More Dust, More Devils

After lunch, I resumed my dusty, devilish trip and drove south-southwest on what used to be old U.S. 40, going under the overpass that I-80 now uses to bypass Lovelock.

As I leave town, a large dust storm looms in the distance beyond the overpass.

Old highway 40 continues on past Lovelock, as I gradually — at the speed limit of 55 mph! — approach the storm.

I always enjoy driving by this lone cottonwood (Google Maps location).

In the picture, you can now clearly see how closely this remanent section of 40 is paralleled by I-80, over there on the right→ (signs are on I-80, as is the semi).

I've now turned more to the southwest, and I have a better view of the dust storm. The dust is blowing along and rising from the Humboldt Sink, end point to the 310-mile long Humboldt River.

Old highway 40 and I-80, side by side, heading southwest toward Toulon.

Granite Point, a smallish ridge of granite on the west flank of the Trinity Range, is just beyond the dark exposure to the right (north) of I-80, which might be basalt. Straight down the road, we're looking more or less toward the center (or south of center?) of the Ragged Top caldera, which was featured somewhat here and here (earlier posts) and in these comments.

Another view of the dust storm on the Humboldt Sink, with sand dunes of Lake Lahontan (Fallon or Turupah Formation? — Geolex does not include all the references about these two formations) and the railroad in the foreground. 

The old tungsten mill at Toulon, with the dust storm raging in the background. 

According to the most recent GSN field trip guide, the mill at Toulon was used over the years (since before World War I) to process tungsten from nearby mining districts including those at Nightingale, Ragged Top, Mill City, and Oreana (Nightingale is off to the west, and Oreana and Mill City are quite a ways to the northeast). It was also used to process arsenic during World War I, and was later used for antimony and gold ores (not sure from where).

A dust devil at the leading edge of the storm, with the West Humboldt Range finally visible across the playa. 

I leave old highway 40 to return to I-80 at the Toulon exit. The old highway can be followed farther on toward the Humboldt Dike gravel bar (location), where at least one trace of the old road gets wiped out or overprinted by 80.

Another view of the Humboldt Sink and West Humboldt Range from I-80.

Looking back. 

I've now passed the gravel bar and Highway 95 exit for the Carson Sink and Fallon. The storm can be seen behind me; the Forty Mile Desert is just south of me beyond I-80.

A dust devil, leaning in the still roaring wind, on the Forty Mile Desert. 

Tumbleweeds roll out to try to block my path. 

Dust blowing wildly just east of Nightingale Hot Springs (interesting write-up about Nightingale, Toulon, and Oreana here at Backyard Traveler by Rich Moreno — a blog well worth reading if you want to learn more about Nevada). 

A distant devil off across the salt flats near Fernley. 

My journey continued onward past Fernley and Wadsworth, into the canyon of the Truckee River, where I was too busy fighting the gusty winds to grab any shots of dust or devils.

Field Trip Day 2: Pinson Pit Overview

After lunch, the two field trip buses took us from Getchell down to Pinson. All 79 of us (more or less) then stood near the edge of the Pinson CX pit and looked in, while a guy who acted like the safety guy went around trying to get us to back away from the edge. Prior to this pit overview, we viewed some posters and examined some nice-looking, high-grade drill core.

The stitched-together photo above looks mostly west: southwest to slightly north of west from left to right. Miscellaneous equipment and things in the pit are related to currently suspended underground development and exploration, and possibly to ongoing dewatering.
Above, a closer view looking at the north part of the CX pit. The mine dump in the upper right part of the photo is a dump from some old tungsten workings. The upper benches of the pit on the northwest side (right) are in unconsolidated alluvium.
And this is what it looks like on the next to bottom bench of the CX pit: a geology field trip invasion. Geologists on this kind of field trips do a lot of talking and, for some reason, seem to want to examine rocks when the buses are trying to leave!
And why did we go down there, besides the fact that it was there? To look at rocks and to argue over features like this one, above: was the feature caused by soft-sediment deformation or by post-lithification structural deformation? Keep in mind that these rocks are Cambrian or Ordovician, that they were around during two orogenies during the Palaeozoic, have been intruded and contact-metamorphosed during the Cretaceous, and were mineralized and subjected to Basin-and-Range extension during the Tertiary. The immediate pit area is cut by so many faults that developing and maintaining the underground workings has been difficult to say the least. Geologists on the trip did not reach an agreement about the origin of the deformation seen at Pinson. Some agreed that the answer might be both: soft-sed and structural.

Scale for that last photo is unclear, but the plants are probably very small ones (smaller than my hand).

Old Junk in Ophir Canyon

Okay, so yesterday's post was really a lead in and good excuse to get to one of exploration's finest perquisites, that of being able to wander around old mining districts and check out everything left behind by previous operations, sometimes going back to the late 1800's.

The miscellaneous piles of junk and still-standing or semi-standing parts of mills and old buildings that I found at the mouth of Ophir Canyon is supposedly part of the old Warfield-Ophir group of claims (any current claims may have different names by now), according to Kleinhampl and Ziony, 1984. The area was worked for tungsten (and molybdenum?) in the past, with the most recent mining efforts possibly being from the mid-1970's, but reports and locations are unclear.

The main part of the Ophir or Twin River silver-tungsten-gold mining district, at the old townsite of Ophir, AKA Toiyabe City, is farther up the canyon and is also well worth visiting.

This appears to be a fly wheel flat pulley, possibly from a crusher. If anyone can identify this equipment more completely, please let me know. I just like the shapes and colors, and didn't spend a lot of time - this time - looking for manufacturers' names and dates.
Yellow-painted meal framework and grating, with pipes and wires.
And old dump truck or haul truck, filled with rock. Is it scheelite ore?
A nicely colorful metal roof on an otherwise falling down shack. Photos of this cabin from about 2002, when it was still standing, along with photos of the entire equipment setup, can be seen here, near the bottom of their webpage.
Falling down cabin, with the metal roof being much sturdier than the rest of the building. A low part of the Toquima Range can be seen in the background: Moore's Creek to Dry Canyon to Road Canyon (or Charnock Pass) - a scenic, volcanic-rock ridden way into Monitor Valley.
Here's a view of the northern and central Northumberland caldera, which erupted the Northumberland Tuff about 32 million years ago. Also seen in the view is the area in which I stayed out all night once, just south (right) of Wildcat Peak, the pointed peak on the horizon, and the tuff of Hoodoo Canyon, a bit to the north (left) of that peak.
Another view of the central part of the Northumberland caldera, through more metal frameworks.
I've retreated now to my parking area, near the creek seen in yesterday's post, giving yet another view of the central and northern part of the Northumberland caldera, across the vast expanse of Big Smoky Valley.
And here, on a ledge where possibly some old buildings once stood, one can see across the valley to the southeast, getting a good view of Mt. Jefferson, which at 11,941 feet is essentially the third highest mountain in Nevada. Mt. Jefferson consists primarily of a huge pile of Tertiary volcanic rocks, mostly moderately to strongly welded ash-flow tuffs, including the tuff of Mt. Jefferson, which erupted from Mt. Jefferson caldera about 26.7 million years ago. Much more detail about the calderas in and around Mt. Jefferson is discussed here.

Mt. Jefferson is a great place to hike up, if you can stand the elevations, and even if you can't. The top, which is not accessible by vehicles, is almost surreal somehow - or maybe I was oxygen starved. It's mostly flat, with little hills of tuff. The Alta Toquima archaeological site sits up there at about 11,000 feet, above tree line.
Driving away from Ophir Canyon, I had a great view of the Round Mountain gold mine to the southwest. Round Mountain has been in operation since the early 1980's 1977.

References:
Kleinhample and Ziony, 1984, Mineral resources of northern Nye County, Nevada, NBMG Bulletin 99B.

McKee, E.H., 1974, Northumberland caldera and Northumberland tuff, in Guidebook to the geology of four Tertiary volcanic centers in central Nevada: Nevada Bureau of Mines and Geology Report 19, p. 35-41.

Thomas, D.H., 1982. The 1981 Alta Toquima Village Project: a preliminary report. Desert Res. Inst. Soc. Sci. Cent. Tech. Rep. 27.