CompuServe Messages

Hi, Kamron– >> The cutting process would have effected the curves much more making them progressively wider than the straight sections and in deep canyons this is no the case. I see no reason why curved sections should be wider than straight sections (I would guess the opposite, since straight may mean faster-moving), unless you are looking ahead to when entrenched meanders connect up. >> True but there should be small side canyons on both sides or there would be a different set of layers on each side of the canyon which i believe isn't the case. Given an asymmetric low, one side would collect water over a wide area (the shallow downtrend) and dump it into the low, but the steep side would collect very little water on the side of the low (the watershed is much closer to the depression we speak of). No tributaries worth mentioning means no side canyons worth mentioning. If it is a fault scarp creating the asymmetry, the layers should indeed be mismatched on either side. But if an anticline, that does not follow, depending on how closely the river cut approaches the axis of the anticline, and how much the anticline is folded – it could be very subtle. I am not sure what sort of feature governed the asymmetry of the Grand Canyon; there are surely other possibilities. Indeed, given a shallow general downtrend, if a river crosses it rather than flowing downwards (perhaps because the downtrend was established after the river course?), it should create its own asymmetry of tributaries. Any water on the upslope side will tend to flow to the crossing river, any water on the downslope side will tend to flow away from that part of the river. In the matter of creating vertical walls by undercutting, I agree the canyon should be made wider than otherwise. I have not seen the Rio Grande (I probably drove over it, but I was not aware of it as the Rio Grande at the time). –Doug