Day #50 Deskcrop: Vesicular Porphyritic Basalt

We’ll end the work week with a deskcrop of Quaternary basalt from the McKenzie Pass region of the central Oregon Cascades. This sample is from a relatively young (~1.5 ka) lava flow, just east of the Dee Wright Observatory on Oregon Highway 242. The sample has both vesicular and porphyritic textures, and thought the former didn’t photograph well, one can see small phenocrysts of both olivine and plagioclase, especially if you zoom in to a larger version of the photograph.

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Vesicular Porphyritic Basalt

Explore this and all of my 2010 Deskcrops and Outcrops in Google Earth!

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