[WIP] World of Aduhr

[Charerg]

Hi, I've been lurking on this site since February, and thought I should finally post some of my work here.

So, I've been working over the summer on a world-building project. Based on the inspiration provided by similar world-building threads on this site, I decided to do a thorough job of it and build the tectonics at least roughly, as well as do the climate in detail.

More recently, I decided to do something of an "artistic rendition" of a topographic world map using a Kavrayskiy VII projection. So far, I've finished one continent (the large eastern continent called Rheada) and the oceanic topography. Unfortunately even the single continent took me about 2 weeks of work to reach its present state, which means it would be too time-consuming to do the entire world with this technique.

But, since the map looks decent even in its present unfinished state, here it is:
Aduhr.jpg

The map is mostly done using the instructions found in Arsheesh's Eriond tutorial, although the mountains are generated separately and pre-processed through Wilbur before copying them to the actual map. I said the topography is an "artistic rendition" because some features such as mid-oceanic ridges and oceanic trenches are somewhat exaggerated.

I also did more of an actual topographic map of Rheada using the same black-and-white height map that the world map is based upon. Here is the result:
Rheada.jpg

For the moment, I'm thinking about switching to an Equirectangular projection for the world-wide topographic map in order to make it possible to switch projections in GProjector. This time, I'm trying to find a technique to do the global topography within a reasonable timeframe, and I'll probably skip the oceanic topograhy. However, I'd like to first revisit the tectonic layout of the world and ask for some feedback on it.

I'm working on a draft of the revised tectonic layout, and I'll post it here for criticism once I complete it, but here is the old version of the tectonics for reference (the plate names are not final):
Aduhr Tectonics.jpg

Any suggestions and criticisms are welcome, and I hope you enjoy the maps!

[Chick]

What a nice start! This map has a lot of potential and I hope you continue to build on it

And Welcome to the Guild!

[Diamond]

I'm not the guy to offer suggestions on tectonics, so I'll merely say that is beautiful work. That first map reminds me of something out of National Geographic; it's lovely.

And thanks for de-lurking - have some rep!

[Azélor]

The mountains look really convincing!

[Pixie]

Wow, you've done a whole lot of work and quality work! I like the artistical rendition a lot! I'm giving yuo some instant reputation for that one alone.

I understand you want to rework your tectonics, so I will wait for that new version before I post any criticism (constructive criticism, of course). For now, make sure you think of plates movement in terms of a sphere.. I think that's a key advice. Welcome to the Guild

[groovey]

I agree with the guildies above, what a great introduction to the Guild. Lots of potential and you seem to have the skills to pull it off, so I'm definitely keeping this thread on watch.

Both topographic styles look great, you've done a great job on them visually.

[Charerg]

Thank you for the compliments!

Here is the revised draft of the tectonics:
Aduhr Tectonics.jpg

Legend:
- Blue: a subduction zone
- Red: rift
- Green: transform fault
- Purple: convergent boundary

Some of my observations concerning Earth's tectonics which I tried to include in the revised tectonic layout:

1. There is an "expanding ocean" (or oceans) centered at the seams where the previous supercontinent broke apart. Right now on Earth the Atlantic and the Indian oceans are expanding. On the other hand, there is also a "closing ocean". In the case of Earth this is the Pacific.

- On Aduhr, the expanding ocean in the revised layout is the "inner ocean" (called Valkathain), while the "outer ocean" (Agalhain) is in the process of closing. I toyed with the idea of reversing the roles, just to make things different from Earth, but ultimately decided against it since I had so many island chains east of Rheada and it would have been difficult to justify their existence without a situation similar to one that occurs in the Western Pacific on Earth.

2. A major continental plate usually has a "leading edge" of continental crust and a "trailing edge" of oceanic crust.

- This is a result of the fact that oceanic crust always sinks beneath continental crust, whereas new oceanic crust is created at the seams where continental plates are diverging.

- The major exception to this rule is the Antarctic plate, which is surrounded by oceanic crust. Probably related to the fact that Antarctis is moving relatively little compated to the other continents.

And while speaking of Antarctis, can anyone explain the Transantarctic mountains?
The mountains are located in the middle of the continental plate, yet the highest peak reaches 4 500 metres. From what I gather from wikipedia, the mountains are formed largely because of the West Antarctic Rift. Does this mean that the Antarctic plate is actually two separate plates, or is it possible for major mountain chains to form even inside a plate with no external tectonic influence?

[Pixie]

I feel I have to point you to this tutorial - not because I made it but because you need it In some plates, namely the larger ones, your directions for the movement won't hold when on a sphere... Try using g.plates. It will help a lot.

It also helps, sometimes, to draw in a sphere. Using this site.

Second resource to get things right is this set of animations. Your world seems to be in an advanced stage of supercontinent breakup, so it will help to see animations of continents drifting.

Now, concerning what you've done so far. From what I see the Eocidarian, Druegian and Tyandorian plates were the core of that supercontinent and started their separation long ago. The Tyandorian and the Druegian followed together for a while and the Tyandorian recently started to move northwards. This much is clear and believable - you should use it as a base.

Have you noticed that, on Earth, Oceanic subduction will create curved boundaries, with the concave side on the ocean and the convex side on the continental plate. That's not happening in a few places in your planet.

Also, the way the "zig zag" of mid-ocean ridges takes form isn't random, it will fit the direction of the spread... originating in this sort of situation:
SAmerica_Africa_rift_large.jpg

Finally, as for your question about Anthartica - yes, it seems it will breakup in the future, it has a linear highlands system and volcanoes in that area, just like the line that more or less goes from Mozambique to Ethiopia in Africa, which is a well known rift.

But I've got to say - this step is a heck of a great step from your first draft. You seem in the right track, but you are aware that your landshapes need to be a little flexible for this part of the process, right?

[Charerg]

Thanks for the criticisms, Pixie.

I did check the plates on Map to Globe, but I didn't see any obvious flaws as regards the direction of movement. Mind you, the arrows pointing the movement direction in the revised layout are primarily intended to show general direction of movement. Can you provide some detail as to which plates exactly have problematic movement?

Awesome resource concerning the "zig-zagging", btw. When I drew the tectonic map, I was mainly intending to portray the location of the ridges, rather than portay their shape accurately. Though if I ever figure out a nice way to animate the plate movements, I might try to make the ridges a bit more accurate. I did actually check your tutorial recently, but only managed to get as far as rotating a single plate around a pole. I don't think GPlates has enough functionality to actually simulate plate movement on world scale (at least not in the long run), since this would involve some plates getting larger and others smaller, plates breaking apart and so forth. That said, I might give GPlates another go, and see what the program has to offer.

As to the subduction boundaries, I did indeed try to give the "upward" side of a subduction zone a convex curve. But if you look at Earth's tectonics, you'll note that there are actually a few places where the convex curve is on the oceanic side. One such istance occurs west of Ecuador, second north of Venezuela and a third south of Peru. The "Juan de Fuca" subduction zone is also slightly convex on the oceanic side.

So, while the rule of "convex on upthrown side" generally applies, there are also instances where it doesn't apply. Namely said instances seem to occur where existing continental crust of a large plate meets oceanic crust. In areas where oceanic crust subducts beneath oceanic crust (forming island chains), the "convex rule" seems to apply almost always.

With that in mind, I'll try to check if there are any "weird instances" in my tectonics, where convex curves on the side being subducted occur where they shouldn't. Once again, if you have any specific instances in mind, that would be very helpful for me to identify the problematic areas.

And to your final point concerning landshapes: while I may make some adjustments on the land, particularly adjusting the island chains to suit the tectonic layout, the general plan is to arrange the tectonics in such a way to explain the present geography. Mind you, I can always adjust the shape of the under-water continental crust, which gives some playroom. Throwing some hot spots in the mix can also explain some island chains (indeed, the idea behind several of them is that they were formed in such a way). And in any case the forms of landmass have underwent drastic changes even on Earth since the Pangaia stage, so it goes to reason that the same would have went on in Aduhr. That said, if a situation occurs where a landshape absolutely must be changed due to the tectonics, I'm not completely set against the idea. But I reserve that option as a last resort, since it would involve some extra work.

EDIT: New Version:

Aduhr Tectonics III.jpg

I modified the previous tectonics, trying to take Pixie's comments into account. Major changes:

1. The Lokyarian plate has been removed since it didn't really fit into the "supercontinent cycle".

I also did several more minor changes. Note that some microplates are left out in order to focus "on the big picture" first. The basic tectonic history envisions the Eocidarian, Xeteyarian, Druegian and Tyandorian plates forming an equatorial supercontinent (as in Pixie's suggestion). The Menduleic and Anaparian plates formed a 2nd continent in the southern hemisphere, whereas the Urgaleonic and Rheadan plates formed a 3rd continent in the northern hemisphere. The present oceanic ridges between aforementioned continents are a result of the breakup of these "prehistoric" continents.

[Pixie]

Hey Charerg, another step forward.

First of all, let me admit that I sometimes jump into these kind of threads a little too strong or too ambitious, and you're free to remind me that it is your world. I won't take offense. But it seems to me you are willing to put in the necessary effort to get this right, and that makes it motivating for those willing to help.

So... a few more constructive comments:

- the general idea is fine and a good base, but have you considered an alternative where Xeteyarian is moving north and was part of the south polar continent?

- have you ever seen a map like this one? Do you think you could do a likewise map of your world, using the present ridges and present directions of movement? I see a few places where it would become problematic - the southern and northern parts of ocean floor in the Druegian plate were clearly created at different rates (a solution would be to split that plate in two) - and I just can't imagine how it would be in the area where the word "Xeteyarian" is written.

- the boundary between the Urgaleonic plate and the Eocidarian plate makes more sense where you had it before (with the Lokyarian), this would make it a continent-continent, and the sea north of it would be a failed rift - as it is, with a convergent boundary between two continent plates but at the center of an area so low in altitude that is under water makes less sense.

- that very large island (islands) in the east coast of Eocidarian can only be explained by a cataclysmic rate of volcanic activiy (as far as I can see it)... thoughts on this?