Last week I took two students on a drive to look at some of the rock outcrops in the area. I often complain that all you ever see around the area are Columbia River Basalts, but we did find some other outcrops too. Our first stop was a whole 1/4 mile from the college parking lot, at the bottom of the hill. From there we got a close up look at the ubiquitous CRBs in the area. The three layers seen in this photo are accross the river valley from the same (but better) formation I posted about in September.
The top layer, characterized by the grayer more blocky rock is the Frenchman Springs member of the Wanapum flow. The broad reddish band in the middle is the Vantage soil horizon, on the edges of the horizon there are some baked contacts where the clayey soils have been baked into a marble. At the bottom, looking more like a talus field in this image is the Sentinel Bluffs Member of the Grande Ronde Flow.
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