Outside The Interzone: Jul 14, 2013

Saturday, July 20, 2013

Geo 365: July 20, Day 201: Drilled Rock

The first sampling area after the ruckus. Chris left the cores sitting in the boreholes until he'd finished all the drilling, then came back and measured azimuth and dip (compass orientation and departure from horizontal) for each. Below is a crop of the sampled spot.

Photo unmodified. July 2, 2013. FlashEarth location.

Friday, July 19, 2013

Geo 365: July 19, Day 200: Drilling Rock

The rock drill on its inaugural borehole. Chris sampled five of these silty/muddy horizons, working down section, and successfully collected 19 cores. I didn't actually count the total number of holes, but many of the cores fell apart. I imagine the number of holes drilled was nearly double the number of cores actually collected.

In this crop of the above photo, you can see the muddy cooling water flowing out of the drill hole.

Photo unmodified. July 2, 2013. FlashEarth location.

Thursday, July 18, 2013

Geo 365: July 18, Day 199: Ready to Drill

The rock drill on its first start up was a little stubborn, but Chris finally got it going and warmed up. He had already cleared a spot of weathered, broken rock near the top of a muddy/silty layer of the Tyee, which you can see just to the right of the top of the water canister. Donning his ear muffs, he started the engine, and was ready to drill.

Photo unmodified. July 2, 2013. FlashEarth location.

Wednesday, July 17, 2013

Geo 365: July 17, Day 198: Rock Drill

@Allochthonous holding his spiffy new rock drill, prior to its first use: drilling core samples from the muddy intervals of the Tyee Formation road cut shown here. The drill is essentially a chain saw engine with a tubular corer attached to the axle instead of a gear to drive the chain. The pump canister holds water, which feeds through the black hose, to cool the tip of the corer.

Photo unmodified. July 2, 2013. FlashEarth location.

Tuesday, July 16, 2013

Geo 365: July 16, Day 197: Devils Punchbowl

Looking down into Devils Punchbowl, a collapsed sea cave at the park of the same name. Numerous small faults cut through the Astoria formation in this area, and I assume two or more intersected to create this zone of weakness and susceptibility to erosion. During especially low tides, one can access this cave from the north cove. I've been into it a few times, but the first was sight-seeing, and I wasn't paying very close attention to the rocks.The others I was shepherding middle schoolers, not paying much attention to rocks. So I need to get back into it at some point and see if I can actually spot the faults. But I know the next target for Dana and I in this area is the ring dikes in the opposite direction.

Photo unmodified. July 2, 2013. FlashEarth location.

Monday, July 15, 2013

Accretionary Wedge #58: Signs of Doherty Grade

Evelyn has turned her geological road signs meme into Accretionary Wedge #58. I don't have a lot of signs photographed, though I am starting to accumulate some of roadside interpretive signs. But the following is my favorite, and a crop is featured as the header on my Twitter profile. Driving east out of Lakeview, Oregon on Route 140, about 45 minutes out, one crosses Guano Valley, just north of the Nevada-Oregon Border. On the first visit, one realizes with stomach-churning uneasiness that the road goes right up to an enormous cliff... then up it.

Taken during 60 mph reconnaissance geology, with Dana Hunter at the helm, you can see the lighter stripe of the road grade climbing the side of the Basin and Range escarpment. The road is actually very well engineered, and there's more berm than you realize, but the sheer drop off and lack of a guard rail can make it feel more like you're driving up a balance beam than a two-lane road. The first trip up Doherty Grade is definitely a memorable experience. Heading into the turn at the base...

...feels a little like reaching the first crest of a big roller coaster. "Dear Lord, what have I got myself into!?" Then just after starting the grade proper, they decided to reassure nervous drivers that, yes, it could be worse. After all, you're driving up a cliff, and rocks do fall off cliffs, right?

It's not terribly obvious at this scale, but just beyond the "Rocks" sign is also what I refer to as the "pointy-headed snakes" warning (winding road).

And yes, there is a pull-out about a mile or so into this climb that I like to stop at. Fortunately, there's not much traffic on this road: it's on the inside of a curve, across oncoming traffic. I've posted a ginormaous panorama of Doherty Rim at Flickr; right-click the image for viewing size options. Guano Valley is notable as the source of the USGS Andesite "AGV-1" geochemistry standard, though I don't think it's available any more, and I've never been able to figure out exactly where it was collected.

Geo 365: July 15, Day 196: Bioturbation

Bioturbation, probably feeding traces/burrows, in a siltstone or fine grained sandstone in the south cove of Devils Punchbowl State Park, Oregon. This is a loose boulder, but it's certainly from the cliffs nearby, which are composed of the Miocene Astoria Formation.

Photo unmodified. July 2, 2013. FlashEarth location.