Friday Field Foto #30: Cross section in a gravel quarry

A few years back, when I was doing my master’s in Colorado, we went to a gravel quarry for the clastic sedimentology class I was taking. They were quarrying very recent fluvial sediments laid down by the South Platte River, which provided some great cross-sectional views of the deposits.

Note the distinct surface separating the underlying red-brown sediments from the overlying, more buff-colored and much more poorly sorted sediments. The entire quarry was full of the deposits of sand-gravel bar formation indicative of a river with relatively flashy discharge.

I love being able to observe the products of very recent geologic processes. It helps make the all-important connection when observing the products of ancient processes.

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