Friday, October 31, 2008

Friday Fault Photos #7

As long as you happen to be at Ophir Creek in Big Smoky Valley, you should make sure to notice the nice triangular facets along the eastern range front of the Toiyabe Range. The above photo, looking south from the road going up the Ophir Creek alluvial fan, shows the overall faceted nature of the range front near the canyons cut by North Twin River and South Twin River.

Photo from the road to Ophir Creek, looking southwest, the canyons in view having been cut by South Twin River (the southernmost canyon barely in the far left of the photo), North Twin River (the next large canyon to the north), with the canyons of Hercules Creek and Last Chance Creek just barely seen north of North Twin River.

Triangular facets
- a geomorphologic feature or landform - sometimes result from erosion along an active to fairly active fault. Triangular facets can result from other processes, but here in the Basin and Range country of central Nevada, they are almost always indicative of the approximate location of the range-front fault. By fairly active, I mean that ranges and valleys in the Basin and Range are moving with respect to each other, and that fault motion has historically produced earthquakes and fault scarps on some of these range-front faults - for example at Fairview Peak and Dixie Valley. Most range-front faults have not had historic earthquake activity, but many have been active sometime during the last 1.6 million years (Quaternary). On the Google Earth image below, the Toiyabe Range fault zone - the range-front fault on the east side of the Toiyabe Range - is shown as being Late Quaternary, or younger than 130,000 years old.

UPDATE 28May2010: These geomorphic features are also commonly known as faceted spurs.
Nice triangular facets on the range front south of Ophir Creek and north of Hercules Creek.
As the road goes farther up the alluvial fan and gets closer to the mouth of Ophir Canyon, our view of the range front is more southward, and the triangular facets are seen at a more oblique angle.
Above, an enlargement of the previous photo.
Another enlargement.
Above, the Google Earth image mentioned earlier, with reference cited below, and color scheme for faults listed, as given here.

Reference:

U.S. Geological Survey and Nevada Bureau of Mines and Geology, 2006, Quaternary fault and fold database for the United States, accessed 10-27-2008, from this USGS web site: http//earthquakes.usgs.gov/regional/qfaults/.

Historic are the most recent, known movement less than about 150 years (in red).

Holocene_LatestPleistocene are younger than 15,000 years (in orange).

LateQuaternary are younger than 130,000 years (in yellow).

MidToLateQuaternary are younger than 750,000 years (in green).

Quaternary are younger than 1,600,000 years (in blue).

Thursday, October 30, 2008

Re: Rainbow Meme

I didn't really plan to start a meme this morning, but apparently some people jumped on - and on, with Ron Schott deciding that this 'meme' actually started sometime last year (he says it's Kim's Fault)! I did post A Rainbow in the Field Area earlier this month (or whenever), but feeling rather challenged by this meme-ish idea, which I didn't intend to start, I thought I'd better post a rainbow from the field area that goes with my last post of One Year Ago Today! (I hope I didn't link to myself too many times, here - just trying to pass the links around and record the geologic history of this thing.)

Memes are fun, but Eric says that silver and garlic will keep them away. I always cross my fingers (from two hands) in the form of a cross, and that works for me. See you tomorrow!

Ha! I mentioned one food source - garlic - in case anyone is actually doing the October Accretionary Wedge!!

One Year Ago Today: Rainbows




These are photos from last year (as you might have guessed from the post title) - a full-sky double rainbow over our little house in eastern Nevada. The afternoon had been cloudy with rain, and I came back from work to find a dark sky and this wonderful, long-lasting rainbow. The sky was a strange color, kind of yellowish gray - it reminded me of a color I remember mostly from the East Coast, a color that during thunderstorms can precede tornadoes, although it often doesn't.

Wednesday, October 29, 2008

Up a Tree

MOH hikes farther up the hill...
...while the Silver Fox climbs a tree,
...in order to take a few pictures.

Isn't fall great!

Trees and Leaves

This is a case of trees and leaves and more leaves. The elm trees above are finally letting go of their green to brown leaves! It's fall, already, so it's time for that.
Leaves and shadows...
More leaves...
And more leaves! They are everywhere, and make nice crunching sounds when I go out for my morning walks.

Tuesday, October 28, 2008

Layering Reversed

By popular request, I've turned the photo of limestone from the previous post so that it's right-side-up in a stratigraphic sense, and added a touch of contrast, hopefully not too much. So, the layering is right-side-up and my finger (for scale) is upside down! For comments to date, see previous post.

Posted 10/29/2008 and pre-dated.

What is this Layering?

This is a limestone, maybe a dolomitic limestone, probably Devonian, with some layering. What is the layering? Is this soft-sediment deformation or tectonism or both or... ?

I really want to know! Any opinions?

Old Junk in Ophir Canyon

metal 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.

machinery 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 metal Yellow-painted meal framework and grating, with pipes and wires.
dump truck And old dump truck or haul truck, filled with rock. Is it scheelite ore?
roofA 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.
roof and rocksFalling 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.
Northumberland view 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.
view through frameworkAnother view of the central part of the Northumberland caldera, through more metal frameworks.
south Northumberland 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.
Mt. Jefferson 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.
Round MountainDriving 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.

Monday, October 27, 2008

A Saturday Drive

smokyThe other day I decided I'd go out to Big Smoky Valley to explore a few things and places related to my past - things and places from days gone by when I worked in the area, which was primarily from 1977 through 1981. I was out to revisit some ancient Highway 8A history, as it were, although that particular section of old Highway 8A - which runs from Highway 50 east of Austin to Route 6 east of Tonopah - is now known as State Route 376.

8aI turned onto old Highway 8A and headed south. A long straight stretch of road immediately ensues, and so unless you are turning off to Spencer's Hot Springs or Pete's Summit, it can seem like forever before you get anywhere. It is, in fact, 19 miles of straight, paved pavement before you come to the first turn in the road, which is just after you cross over the Nye County line, and just before you come to the old road up the south side of Bowman Creek, where I made a little stop.


road Although I didn't really know where I'd end up after stopping at Bowman Creek, I finally continued south on old 8A, and then turned west to drive up the road to Ophir Canyon. Ophir Canyon is on the east side of the Toiyabe Range between Kingston Canyon (a canyon with a small retirement community) and Carver's Station, which was mostly a gas station, bar, and restaurant back when I lived in Big Smoky Valley.

I drove there to see if the road up Ophir Canyon was open - not because I thought that early snow might have closed it - but because I'd heard a rumor a few years back that it may have been blocked off by overzealous government agencies, but those may have been other roads, because Ophir Canyon was open.

steep The road to the canyon turns south right on the range front, where it then drops into the canyon. Ophir Canyon is the narrow notch above the little yellow sign on the side of the road.
very steep The sign is there to make sure that you know that the road is steep and narrow. In fact, the first time I went up the canyon, the day after resting up from my overnight helicopter escapade on volcanic hills across Big Smoky Valley, I had to grit my teeth in places and was glad another young geologist was driving. I would have rated parts of the road as 8 or 9 out of 10 on the 4WD scale of difficulty, but experience changes things like that. I do recommend the drive: it makes a good alternate route over the Toiyabe Range - not a short cut, but a scenic route - steep on the east side, and shallow with a broad view on the west side.
canyonAbove, driving into the mouth of the canyon.
4WD sign I drove a little past the initial entry area of the canyon, to see what the sign said - lot of signs in this canyon. This one says, "4WD ROUTE MAINTAINED BY CENTRAL NEVADA FOUR WHEELERS." And trust me, in these parts, that's a good thing. Some county roads have been closed, and then reopened with bulldozers.
flood Just before the road is about to drop back into the canyon for good, another sign pops up, this one warning of flash floods. Fortunately, there was barely a cloud in the sky. Little stickers on the sign also indicate No Cars and No 2WD Trucks. ?The sign also suggests that open-topped jeeps aren't recommended.
creek I parked near the mouth of the canyon, where some old mining stuff is lying around, and went over to the creek.
bridge I crossed the little foot bridge - woh, be careful, it's a little wobbly.
waterOf course, the creek isn't very deep if you happen to fall in, like most Nevada creeks.
viewThere is some nice old mine and mill miscellany on the other side of the creek - mining and milling equipment from operations now defunct, falling-down to skeletal buildings, and pieces of metal, wood, and glass - along with a nice view of the Toquima Range across the valley.

Sunday, October 26, 2008

Saturday, October 25, 2008

Phone Posting

I started a bit of road posting on my last road trip, sending posts by email with pictures taken by my 2 megapixel phone camera. I only got one sent, took several photos and was preparing to send more, when I went out of range of the internet connection provided with the phone package. I had cell service, but no internet.

I've been a bit disappointed with the quality of the pictures taken by the phone. They are fine on the phone, but look bland when posted here. It's kind of fun to do, though - entertainment while traveling through countryside I've seen many times. I continued the road posting for the last trip at another place [MojaveEx blog not currently available], but then stopped phone-picture taking when the internet uplink disappeared.

I will be on a mini - road trip for the next two days, and will have, at best, intermittent cell service. I may not be able to check for winners of WoGE #150 - I may get comments by email, but only if I have cell service. Posting times for WoGE players will, nevertheless be recorded by the blog, so not-to-worry! Also, I'll probably have internet service tonight and tomorrow morning; haven't decided on my exact destination.

So, best of luck!

Friday, October 24, 2008

Where on (Google) Earth #150

Above, the WoGE #150 image for y'all to give a shot at. I doubt it's very difficult, but don't know - they've all seemed impossible to me until the last one, and they've seemed hard to locate in cyberspace, also. I can only recommend that Peter Lufti's postings for WoGE be somehow added to the Allgeo feed so we can tell easily when and where it's been posted (since he wins so often!). But maybe we are just meant to search for it!

To play WoGE, post the location of the above place in the comments - latitude and longitude or a description. To win, post the location first! If you win, it passes to you. If you can comment about the geology, that would be great! I'm invoking the Schott Rule: wait one hour for every time you've won WoGE.
I've never won one of these things before - I used to try a lot, but finally stopped after realizing that even in an hour I usually wasn't even coming close. WoGE #149 looked very familiar to me, so I GoogleEarthed it quickly (I think that if you can Google something, then surely you can GoogleEarth a place - a new verb!), and then posted the answer as fast as possible, only stopping to look up a couple place names in my handy-dandy Oregon Atlas. And I checked out TerraServer, also [now MSR Maps].

Yes, it was the Three Sisters near Sisters, Oregon. For certain former Oregonian readers of mine, please click here to see the Three Sisters as seen from Google Earth! And please read the comments, Tuff Cookie of Magma Cum Laude gave a spectacular description of the geology of the Three Sisters, far surpassing mine!

Posted at 6:40 PM Pacific Daylight Time, (GMT -7 I think because of summer time) October 24, 2008.

Treeees!

Well, actually just one tree, in a nice desert shadow, probably a piñon tree.

A mini-tree meme is going around the GeoBlogosphere - started here by Geotripper, and followed on with here at Clastic Detritus. I've had a couple posts recently showing some trees, but I don't really have a favorite tree, unless it would be one in those previous posts, a tall aspen tree in our backyard.

I picked the above tree photo, because it was the shadows in the Basin and Range of Nevada that made me realize a long time ago that I loved the place.

UPDATE: More trees are sprouting here and there. Geotripper is keeping track of them - be sure to check them all out.

UPDATE AGAIN: More sprouting going on all over the place, and here, too! Many posts mention some link between trees and geology. And another one!

Friday Fault Photos #6

Fairview Peak Revisited:
A few more photos of Fairview Peak, Nevada, site of Nevada's 1954 earthquakes.

Fairview Peak, like many places in Nevada, looks different every time I drive by, so I've taken a lot of photos of it over the years. The photo above, taken recently from a vehicle on Highway 50, looks southward toward the peak along a hill with the 1954 fault scarp near its eastern base (to the left).
Here the road drops into Stingaree Valley; it's about to cross the fault scarp, which has been modified by highway construction.
Another view of the east side of Fairview Peak after driving over the scarp, looking back a little to the southwest.
In this photo of the east side of Fairview Peak, not only is most of the eastern side in shadow, but this time it's snow-covered. The actual fault scarp from the 1954 earthquakes is hidden in the shadow in these photos, and is often difficult to see from a distance. A line seen in the sun, in snow toward the left side of the photo, is a poleline road along the base of the slope, quite a ways below the actual fault scarp. A good photo of the original scarp can be seen here; additional photos, probably taken in 2004, can be seen here.
This view of Fairview Peak was taken from a little pullout on the north side of Highway 50 near the center of Stingaree Valley, with field vehicle in the foreground.

Related Posts:
Fairview Peak, Nevada
Where in the West, March