Saturday, February 9, 2013

Geo 365: Feb. 9, Day 40: Dune Crest

Standing on the dune crest of the first dune, south of where the trail debouches into open sand, at Eel creek. The view is to the east, over the coast range, and there's some nice festoon cross bedding in the knobs in the mid-ground. This area is part of the John Dellenback Dunes Trail. I like getting out on the sand, but the idea of slogging through 2.7 miles of it to what is undoubtedly a gorgeous, secluded beach, then the same back, has just never appealed to me. On the other hand, I've stayed at Eel Creek Campground a few times- it's much closer to the dunes than the day use area, and like many coast campgrounds, the dense shrubbery gives each site a sense of seclusion and isolation. Some sites back right onto the dunes. I would have no hesitation in recommending this spot for an overnighter, if you're a camping type.

Photo unmodified. March 8, 2012. FlashEarth Location- cross hairs on day-use parking area.

Friday, February 8, 2013

Geo 365: Feb. 8, Day 39: Eel Creek

The best spot I've seen for dunes along the central Oregon Coast is at Eel Creek. It's a bit of a walk in, but a pretty easy half mile or so, and very much worth it. This is where the trail rather suddenly turns out of the trees, and into a large area of open sand.

Photo unmodified. March 8, 2012. FlashEarth Location- cross hairs on day-use parking area.

Thursday, February 7, 2013

Geo 365: Feb. 7, Day 38: Darlingtonia

Following yesterday's discussion of how the geological setting affects plant life, I'm compelled to post a photo from Darlingtonia Wayside, a pocket park just north of Florence, Oregon. These odd plants, Darlingtonia californica, are elegantly adapted to capture and digest insects, to supplement the paucity of nutrients available in the water-saturated, nitrogen-poor, soil of this low spot in the dune environment. The geological situation is somewhat different here from yesterday's setting. Obviously, sandy dunes are very water-permeable. Streams coming out of the coast range in this area frequently terminate in lakes on the east side of the dunes, and drain as groundwater to the ocean. In this spot, a low area ended up below that groundwater table, and turned into a peat bog. Because of a lack of aeration in the water, organic material decays very slowly, and the nutrients bound therein are not released. This is exactly the kind of environment in which carnivorous plants compete best.

Photo unmodified. September 21, 2010. FlashEarth Location.

Wednesday, February 6, 2013

Geo 365: Feb. 6, Day 37: Oregon Dunes Viewpoint and Clay

Looking approximately NW from one viewing platform to another viewing platform in the Oregon Dunes. I don't want to try to guesstimate the elevation here, but from the ocean in the distance, you can see we're up at least a few hundred feet. The Wikipedia article says these dunes can get up to 150 meters (~500) feet in height.

What with the heavy coastal rain (The coast gets substantially more than we do here in the valley; we get about 40-45 inches/year, the coast gets 60-80) and temperate climate- rarely below freezing- plants desperately want to colonize these surfaces. However, summers are dry, and there are only a few species that can get roots down deep enough into open sand in a few wet months to tap sufficient moisture during the dry season. A second, more complicated, barrier to colonization is that the sand is dominated by quartz. Typical soils have lots of clay, and clay is the result of weathering of (in particular) feldspar.

Clays are complicated, but very important. In geology, the term has two very distinct meanings: a particle size and a mineral group. In the first sense, it means a particle size of less than 1/256th mm- way tiny. In the mineralogical sense... well, it's complicated. Clays are platy minerals, phyllosilicates, like micas. So they split easily into very thin sheets. Here's the important part with respect to this discussion: first, their inclination to split into sheets means they have stupendous surface area. Second, their composition gives them areas of weak positive and negative ionic charges distributed across those surfaces. This means they bind weakly to all sorts of anions and cations, and can capture them as they're transported by water moving through the soil. That may not seem like a big deal, but here's a partial list of things that clays will glom onto: ammonium, nitrate, potassium, phosphorus salts, and magnesium, among others. That list should ring a bell: it's the major set of soil nutrients needed by plants.

In short, clays allow soils to hold onto nutrients that plants need to grow and thrive, rather than just being carried away by seeping groundwater. Quartz and feldspar don't do that.

Incidentally, the term "clay" is often used loosely, because the things we call by that name tend to be both at the same time: clay minerals are most often clay-sized particles.

Now there is some feldspar in the sand, which is undoubtedly weathering to clays. The problem, in this eolian environment, is that when the wind is strong enough to blow the sand around, it's strong enough to remove clay from the area entirely. While sand bounces and rolls, "saltates," in the jargon, clay just goes airborne, and is probably deposited inland somewhere, or is washed out by rain.

What we're seeing, in the picture above, is an area that has been stabilized long enough that the clays have had a chance to develop without being removed, vegetation of one form and another has grown there long enough that the clays have captured a rich store of plant nutrients. This, in turn, has allowed a mature Douglas fir forest to be established and thrive. If we were to turn and look south from here (see this photo, from this post), we'd be looking over an area of open sand, moving and migrating through the years, and other swaths of forest in the distance.

This patch of forest is almost certainly doomed over a period of decades to centuries, but that's not really a bad or sad thing. Other areas will stabilize, and the process will repeat. While on one hand, geologists cherish life just as much as anyone else, on the other, I think we're more accepting of the idea that, in the long term, we're all dead. Oregon Dunes is simply an environment where "the long term" is shorter than many other places.

And one of the smallest and least obvious components of that environment, clay, is the thing that allows it to happen.

Photo unmodified.  March 8, 2012. FlashEarth Location, cross hairs on the viewing platform on which I was standing when I shot this photo, if you care to zoom in a bit.

Followup- meant to add that clays also cling to water, which means plants that can't colonize open sand, because they desiccate during the dry season, have at least some, if meager, water available year-round.

Tuesday, February 5, 2013

Geo 365: Feb. 5, Day 36: Overlooking the Oregon Dunes

View to the south as we descend from the Yachats Basalt headlands between Florence and Yachats, Oregon. This is the northern end of the longest stretch of coastal dunes in the US, extending from this point to Coos Bay, which is about 45-50 miles in the distance. The Oregon Dunes National Recreation Area covers the bulk of this extent, from the Siuslaw River, about 5-10 miles south of here at the town of Florence, to the Coos River at North Bend and Coos Bay. According to the Wikipedia article, Frank Herbert's classic science fiction Novel, Dune, was partly inspired by his research on this area. Certainly not the desert part, though.

Photo unmodified. March 8, 2012. FlashEarth Location.

Monday, February 4, 2013

Geo 365: Feb. 4, Day 35: Alsea Spit

Looking from a pullout along Route 101, just south of the town of Waldport, across Alsea Bay to the heavily developed Alsea Spit. Oregon land use laws allowed development of a number of these spits during the 1960's and 70's. The seismic and tsunami risks were not really grasped until the late 8o's, and I've seen claims that they weren't taken terribly seriously by the general public until the aftermath of the Tohoku quake, and the relatively small tsunami that followed. I would feel okay visiting a spot like the one we're looking at here, though I would definitely be thinking about fastest escape routes on the way in, and feel a little jittery until we were back on the mainland. But you'd never catch me sleeping overnight in a spot like this, let alone setting up house. This is an extremely hazardous situation.

Photo unmodified. March  8, 2012. FlashEarth Location.

Followup: My, this is timely! "Cascadia earthquake, tsunami could cost Oregon economy $30 billion" Also, the Draft Executive Report that article is about is scary, must-read stuff for those of us living on this side of the Cascades, from southern BC to Northern CA- I'm sure similar risks are in place throughout the region, not just Oregon. The nice part of this report though, is that the risks have been soberly assessed, and there's a plan to address our vulnerabilities. Don't let the 21-page length put you off- there's a lot of blank space, and the font is large, with generous spacing between sections. The number of pages with substanctive information is about ten, and taking into account the layout, it's probably only five pages or less of reading in a more typical, condensed format. Also, it's very clear, and not very technical. Please read this item!

Sunday, February 3, 2013

Sunday Funnies: Living Dangerously Edition

Bits and Pieces
Senor Gif
Bizarro, via Are You Talking to Meme?
Tastefully Offensive
Non Sequitur
Tastefully Offensive
Hammer for Scale
"Fail Whale" The High Definite
"Frosty, the Golem" ChannelAte
Top that, Gandalf. Senor Gif
Derpy Cats
Eat, Sleep, Sniff
Perpetually astonished kitteh is astonished. Sofa Pizza
Bird and Moon
Very Demotivational
Funny to Me
Savage Chickens
One in a series of "Photoshopped Animals" at Now That's Nifty. Chimeras galore at the link.
Bits and Pieces
Tastefully Offensive
The Far Left Side
Amazing Super Powers

Superb Owl

Is everybody ready for a Superb Owl!?

Geo 365: Feb. 3, Day 34: Lava Gutter

A lava gutter, near the beginning of the interpretive trail to the east of Dee Wright Observatory. This is a paved pathway that takes the user into this terribly rugged landscape safely- I don't recall any steps; I'd go so far as to call it handicapped-accessible. There are some narrow spots though, and pre-trip scouting might be wise. Signage is well done and in a few cases, the art is quite charming. Finally, the diversity of features is much greater than I'd have expected. I walked this trail in 2001, before a lot of the signs went up, and while it was interesting, there's no doubt I didn't know much about what I was looking at. I was pleasantly surprised at how much I learned on the trip last fall.

Photo unmodified. October 9, 2012. FlashEarth Location- the rest of the trail is visible as a pair of loops on the right/east side of this view. I have a slew of other photos in this area, but this winds up McKenzie Pass week for now. We'll come back to it later.