Monday, November 3, 2014

Geo 730: November 2, Day 671: Unconformal Contact

In this final photo from our mid-July coast trip, it's clear that the contact between the Columbia River Basalt and the underlying Astoria Formation is not conformal- that is, the basalt is not resting on a single bedding surface, but cuts across them. In particular, if you look at the contact just above where the small wave is breaking on the left, you can see the basalt protruding down into the sediments, but just a bit to the right, at the water's edge, the contact is significantly higher.

Photo unmodified. July 15, 2014. FlashEarth Location.

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