The Faith "Great Debate" sedimentation and erosion topic

Unfortunately the picture isn't available to me, either because my computer isn't powerful enough or because the website shut it down, which could be the case as when I click on "enlarge" it says it's unavailable.

Now the picture is coming through. Yes I do think about rates of erosion having to do with different hardnesses. The stepped shape of the walls of the Grand Canyon show this kind of differential erosion, probably also the pattern of runoff from the top of the canyon, taking more from the top layers than the lower layers.The erosion within the layers of the canyon is supposed to have occurred upon an already pretty flat surface, as these surfaces were supposedly built up over great periods of time, most of them underwater where they would have been quite horizontal. I've been thinking of erosion UPON a flat table-like surface over the millions of years supposed for any given layer -- or whatever relatively shorter period (half a million being conservative?) that layer is thought to have been out of water. Seems to me rivulets would have starting cutting into the surface and eventually spread out taking a lot of material with it over huge periods of time, making short order of the flat table-like appearance. It would have dumped sediments moved from it somewhere else in no particular configuration, the whole thing being an incoherent mess at the end of the supposed millions of years. I'm sure it's an interesting story. What the monuments look like to me is islands of some kind of layering, left after water removed everything in the surrounding area. The tops look like something that was pushed upward, then the whole thing eroded first by more water than that which cut the canyon, as it left the surrounding area denuded and flat for miles in all directions, then eroded by normal weathering since then.So what's the real story?

That crossed my mind but I figured water is coming at this area from many directions, including rain from above, and this is a LARGE area after all, acres at the very least. If one rivulet could get started across a flat surface others also would, many of them, and then of course eventually some grooves will get deepened and some channels become quite deep and so on. The layer won't be perfectly flat either and the water will head for the lower areas. But remember, this is happening over how many years? ONE layer of sediment how deep? I've wondered if it would be possible to set up an experiment by spreading out flat wet clay in a field and letting it harden a bit and then run water across it or sprinkle water from overhead to see what happens. How does water travel across the Great Salt Lake or other dry bed? It ought to be possible to set up smaller versions on the kitchen table and come to some kind of conclusion even. I'm sure some scientists have already conducted these kinds of experiments. We should probably ask them.This message has been edited by Faith, 03-24-2005 06:37 PM