it grows too late to change and comes to bother you later) that your continental shapes will be subject to some polar distortion at the north and south poles. In other words, if you map this to a sphere, you'll get some very odd-looking warping at the north and south. I'm not expert here (my own map fails miserably at the poles, so I speak from that experience) on how to fix that, but there are some threads on some ways to get some accurate, and aesthetically pleasing, polar distortion, so it might be a good idea to do that now, while in the black-and-white stages if you think that might be important later on.

I agree with thebax2k: a couple more plate collisions might be in order. Most of your plates seem to be like London drivers - moving at breakneck speed and missing each other by bare inches. (Or, at least, like my impression of said drivers over a week's stay!)

Then again, it's quite intriguing to think about a world where the plates all seem to be somehow spending much of their time sliding beside each other, rather than most of their time spreading & consuming, like Earth. Your world wouldn't have as much recycling of crust, I think, which is an interesting concept. Fossils would be found much older, landmasses would probably be pretty eroded, and it might even have a few interesting effects on the magnetic field and such, though I'm shakiest on that last one. I think that's more just convection in the mantle than the recycling of crust, now that I think about it.

Regardless, as they are now, I think you'd see a mountain chain or two between 16 and 15. When two oceanic plates collide, usually one of them is just slightly less dense and goes above the other, and you get strings of islands along the boundary. As the bottom plate breaks up and becomes part of the molten material underneath, lots of gases get trapped and cause magma to upwell through the plate on top, and it forms volcanic islands. At least, I think that's more or less it; I forget the specifics of it at the moment.

I think the strangest thing in your tectonics, to me, is the number of them going in the same direction: 18, 14, 8, 9, and 6, specifically. It seems a little unusual that they'd all move in the same direction. At least on Earth, I don't think more than two or rarely three plates move in the same direction, and then they seem to be more beside each other, rather than chasing. Then again, our tectonic knowledge comes from a whopping data pool of one planet, so we might know absolutely nothing. ;) Have at it, and I can't wait to see more!


Also, as you go into later stages of this worldbuilding, you should check out Karro and Korba's respective world maps. They were one of the primary guides, artistically, that I used for representing all the worldbuilding data you need.
Karro's is here: http://www.cartographersguild.com/regional-world-mapping/2463-world-map-wip-gimp.html
Korba's is here: http://www.cartographersguild.com/regional-world-mapping/4812-wip-world-calen-ndor.html

There's also that Climate cookbook lurking around here someplace that's invaluable for its help in this. Let me see if I still have it in my bookmarks. Ah, here it is: http://www.cix.co.uk/~morven/worldkit/climate.html

-asp

There are some good points made that I forgot to look at, in detail. You'll get your highest mountains when two continent-bearing plates smack together in head-on collisions. If one or the other is moving in a slightly different direction, the mountains are likely to be lower. Where plates are slipping past eachother, rather than colliding, you'll get an intense earthquake zone. And underwater plates colliding tend to produce island chains. Meanwhile, and ocean plate colliding with a continental plate will sometimes produce chains of islands just offshore of the mainland (like Japan).

Meanwhile if two plates are moving along together in the same direction (like 6 and 9) if we assume they're moving at different speeds, then at most the fault will be an earthquake zone and maybe some low hills. If the same speed... well... what's differentiating them as plates? Large mountain zone there will depend on collisions.

Then, if one plate is moving away from another, you'll either get trenches (under the sea) or rift valleys (on land).

One thing that I tried to do on my plates was consider not only the overall motion of the plate as a whole, but the motion of individual pieces of a plate, and the impact of other plates on the movement of any given plate, as well as the impact of subterranean magma flows (which I believe, being somewhat liquid, will follow the coriolis effect). So, I tried to have different forces tearing and pushing at the plates in different ways, and defined plate motion in roughly circular patterns.

*Smacks forehead!*
Karro, that's brilliant! I never thought to consider possible coriolis effects on the magma in the mantle & lithosphere. I'm going to have to go do some research on that tonight and compare with Earth's plates. That might make some interesting research, and it might make plate-creation a little easier in that it limits what currently are far too many options.

As for considering the individual parts' motion, like he says, I've found one of the most universal and quick ways to do it is to shade the plate boundaries in a certain colour, according to the type of interaction between the plates (convergent, divergent, subductive, etc). My favourite example of that is here: http://upload.wikimedia.org/wikipedi...etailed-en.svg

And I think that's enough thread hijacking out of me for today. ;)

-asp

Wow, thanks for your all help guys ^_^ I don't think I had that much positive reinforcement on my projects in my life :oops: You're great.

I'm currently working on refining the coastlines (they look blurry and splotchy on my original map so I'm redrawing them o_O) and trying to draw islands in place of markers, but I've looked over the forums and (unsurprisingly) found a lot of cool articles and tutorials here. I'm going through them but since I'm not that good at science in my native language, you can imagine how slow it is in Enlish... @_@

What I've done with the map I'm posting now:

1. 6 and 9 are now colliding, as are 15 and 11! Yay for London drivers smashing into each other head on! (thank you for that image, altasilvapuer ;) )
2. 7 is moving in another direction, which I guess means islands on the collision site (thus brown triangles abound). I also changed the boundaries a bit since I wanted the islands closer to the continent.
3. Islands added: 9&10, 2&17, 16&15, 13&15
4. I hid the mountains for now since there were too many things on the map already
5. I tried to do the whole "shade plate boundaries with according to what plates do what to each other" thing altasilvapuer suggested, but only gone so far before going completely stumped o_O My problem is, I can't quite figure out some of the plates since they move under an angle that doesn't make it absolutely clear whether they, say, collide or slide near each other. For example, plate 1 slams into plate 6, but plate 6 slides past plate 1. How do you handle that? I marked the borders with mixed colors, but how does this tectonic confusion affect the above-groundy stuff? Do these borders behave like one type or the other? Is it the matter of simply what plate moves faster?

thebax2k, with the 16th plate I figured it's moving away from the 9th and and sort of away from the 14th, so I thought the ocean would be very deep there, with no islands. Am I missing something?

Karro, I haven't yet even thought about projection... I'll add more ocean to the sides to make it less square when I start coloring. It's just that it's a very big file already (the images you see are 7 percent of the size) and I didn't want to make it even bigger. As for distortion, I pasted the map onto Google Earth and it looked alright for me. Maybe that's because continents are not that close to the edge of the document. Anyway, the world is fantasy and I think I'll be going for a stylized look, so distortion won't be that much of a concern. I guess this is the place where my desire for realism gives way to my control impulses (distort something I've made? O_O make it all weird-looking and unintelligible? Oh noes! Never!)

Thank you again for all your help :D