Methods to Stabilize Geology in Large Artificial Space Environments

Question

Everyone loves a Dyson Sphere or a Ring World, so much more room to enjoy than a traditional round planetoid, it's all about space efficiency for the advanced civilizations. There are however a number of problems with these large artificial space environments, the one I would like to focus on today is erosion and other geological instabilities of artificial environments.

They all start out so pristine; an underlayer of unobtanium for structural support, lay down a few (approx. 1-10) km of rock, sculpt some mountain ranges, pepper the landscape with some comets for water, lay down some beginning soil layers and some desired flora and fauna, and enjoy your species ideal biosphere. But as the millennia pass there are problems; the mountains are eroding! All the rivers are dumping sediment and clogging up the seas, turning our ocean front property into swamp front disasters. What's a Ring World engineer to do, seriously what should they do?

Those inefficient spherical planets move their continents around on a huge masses of molten rock, this makes new rock, raising the continents and recycling the materials over long timescales counteracting that pesky erosion. That inefficient cycle won't work on our thin space structure.

Some ideas our engineers have been exploring:

• We could run some massive de-silting operations, dredge the seas and ship the mineral materials uphill to form new mountains, we could even try some massive automated pipeline type systems to create artificial subduction and mountain uplift zones.
• Maybe we're over thinking the problem, erosion is going to be fairly slow, we could just thicken the "crust" in areas subject to erosion. Surely this will be able to ensure a functional structural lifespan to meet or exceed our species lifespan (several million years).
• Could we make the rocks "harder" to resist erosion? But this wouldn't stop our topsoil from eroding.
• Perhaps an unorthodox method might work, could we flex the substructure to change the terrain periodically.
• Undersea nuclear detonations to blast the dust into the air?
• Put some asteroids in orbits to periodically drop meteors at low relative velocity to make new mountains?

What's the best method to keep our space construct's geology fresh? Something our engineers have proposed, or are our ideas flawed, is there another better solution we haven't thought of? Preferably something with a minimal input from the inhabitants societies (they have a nasty habit of technological regression over geological timescales). We owe it to our descendants to do this right.

Answer 1

If you are thinking dredging operations then why not take the small extra step of robotic maintainers. They will handle the dredging an mountain building.

Anyways my actual idea in addition to that

Recreate the subduction process. Create low points in your water bodies such that material inevitably flows there. Then create an artificial lava tube/smelting pipe that collects and melts that material into lava. Then that pipes the lava over to an artificial volcano. Granted this does nothing for non volcanic mountains but it does result in mountains. The volcanic process can be easily controlled to not be too destructive while building up the mountain.

Plants are also a great erosion controller, their roots can lock soil into place preventing soil erosion.

Answer 2

You can have your unobtainium bed sculptured to mimic tectonic activity.

When too much sediment is mucking the ocean you can have that section of the "baseplane" to rise (very slowly, in geological ages) to create new mountains while depleted rocks are submerged to form a new oceanic basin.

Real challenge would be to be slow enough.

Answer 3

Sounds like just the question for me :o) If we can go to enough trouble to build 1-10 km of surface rock surely we can add a bit of semi molten mantle for it to “float” on directly above the unobtainium hull? If required we should be able to provide some additional heating to “grease the wheels” (I’m not sure off the top of my head what the thermal properties of unobtainium are).

We could also provide some strategically placed unobtainium ridges to direct movement and some local hot spot heating to allow lava to form and rise to the surface as the liquid will be less dense than the solid crust (like one of those old lava lamps – well not really but you get the idea). Of course it will be necessary to apply a lot of additional measures to prettify things but that’s just the fiddly artistic bits.