Thanks for these details. Am I right that your model’s erosion is not based on water flow, just a constant weathering? The mountain edges look quite good, and I would have assumed water flow — since that’s how I did it in the model I’m working on. It’s interesting that similar results can be had both ways (just erosion or just deposition). I played around with silting up like this, but abandoned it, since it seemed like modeling river momentum and sediment load would be necessary, and a major increase in complexity. Do you see the marching mountain phenomenon as a problem to fix, or just an unexpected feature?