This is essentially a place marker, since I don't have time for the next couple of weeks to post the full answer.

For now, let me suggest that meanders are merely diagnostic of fluid flow and density contrasts. They don't mean "water" and they very specifically are not limited to subaerial environments.

My website makes this point in a few places, but it's a fundamental misconception that we must all cross before we can properly evaluate what is ahappening on another planet.

I just found a new picture which is quite beautiful and which I will post soon. Meanwhile, I'm preoccupied with actually earning money to feed my kids!

More anon....