Outside The Interzone: Nov 2, 2014

Saturday, November 8, 2014

Geo 730: November 8, Day 677: Blurry Beacon

Sitting below and a bit to the right of the peak on the central skyline, Beacon Rock, a Washington State Park, rises nearly 850 feet from the edge of the Columbia River. Despite the post title, this is actually a pretty clear view, and if our recent experiences with the smoke and haze hadn't been so frustrating, we might have considered crossing the river and climbing it. There a crazy system of trail segments, staircases and switchbacks that allow non-climbers like me to get right up to the summit. It's a strenuous hike but the views- on a clear day- are well worth the effort. In particular, features from the Missoula Floods, the landslide at Bridge of the Gods, the Dalles Dam and the Oregon side of the Gorge are well displayed.

The best generally accessible information on Beacon Rock's geology I've found is here, (it's considered part of the Boring Lava Field, and is much younger than one might guess- about 57ka) and there's some interesting (non-geo) background on its history at the Wikipedia article.

Photo unmodified. October 10, 2012. FlashEarth Location.

Friday, November 7, 2014

Geo 730: November 7, Day 676: Murky Multnomah

It was here that the second consequence of a late, dry autumn made itself evident: the waterfalls were mere trickles. So both of the outstanding scenic qualities of the Columbia River Gorge, the vistas and the waterfalls, were at low ebbs. We parked in the central island of I-84, and walked over to Multnomah Falls for a couple quick photos, but we decided that this was not really a good day to spend in the gorge. Dana wanted to get a better look at Bridge of the Gods, which I was familiar with, but had not spent much time looking at in any detail. So we quickly set off with new plans.

Incidentally, you can get a sense of the size of the upper falls by looking near the bottom center of the photo, where there's a bridge with a couple of people sightseeing.

Photo unmodified. October 10, 2012. FlashEarth Location.

Thursday, November 6, 2014

Geo 730: November 6, Day 675: Smokey Sentinal

The Columbia River Gorge is rightly famous for two scenic aspects: its incredible vistas, and its waterfalls. Above we almost see Crown Point, and if you know where to look, and for what, you can make out the silhouette of the Vista House at its summit. The vistas were not so incredible on this day. Shifting winds had brought smoggy haze from Portland, and smoke from fires in eastern Oregon. Dana and I were disappointed.

Photo unmodified. October 10, 2012. FlashEarth Location.

Geo 730: November 5, Day 674: Willamette Falls II

Even though, as I mentioned in the previous post, the water level was quite low for mid-October, the Willamette River is substantial even in dry conditions. Here we're looking at the upper portion of the amphitheater-shaped falls, and there's plenty of water moving.

This is an easy pullout on north-bound Route 205, which bypasses downtown Portland, and takes those of us from the Willamette Valley to PDX and The Columbia Gorge without dealing with the downtown's congestion. I don't believe there's access to this stop for those coming southward. It was the Gorge, in fact, that was our intended destination on this crisp fall day.

Photo unmodified. October 10, 2012. FlashEarth Location.

Tuesday, November 4, 2014

Geo 730: November 4, Day 673: Willamette Falls I

On October 10, 2012, we hadn't had anything but a few sparse showers, and those were in early to mid-September, so the water was quite low. As you can see, the fall colors were pretty nice, by Western Oregon standards, but we were definitely antsy for our fall rain. The lack of precipitation would shortly play a major role in changing what we had decided to do on this day. The size of the driftwood logs resting on the falls, though, gives a sense of what a more swollen river can accomplish. During the great flood of 1996, the falls were barely visible as a riffle in the torrent. See, for example, this photo (several other good ones at this page). As I mentioned yesterday, the bedrock here is Columbia River Basalt.

Photo unmodified. October 10, 2012. FlashEarth Location.

Monday, November 3, 2014

Geo 730: November 3, Day 672: Rooted in Geology

The factor that drew settlers to Oregon was its rich farmland, but the factor that shaped the first incorporated city west of the Rocky Mountains was geology. Skipping inland and north from the previous post, we find... Yes! More basalt. Specifically, more Columbia River Basalt. Here it forms a resistant lip over which the Willamette River pours, creating the largest waterfall by volume in the Pacific Northwest (see note). That sort of hydraulic head is a wonderful source of cheap power- early on, mechanical, later, as you can see from the sign, electrical.

Note: Celilo Falls, in the Columbia River Gorge, was the most voluminous in the PNW, and it certainly deserves the title, but it was inundated by the construction of the Dalles Dam. I'm very sorry to have missed it. Among other interesting trivia, "Celilo was the oldest continuously inhabited community on the North American continent until 1957..."

Photo unmodified. October 10, 2012. FlashEarth Location.

Geo 730: November 2, Day 671: Unconformal Contact

In this final photo from our mid-July coast trip, it's clear that the contact between the Columbia River Basalt and the underlying Astoria Formation is not conformal- that is, the basalt is not resting on a single bedding surface, but cuts across them. In particular, if you look at the contact just above where the small wave is breaking on the left, you can see the basalt protruding down into the sediments, but just a bit to the right, at the water's edge, the contact is significantly higher.

Photo unmodified. July 15, 2014. FlashEarth Location.