Angular Unconformity Along OR Hwy 207 To Mitchell

Angular Unconformity

I love geology. I went to school to study it. So when I travel, I like to read about the geology of the places I visit and the roads I travel. In hindsight, I wish, now, that I’d have bought and looked through the Roadside Geology of Oregon, by Marli B. Miller *before* rather than after I’d driven to John Day Fossil Beds National Monument. At least, then, I would have been able to follow the mile markers and understood what I was seeing.

Anyway, I’d stopped here because I happened to turn my head to look at the scenery right when my car was passing by these awesomly-colored outcroppings. Turns out, my inner geology radar must have been working intuitively. What you see here is called an angular “unconformity.” An angular unconformity is – in easy terms – when you see tilted beds (the green and reddish outcropping of beds) overlain by straight beds (the red-brown lines of columnar basalts you see above. It shows there is a gap in the geologic time record. So, if you are following a series of formations along a geographic distance, you might suddenly see that one formation or sediment layer of that formation is totally missing from the order of deposition, and all you see is this contact line dividing angular tilting beds from straight layers above. Any of this make sense? If not, then just admire the pretty landscape.

This image was captured using my new Sony Alpha a7r IV and 24-105mm lens. I am loving this camera!

Copyright Rebecca L. Latson, all rights reserved.

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Filed under Geology, HDR, Landscape, Oregon, Photography, Sony Alpha a7r IV, Travel

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