A Micro-Bloom

I pulled off for a pit stop at Bob Scott Summit and started seeing little tiny wildflowers everywhere. I looked around, hoping to see a superbloom, like so many were reporting this year, but the flowers were either somewhat far between, or—where covering the ground—were itsy bitsy.

Spring was just beginning on the second highest summit along Highway 50 in the Toiyabe Range of central Nevada, so I suspect that these flowers are just the start of what might be spectacular in places later this month, or even in June or early July.

I don't have the names of all these flowers, but the first photo features locoweed (Astragulus sp), and the second photo is of Phlox (Phlox sp.).

Here, a few sunflower-family plants are starting to come up; these are either Wyethia or Balsamorhiza of some type (likely the former, I think). I don't know what the little blue flowers are, but they are beautiful.

And here is some locoweed again, with a few white flowers, possibly Eriogonum, and more unknown tiny yellow flowers.

Barbecue down!

In a few of these shots, I got really low to the ground to try to make it look like some of the more spectacular superbloom-type photos, wherein you can see flowers up close going off into the distance...

...but that didn't really work for me, and getting a good focus was problematic.

Nevertheless, I persisted, and got some good photos of several different types of wildflowers.

Too bad I won't be passing this way until sometime in July. Perhaps the lupine, which has been forming thick fields up on top of Austin Summit ever since a burn in the 1980s, will be blooming then, but the flowers at this lower pass will most likely be done.

Pine Valley and Carlin Canyon Squiggles

What is this?!!1?1!?

It all started when I was trying to find out what rock formations and rock types I was seeing while making the long trip to work and back out near Elko. Looking around, I found this geologic map (Smith and Ketner, 1972), which even had a kmz file so I could load it directly into Google Earth—and so I did.

There I was, fiddling around looking at rock types and contacts. The map wasn't easy to look at in Google Earth (GE) because it was in black and white, so I started drawing the contacts on to GE, and lo and behold, the contacts were all screwy. It took me a while to figure out that the kmz file didn't register properly on GE; perhaps it didn't have a NAD27 to WGS84 correction or some such thing. I plotted a few static, known localities that I could identify on both the map and GE and determined that everything was off in a northwesterly direction (map to GE) by about 1500 to 1900 feet.

The map and GE locations of a small dam and the ghost town of Palisade.

I thought Palisade looked occupied the last time MOH and I visited, which was in the summer of 2013 (it was the only time either one of us has ever been there), so I was surprised to find it listed by search engines as a ghost town, rather than as a "census-designated area."

I was frustrated by this mis-registration of the map on Google Earth—what is the point of a kmz file of a map, after all, other than to be able to use it easily and forthwith—so I continued drawing on a few contacts in the area I was initially interested in: the area near the small (or old) dam shown above.

Oh look, there's a huge landslide or slump block mapped! I always find these fascinating, so I zoomed in on that, after figuring out that, indeed, I had stopped along the road once—in a pullout near the dam—and had found ash-flow tuff in the roadcut, just like I had remembered! (Although in this case, it was probably slumped or slid ash-flow tuff rather than 100%-in-place ash-flow tuff.)

And then I remembered that I'd always thought there was a pediment in Pine Valley, and recent drives through the area seemed to confirm that, though I wasn't sure if it would be considered a pediment because it seemed to be formed on Quaternary-Tertiary sediments. A couple of old reports (Regnier, 1960 and Eakin, 1961) confirmed that a pediment (or two, even!) had been identified in the valley—and that's when I went nuts with my GE squiggles, and started drawing in all the Quaternary gravels so I could better visualize the valley's geomorphology. That resulted in the squiggles seen in the first image: an incompletely labeled map with missing contacts but with pediment gravels outlined in great detail.

Then, I moved up to Carlin Canyon and—unsuccessfully in my opinion—tried to plot the unconformity contact. (See Ron Schott's Gigapan of the Carlin Canyon unconformity here.) And then I moved to the Carlin Formation east of the Carlin Tunnels. The Carlin Formation forms golden-brown outcrops and cliffs right alongside the highway, great examples of tafoni weathering, so close but inaccessible. I wanted to see if any roads led into the area, and there are none, but I drew some squiggles for the geology in that area anyway, and then moved south of the highway to draw in a few more areas of the Carlin Formation, because once I've started on something, it's hard to get me to stop.

An expanded version of my GE squiggles.

And that's what it all looks like at this point. Hopefully I'll be able to grab a few great photos of the pediment surfaces later this summer, when I move back into the area for another round of work way out there.

By the way, the completed geologic map (Smith and Ketner, 1978), published in color, can be viewed here (but without a kmz file).

From the Road: Some Nice Gneiss

Every time I drive Highway 6 between Idaho Springs and Golden, Colorado—and I almost always take that route when heading east, rather than the section of I-70 between Idaho Springs and the hogbacks—I try to get a few photos of the great gneiss forming the canyon walls. If I'm going eastward, it can be hard to stop because I'm almost there. This time, in the fall of last year, I was heading west, but I still found it hard to stop, partly because of traffic and unexpected road work. Nevertheless, I managed to make a few pullouts that were rewarding.

The first shot is typical of the biotite gneiss that underlies much of the region: darker bands with more mafic minerals, and lighter bands composed almost entirely of felsic minerals.

Here's a little more of that same biotite gneiss showing complicated deformation.

The geology of the area, seen below in a cutout from a USGS map, looks a little complex! Our first two photos (the two easternmost dots that are rather close together) are in what is mapped here as Xb: Proterozoic biotite gneiss.

Map courtesy USGS (Kellogg et al, 2008).

A little farther into Clear Creek Canyon, I pulled over and grabbed a couple shots of this second roadcut (single dot to the west, above), primarily because of all the light-colored dikes and masses. These rocks are probably what is mapped as Xh: hornblende-plagioclase gneiss and amphibolite.

All of the rocks we're looking at today are thought to have originated as sedimentary and volcanic rocks that were deposited in a basin 1780 to sometime after 1750 Ma (million years ago), as per this pamphlet accompanying the map.

A shot of the entire roadcut. 

Somewhat darker gneiss is above somewhat lighter gneiss in this roadcut. The darker portions may qualify as amphibolite, which is part of the Xh unit.

The same gneiss, zoomed in a bit.

I noticed what looks like a little folding while I was processing these photos, so I drew in a few lines. The rocks look darker inside the fold nose, and there has been a lot of injection of the light-colored material, which might include felsic dikes like aplite or pegmatite, and also might include some quartz veins. I really don't know how common quartz veins are within these gneisses, and the roadcut is too close to the often busy, narrow and windy, two-laned U.S. Route 6 for safe examination.

If you want to see more of these rocks, here is Robin Rohrback's set of gigapans of the roadcuts along this stretch of Highway 6, along with gigapans of hand samples of the gneiss.

Reference:
Kellogg, K.S., Shroba, R.R., Bryant, Bruce, and Premo, W.R., 2008, Geologic map of the Denver West 30’ x 60’ quadrangle, north-central Colorado: U.S. Geological Survey Scientific Investigations Map 3000, scale 1:100,000, 48-p. pamphlet.

From the Road: The Book Cliffs in Western Colorado (Mount Garfield)

Earlier that day (the same day I stopped in Parachute and Rulison, resulting in three posts about the Roan Cliffs), I had pulled over at the convenient viewing pullout on I-70, which is east of Grand Junction and a bit west of Palisade. It's hard to pass by this cliff, part of the Book Cliffs, without taking a picture or two. This time, unlike most other times, I took only one photo!

The Book Cliffs are capped by sandstone and lesser shale of the Upper Cretaceous Mesaverde Group, which overlies shale and minor siltstone and sandstone of the Upper Cretaceous Mancos Shale. The Mesaverde Group (sometimes Formation, see Geolex) usually consists of several recognized sandstone tongues, members, and formations, with intertongues of Mancos Shale in its lower part. In the area of these photos, the mapped sandstone formation—the buff-colored cliff-former above the Mancos—is the Mount Garfield Formation, obviously named for Mount Garfield, the highest point above the cliffs, on the upper left.

I cropped the photo to zoom in, partly because the nearly white layer just below the sandstone cliff caught my eye. While here, we might as well take a peek at the geologic contacts.

Kmg is the Mount Garfield Formation; Km is the Mancos Shale. The contact I’ve drawn in is largely from the Geologic Map of the Clifton Quadrangle, Mesa County, Colorado (Carrara, 2001), with extrapolation from the Geologic Map of the Palisade Quadrangle, Mesa County, Colorado (Carrara, 2000). The contact very roughly approximates the one shown on the Macrostat online geologic map.

Other photos of mine of the Book Cliffs can be seen here (photos from 2006) and here (photos from 2008). Also check out Ron Schott's GigaPan of the cliffs.

From the Road: Talus-y Goodness and More of the Roan Cliffs, and a Question (at the end)

I was looking back through some photos and realized I had some of the Roan Cliffs from the spring of 2006. These first two photos are taken from an impromptu campsite MOH and I found not far from the Rulison exit on I-70, and they somewhat approximate the views seen in Ron Schott's excellent gigapan of the cliffs. I'd embed the gigapan here, but Blogger seems to have some problem with either the iframe coding or the flash implied within the code (or maybe it's Chrome, and I'm being deluded as to what's possible). In either case, we're looking northwest toward the cliffs in the first photo (above), and northeast toward the cliffs in the second photo (below).

It was a very green spring, according to these photos, so the color balance doesn't match with my fall 2016 photos below, which were taken from near or at the Rulison exit. Also, my Nikon tends towards blue.

The reason I stopped for these particular photos during my semi-mega roadtrip of last fall was the talus. I found the striping caused by alternating zones of vegetated and non-vegetated slope areas to be fascinating in the way that perhaps only a geologist, geomorphologist, or photographer can. So I grabbed a few quick shots focusing largely on the talus slopes. More recently, I decided some approximated geologic contacts were in order.

In this photo (above), the cliff and talus slope below the cliff are formed on the Tertiary Green River Formation (Tg), and the colorful beds near the bottom of the photo consist of the Tertiary Wasatch Formation (Tw). The thin cyan line near the base of the cliff marks (hopefully) the top of the Mahogany ledge as extrapolated from this USGS preliminary geologic map, as deduced from this report (Fig. 9, p. 16)—which points out the top of the ledge in a cliff to the west—and as mapped from Ron's gigapan of the cliffs. A few other reports were helpful for exploring the general geology and reading some background info about the ledge and zone—it's called the Mahogany zone when intercepted in drill holes.

In this set of two photos, I've zoomed in on the striped talus section that was on the far right of the previous two photos. The vertical striping of the talus contrasts nicely with the horizontal layering of the Wasatch beds, don't you think? I've labeled the photos below. This time, a tiny bit of the Tertiary Uinta Formation (Tu) is barely visible at the top right. The stratigraphic contact between the Tg and Tw is crudely outlined in faded cyan: It crops out behind the foreground slope where we can't see it.

This set of two photos is not that different from the previous set, but here (below) I've sketched in the Mahogany ledge (as approximately extrapolated), and I've broadly labeled the geologic formations without drawing in the contacts. The circle is where an old mine, the Rulison Oil Shale Mine is shown on the topo map of the area  (USGS TNM 2.0 Viewer link). I can't see it there in the photo—though maybe it's just not apparent—but there is a tiny black area that *might* be an adit just beneath the arrow.

The cliffs in these 2016 photos lie northwest of the Rulison exit and occur between the first two 2006 photos.

In this last set of two photos, we're looking northeast from the Rulison exit, zooming in on cliffs that approximate what we can see in the second of the two 2006 photos. I once again focused in on striped talus, but then I really zoomed in on some switchbacked roads that I thought might be drill roads. It turns out that the switchbacks climb up to some underground workings into the Mahogany ledge, which I've marked approximately with a thin cyan line (below, with thicker lines marking formational contacts; Tu = Uinta Formation; Tg = Green River Formation). The line is taken directly from the previously linked-to preliminary geologic map of the Anvil Points Quadrangle (O'Sullivan, 1986). The map can be viewed directly in Google Earth, an option I always appreciate.

The underground workings here consist of several adits comprising the Anvil Points Oil Shale Mines. The mine was active intermittently from 1925 to 1982 (the last link includes some undated photos), with some clean-up operations running from 2008 to 2013.

How do you spell Talus-y? I see 3 options: talus-y, talusey, and talusy. I went with the first option in the title but prefer the last. Yes, I know it's not a *real* word.