Saturday, June 29, 2013

Textures from a Tufa Dome I

Just a quick post in a new, short-lived series of photos of tufa from a tufa dome. The dome is discussed in more detail here, a post which includes directions to the dome from the junction of I-80 and U.S. 95 at Trinity.

Thursday, June 27, 2013

Things You Find in the Field: Old Horseshoe

Recently, while out wandering in the desert two to three miles west of Humboldt House — formerly a resting area on the California trail and later a stage stop — I found this rusty horseshoe of unknown age.
A more traditionally "lucky" view of the horseshoe.
The underside of the horseshoe.
I have no idea how to discover the age of a rusty old horseshoe, and it looks like a fairly standard one to me, not that I'm really in the know.

Monday, June 24, 2013

Tufa Dome north of I-80–U.S. 95 Juntion

A somewhat eroded tufa dome.
Every now and then, when driving east or west on I-80 in northern Nevada, I get off and check out local items of geological or historical interest.

Here I've stopped at a partly eroded tufa mound located north-northeast of the junction of U.S. 95 and I-80 (map and location below). It's fairly easy to reach with an SUV or other 4WD vehicle.
View of the tufa mound looking northward toward the low hills of the Trinity Range.
Another view, this time with more of the basaltic-looking hills in the background.
Closeup of some the tufa structures, looking in toward a small crevice.
I tried focusing on the tufa textures in the foreground and background at the same time, but it was a cloudy day: not quite enough light.
Tufa covered by bright orange lichen on the north-facing side.
Looking south toward the U.S. 95–I-80 junction, and 95 beyond that going south toward Fallon.
The view above shows the eastern part of the White Plains of the Fortymile Desert, with the west end of the Mopung Hills of the West Humboldt Range in the left part of the photo (MSRMaps location).

Embedding this map directly from Scribble Maps (see original map here); didn't work, so I imported the "scribble" to Google Maps.

To get to this particular tufa dome (there are many in the general area between a few miles east of Nightingale Hot Springs and Toulon), take I-80 exit 83 from either the eastbound or westbound lane. If going west, turn right nearly immediately (at a location known as Trinity, now with former buildings gone), and follow a paved road to the north-northwest. If going east on I-80, turn left from the off-ramp onto highway 95, go under the I-80 underpass, follow the road as it curves to the east, and turn left on the same paved road just before entering the on-ramp loop for Reno and points west.

Drive about 0.3 miles on the paved road until you reach a power line access road, a dirt road that may not be appropriate for cars. Turn right, taking this road for about 0.7 miles, including a deviation from the power line itself, where the original road is at least partly washed out. You will then reach just the right sand wash road, which will take you up to the tufa dome (and beyond to a small prospect). I can't say for sure that the turn I marked into the wash road is exact; look for tracks heading in the right direction.

Careful examination of a Google Maps or Google Earth view of the area will reveal another road that comes in from the west just uphill from the tufa dome. I have no idea whether this road will work as an access route, but it will (or would?) go past a couple other domes.

While there, note the several Lake Lahontan shorelines and the desert pavement.

Friday, June 21, 2013

Seeing Geology in Patterns

"This month’s Accretionary Wedge topic is “Seeing Geology Everywhere.” Like many geologists, I often see geology in places where there are no rocks. ...

"Do you see geology in unexpected places? Do you often find yourself viewing the world through geology-tinted glasses? Do you have any adorable cat pictures that could be used to illustrate geology?"

     – Evelyn Mervine, Accretionary Wedge #57 call for posts.
Stucco plaster wall texture by Sherrie Thai, some rights reserved.
It began a long time ago: maybe I was about 8 or 10 years old, and I'd stare at the wall next to my bed when trying to sleep. I'd see land masses or continents in the wall texturing, something that perhaps came from my early love of maps and globes, which naturally showed countries and continents. In fact, my brother and I had played a game in the back yard on lazy summer days: while looking up at the afternoon cumulus clouds passing by, we'd name them as though they were foreign or alien land masses of the sky. And then we would play a form of the floor-is-lava game, wherein we'd have to jump from the shadows of the cloud continents in order to not fall out of the sky (because we'd be imagining ourselves on the clouds, not on the ground).

What happens now most commonly, is that I'll be working on some geological problem or project, and I'll start seeing textures or patterns related to certain rocks or maps in floor tiles, walls, trees, clouds, or anything else that happens to resemble some geologic texture or map pattern.
Recently, having spent a lot of time looking at certain hydrothermally altered rocks, I noticed this floor texture that appeared nearly identical to a patchy quartz-sericite alteration style with irregular to wavy chloritic seams.
Enlargement of floor pattern.
Then, while taking photos of clouds the other morning, I noticed this pattern that reminded me of a vein with horsetail structure.
Cloud picture with added lines.
And finally, I often notice a color in the clouds that reminds me of the anomalous Berlin blue birefringence color typical of certain chlorite minerals.

Friday, June 14, 2013

Update from the Lake: Hornets' Nest

It's a beautiful thing, but has got to go.
And, AFAIK, it's gone by now. At this stage, it reminds me of a delicately spun, upside-down dreidel. I think you can just barely see a few of the little suckers up near the top: the black variety, not the more common (in our area) yellowjacket type.

Monday, June 10, 2013

Update from the Lake: Baby Robin Edition

It was MOH that first spotted the baby robin perched on a limb in the lilac bush. I took a few quick pictures through the screen door; the first photo reflects a funny blur and graininess that must be from the screen. I then went outside and carefully creeped [crept?] down the back sidewalk for a better view:
A peek-a-boo through the leaves.
After quietly moving onto the back deck, I found that one reason for the graininess and blur of the first photo was that I needed to use manual focus, an awkward process because the camera kept jumping back to an infinity setting, requiring refocusing between most shots.
I then got brave and zoomed farther using the digital zoom, while continuing to focus manually. I don't usually use the digital zoom because the blur seems greater than enlarging a photo made with max optical zoom.
A little baby robin gets fidgety.
Oh! Mom or Dad has come for a feeding!
Before the feeding, the little robin flapped its short wings in anticipation; I had the camera zoomed all the way out and was trying, in vain, to manually focus, so got this blurry photo:
Our baby robin catches just a tiny bit of air, with feet still attached to the branch.
MOH and I thought the robin was out of its nest prematurely, and we wondered how it would fare. Not long after I took these photos, the bird was no longer in the bush, but it likewise wasn't on the ground anywhere nearby. So we don't really know what happened.