In my worldmap, I'm using largely the same approach. I had a few basic ideas about where I wanted continents to go, and a few shapes I wanted to use based on some old maps I had done as a child, but mostly I wanted to fashion the world from scratch using some basic understanding of plate tectonics.
I'll be working on this more after I finish my little side-jaunt learning how to use GIMP.
Well done - this is shaping up to be a great thread and read. Keep it up ! Have some more rep...
It may be important to remember that plate motion can't really be described by simply drawing an arrow on the plate and saying "it moves that way." Actual plate motion is actually a rotation around a point on the earth's surface. What you really need to know for this exercise is relative motion; it is completely possible to say that plate 1 is moving west (with respect to plate 2) and at the same time moving east (with respect to plate 3). This situation happens all the time.
Here is a quick tutorial on velocity space analysis:
Say you have a situation like in the first attachment here. Plates A and C are moving toward each other at a rate of 4 cm/yr. Plates A and B are moving away from each other at a rate of 3 cm/yr. What is the motion between plates B and C?
Construct a velocity space diagram to find out (see second attachment). Since plate B is moving west at 3 cm/yr (with respect to plate A), place a point for B 3 units to the west of A. Since plate C is moving south at 4 cm/yr (again, with respect to plate A), place a point for C 4 units to the south of A. Now it should be clear that plate C is moving southeast at 5 cm/yr with respect to plate B, as the point for C is 5 units to the southeast of the point for B.
This means that the B/C boundary is convergent, with an element of right-lateral strike-slip motion as well. The third attachment here shows the solution.
I hope some of that a) makes sense and b) helps.
-Rob
Excellent information to add to this! Thanks! The plate tectonics rabbit hole goes pretty deep if you really get into it. And there is a lot more that what I said to be considered if you want total accuracy. (which is precisely what I meant when I said a legitimate geologist could find a thousand things I did wrong.Originally Posted by HandsomeRob
)
I initially entertained the thought of taking the rotational motion into consideration, but my desire to have a new map overtook my desire for scientific accuracy, and decided that it would add considerable complexity, and thus time, to my project. So that's why I stopped at the point of drawing an arrow on the plate and saying "it moves that way".
I take that back, I did take rotational motion into consideration for a few of the plates on my map, but I didn't note it. In particular, my southernmost plate is rotating anti clockwise.
Last edited by dhalsimrocks; 06-12-2008 at 10:09 AM.
I think this can get even more complicated, based on an observation of real-world plate. Many of the plates have highly irregular shapes, and those with plate-peninsulas seem to have different parts of the plates moving in somewhat different directions relative to a neighboring plates. I assume this is do to the interaction of the forces from the main part of the continent's rotational velocity (which I believe is influenced by subterranean magma currents) and the friction and pressure caused by collision with neighboring plates. In some of these scenarios, it looks like a larger plate may be torn assunder by another plate smashing through it.
There are also several dozen or so more smaller plates on the Earth than that image I referenced in my first post. It's a lot more complex than "7 big ones and 8 small ones".
Very interesting.
I will use it to define my world map.
I can imagine the convection zones (from top) to define the direction of the plates.
"Mapping Infinity: An impossible mission? Not if you're a real blood, it ain't." -- An explorer mimir
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