Finding a Thesis: A Joshua Tree Aside

South of the Klondyke district (our previous stop on this journey) and just north of Goldfield, one reaches one of the northernmost populations of Joshua trees (Yucca brevifolia) — or the northernmost population, depending on what range map you use. These unusual plants continue southward past Goldfield toward and beyond Beatty. They occur in dense stands or forests in several places, notably along Highway 93 approaching Caliente, Nevada, and in a few places in the Mojave Desert of California.

To take the pictures I've included here, I drove off Highway 95 onto the Silver Peak Road about three to four miles north of Goldfield. Joshua trees are scattered all along the five to six miles between 95 and Alkali, Nevada.

Looking NNE toward Tonopah and the Klondyke Hills.

Joshua tree with Hasbrouk Peak to the left (reddish hill underlain by Tertiary volcanic rocks) and the Klondyke Hills to the right (brownish hills in front of the volcanic rocks of the southern San Antonio Range).

Joshua trees, especially those near Goldfield, make me think of my Former Mining Company days and Roquemore, who was the head of the Nevada District. (We were divided into four districts for exploration and management purposes, with Nevada being covered by one district’s worth of geologists. Our district, the Western District, covered all Pacific states up and down the coast from SoCal to Alaska, and we claimed Hawaii, though we were never lucky enough to be stationed there). Roquemore told me — years after my thesis-hunting pass through the Goldfield area when we were exploring Mineral Ridge near Silver Peak as part of a Nevada-Western joint venture — that Dusty, a dark-haired young woman working in the Nevada District, always waved at Joshua trees every time she saw one; she would wave while saying, “Hi.” Dusty had claimed that Native American tribes, or a particular tribe, believed the Joshua trees held or were the manifestations of the spirits of their ancestors, an assertion that I haven’t been able to verify by Googling.

While listening to this story on that day gone by, we drove past another two dozen Joshua trees, and Rock waved out the window, saying, “Hi,” in a immitation high-pitched voice.

Wild horses amongst the Joshua trees.

I'm not sure what the Nevada District geo-types were doing in Joshua tree country. We of the Western District would later claim as ours all areas where chollas could be found, and gave this new territory, which went as far north as the Gilbert mining district in the Monte Cristo Range west of Tonopah, the name “Cholla District.” Possibly the Nevada geos were out looking at something down near Caliente; possibly they had ventured into Goldfield, Silver Peak, or even as far south as Beatty. Nevertheless, every time I see a Joshua tree, I think of Rock saying hi in that high voice, I think of Dusty’s story about the spirits of ancestors in Joshua trees, and I find myself, on occasion, waving.

The Finding A Thesis series will continue onward, past Goldfield and into the Palmetto Mountains.

Read more about Joshua trees at DesertUSA.

Previous Posts in this Series:
Thesis: Finding an Area
Finding a Thesis: Battle Mountain to Austin to Gabbs
Finding a Thesis: Pole Line Road
Finding a Thesis: Pole Line to Belmont
Finding a Thesis: Klondyke District

Over the Plateau and Into the Canyon

With this belated post, I'm returning to our last trip north, which was now more than a month ago. At first I thought I'd do this in the spirit of Evelyn Mervine's geology picture a day — but these are not all geology photos, and I'm going to bunch 12 together, hoping that will hold me until I can get around to another continuation, whenever that will be.

Our November trip north began here, with some wintry views and with us leaving the Great Basin for the Snake River drainage, and continued here, as we drove by an intrusive contact and then north into Idaho.

The 3 Creek Road begins in the tiny burb of Rogerson, which sits along Highway 93 between the Nevada-Idaho stateline and Twin Falls, ID. From Rogerson, the road rambles west toward Salmon Falls Dam and points beyond (MSRMaps location). The sign at the beginning of the 3 Creek Road says Salmon Falls Dam 7, Murphy Hot Springs 49, and Jarbidge, Nevada, 64. Possibly you can guess our destination.
Here, not long into our side trip (the side trip being the main point of the entire trip), we are driving over the old, one-lane Salmon Falls Dam.
At this point, the 3 Creek Road still shows signs of the earlier snowstorm: a bit of snow on the sides of the road, and ice in shadowy curves. The Jarbidge Mountains sit in shadow in the not-so-far distance.
The 3 Creek Road crosses miles of plains consisting of fairly flat plateaus and rolling hills, all variably incised by creeks and rivers draining northward to the Snake River.
A snowy but inviting road traversing the hills to the north catches my eye. If driven, would it take us all the way to the Snake River?
This is a typical view of the southern part of the Snake River Plain, looking west from the 3 Creek Road where it is about to descend into one of the intervening valleys.
We finally left the 3 Creek Road, dropped into the gorge of the East Fork of the Jarbidge River, came to The Jarbidge Forks, and drove south into Nevada along the main fork of the Jarbidge River. Hoodoos in the rhyolitic Cougar Point Tuff appear near the Idaho-Nevada state line.
Most of the hoodoos are in Nevada, certainly the best ones are!
A bush or small tree grows atop a double hoodoo.
The snowy road curves ever onward, giving us glimpses of the canyon walls and mountains above Jarbidge.
Sun glows on the hills we hiked in the summer of 2010, on stands of subalpine fir, limber pine, and whitebark pine.
We arrive, get a room in the middle of a locally critical football game, go for a walk through the snow, and end up at the Red Dog Saloon for beers and burgers.

The Contact at Contact

We continued on toward the small bordertown of Jackpot, Nevada, having passed out of the Great Basin by dropping into the drainage of Willow Creek – which joins with Dry Creek, which joins Jakes Creek, which enters Salmon Falls Creek near the railroad siding of Henry. Salmon Falls Creek then flows north, eventually emptying into the Snake River below Twin Falls. Skies were clearing somewhat, and snow was no longer thretening.

A few miles south of Henry, China Mountain rises into view east of Highway 93. China Mountain is a good place to see an intrusive-sedimentary contact at 70 mph. The generally rubbly or knobby looking rocks on the far north side of China Mountain are outcrops of the granodiorite of the Jurassic Contact pluton. It’s intruding late Paleozoic limestone and marble (and possibly other associated sediments and metasediments): the layered and moderately dipping beds across most of the mountain.
Here I’ve drawn the approximate contact in hot pink. Granodiorite is to the left (Jgd on this map); limestone and marble are to the right (PMl on the same map). Where I’ve ended the contact, it dives under undivided Miocene to possibly Pliocene tuff, ash, and sediments (mapped as Ts3).
The granodiorite of the Contact pluton shows some spectacular spheroidal weathering between Henry and the small outpost of Contact. This view to the west of the highway, taken just a couple minutes beyond that last photo, shows the granodiorite in the foreground, with Ellen D Mountain in the background. Ellen D is underlain by the same late Paleozoic sediments seen on China Mountain; the contact between the granodiorite and the sediments runs behind the wonderfully knobby mass of granodiorite and the base of Ellen D Mountain.
What isn’t clear from the highway, is that the intrusive contact passes eastward from the present site of Contact, runs west toward Ellen D Mountain, then curves southward. All along that contact, the topo map of the area (from MSRMaps) shows a series of old mines and prospects dug into mineralized, contact-metamorphosed rocks right along the contact. These are some of the mines and prospects of the Contact mining district, which were prospected originally for gold, but have been mined mostly for copper. The original mining town of Contact was moved from its original site fairly early on prior to being relocated a second time at its present location.
While we drive by Ellen D Mountain, the highway passes through some roadcuts in the Contact pluton. The knobby knob on the left and the low mass on the right are in granodiorite. The reddish brown hill to the far right is in Tts: rhyolitic ash-flow tuffs probably about 10 to 12 million years old, possibly erupted from the Bruneau-Jarbidge eruptive center to the west.
After stopping briefly in Jackpot, to gas up and grab a snack, we crossed the Idaho line at 1:20 pm PDT, 2:20 Mountain Time. Jackpot is not the only town in Nevada that operates on Mountain Time.

Oh, by the way, here's my take on the naming of the various contacts. First, the Jurassic granodiorite intruded the Paleozoic limestone. Later, uplift exposed the contact between the Jurassic and Paleozoic rock formations. Much later, people came along prospecting for gold and copper; they were attracted to the contact for various reasons, not the least of which was probably some nice float of copper oxides and copper carbonates. When they staked claims, they listed the claims as being in the Contact mining district, which they named after the mineralized contact they were so hot on. They set up a town and called it Contact, after the mineralized contact and the mining district. Eventually, all the nearby mining districts in the area were consolidated into one district called Contact. The order of the naming and founding of the latter two (Contact the mining district and Contact the town) is entirely speculative on my part.

I have a bit more information on this part of Highway 93, from south of Wells to the stateline, in an earlier post, here.

Map References:
Hope, R.A. and Coats, R.R., 1976, Preliminary geologic map of Elko County, Nevada: U.S. Geological Survey, Open-File Report OF-76-779, 1:100,000

Sheet 3 of the above, covering our area of interest in the upper left.

Sheet 6 of the above, the explanation for the entire map.

A Wintry Trip North

Over the weekend, thinking that it wasn't really wintry enough already, we took off to the north...
...eventually heading directly into the fast-moving storm that was just clipping the northeast part of the state, not leaving a lot of snow in it's wake, but blowing like crazy.
Light and dark patches northeast of Highway 93: the storm moves across Clover Valley south of Wells, Nevada.
Sunlight comes through light snow showers on the west side of Spruce Mountain Ridge, a narrow basin-and-range ridge east of the East Humboldt Range.
Still south of Wells, somewhwere near the turnoff to Ruby Mountain Brewery, we drove by a small herd of elk grazing on the other side of the right-of-way fence.
Over the last couple years, NDOT has installed a couple wildlife overpasses between Wells and Jackpot. This is the one at HD Summit (MSRMaps location).

At this point, Highway 93 is still inside the Great Basin, within the watershed of miles-long Thousand Springs Creek, which eventually leaves Nevada for Utah and the Great Salt Lake Desert northeast of the small town of Montello.

About 10 miles north of HD Summit, Highway 93 enters the drainage of the Snake River after crossing an unimpressive drainage divide atop a small set of east-west hills, south of the "93" on the MSRMaps image below, and here looking north on Google Street View. I couldn't quite locate this major drainage divide while we were driving south, but instead probably thought it was in the small hills just north of the "93" on the MSRMaps view.
MSRMaps image courtesy of the USGS. One mile is shown by the black section line running east-west between the red, north-south township border to the left of Highway 93 and the black, north-south line to the right of Highway 93.

At this seemingly insignificant drainage divide, the internally draining Great Basin ends. The Basin and Range Province, which overlaps the smaller Great Basin, continues a ways to the north, merging gradually with the plateau country on the southern edge of the Snake River Plain.
Scenes like this always make me want to drive off road, but we didn't. Instead, the pavement continued north, and so did we...

Cathedral Gorge II: The Hike

After coming out of of "the cathedrals" at Cathedral Gorge, MOH and I went on a little hike.
The trail goes north up the gorge, from the CCC Picnic area (facilities and water tower built by the CCC in the 1930s) to Millers Point, a one way distance of about a mile (MSRMaps location).
Fascincating textures can be seen in the Pliocene Panaca Formation along the way. Here, differential erosion of harder, thin sandstone layers interbedded with softer mudstone layers have created interesting mini-columns and maybe even some little mini-cathedrals hidden in the shadows.
My hand is straddling two sandy layers and a mudstone layer sandwiched in between. A curious jigsaw-like texture has developed over the mudstone. Essentially these are tiny gullies or rills created by water running down the outcrop.
We've now made it into the beginning of the steep, northern end of the trail, and I've turned around to look southward down the gorge.
Steep: The northern part of the trail is steep, especially in this section of hand-built stairs held up by partially eroding railroad ties. Beyond these wooden steps are metal stairs that go from ledge to ledge over the steepest sections of the trail.
Instead of hiking the stairs all the way to Millers Point, we stopped on one of the middle ledges. Columns capped by sandstone can be seen from several vantage points along this northern stretch of the trail. The scale of these hoodoo-like features is difficult to appreciate: they are often smaller than similar erosional features at Cedar Breaks, for example. These are maybe two hundred feet high at most.
This is one of several holes eroding into the broad ledge we were standing on. I peered in, but couldn't lean out far enough to see anything, so tried holding the camera out as far as possible, having it do the peering for me.
I wondered if this hole could be the top of one of the cathedral-like columns we had seen from below while wandering around near the picnic area (first post).
An overexposed photo showed me that this hole only goes down a few feet (railroad ties for scale).
Some of the other "holes" and irregular erosional features near the edge of the ledge may indeed go downward to become cathedral-like inner columns, but I really didn't want to check them out too closely!
Now I've jumped two or three hundred feet upward and two or three years back in time to show this photo taken from Millers Point. The broad ledge we were on is below; the stairs to the right along with a smaller set of stairs down on the ledge (barely visible on the far left part of the ledge) give some sense of scale to the columns and gorge, and to the broad plain into which the gorge has been eroded. The bentonitic, tuffaceous clays, silts, and sands of the Panaca Formation — essentially water-laid tuffs, diatomaceous in places — were deposited in a closed, Pliocene-aged basin. The source of the tuffaceous material is reportedly the Caliente caldera complex south of Caliente, NV — way off in the distance on the far right — which was active in latest Oligocene to middle Miocene time, from about 24 to 13 Ma.

The Panaca Formation reminds me somewhat of the Triassic Chinle Formation, a partly bentonitic formation seen on the Colorado Plateau at the Painted Desert. Possibly the Panaca will look like the Chinle in the far future, if it has the good fortune to be preserved, rather than being eroded as it is now, southward into Meadow Valley Wash, from there southward into the Muddy River (formerly into the Virgin River), and from there into the Colorado. We are outside the Great Basin!
We finally headed back toward the CCC picnic area, just beyond that final rise of sand highlighted by the early afternoon sun.
Gratuitous sand photo. And darn! I forgot to collect any!

Some References:
Rowley, P.D., Nealey, L.D., Unruh, D.M., Snee, L.W., Mehnert, H.H., Anderson, R.E., and Gromme, C.S., 1995, Stratigraphy of Miocene ash-flow tuffs in and near the Caliente caldera complex, southeastern Nevada and southwestern Utah: in Scott, R.B. and Swadley, WC, eds., Geologic Studies in the Basin and Range - Colorado Plateau transition in southeastern Nevada, southwestern Utah, and northwestern Arizona, 1992, U.S. Geological Survey Bulletin, 2056-B, p. 43-88.

Rowley, P.D., Snee, L.W., Mehnert, H.H., Anderson, R.E., Axen, G.J., Burke, K.J., Simonds, F.W., Shroba, R.R., and Olmore, S.D., 1992, Structural setting of the Chief mining district, eastern Chief Range, Lincoln County, Nevada, in Thorman, C.H., ed., Application of structural geology to mineral and energy resources of the central and western United States: U.S. Geological Survey Bulletin 2012, p. H1-H17.

Nevada-Utah series so far (in trip-time order):
Cathedral Gorge I
Cathedral Gorge II: The Hike (this post)
May Utah Trip to be Continued
Cross-Bedded
More Cross Bedding
Bighorns on the Overlook Trail

Single Shots: Narrow Trail

A narrow part of one of the passageways at Cathedral Gorge, NV

Related Post:
Cathedral Gorge I

Cathedral Gorge I

Cathedral Gorge is a small state park in southeastern Nevada, part of a lowlands that is hot in summer and reportedly cold in winter, though I have only stopped in the non-winter months.

It's a bit of a weird place, in a way, maybe because most pictures make the place look larger than it really is. The Pliocene Panaca Formation is soft, not hard, and it is eroded into a fabulous badland. I swear it used to be billed as the Grand Canyon of Nevada, or some such, but can find no references to that, so maybe my memory has slipped into Never Never Land (the good place, not the bad), or maybe I'm remembering some touristy postcards. The place lacks a decent sense of scale, so one has a difficult time getting a feel for the size of the fluted columns and spires and the cliff heights.

Most of the gorge is 1000 to 2000 feet from cliff base to top.

One neat thing I hadn't experienced before — at the end of the road, indicated by a loop near a water tower marked "Tower" on MSRMaps, and maybe in other places, also — you can find little hidden entries into what I'm assuming are the "cathedrals." (Google Maps location, and a photo with a person for scale.)

In places, the passageways are narrow enough that one has to squeeze through.

I've also seen these referred to as slot canyons, although they don't really lead anywhere other than by huge vertical jumps to a broad alluvial to pedimented plain surrounding the top of the gorge, and they are way too small to show up on the scale of a topo map. They are, nevertheless, fascinating and surprisingly spectacular.

Columns at the base...

...an opening or cathedral at the top.

The whole thing.

Pillars and a narrow hallway. The board appears to be wedged in as an overhead bridge. The Panaca Formation is too old (Pliocene) to have a board weathering naturally out of it, so someone put it there for an unknown reason, maybe climbing?

The columnar end of one of the side trails.

The entire column or "cathedral," with a tumbleweed at the base.

And now it's time to find our way back out...

To be continued...