Geo 1095: May 8, Day 858: McKenzie Summit, Both Sides Now

On the north side of Route 242 (top) we see Dee Wright Observatory. On the south side, the sign marking McKenzie Pass. In both photos, Black Crater provides the backdrop.

Photo unmodified. August 21, 2011. FlashEarth location.

Geo 1095: May 7, Day 857: Black Butte and Green Ridge

The flat ridge on the middle to left horizon is Green Ridge, which marks the eastern fault (system?) of the High Cascades Graben. Black Butte, on the right (south) end of Green Ridge, is a large cinder cone which erupted where magma was able to use that fault as an easier conduit to the surface. A bit to the left (north) of Black Butte, and a bit west of Green Ridge, lies the headwaters of the Metolius River, the east side's equivalent of Clear Lake, but without the lake. (The description of the Metolius' water source at the first link is not entirely accurate; it is believed, with good support, that the source includes the landscape up to, and past, the current Cascade Crest.) The Metolius River simply emerges full-blown as a series of springs over a distance of few hundred yard. I've only been there once, and I didn't have a camera at the time, so no photos. But it's a spot I hope to get back to soon.

In the FlashEarth location, I've backed out far enough to see the two features. Black Butte is the cone just north/above the labeled Black Butte Ranch. Green Ridge runs north-south under the label "Camp Sherman."

Photo unmodified. August 21, 2011. FlashEarth location.

Geo 1095: May 6, Day 856: Volcano Observing

While I have four or five of these couplets, I'm just going to share this one, but I'm sure you'll get the idea. The reason the Dee Wright structure is called a "volcano observatory" is not just that there are great views of a large number of volcanoes,  nor the compass rose on the top platform, but the first floor has a number of windows, or ports, that frame particular peaks, with their identifications and distances on signs below the ports. They're sized in such a way that if a visitor is standing with their face near the port, the peak just fits that frame. This means that more distant peaks have smaller windows. In the top picture, we see Mount Washington, in the lower one, its name and distance, 5.2 miles.

Photo unmodified. August 21, 2011. FlashEarth location.

Geo 730: March 25, Day 449: Goose Lake

Goose Lake proper is a few miles south of the downtown area of Lakeview; here, we're a few miles north of the town. (FlashEarth location, centered on photo location, but backed out to show Goose Lake) So this isn't really Goose Lake, but as you can see, there are quite a few geese. This is classic Basin and Range landscape, and nicely illustrates how, despite its general aridity, ponded basins create an enormously important resource for wildlife. Birds are just some of the most obvious- and transient, in many cases- examples. Word to the wise: the geese here are wild, but quite accustomed to humans, and very aggressive beggars. I believe this pond is somewhat warm as well, though to be honest, I'm not sure I've ever stuck my hand into it to be certain.

To conclude this sequence (August 19, 2011), I want to point out that though the recent photos near Klamath Falls and at Hunter's Hot Springs were the beginning of the day, I started this set on February 6, took a break for a few days to document a record-setting snowfall here in Corvallis, then resumed Feb. 10th. This region is as spectacular as any other in Oregon, but remote, very lightly inhabited, with few visitors, and as a result, not widely known or appreciated.

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 24, Day 448: Siliceous Sinter

Hot water is much, much more effective at dissolving silica than cool water. With some materials, like table salt (NaCl) the change in solubility doesn't change with temperature as much as one might expect. With others, such as washing borax and silica, it's much greater than one expects. With silica, the solubility continues to increase beyond what we think of as "boiling," which is dependent on pressure. If there's significant confining pressure on a volume of water beyond that of the atmosphere, it's boiling temperature goes up- and so does the amount of silica that water can dissolve.

So when pressurized hot water is relieved from that pressure and cools down, it's often carrying more silica in solution than it can continue doing. The silica precipitates, generally as hydrous, amorphous silica, known as opal. Sinter has a characteristic "foamy" texture, like styrofoam. I suspect the circular voids are spots where gas bubbles prevented water from occupying that space, thus preventing silica from precipitating there.

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 23, Day 447: Anthropogenic Geyser

The white pipe sticking up from the surface of the pond near the right center of the photo is the nozzle through which "Old Perpetual" erupts... when it erupts. The story I heard about this, which I won't vouch for, is that a crew was drilling down hoping to get to hotter water, hit an over-pressured steam pocket, and blew the drill string out. Subsequently, the hole and casing served as a conduit for the geyser, which erupted every few minutes. My suspicion, from the sound of it, is that this a a dramatic exaggeration of events- that, yes, they were drilling and hit a pocket of high pressure, but it was simply too hot to be of utility, and was abandoned. Either way, there seems to be widespread agreement that Old Perpetual was not a "natural," discovered feature, but one that accidentally faithfully mimics the physical setup and activity of a natural geyser, as a result of human intervention. As I describe in the post title, it's an "anthropogenic geyser."

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 22, Day 446: Old Perpetual... Not

Three years ago, I posted a piece titled "Oregon's Geyser Geysing Again," then (presciently, in retrospect) followed with the first line, "...though maybe not for long." "Old Perpetual" was the initial impetus for this whole trip, and when we arrived, it was no longer active. Hunter Hot Springs is still a point of interest, but it was rather disappointing that the star of the stage was a no-show. On the other hand, it was a good excuse to go see some of the great geology in Oregon's southeast quadrant, an area that very few ever bother to explore, to their loss. See this post for just a few of the features in the area, some of which we visited, and others which we didn't get to. In the FlashEarth view, the mouth of the geyser is the small white dot in the upper left (northwest) of the northern pool.

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 21, Day 445: Wanton Water Waste

We had actually started August 19, 2011, the most recent sequence, out of Klamath Falls, Oregon. It was a couple hours' drive to Lakeview, which partially explains why the end of the day got clipped so badly. I had hoped to spend the previous night in Lakeview. But driving out of K-falls, I was aghast at all the water going into the air. The Klamath Basin proper gets limited precipitation, though more than drier areas farther east, but quite a bit of runoff from (especially, but not only) winter snowpacks in the southern Cascades. That water serves many needs, from residential (trivial in the grand scheme), industrial (I suspect likewise, in this region), agricultural (enormous), and last but not least, providing enough flow in the Klamath River to support its rich native fish populations, especially salmon. The US has (suppposedly) binding treaties with the Klamath Indians committing to supply enough water to support healthy salmon runs.

To realize just how much of that water is spewed into the rapidly warming mid-morning air was a bit of a shock. The realization that most of it was to irrigate fodder for cattle, which themselves consumes vast quantities of water, was almost angering.

Photo unmodified. August 19, 2011. FlashEarth Location (approximate).

Geo 730: March 20, Day 444: Around Virgin Valley

A final shot of the warm pool. A group that I believe calls itself "Friends of Virgin Valley" (I can't find any info about them on the net) has taken a fantastic role of maintenance and restoration here. From rebuilding and mortaring the shower house and wall around the pool, to clearing algae from the pond, installing the fence, sidewalk and benches, these good folks have used their own sweat and private donations to restore an installation that was on the verge of utterly falling apart in the late 80's.

I mentioned Thousand Creek Canyon in passing yesterday, and I want to spend some time on it simply because it doesn't seem to be a widely known feature that is quite spectacular in several ways. It's a narrow, vertically walled cut, mostly into very competent rhyolite similar to the outcrop to the west along 140 (See March 11- March 17). The sheerness of the walls combined with the narrowness of the gorge, flatness of the floor, it's more-or-less east/west orientation, and apparently year-round water flow (though very low at times), all work together to create a lush, cool, and verdant microclimate that one doesn't expect at all in the midst of this arid land. It's like a lawn, in places. Though Sharkey originally took us in to look at a contact between two rhyolite flows, I've long forgotten exactly where that spot is, or what made it notable. Normally when I've visited the spot with others, it's more out of ecological interest than geological. And sightseeing... it's utterly beautiful!

Getting into it is a bit problematic; the mouth is clogged with small willows, brush and beaver dams, and it's been different every time I've been there. There are pretty clearly occasional large flow events, which rearrange the entrance and deposit woody debris at surprising heights above the canyon floor- 15 to 20 feet. At any rate, the first bit is tangled and slow going, but keep pushing toward the north side of the canyon. There, turn into the canyon, and follow the rudimentary path. Once you reach the more vegetated areas, the path disappears and reappears as options to spread out are available or not. I know some people have pushed all the way through to the far end, but I'd guess I've been no more than a mile or so into it. It does get rugged. But it's an amazing thing to experience. In this FlashEarth view, you can see the entire canyon, with the downstream end of the canyon under the crosshairs, and a sweet bit of inverted topography at Railroad Butte. This is a spot where a basalt flow followed a drainage, making the infilled, lower area more resistant to subsequent erosion. This in turn caused the originally low area to remain high while the originally higher ground around it has eroded down- effectively inverting the topography.

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 19, Day 443: Eternal Shower

The shower house at the Virgin Valley Campground is a kick. Anyone who's done desert camping knows how the scarcity of water can lead to, shall we say, some sticky (and stinky) situations. Personal hygiene with a shortage of water is not trivial. Often one ends up paying for a metered shower which gets one enough time to lather up, then paying again to rinse off. Or else what amounts to a rinse in some natural source of water that one doesn't want to contaminate with soap/shampoo. This location was a CCC camp where I imagine a fair number of young men (though I have no clue just how many) were doing hard labor under the hot desert sun; you know they weren't going to be happy about staying unwashed for any significant amount of time.

The solution? Shove pipes down into the same warm aquifer that feeds the pool. Yes, it's tepid, lukewarm at best, and the flow isn't large, but this shower house has a pair of heads that run literally continuously. As in all the time. Forever (in human terms). It's a real pleasure to stay in a free desert campground  to begin with; add an eternal shower, (not to mention the warm pool) and I'm practically drooling. Also, note to the right of the "Do Not Wash Vehicles" sign, on the back side of the concrete pad, is a standing spigot. This taps into the same aquifer, so the water is lukewarm. I've mentioned before that it's a good idea to carry plenty of water when you're toddling around in arid environments; it's also a good idea to know where sources of safe water are available. This is one. When I've camped here, I've made a point of topping off our containers before leaving.

As best as I can tell, the CCC operation that created this camp- and undoubtedly the shower house and improvements to the spring- was a quarrying and stone working operation. If you enlarge the picture and look carefully at the blocks making up the walls of the building, you will see they're made of an attractive, pink, nicely laminated tuffaceous siltstone. You'll find similar rock in buildings throughout the region, and I suspect this location is the source of all of it. I've only been to the spot once, out of the maybe fifteen times I've visited the area, but the quarry is here, a couple miles north of the camp. I'm not sure whether it's okay to visit; the cabled-off gate doesn't make it clear whether the road is simply closed to vehicles, or to pedestrians as well. We walked in, and some of the equipment from the operation- very rusted and nonfunctional- was still present at the time (this would've been late 80's). One could get a pretty good idea of how the dimension stone was carved out and removed. In addition, the overburden of the target stone was full of rounded obsidian clasts, as we saw in the road gravel at the rhyolite outcrop. However, it was clear from the disuse that this spot is not the source of gravel used on current roads. Should you visit the quarry, treat it as an archeological site, because that's what it is. Don't mess with, break, or remove any artifacts, and don't leave anything behind. It's a fascinating spot that records a brief period of US history, and along with the campground and other structures, is a part of our collective heritage.

Backing out a bit, and putting everything into perspective, this is the layout of the area. I'll discuss Thousand Creek Canyon, which looks to me like an antecedent stream carved into a horst block, tomorrow. And a final note: Despite there being one shown, the road goes from the camp up to the mouth of the canyon, but does NOT cross the stream. And the road segment between the quarry area (which is close to the refuge headquarters) and the mouth of the canyon is closed off.

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 18, Day 442: A Swim in the Desert

The warm spring in Virgin Valley is a very special spot to me. It's not all that warm, perhaps body temperature, though I've never actually measured it. But you can see, it's quite sizable as these things go, and about shoulder to neck deep in most areas. The bottom is gravel, not muck, which is a nice change from many warm springs, and if you grab a handful, you can spot little tiny gem opals. They're not common, and as I say, they're tiny, on the order of a millimeter, but hold the pebbles in the sunshine, and you can spot dazzling flashes of color, most often blue, from what appear to be glassy blebs. There are scads of little fish that look like guppies, which will amusingly mistake hairs on one's skin for worms, and worry at them. It kind of tickles. This pool is at the south end of a fairly large, free campground. It's not the most comfortable camping spot in the world- the ground is rocky and hard- but there's so much to see and do in the general vicinity, and this camp is very conveniently located for day excursions.

Unfortunately, we had squandered so much time on this day... well, not so much wasted, but seen other, unplanned, spots... that we only had a half hour or so before we had to turn around and head back to Lakeview. I have a few other photos of this spot coming up, and I'll squeeze in some descriptions and locations nearby, which sadly, we didn't get to on this trip.

It's no exaggeration to say Virgin Valley is one of my favorite places I've ever been to!

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 17, Day 441: Walking the Cut

Another shot by Dana, from this post. I've gone into "scan mode" here. Many people conflate the meaning of "scan" with that of "skim," incorrectly. Scan means to examine intently, skim, to examine at a glance, superficially. Here, I'm amused by how fixated I apparently am on the rocks. I love this state of mind. I'm simultaneously alert to my total environment and focused intensely on a very narrow aspect of it. I think geology is about as close to nirvana as one can get. With hammers.

Photo by Dana Hunter, unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 16, Day 440: Colorful Coatings

I realized that despite the few photos I took at this rhyolite outcrop, Dana got some good ones too. The above photo, from this post, shows a pretty sample with its vesicles infilled with opal and agate. The agate tends to be a flat white or colorless and translucent at this location, and the opal tends to be vividly colorful- generally reddish to orange and yellow, but occasionally a dirty green. The texture of the opal below the tip of the hammer is called "botryoidal," an allusion to bunches of grapes. If you look at the full-sized image, you can see that spherulites are prevalent throughout the ground mass.

Photo by Dana Hunter, unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 15, Day 439: Sedimentary Obsidian

Yes, yes, I know, obsidian is volcanic. But this obsidian is also sedimentary. The road gravel here is full of rounded clasts of this volcanic glass. I don't know where it crops out, or if the original erosion surface even exists anymore, but clearly, there was at one point an obsidian dome or flow that was exposed to enough running water that cobbles and gravel were transported some distance to round them- which wouldn't necessarily be very far.

It's fairly easy to get some very, very pretty examples of conchoidal fracture from these. The "trick" with glassy rocks like this is to *gently* tap the rock. If you whack on these as you would with a more typical stone, you'll end up with shattered splinters, and more likely than not, blood. The other part of the trick is to "pluck" rather than strike. It's probably best to show this in a crude picture:

Striking the obsidian cobble, again, *gently,* as shown will cause it to fracture approximately as illustrated by the thin dotted line. I've spent many hours "breaking glass" to make arrowheads, and have no hesitation doing this with my bare hands (as Dana can attest), but do be careful. The edges are pretty much as sharp as it's possible for any material to be- much sharper than a razor blade. I don't do this with kids around- I don't want them to see how easy it is before they've developed a healthy respect for the stuff and its edges. Another trick is to immediately take a decently large (fist-sized), fairly soft rock of another type, and "brush down" the edges to dull them. Fun! Remember, every time you break open a rock, you're seeing something no one in history has ever seen before.

Note: If you decide to visit this spot, please see Tuesday's comments on safety issues.

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 14, Day 438: Spherulites

A nice example of spherulites, devitrification structures formed when glass crystallizes into minerals like feldspar and quartz. I have the sense that they form quite quickly after an eruption. Vapor phase minerals must, by their nature, form while the lava is still quite hot, and I've seen cases where those minerals coat spherulites- meaning the spherulites formed first.

Note: If you decide to visit this spot, please see Tuesday's comments on safety issues.

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 13, Day 437: Opal and Chalcedony

Dana commented repeatedly, about this stop, that on approach and drive-by, it just looks like a pile of uninteresting, dull gray rock. And it's true: not until you get your nose up against the outcrop do you see the brilliant splashes of color. Most of the wild coloring is in opal; the chalcedony/agate tends to be either white or colorless and translucent. Opal is amorphous (non-crystalline) hydrated silica, while chalcedony is microcrystalline quartz, most often with a fibrous habit that may or may not be visible to the naked eye, but can be made out clearly in a microscope. Under the scope, you can't resolve the individual crystals, but you can see their orientations en mass. Opal tends to have a vitreous luster, while chalcedony has a more waxy luster on broken surfaces. And "agate" is a term that is more useful to collectors of pretty rocks, but to geologists simply means color-banded chalcedony.

Under the chisel tip of the hammer, another lithophysa is visible, with an inner rim of vapor-phase silica, and above the head is a patch of white agate, with a brilliant patch of reddish-orange opal to the left. None of the opal here is gemmy- that is, it doesn't have the shimmering play of color that one would see in jewelery opal. There is gem-quality opal in the area, but sites where it occurs are mostly claimed (there are quite a few pay-to-dig sites in Virgin Valley), and the gemmy material is mostly opaline replacement of wood. Finally, spherulites are abundant throughout the mass.

Note: If you decide to visit this spot, please see Tuesday's comments on safety issues.

Photo run through Paint.Net's autolevel routine for contrast and saturation. August 19, 2011. FlashEarth Location.

Geo 730: March 12, Day 436: Lithophysal Rhyolite

Rhyolite is a high-silica lava, typically 70% (plus or minus a little) SiO2 by mass. In molten form the silica tends to stick together in chains, like a polymer, so it's "sticky." It tends to be quite viscous, or resistant to flow, and ions have a difficult time migrating into stable crystal nucleation and growth sites. Thus, when they cool fairly quickly- and especially if they have low water content (Water acts in an opposite manner to silica: it makes molten rock less viscous and increases ion mobility)- lavas like rhyolite tend to be glassy. And as I mentioned yesterday, this outcrop is quite glassy. I was warned by Sharky on my first visit to this spot that "They're glassy, so be careful." Being the bright student I was (and dressed in a tee-shirt and shorts, but thankfully, also thick glasses), I walked up to a solid exposure and gave it a sharp thwack with my hammer. Then spent several minutes picking out splinters of glass from my arms, legs and face. Ah, the joys of field geology...

Glass is not "stable" in a geologic sense- that is, it would "rather" be in mineral form, such as quartz and feldspars. Glassy rocks are referred to as "vitreous," and processes and textural forms associated with that glass turning into mineral crystals are referred to as "devitrification (structures)." This photo is crammed full of such structures. The most obvious to me are the vuggy vesicles partially filled with agate. The agate is clearly layered from the bottom up, and is a good geopetal indicator- that is, the layering is horizontal, and the flat, open, surface is the direction of "up." (This is the solution to the problem rock I sent along to Cannibal Panda about a year ago, and another sample from this outcrop is pictured several times in that post.) Vuggy vesicles with secondary infilling of this nature are referred to as "lithophysae" (singular, "lithophysa"), meaning "rock flower," and at times, the resemblance to a flower or bud can be striking.

But wait! There's more! If you look carefully at the full size image, you can see that the inside of the lithophysae are lined with a thin (~2-3 mm) ragged coating of silica that was deposited before the agate. This is likely vapor phase silica, possibly tridymite, but one would have to use x-ray diffraction to be certain- they're too fine-grained to distinguish with a petrographic scope. In fact, the only thing one can distinguish in a thin section of this rock is abundant sanidine- a discovery that disappointed, but shouldn't have surprised, me.

Wikipedia just cleared up a ponderment I've had since igneous petrology, lo these many years past... what is the actual distinction between lithophysae and spherulites? Apparently, lithophysae are simply one division of the larger group of devitrification structures known as spherulites. The former are just larger, cavernous (that is, open, with void space) examples of the latter. With another glance at the photo, you should be able to quickly see that the rock is choked with roughly spherical, pea-sized forms; these are spherulites, where a devitrification front radiated outward from a central nucleation point, probably halting when the rock cooled to the point that crystallization was no longer possible.

If that's not enough to flabber your gast, this may represent a rheomorphic flow (See Magma Cum Laude for a good discussion), but I don't know enough to say how likely that possibility is. There is definitely some deformation in this flow. The question is, did the flow erupt as a viscous mass, and flow into place in its current form, or did it erupt as an ignimbrite, settle to the ground, weld into a sticky mass, and subsequently undergo some plastic deformation? The latter would make it a rheomorphic flow. If I knew where the lower contact of this flow was, I might be able to tell- for a simple flow, I'd expect a blocky, brecciated contact, for a rheomorphic flow, the contact would be pretty sharp, and likely start off ashy, then get more vitreous upwards. However, I don't know where that contact is, and don't particularly feel like jack-rabbiting off through the sage in an attempt to find it. As is often the case, I'm content just to ponder the puzzle.

Safety note: If you choose to track this spot down, please see yesterday's safety comments.

Photo run through Paint.Net's autolevel routine for contrast and saturation. August 19, 2011. FlashEarth Location.

Geo 730: March 11, Day 435: Setting the Stage

This is the scene at the best rhyolite outcrop I know of, at least in terms of "pretty." It was getting later in the day, and I was getting tired. When that happens, I'm less focused on getting photos, more focused on staying coherent, and this outcrop is plenty confusing. As a result, I only have a few pictures here. But the primary purpose of this shot is to help establish the location with some notable landmarks. The big hill on the right is composed of horizontal layers of ashy tuff; you can tell in other, accessible, locations that it has mostly been reworked by water, though there are some spots where it looks as if it's more likely direct airfall. The hill looks to be capped with one or more basalt flows. Also in this photo, the farther slope looks deceptively dark due to it being in the shadow of a cloud. The road cut on the left is our target.

The best spot to park is about a hundred yards up the hill (westward) on the north side of the road. There are some real safety issues here, mostly due to traffic. It tends to be very fast in remote areas like this, and as you can tell from this shot, the visibility into (and out from) the cut is basically nil. The best exposures are on the outside of the turn, unfortunately, but the berm is good and wide. The upside of being remote is that you can hear isolated vehicles approaching well before they arrive. Move away from the road as best you can, and turn to face the oncoming vehicle- as with crossing an intersection, everyone is more comfortable when everyone knows that the other one is aware of and paying attention to them. The other issue is the nature of the rock itself: even though it doesn't really look it, it's very glassy. Use hammers carefully, eye protection is a must, and leather gloves wouldn't be a bad idea (though honestly, I've never used them here- but I almost always shed a minor amount of blood at this site). All that said, it was still a spot I stopped at with properly prepared and informed high school students.

And speaking of setting the stage, the valley in the distance is Virgin Valley, one of the few places in the US where one can find gem-quality opals, the site of a CCC camp, and home to a very pleasant warm spring, which was our ultimate goal on this day. Among numerous other features, it's also the headquarters of the Charles Sheldon Antelope [Pronghorn] Refuge. Virgin Valley is very high on my list of "most awesome places you've never even heard of."

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 10, Day 434: Vesicles

Geology has lots of words for things that aren't there- that is, holes. In this case, the holes represent gas coming out of solution in molten rock; you can think of it as effervescent lava. When the lava cooled and solidified, the bubbles remained. We call these vesicles, and the texture, vesicular. It's extremely common in lava flows. This was a loose cobble that had rolled down the slope, so I didn't see the actual exposure, but often, the vesicles are more abundant toward the top of the flow- just as with bubbles in water, they tend to float to the top (though lava is much more viscous than water, so the rate of rise is slower). The concentration of bubbles to the top of a flow can give an observer a good sense of what direction was up at the time. In this area, though, I have no reason to believe there has been significant folding or deformation to make the question of stratigraphic "up" an issue of concern.

Photo unmodified. August 19, 2011. FlashEarth Location.

Geo 730: March 9, Day 433: Jointy Plating

This is the same rock as yesterday's, turned sideways to show how the platy jointing breaks this exposure into thin sheets. It's an odd phenomenon that I don't understand, and that by itself appeals to me.

Photo unmodified. August 19, 2011. FlashEarth Location.