Twelve Months of LFD (2012)

I missed this retrospective meme last year, but here it is, back again, as per DrugMonkey:

The rules for this blog meme are quite simple.
-Post the link and first sentence from the first blog entry for each month of the past year.
I originally did this meme, after seeing similar posted by Janet Stemwedel and John Lynch.  Prior editions include 2011, 2010, 2009 and 2008.

Previous takes on this Twelve Month meme at LFD were posted for 2008, 2009, and 2010. As usual for LFD, I've also added the accompanying first photo of the month, where there was one with the first post of the month.

January:
I went on my first walk of the year earlier today, out along a creek in Anchorage, AK.

February:
I thought I'd back up to a time a week before our stop at The Geographic Center of Nevada, a time just prior to our soak at Spencer Hot Springs. 

March:Upon getting out of the truck at the north end of the Monitor Valley playa, it became rapidly clear to me that it was very cold. 

April:
I thought I'd actually have time over my 5-day break to get caught up on some blogging, but that hasn't been the case, and things aren't looking all that great for the coming 8- or 9-day work week and the break following that, so I'm posting a few views from the new area.

May:
Just a quick post showing a photo I took about two weeks ago at 5:50 am, on my early morning ride to work. 

June:
Yesterday I received an email while at work telling me that there was a hummingbird moth in one of our two pots of chocolate mint, which are sitting outside on the front porch. 

July:
These stitched photos were taken about three weeks ago near the site of Preble (just off the map to the west).

August:
These relatively small pinnacles are located in the canyon of Midas Creek, just north of the town of Midas, Nevada.

September:
Besides the obvious greenish feldspar, the countertop rock is composed of black pyroxene, gray metallic minerals (magnetite or ilmenite are likely, but I didn't bring my magnet, magnetometer, or portable xrf), and pyrite.

October:
In the morning after I wake up—while I'm drinking my first, second, and maybe third cup of coffee—I often think of things to write for the blog, how to write them, maybe even what pictures to use.

November:

I got to thinking after taking another looking at my arc photos, that this shot may show a weak tangent arc above the also weak 22 degree halo around the sun.

December:
We came in from the east or north, depending on how you view the direction of I-80 as it traverses the entire north-south length of the west flank of the Humboldt Range from Florida Canyon to Limerick Canyon northeast of Lovelock.

Back to Midas

At long last, we're back on the Tuscarora Loop, with the turnoff to the small town of Midas just up ahead. On our loop trip, taken way back in early June, MOH and I passed Midas by, in favor of making it all the way to Tuscarora. At the time, I had been to neither place, but Tuscarora seemed more out-of-the-way, and therefore more exotic, so down the road we went.

We came back in mid-July, and instead of following the main road, old S.R. 18, to the right, we took the side road up the canyon to the left.

Signs at the turnoff to the Midas road.

Sign at the entrance to the town of Midas, and green trees.

Acme Beer sign, reportedly dating to about 1936.

I was on the lookout for a bar that had been open in 1979 or 1980, a bar I knew as Kirby's Midas Bar, a name given to me by a friend of mine, a young woman who was working as a geologist while staying in Midas in a company trailer. Seeing the old sign for Andy's Midas Bar made me somewhat hopeful about finding either Kirby's or Andy's bar, although Acme Beer dates back primarily to the early 1950s and before. Acme Beer did have a short revival in 1975 to 1979; could it have possibly been being sold in Midas while my friend was in town?

While in Midas, my friend could make or receive phone calls on one of the two phones in town, which had the phone numbers of Midas #1 and Midas #2. Phone numbers like these were fairly common in the 1970s and early to mid- or late 1980s in the small, outlying towns of Nevada. These numbers confused operators outside the state to no end. To place a call into Midas or Getchell, for example, you would dial 0 for an operator and then ask for Midas #1 or Getchell #2 as needed. If dialing in from out of state when trying to reach one of these types of numbers, one learned quickly to ask the out-of-state operator for a Nevada operator, because many outside operators didn't believe that phone numbers like that could even exist.

While I was looking for, and not finding, the bar I'd heard of long ago, MOH and I were hoping that the one known-to-be-operating establishment in Midas, the Midas Saloon and Dinner House, would be open, but it wasn't. This became a concern during a later, uphill, in-the-rain adventure of ours.

Mine dump, ore cart, and portal (?) a little ways up Midas Creek.

Old cabin, garage, or storage shed.

Road to somewhere.

After a quick pass through town, we headed up the hill to the west on this relatively innocent-looking side road. The partly cloudy weather became more and more threatening as storms to the south moved in, creating an unexpectedly muddy situation.

Folds in Volcanic Rocks near Midas, some Wildlife, and an Aside about How to Use Lizardtech ExpressView

After passing Sawtooth dike on the Tuscarora Loop tour (driving ENE on the Midas Road into the Midas Trough), you need to immediatedly look south for the next three miles or so at some spectacular folds in rhyolitic volcanic rocks. The folds are in hills east of the junction of Evans and Clover Creeks (MSRMaps location), with photos beginning at hill 1762, above, and running to the gap southwest of hill 1938. Also see the Midas Area Google Maps view below for specific photo locations.
An enlargement of the first photo — with giant copyright notice because my online watermark site once again went down — in case the first photo was too small.
Geologic map of the Snowstorm Mountains and vicinity, Elko and Humboldt Counties, Nevada (Wallace, 1993), courtesy U.S. Geol. Survey.

The folds are entirely within an upper Miocene unit mapped by Wallace (1993) as Trpy — younger rhyolite porphyry — which consists of rhyolite and rhyodacite flows and domes.

By the way, I finally figured out how to download useable geologic maps from the USGS website. Here's the map. After downloading, or right-clicking and "Save Target As", one then needs to go here, go to downloads-viewers, and download/install the ExpressView Browser Plug-in (MrSID) for Windows. After installation, then just double-click, or right-click and "Open", the downloaded, saved map file, which has a .sid extension. The map then opens automatically in a useable page in your browser (IE or Firefox). This is so much easier than the old way, when one had to use the command line to open the saved maps. So, ignore these instructions listed as "Help in using this map" on the linked-to USGS map page. Although the instructions might be useful for some purposes, they are unnecessary for making a GEOtiff, tiff, jpg, gif, png, or bmp of a map or some portion thereof. The toolbar that comes with the viewer is a bit obscure; one does some things by right-clicking on tiny icons in the upper left and upper right corners. Saving is accomplished by right-clicking almost anywhere, which brings up options for printing, saving, and other useful items.

The main part of the hills, with some nice folds on the right.

A closer view of those folds.

These last two photos are looking at the northeastern contact area, where the Trpy rhyolite has been faulted against several formations, including the older volcanic rocks of Jake Creek Mountain — rhyolite and rhyodacite flows, domes, and ash-flow tuffs that cap the Owyhee Bluffs to the north — and the older rhyolite porphyry unit (Trpo), which on Owyhee Bluffs is fed, in part, by Sawtooth dike.

First photo, above, is from late spring; photo below is from mid-summer. The cheat grass is partly green and purplish brown in the first photo; everything has turned straw-colored in the second.
This general area, from the WSW opening to the Midas Trough to the turnoff to Midas, is a great place to spot antelope:

Antelope in early June.

Antelope in mid-July.

We also spotted a large flock of ravens coming back out of the area in mid-July...
...and several vultures feeding on roadkill.

View Midas Area in a larger map

Selected Reference:
Wallace, A.R., 1993, Geologic map of the Snowstorm Mountains and vicinity, Elko and Humboldt Counties, Nevada: U.S. Geological Survey, Miscellaneous Investigations Series Map I-2394, scale 1:50000.

Sawtooth Dike

Backing up somewhat from Midas on the Tuscarora Loop, one of the first places of interest on the way to Tuscarora from the Golconda side — besides the Midas Trough itself, which the Midas Road goes through to get to the turnoff to Midas — is a spectacular rhyolitic dike, Sawtooth dike (Zoback and Thompson, 1978), named after Sawtooth Spring (MSRMaps location).

Heading eastward into the Midas Trough on the Midas Road, the Owyhee Bluffs in the distance on the left.

Sawtooth dike running up the face of the Owyhee Bluffs.

This dark-colored, rhyolite dike is a feeder for a thick section of rhyolite flows that immediately underlie the rhyolite to rhyodacite volcanic rocks of Jake Creek Mountain, the latter of which cap this portion of Owyhee Bluffs. The older rhyolite flows fed by Sawtooth dike are, in aggregate, 10 to 400 m thick (more than 30 to more than 400 feet thick).

Air photo of Sawtooth dike (from MSRMaps).

A bit of geology: dike sections in turquoise, fault in blue.

Sawtooth dike is in two main sections, offset by a small left-lateral fault, with a small portion caught up along the fault. According to Zoback and Thompson (1978), the dike is a syntectonic intrusion, syntectonic with extension producing diking in the northern Nevada rift and with extension-related strike-slip faulting (a little more about the northern Nevada rift here). The south end of the dike is reportedly cut off by the north bounding fault of the Midas Trough (Rowan and Wetlaufer, 1973, per Zoback and Thompson, 1978).
Another view of the dike, from Zoback and Thompson (1978), used here as per GSA fair use policy. (Thanks, Andrew Alden!)

View Midas Area in a larger map

By the way, the entire road from its turnoff from I-80 or old Highway 40, through Golconda and out along what is now S.R. 789 to the current road usually called "the Midas Road," past Midas and out to Tuscarora, was known as S.R. 18 prior to the 1976 renumbering program (see this 1975 state roadmap). I'll be listing all non-40, non-I-80, non-789 roadside geology (and other) posts related to the Midas Road under the tag "18" as below.

A Few References:
Rowan, L. C., and Wetlaufer, P. H., 1973, Structural geologic analysis of Nevada using ERTS-1 images: A preliminary report, in Symposium on significant results obtained from the Earth Resources Technology Satelite-1, Vol. 1, Technical representations, Sec. A: Natl. Aeronautics and Space Adm. Paper G-20, p. 413-423.

Wallace, A.R., 1990, Geologic map of the Jake Creek Mountain quadrangle, Elko County, Nevada: U.S. Geological Survey, Geologic Quadrangle Map GQ-1672, scale 1:24000.

Zoback, M.L., and Thompson, G.A., 1978, Basin and Range rifting in northern Nevada: Clues from a mid-Miocene rift and its subsequent offsets: Geology, v. 6, no. 2, p. 111-116.

Tuscarora Loop

View Tuscarora Loop in a larger map

This is a Google Maps version of a road trip MOH and I made back in early June. The loop part of the trip begins in Golconda, goes north on the Getchell Mine Road, east on the Midas Road, past the turnoff to Midas, across a bridge at Rock Creek, past the turnoff to the Hollister Mine and Ivanhoe mercury-gold district (not shown), up Willow Creek to the Willow Creek Reservoir, over the Tuscarora Mountains to Tuscarora, down S.R. 226 (or Tuscarora Highway) to the Taylor Canyon Resort, beyond the resort to S.R. 225 (or Mountain City Highway), south to Elko, and west on I-80 to Golconda. As a loop, one can essentially start anywhere, not necessarily at the gas station in Winnemucca where we started. The Midas Road from the turnoff to Hollister and over the mountains to Tuscarora isn't always open in winter and can be muddy in spring to early summer.

Places shown:
1. gas station in Winnemucca
2. not quite downtown Golconda
3. turnoff from Getchell Mine Road to Midas Road
4. Sawtooth dike
5. folds in rhyolite
6. turnoff to Midas
7. Rock Creek
8. Willow Creek Reservoir
9. Tuscarora
10. Taylor Canyon Resort
11. Elko
12. Golconda underpass
13. gas station in Winnemucca

Besides the pinnacles and "Nodding Rock" in the Midas area, we'll be seeing some other sights from along this route in the coming days and weeks. The Midas Area map will be added to as needed.


View Midas Area in a larger map

Places shown:
1. turnoff to Midas
2. Midas
3. pinnacles
4. "Nodding Rock"

Nodding Rock

MOH and I spotted this rock formation in dark-colored volcanic rocks west of the town of Midas, NV, and called it Nodding Rock. The rock formation is part of a widespread group of rhyolite to rhyodacite flows, domes, and densely welded ash-flow tuffs (and rheomorphic tuffs?) that cap the Owyhee Bluffs and other nearby hills and plateaus of the Snowstorm Mountains near Midas: the volcanic rocks of Jake Creek Mountains, middle or upper middle Miocene in age.
General location (MSRMaps): the ridgeline about 1 mile west of Midas, south of hill 7230 and just north of the change in map coverage.

A Few References:
Wallace, A.R., 1990, Geologic map of the Jake Creek Mountain quadrangle, Elko County, Nevada: U.S. Geological Survey, Geologic Quadrangle Map GQ-1672, scale 1:24000.

Wallace, A.R., 1993, Geologic map of the Snowstorm Mountains and vicinity, Elko and Humboldt Counties, Nevada: U.S. Geological Survey, Miscellaneous Investigations Series Map I-2394, scale 1:50000.

Pinnacles above Midas

Small pinnacles in volcanic rocks just above the town of Midas.

These relatively small pinnacles are located in the canyon of Midas Creek, just north of the town of Midas, Nevada.

The rock formation is probably either the Tlb or Tpm of Wallace (1993), with both units being part of the thick Miocene volcanic section erupted during formation of the northern Nevada rift, or eastern northern Nevada rift (NNRe) of Glen and Ponce (2002).
The pinnacles are two shadowy dots on the ridgeline near the center of this MSRMaps airphoto, west of an in-canyon set of builings and trees.
The [semi] coressponding MSRMaps topographic map indicates that the pinnacles are less than 40 feet high. I would guess that they aren't even 20 feet high, based on my mid-July, driving-through-canyon perspective.

A Few References:
Glen, J.M.G, and Ponce, D.A., 2002, Large-scale fractures related to inception of the Yellowstone hotspot: Geology, v. 30, no. 7, p. 647–650.

Leavitt, E.D., Spell, T.L.m Goldstrand, P.M., and Arehart, G.B., 2004, Geochronology of the Midas Low-Sulfidation Epithermal Gold-Silver Deposit, Elko County, Nevada: Economic Geology, v. 99, pp. 1665–1686.

Ponce, D.A., and Glen, J.M.G, 2002, Relationship of epithermal gold deposits to large-scale fractures in northern Nevada: Economic Geology, v. 97, no. 1, p. 3-9.

Wallace, A.R., 1993, Geologic map of the Snowstorm Mountains and vicinity, Elko and Humboldt Counties, Nevada: U.S. Geological Survey, Miscellaneous Investigations Series Map I-2394, scale 1:50000.

Wallace, A.R., and John, D.A., 1998, New studies on Tertiary volcanic rocks and mineral deposits, northern Nevada rift, in Tosdal, R.M., ed., Contributions to the gold metallogeny of northern Nevada: U.S. Geological Survey Open-File Report 98-338, p. 264-278.