Faults

In 1988 I spent 6 1/2 weeks in geologic field camp in South Dakota, Wyoming, Montana, and Idaho. I took a lot of slides. Recently I've been scanning my slides. The following shots are of some interesting faults.

This first one is from Sun River Canyon, Montana. It's a drag fold fault. The rock above is sliding over the rock below. As it does the layers are folding back forming small anticlines.

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This shot is also from Sun River Canyon. It's a series of small high angle thrust faults. There is at least four faults visible. In each case the rock to the right is being thrust over the rock to the left.

Andreas

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This one is from about 20 miles outside of Glacier National Park. An interesting geologic feature in GNP is rock assemblage. The older rock has been thrust on top of the younger. In GNP the fault picture here is horizontal. In this shot the fault is still at a high angle. The rock on the left is Cretaceous and is about 60 million years old. The rock on the right is Pre-Cambrian and is about 1.5 billion years old.

Andreas

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