Plate tectonics of still-unnamed planet

[zoqaeski]

Hi everyone, I thought I'd finally start posting here.

I've been working on this world for a while, but have only recently started to develop it with some degree of rigour. When I drew the original draft, I left hints for myself as to the approximate locations of tectonic plate boundaries by drawing the continents so they kind of fit together if you squint a bit. I haven't named any of the continents yet, but I've numbered all the plates with the same IDs I intend to use in GPlates when I model all this. I haven't yet drawn in the mountain ranges as getting the contours right is the longest and most-involved part of the entire map-drawing process for me.

The movement of the plates is indicated by the arrows (just the direction, not the magnitude at this stage), and the colours indicate the type of boundary:

• red boundaries are divergent;
• purple boundaries are convergent;
• green boundaries are transform boundaries; and
• blue boundaries are subduction zones (for some reason Inkscape wouldn't draw the triangles on the remainder of the blue lines)

At some point in the distant past (~150 Ma), Plates #201, #401 and #301 were joined as one continent, and #501, #601 and #602 as another continent. #120 and #121 are the remnants of a larger plate that were subducted under #201; #221 was in-between that plate and #201, and the expansion of #101 and subduction of #12x pushed it north.

#401 split off first around 140 Ma, followed by #301 approximately 50 Ma later. Around 40 Ma, #501 broke up from #601; #601 and #602 are in the process of splitting. It's likely that at some point in the distant future, #501 will collide with #201, and #401 will collide with #601.

How am I doing so far? Are there any obvious problems with these motions? It's hard to see what's driving the movements because the continents are so small and far away by terrestrial standards. I'm thinking of adding another continental landmass somewhere near the south eastern corner of #101 that might act as a slab to pull #601 and #401 towards it, but I don't want to add too much more land as I'd rather have a higher percentage of oceans on this world.

The planet itself is slightly smaller than Earth, with a diameter of 6090 km.

[zoqaeski]

After a few days of wrestling with GPlates, I managed to create an initial draft of the evolution of the continents. Some of the motions seem a bit awkward, and the timescales seem a bit off in places as continents have a tendency to suddenly take off across the globe, but I'm otherwise happy with the results.

Now that I know how to do it, I can refine this model and improve it over time. The other benefit is that I can get a good idea of where various geological features will go so I don't waste time drawing details in the large map that don't make sense.