Saturday, October 12, 2013

Geo 365: Oct. 12, Day 285: Phantom Ship

The Kerr Notch pullout is a nice, pick-nicky spot, with the best roadside view of Phantom Ship in the park. We were here shortly before sunset, so the lighting wasn't the best, but still, a lovely view. Eagle Crags loom behind the "ship."

Photo unmodified. August 18, 2011. FlashEarth location.

Friday, October 11, 2013

Geo 365: Oct. 11, Day 284: Remnants of a Zoned Magma Chamber

The bimodal composition of this deposit is quite apparent in this shot of Dana framing a photo at The Pinnacles. An article and an abstract referred to me by @Volcanologist and @eruptionsblog, respectively, may be of interest to those wanting more detailed information. Among other things, those two sources have clarified the compositions of the two phases: the lighter is rhyodacite, and the darker is andesite. The article, maddeningly, flaunts the term "supereruption," which I abhor, but the discussion is good. The abstract is dense (as they tend to be), but useful, and focused specifically on the compositional zoning of the Mount Mazama magma chamber.

Photo unmodified. August 18, 2011. FlashEarth location.

Thursday, October 10, 2013

Geo 365: Oct. 10, Day 283: Boundary Gate

The Pinnacles trail, atop the flat ignimbrite deposits in Kerr Valley, is an easy, horizontal half mile, one way. The Crater Lake Institute goes so far as to say "Accessible to wheelchairs with assistance." It ends at what appears to be an abandoned entry gate. There was some children's science/geography magazine I was subscribed to in early elementary school- darned if I can remember what it was called- that showed a photo of this entry in use. It might have been an older picture even at the time, because the trees that have grown back on the former road look pretty mature. I'd have a hard time believing this gate/checkpoint was closed much after the 60's.The stonework has that "look" to it of a CCC project; much of western park lands' architecture dates to the 30's.

Photo unmodified. August 18, 2011. FlashEarth location (approximate).

Wednesday, October 9, 2013

Geo 365: Oct. 9, Day 282: Glowing Spires

We visited the pinnacles shortly before sunset, which gave the light a warm quality that's difficult to capture. Photos weren't easy; there was a lot of glare looking upstream. On the other hand, I found a trick that made for some very nice shots: get the lens shaded. I think in this case I simply held my left hand in such a position as to cast a shadow on the lens. In others, I stood in the shade of foliage. In either case, shoot under the object casting the shadow. The duel composition of the tephra is apparent here, and creates the illusion of luminosity in the deeper deposits.

Photo unmodified. August 18, 2011. FlashEarth location.

Tuesday, October 8, 2013

Geo 365: Oct. 8, Day 281: Toes of the Slope

Runnels cut into to weak, erodible, rhyodacite tuff, truncated by meanders of Sand Creek, give the appearance of an enormous set of toes. The Old Gods arise!

Photo run through Paint.Net's autolevel routine to cut through glare. August 18, 2011. FlashEarth location.

Monday, October 7, 2013

Geo 365: Oct. 7, Day 280: Valley Fill

Looking across Sand Creek, you can see the basically flat surface that was repaved with 200 to 300 feet of tephra when ignimbrites from the great eruption swamped Kerr Valley. The eastern toe of Mount Scott appears in the top left of the photo.

Photo unmodified. August 18, 2011. FlashEarth location.