Monday, January 26, 2015

Geo 1095: January 26, Day 756: Winter Falls Pillows?

This is Winter Falls, on the next drainage south from North Falls, so named due to the fact it's more of a steady drip than a waterfall by mid summer. There are at least two Columbia River Basalt flows, with the boundary visible as the recess through the upper middle of this view of the cliff. About halfway up from that is another boundary, but I'm suspicious that's a textural change within a single flow- from hackley jointing to columnar jointing, for example, rather than a third lava flow. Something I hadn't noticed until reviewing the photos, though, is that the upper portion of the lower flow and lower portion of the upper flow appear to have a pillow-like aspect to them... but I can't... quite... tell... at the best resolution of this shot. It's also at a spot where hikers are making a prolonged, steep climb, and all they can think about is "Get me to the top, now!" So not the best spot for thinking about what you're seeing, geologically. But if I ever get back here, pillow basalt is definitely something I'll seek evidence for or against in outcrops closer to the trail where I can get a better look at textures.

Photo unmodified. August 30, 2012. FlashEarth Location

Sunday, January 25, 2015

Geo 1095: January 25, Day 755: Another Pool

Another pretty pool on the hike from North Falls to Winter Falls at Silver Falls State Park. I quite possibly wouldn't have posted this one, but Anne liked yesterday's shot and sent me a couple links to relevant papers (both PDFs) on pool and riffle morphology. I haven't had time to look them over carefully (Honestly, I've just read the abstracts thus far.), but the first discusses how large woody debris (notice the lack of such in today's and yesterday's photos, compared to the left side of this one) influences characteristic pool spacing. The second involves an idea I hadn't heard before, "velocity reversals," but which makes intuitive sense to me. It's the idea that at low water, pools are lower velocity, but experience higher velocity than riffle areas during high water. This means that pools get scoured during high water, but riffles are depositional environments in those conditions. When the stream returns to a lower stage, it no longer has the competence to move the debris deposited in high water.

Photo unmodified. August 30, 2012. FlashEarth Location (pretty much guessing on this one too, but right general area).

Sunday Funnies: Muzzled Edition

Bird and Moon
V-yctoria
Gone Into Rapture
"Kitty remembers stupid thing you did just yesterday." Senor Gif
Wil Wheaton
"Has science gone too far?" Tickld
Dierdre Treacy
Yeah? I'd take that job. Bad Newspaper
"I made soy milk." Tastefully Offensive
"A recap of the State of the Union Address." Tastefully Offensive
Tastefully Offensive
Blue Gal
Tastefully Offensive
Senor Gif
Blackadder
Two of many "brilliant shower thoughts," at Tastefully Offensive
Tastefully Offensive
"Gotta pee. Gotta pee. Gotta pee." Sober in a Nightclub
Cyanide and Happiness
What Would Jack Do?
"Sesame Street has gotten really wild..." Senor Gif
"If Bryan Cranston and Neil Patrick Harris had a baby." Tastefully Offensive
Darius Whiteplume
Darius Whiteplume
Scariest. Beer. Ever. Senor Gif
Toothpaste for Dinner
Sober in a Nightclub
Pregnancy announcement. Wil Wheaton
Indexed
Sarah Walker
Bizarro
Very Demotivational
Cyanide and Happiness
Spud Comics
Tastefully Offensive
Sober in a Nightclub
Chaos Life
Fake Science
Maximumble
Senor Gif
"She unmatched me pretty quick." Tastefully Offensive
Sober in a Nightclub
Cheezburger
Pygalgia
Very Demotivational
"Catzilla" Tastefully Offensive
 Funny to Me
Tastefully Offensive
Funny to Me
Funny to Me