Pangarap: Building a world from the ground up

[Tiluchi]

Thanks all for the comments! I'm finally back- seems starting to design a planet at the same time as I'm trying to finish up end-of-year work isn't the best time-management decision...

I've been forging ahead with the geology; I made a couple of corrections to the overall plate tectonics, and added some microplates in the more geologically complex regions. I also added a small antarctic continent and some extra islands in the north pole. Overall I think I'm fairly happy with how the overall plate tectonics stand at the moment, which probably means there's something dreadfully inaccurate somewhere in there.



I've also slapped together a map of some other useful geological features. I went through the continental drift history in GPlates to figure out where older mountain ranges would have formed, then sketched in more or less where the older mountain ranges would be today. I also put in where the currently uplifting mountain ranges are, along the subducting and convergent plate boundaries. Also added in some former failed rifts so I know where to put some major lowlands and river valleys. and added hotspots where I can put volcanic island chains or calderas. Just for fun, I also put in where I figured cratons would be, and where more or less there would be zones of active volcanism. Perhaps not immediately relevant for mapping purposes, but good for figuring out important features and landscape types later.



Now I'm working on refining my coastlines on a larger file, so that I can start mapping the elevations and later the climates. Of course, I should be spending this weekend working, but this is such an entertaining distraction...

As always, I welcome any comments, corrections and criticisms!

[Charerg]

I had a feeling you might outpace most feedback with this one .

Anyway, now that it's weekend and I've had a bit more time to look at Pangarap and think about some scenarios, I do have some ideas about the plate tectonics. Since you're an old hand, you know the drill: it's up to you if you want to incorporate this stuff, or how much time you want to spend with refining the tectonics (as you know, getting a really good tectonics model takes at least weeks, especially if you incorporate feedback from others).

Oh, and btw, I don't take any responsibility if reading this feedback results in further diversions from work, or throwing your computer out of the window in frustration .

Right, so I had a look at the overall plate tectonic model. While the present model probably is workable if you don't pay too much consideration to the forces responsible for the movement of the plates, I do think it could be made a lot more plausible without absolutely massive modifications. Like I warned you, I'm going to plunge pretty deep in the rabbit hole here, so you might want to stop reading at this point if you feel like you've had enough of the tectonics.

Overall, I guess my main criticism is that there doesn't seem to be a plausible driving force for most of the continental breakups. For the breakup of Gondwana, most of it can be attributed to subduction by Eurasia moving southwards, but with Pangarap there's not really anything comparable to the "Tethys subduction cycle". I had a bit of a thought about this, and I came up with a different model of sorts, that results in more-or-less the same present-day continental arrangement.

This is probably easier to explain with pictures, so I made a quick GPlates model. So far, I've only modelled the movements of Malobago and Molave, to give an idea about the concept. So, essentially I thought the model would work better if Malo and Mol were to form a supercontinent over the North Pole, that way the opening ocean looks a lot more plausible (to me, anyway). Essentially the "opening of the Northern Ocean" is visualized as something akin to the opening of the Atlantic: neither Malobago nor Molave are themselves subducted, but rather they subduct crust to the south of them, which can be used to explain the movement of all the smaller pieces (Abaca, Ipil, Narra, Bakawan).

So, here's my idea about the "northern supercontinent":

200 Mya, the supercontinen is intact. As you can see, I think this fit could be achieved with relatively little fiddling with the coastlines to make them match.


100 Mya, the ocean opening. At this point, the Abaca-Ipil block would probably be colliding with Malobago (the Ipil block would later detach due to subduction applied by Molave, and start moving eastwards). I've also used flowlines here to depict the creation of new oceanic crust. Although the flowline only work for Malobago (blue lines), because I changed the present-day location of Molave slightly (messing up the orange flowlines, so ignore them.)


0 Mya:


As I mentioned, I changed the present-day location of Molave somewhat, in order to make the movements look more plausible. This is how it looks like in equirectangular (note that the oceanic ridge looks a bit weird in this projection, since it "walks across the North Pole").


And compared to the original arrangement:


Right, so those are essentially my thoughts and ideas so far. Again, feel free to ignore if you want to move on from the tectonics phase. I'll try to post some more stuff later today (or maybe tomorrow), if you're up to spending more time with tectonics. Again, good to see you back in the saddle, so to speak !