Not all canyons are created equal. Steep canyons with amphitheatre-shaped heads are thought to result from the activity of groundwater, on the basis of studies of such features that developed in ...
The layer developed on the top of a bouldery gravel. This gravel is overlain by loess, which is capped by a megaflood diamict deposited during the last glaciation around 18,000 years ago. The ...
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