Geology on the Road: Austin, NV

Austin, Nevada: Just a little bit of the geology you can see in Austin - either while staying there or when driving through. At the very far west end of town, right about the time the speed limit is increasing on your way downhill out of town (or decreasing on your way uphill into town), you can see a small powder house in an adit dug into Jurassic quartz monzonite on the north side of the road by old-timer miners. The photo of the powder cache door looks more or less northwest and was taken while heading west out of town. If you are coming in from the west, you will probably have to pull out on the side of the road to even see this.Above, just uphill from the powder house, toward town and a little to the east: a nice exposure of the quartz monzonite, with its inclusions, pegmatite dikes, and a few small quartz veins. The old-timers reputedly dug on some fairly thin quartz veins for the silver they mined - I haven't knocked around in the hills much to see what the veins actually looked like. Above, a nice exposure right across the street (Highway 50 or Main Street) from the Pony Canyon Motel, looking north. This exposure shows several fine-grained mafic dikes in the center (dark colored and steeply dipping to the west) with some sub-parallel, light-colored, coarse-grained granitic to pegmatitic dikes. To the left of the dark-light dike zone you can see a brownish, Fe-oxide-stained zone, which is where you can find a narrow quartz vein or two with strike and dip sub-parallel to the dikes and fractures. The mafic dikes can be considered diabasic, and they look similar to Jurassic dikes at Yerington; the light-colored dike to the left of the Fe-oxide zone might be a quartz-eye porphyry.

These dikes, veins, and associated fractures all cut the highly weathered quartz monzonite that is exposed on the east and west sides of the exposure (right and left in the above photo, respectively). On the west side of this exposure, you can see that the weathered quartz monzonite is cut by numerous thin pegmatite dikelets that strike generally east-west and dip shallowly to moderately to the north, also cut by the dikes, veins, and fractures.

And, not being able to resist playing around, I've included a few One Geology overlays on Google Earth. The first one attempts to recreate the scale of the geologic map shown in an earlier post and reprinted below.
The second just shows a nice view of Austin from the south, using a 2x vertical exaggeration as suggested by hypocentre at Hypo-Theses. The One Geology at this scale is simplified compared to the reality of chopped up, ever-widening Nevada (to quote Brian at Clastic Detritus).Several other geoblogospheric types have played around some with this - go to All of My Faults are Stress-Related and Sismordia - Seismology at Concordia to see a couple more examples of how to use One Geology.

Map from: NBMG Report 40 - Sediment-Hosted Precious-Metal Deposits of Northern Nevada - Road log/trip guide for SEG precious metals field trip, fall 1984, by J. V. Tingley, H. F. Bonham, Jr.

Sitemeter Down

For those of you who have sitemeter displayed on your blog page, be aware that currently IE7 will not load any webpages with the sitemeter script. And IE7 won't go to the sitemeter site, either! That will be affecting some geoblogospheroids, whose sites I can't link to right now. (I know I know - get Firefox they all say, but people who don't have it, won't be reading your blog.)

Bugs me when I can't even read my own blog! Took the sitemeter thingy off, at least for now.

UPDATE 8/2/2008 4:30 pm PDT: Sitemeter is now working again.

Friday from the Road: Austin, NV

Perhaps by now, you've gotten tired of Middlegate Station and want to move on. Well, here's a place for you: the well-known town of Austin, Nevada, which sits in the center of Nevada, and which used to be the county seat of Lander County (until 1979 when it moved to Battle Mountain, amongst much consternation and outcry by the locals).There it is above - Austin - sitting on the side of the hill on the east side of Reese River Valley. You can see the old mine dumps and bits of granite sticking out here and there.

Oh, did you miss the Reese River when driving through Reese River Valley? It's easy to do. I just happened to get a picture of it from Highway 50. In the photo above you can see the Toiyabe Range on the east (left) and a bit of the Shoshone Mountains on the west (right). The Reese is not a big river, as you can see - usually you can leap across it with a large step. In places, it can be wide enough to put a canoe in, although that depends on the time of year, the year itself, and the section of river in question. Trust me about the canoe thing.

Well, here we are in Austin, at the Pony Canyon Motel, the first of three motels, all on the right (south) side of Highway 50 as you come into town from the west. If you happen to drive in from the east, all the motels are on the far, downhill side of town on the left (still the south!!). If you are going downhill at that rapid speed of 25 mph, you might just miss the motels. A higher speed, whether going uphill or downhill, is not recommended, because Austin has long been known as a Speed Trap. Be careful!

From the Pony Canyon Motel sign in the previous photo, going around the parking lot in a counter-clockwise fashion, we come to this little meeting room - I guess that's what it is (just a table or two and some chairs inside).

Then, a nice view off the corner of Room #5.

Coming around a bit farther, we have Room #3, and the front end of a Prius. As you can see, the Pony Canyon sits in the shade of some nice, tall cottonwood trees. Trees are next to nil at the two other motels.

All the way around the lot, and here is a view of the entrance to the office. You will need a charge card to stay here, because it is not cheap (at least by small town Nevada standards, IMO)!

MOH and I fell for the long-standing tradition of staying in this motel, and after all, it's the only stick-built motel in town. The long-standing tradition of prefering this motel over the other two dates back to 1977 when the Quito Gold Mine was being discovered by former employees of Former Mining Company, geologists who happened to include some of the very same geologists who discovered the Jerritt Canyon gold mine. (Those former employees did not include me; I was doing Other Things in Austin that year.)

One can see some nice greenery and a small garden out the back of the rooms, the back being the south and hot side of the building.

Ah, but one can step out on the cool, north side and sit in the shade, getting away from the heat that has built up inside the room. Sit awhile, smoke a cigar (there are ash trays on the table).

Another pleasant view of the office area, through the screened-in, north-side porch and deck area.

But hey, since there isn't any AC in this motel - next time I will forego long-standing tradition and consider staying in one of the other motels! Like the Mountain Motel.Or the Lincoln Motel.

And because there is no AC in the rooms at the Pony Canyon, you might as well head uptown and shoot some pool somewhere while having a pitcher of beer (if you can find pitchers and pool tables in the same bar, that is!)

Don't get me wrong, though: Austin is one of my favorite places, ever since I spent most of a summer working there and staying in the Lincoln Motel back in 1977.

Pink Playa Phenomenon

On Highway 50 looking west, with the Huck Salt Road turnoff just behind that little hill sticking south into the playa.

While driving through Four Mile Flat on Highway 50, between the turnoff to Sand Mountain on the east end and the dirt road to the Huck Salt Mine in the middle of the flat, MOH and I recently came across a somewhat common playa phenomena, wherein bacteria growing in the salty brine and partly dried-out salt crust left behind after the water evaporates (Google Maps). Fortunately, there is a regulation road sign for Huck Salt Road on the west side of Fourmile Flat, so you won't get lost...

...and a sign at the turnoff to Sand Mountain on the east side of Fourmile Flat.

Pinkish salt flats as seen from Highway 50 looking east toward the turnoff to Sand Mountain.

The three photos above show closer views of the pink to red to orange salt on the south side of Highway 50.

And two more views, above, one showing some actual water. In my experience, the pinkish salt does not occur year-round. It appears to need the right combination of water and evaporation, and possibly the right temperature.

The color is caused by salt-loving bacteria which are known as halophilic bacteria, part of the ancient archaebacteria kingdom or Domain Archae. Wayne's Word has this - and a lot more - to say about halophilic bacteria:

The bacteria produce a red carotenoid pigment which is similar to that found in tomatoes, red peppers, pink flamingos, and in many colorful flowers and autumn leaves. [Flamingos actually get their carotenoid pigments from their diet of shrimp and other crustaceans.] Carotenoid pigments are also the source of Beta-carotene, an important antioxidant and the precursor of vitamin A.

References:

Armstrong, W. P., 1981, The Pink Playas of Owens Valley, Fremontia 9: pages 3-10. 

Armstrong, W. P., 1981, Why Owens Lake is Red, Desert Magazine, May 1981, pages 22-26. The Halohandbook.   

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Trilobite for Sale

ReBecca at Dinochick Blogs has already pointed this one out, but being a consummate trilobite lover, I just had to pass this on to anyone who might have missed her excellent post.

Besides being able to purchase a neat, colorful trilobite - for play, for teaching, or for decorating one's house or improving upon one's otherwise dull-looking collection of rocks and minerals - you can get a collection that includes replicas of 500 million-year-old animals of the Burgess Shale from the Royal Ontario Museum online. (The trilobite comes with the collection - see ReBecca's photos replete with scale bars, like this one, or go to the ROM webpage directly for your purchase.)

Trilobite for sale or rent
Olenoides makes a nice present.
Burgess Shale toys all around,
That's as much as I will propound...