Monday, April 23, 2012

SWxS to SSW of Center: The West Northumberland Canyon Springs and Northumberland Pass

In summer, the spring area in West Northumberland Canyon is one of few sources of water on the east side of Big Smoky Valley, and it's way up the canyon and out of the way for Highway 8A travelers (now S.R. 376). Better bets for finding water while traveling through Big Smoky Valley are the many running creeks coming off the east side of the Toiyabe Range, more than 15 miles across the valley from this often wet and muddy spring area (MSRMaps location).

On our mid-January trek up West Northumberland Canyon, we came to a large ice floe that had completely cut the road in the area of the West Northumberland Canyon springs. The slick ice was easy to track across, though staying to the right was entirely necessary to prevent sliding off into the ditch on the left side of the road.
I didn't stop to examine the ice prior to crossing; I instead followed existing tracks and stopped on the far, uphill side of the ice, to get this shot looking looking west-northwest, back down the canyon.
Like I said, the ice floe went entirely across the road.
In fact, the entire spring area was covered with ice, as seen in this shot looking northwest toward the lower end of the spring and the remains of a small mill.
The frozen spring upstream a bit: Freezing aparently caused the water to flow around the spring and marsh area and onto the road, where it froze solid in a shady spot.

From the springs, we wound our way up a few switchbacks toward the Northumberland gold mine (currently inactive), making it to the pass, which has been somewhat relocated from its original sit by mining activity. (Original map location of Northumberland Pass; a newer air-photo shows the pass a little to the north of the old site.)
We had a fine view from the pass, looking back to the northwest over the north part of the Northumberland caldera, and across Big Smoky Valley, all the way to the Toiyabe Range. The high peak in the Toiyabe Range north of Kingston Canyon (the low-ish spot beyond the reddish hill of tuff of Hoodoo Canyon) is Bunker Hill, at 11,473 feet.

From the pass, we drove down East Northumberland Canyon into Monitor Valley, to the Monitor Valley salt flat, the Potts Ranch hot springs, and The Geographical Center of Nevada.

Related Posts (in order of posting; #s indicate order in real time):
A Soak at Spencer Hot Springs (1)

The Geographic Center (8)

West to Southwest of Center: Beers and Roads and Folds and Things (2)

ENE of Center: Breccia at Devils Gate (3)

South of Center: Potts Ranch Hot Springs (7)

South by West of Center: Monitor Valley Salt Flat or Dry Lake (6)

Backroads: Too Cold to Change a Flat, and other Considerations (9)

SW to SWxS of Center: Northumberland Canyon (4)

SWxS to SSW of Center: The West NU Canyon Springs and Northumberland Pass - this post (5)

Thursday, April 19, 2012

SW to SWxS of Center: West Northumberland Canyon

In our backwards trek away from The Geographic Center of Nevada, we've reached one of the last stretches of dirt road prior to the start of our now long ago January day in the center and south-center of the Northumberland caldera. And what stretch of road would that be? That would be the Northumberland Mine Road, the section running from the mouth of West Northumberland Canyon on the west side of the Toquima Range, east and up West Northumberland Canyon past the springs, the old barite mine, and the Northumberland gold mine, to Northumberland Pass. Beyond the pass, the road continues eastward, down into East Northumberland Canyon, past another old barite mine (the larger of the two, both of which operated in the 1970s and 1980s), finally ending at the Monitor Valley Road about 7 miles southwest of our last stop.

Compass Card, on Wikimedia Commons

The mouth of West Northumberland Canyon, up on the west pediment of the Toquima Range, is about 27 miles southwest of center; the springs are about 26 miles southwest by south (SWxS or SWbS) of center; Northumberland Pass is about 27 miles south-southwest of center (see Boxing the Compass).

I had planned to post this section of our trip — that is, the entire Northumberland Canyon section, in one post — but due to limited editing & writing time (I did my initial editing of this on a funky phone while riding one of the better (read: smoother) buses back from a day's work at the mine) — I'm now posting just the first part: West Northumberland Canyon from it's western mouth to just below the springs. The second part will post in a few days.

After returning from our 5 mile excursion up some canyon near Mt. Ziggurat, which we'll hopefully see later, we hightailed it north on the range-front road, turned right on the Northumberland Mine Road, and entered West Northumberland Canyon. (MSRMaps location of the area.)

Northumberland Canyon cuts southeast through the northern part of the Northumberland caldera, a large caldera about 21 miles in diameter that erupted a moderately large volume (15 cubic miles) of rhyolitic quartz-sanidine ash-flow tuff about 32.3 million years ago (McKee, 1974a). The canyon wall is cut into typical exposures of the typically goethitic golden brown, strongly welded Northumberland Tuff, which usually shows intense vertical fracturing and imperfect columnar jointing.

Driving up the canyon, one can see a good deal of geology related to the formation of the caldera, including large, often irregular, and at least sometimes internally brecciated landslide blocks of often dark gray to black Ordovician Vinini Formation (Ov).

A couple of the smaller slide blocks or masses are shown in the photo above; these particular masses are apparently at least partly contained within welded tuff.

The reddish hill in the distance to the north is capped by the tuff of Hoodoo Canyon, K-Ar dated at 31.4 Ma (McKee, 1974b). The reddish portion of the hill is underlain by moderately to strongly welded tuff; a black vitrophyre can usually be found near the base of the upper reddish zone, above a white, relatively thin, poorly welded zone. The tuff of Hoodoo Canyon (Hoodoo Canyon is the canyon north of West Northumberland Canyon), overlaps and rests on intracaldera sediments (what we called Ts2 through Ts4; what was sometimes called Ts5 turned out to be the poorly welded portion of the tuff of Hoodoo Canyon). These intracaldera sedimentary units were deposited on the Northumberland Tuff and on the Ov landslide blocks in an irregular intracaldera moat lake that may have been deeper on the north side of the caldera, resulting in a sedimentary package that was thicker to the north (it was thinner to the south, or maybe partially to entirely eroded in places).

The fractured dark brown to black mass capping this hill of golden brown Northumberland Tuff on the north canyon wall, is one of the larger Ov landslide masses or blocks.

Several of the largest of the landslide blocks and masses occur close to the mouth of the canyon. At least one near the canyon mouth can be seen from the road, others can be reached by hiking north of the road. Several, if not all, of the dark patches and outcrops in this MSRMaps airphoto are landslide blocks or masses composed of black chert of the Ordovician Vinini Formation (Ov). I keep saying landslide "masses" and not just landslide "blocks" because we found from mapping and drilling that many or most of the masses join in what is probably a basal layer to the intracaldera sedimentary section, a unit we called Ts1. A couple of these larger masses can be seen in the first photo here and the second photo here.

Here's a somewhat closer view of the irregular contact between the same Ov landslide mass sitting on top of the Northumberland Tuff. The internally brecciated fragments of the black chert in Ts1 are often glued or welded together, presumably from the heat of the tuff beneath it. Where drilled at depth, the angular to subangular breccia fragments are sometimes rimmed or cemented by pyrite. In places, the brecciated Ov landslide masses or layers look more like cemented talus deposits than landslide blocks.

In the central part of the caldera, these intracaldera landslide or talus deposits are thinner and are overlain by a later pulse (or more than one pulse) of Northumberland Tuff, which in the central part of the caldera show strong welding and compaction foliation like the tuff in West Northumberland Canyon. This upper part of the Northumberland Tuff correlates with what we called Ts3 in the northern intracaldera moat sediments: an ash flow or series of ash flows that flowed into the intracaldera lake, retaining some semblance of ash-flow tuff in places, and looking more like disrupted ash-flow tuff or even waterlain air-fall tuff in other places.

And now we've arrived at the springs in West Northumberland Canyon.

McKee, E.H., 1974a, Northumberland caldera and Northumberland Tuff, in Guidebook to the geology of four Tertiary volcanic ceters in central Nevada: NBMG Report 19, p. 35-41.

McKee, E.H., 1974b, Road log to Austin-Northumberland caldera-Carver Station, in Guidebook to the geology of four Tertiary volcanic ceters in central Nevada: NBMG Report 19, p. 3-5.

Related Posts (in order of posting):
The Geographic Center
South of Center: Potts Ranch Hot Springs
South by West of Center: Monitor Valley Salt Flat or Dry Lake
Backroads: Too Cold to Change a Flat, and other Considerations
SW to SWxS of Center: West Northumberland Canyon - this post

SWxS to SSW of Center: the West NU Canyon Springs and Northumberland Pass - a coming post

Monday, April 16, 2012

Names of Goldfield Headframes

I found a source for the names of some of the Goldfield, Nevada, headframes I took pictures of a couple years back. These photos first appeared here.
Little Florence Mine.
Florence Mine (the headframe on the left and buildings in the center).
The Florence Mine from the east, with the Little Florence headframe to the left near a brown hill.
Headframe of the Merger Mine behind a rocky knob.
A closer view of the Merger Mine headframe.

Friday, April 13, 2012

Views from Winnemucca Mountain

MOH and I drove to the top of Winnemucca Mountain during my first work break last month to check out the road to the top and the potential for bicycle riding up and then down (good potential: we met at least one cyclist on our way up). It was cold, wintry and windy, so I barely got out of the truck at the top, and just walked over to two edges of the mountain to take a couple pictures.

Orientations in the Winnemucca area seem a little crazy because the town runs from the SSW to the NNE, and because I am in the habit of thinking of it as an east-west-oriented town. Nevertheless, in the first photo we are looking mostly to the southeast toward the north part of the Sonoma Range. Sonoma Peak, at 9396 ft (2864 m), is the highest peak in view. Large meanders of the Humboldt River, with the river running to the south-southwest toward Rye Patch Reservoir (left to right), can be seen in the flats below us.

This view is to the north, with the low hills in the foreground being part of the Krum Hills. That's the Bloody Run Hills and Bloody Run Peak behind the low hills on the right, and the high, snow-capped Santa Rosa Peak in the Santa Rosa Range off in the distance to the far right. The Bloody Run Hills are considered part of the Santa Rosa Range, although they are a somewhat separate tectonic block. Silver State Valley is the flat area off to the left.

The parabolic sand dunes north of Winnemucca cross through a low area between the Krum Hills and the Bloody Run Hills. You can see a bit of this large dune field in the photo, most notably a boomerang shaped portion of the field just below Bloody Run Peak (compare my photo with this air photo from MSRMaps).

A few references:
Davis, J.O., 1990, Giant meanders on the Humboldt River near Rye Patch Nevada due to catastrophic flooding: Geological Society of America Abstracts with Programs, v. 22, no. 7, p. A309.

Trexler, D.T., and Melhorn, W.N., 1986, Singing and booming land dunes of California and Nevada: California Geology, v. 39, no. 7, p. 147-152.

Tuesday, April 10, 2012

A Few Views

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.

First, an early morning view: inside the bus before it's left the parking lot for the mine.

Next, a view on the way back from work on a relatively clear day, looking off to the southeast toward the North Valmy Power Plant, Battle Mountain, and the Betty O'Neal mine near the range front below the snow-covered peaks of the Shoshone Range.

And last, a fairly typical view inside The Griddle, one place to be if you happen to be hanging around The City of Paved Streets, the starting point of the Winnemucca-to-the-Sea-Highway.

Winnemucca-to-the-Sea Highway posts at LFD.