Tuesday, June 28, 2016

Approach to Titus Canyon: To Red Pass

It looks to me like you can see Quail Rock from White Pass!
We've gone over White Pass—btw, here's a gigapan looking west from White Pass—and we've gone across the flats in the east fork of upper Titanothere Canyon. The road has become a fairly normal dirt road, and although it's still a little narrow, there are places to pull over, or pass, if you happen to be traveling faster than someone ahead of you—although by this point on the road, there is plenty to look at, everywhere, all around, so going slow behind someone (back far enough not to eat any of their dust) is an acceptable option. All through this section, until about the unnamed pass between the east and west forks of upper Titanothere Canyon, the age of the rock formations is Cambrian to the south and Tertiary to the north. The unnamed pass is marked by "Gate" and a gate symbol on the USGS topographic map of the area (USGS TNM 2.0 Viewer)—not that I noticed a gate.

The geology changes a little at the unnamed pass, and the road goes into a series of curves, while also going up and down quite a bit. We've entered the territory of the Tertiary Titus Canyon Formation. The exposures right along the road from here to Red Pass will be either Titus Canyon Formation or Cambrian formations, though not much of the latter, and none that I have photos of.
This photo looks up the western branch of the western fork of upper Titanothere Canyon (Titanothere Canyon is not actually divided into forks and branches, but I've got to call them something!). A fault runs up this canyon, dropping the Tertiary section downward on the northeast (right) side.

You can see the southeast-northwest trending fault in this geologic overlay I made on Google Earth (G.E.). The geology is from Niemi, 2012. Using the "Add Path" feature of G.E. creates lines that hang up in the air above the topography in places, making the contacts as drawn look a little ragged. They also disappear behind topography, going in and out unexpectedly in places, so they are best used for quick visualization. My drawing of the contacts may not be precise, as Niemi's geologic map wasn't associated with an air photo (as published, anyway), and his topo base was digitized somehow, so it doesn't correlate directly with USGS topographic maps (TNM 2.0 Viewer), which can be directly correlated with air photos. I also may have modified some contacts based on what I was seeing on the air photos (G.E.).
Here, above and below, we can begin to see a little of the geology, including a lot of Quaternary alluvium (Q). Notice the terraces of older alluvium, especially the nice one up the canyon. And, by the way, I use blue for faults.
I've labeled the foreground units, from EOgtc to Q (Quaternary undivided). I've emphasized the southeast-northwest trending fault I mentioned earlier by thickening the blue line to the right of the little canyon we're looking up.
Most of these formations were described in a little detail in my last post. Briefly, the Trp is the Miocene Rhyolite of Picture rock, a rhyodacite to latite flow; the Tw is the Miocene Wahguyhe Formation; the Tg is the Miocene Panuga Formation; and the EOgtc is the latest Eocene to Oligocene Titus Canyon Formation. What is shown as Tg in these posts (and on Niemi's map) was once considered to be the upper part of the Titus Canyon Formation, a section known as the Green Conglomerate facies, which sits atop a disconformity on the Variegated facies of the Titus Canyon Formation, formerly considered to be the middle unit of the Titus. All that changed with the publication of Snow and Lux's Tectono-sequence stratigraphy of Tertiary rocks, California and Nevada in 1999, when the Green Conglomerate facies was assigned to the Panuga.

Below, you can see the sort of thing one can work with if geologic contacts are transferred to Google Earth.
This map is a small portion of Niemi's 2012 geologic map of the central Grapevine Mountains.
This image overlays Niemi's map (above) fairly well. I'm sure there is some distortion, and I didn't mean to leave my photo locations turned on!! I've extended a fault or two based on the air photo imagery in G.E.
Not far past this stop, beyond the sharp curve shown in the second photo and the images above, the road crosses a fairly major fault. (This fault is shown as "Fault Zone" in the portion of Niemi's map shown above; it's actually labeled "Fall Canyon Fault Zone" on the full map. I'm not sure if that is really correct, since the Fall Canyon Fault is actually in Fall Canyon, quite a ways to the west. Possibly this fault is considered part of a much larger Fall Canyon Fault Zone: It is parallel in part to the Fall Canyon Fault. (There are at least a couple "drafting" boo-boos I noticed on the map, besides this possible glitch. Labeling and coloring mistakes on published maps is really not uncommon, if you look closely.)

We're getting closer and closer to Red Pass. MOH and I decided to pull over in a slightly wide spot near the next curve so we could hike around a little and look at rocks. I took the next photo just before that curve, primarily to grab a shot of what appears to be an example of two normal faults forming a small, asymmetrical graben on the hill beyond the curve.
Is this a small graben?
A closer view of the hypothetical graben.
The top of the crystal tuff (xtl tuff) formerly marked the change from middle Titus Canyon Formation to upper Titus Canyon Formation. This generally greenish formation is now assigned to the Panuga Formation (Tg).
Looking around from various angles on Google Earth, I have to conclude that there is definitely something going on up there, probably more than two intersecting joints, although the offset on both structures is quite small.
The two hypothesized faults, as seen from a different angle thanks to G.E. The lower, lighter cyan line marks the base of the crystal tuff seen in the last photo.
The crystal tuff has been correlated with the 15.7 Ma Tuff of Unconformity Hill (Snow and Lux, 1999).
A bit of the Titus Canyon Formation, I'm not sure which part.
Here's a nice piece of gneiss (yes, we geologists really say things like that), a boulder that was once a rounded clast, probably in the Titus Canyon Fm, but possibly in the overlying Panuga Formation. "RUB" in Rubicon for scale.
From this same spot, we get a great glimpse of our next section of road: the climb up Red Pass.
We're looking in a southerly direction at the main switchback going up Red Pass. You can see why it's called Red Pass!
The road through here is in the Variegated facies of the Titus Canyon Formation, according to Lengner and Troxel (2008). I'll have to trust them on this. It is within the lower portion of the Variegated facies that late Eocene to early Oligocene fossils have been found (Lengner and Troxel, 2008), including the fossil Titanothere (Protitanops curryi) for which Titanothere Canyon was named. Read more about the Titanothere and other fossil finds here at Geotripper.

With this next photo, we've begun to climb the east side of Red Pass. We turn back around, after pulling over to the side, to see where we've been. The unnamed pass is right at that little white bit of road nearly at the center of the next photo. Just below that section of road, you see the Cambrian part of the latest piece of our journey: The jagged reddish brown rocks on the right side of the photo (south) are Cambrian Zabriskie Quartzite dipping northward (left), overlain by a thin, dark gray section of rock mapped as Cambrian Carrara Formation (although on G.E. the rock looks about the same as the Cambrian Bonanza King Formation did near White Pass).
We're looking northeast into the part of upper Titanothere Canyon.
With that view, we'll stop for now. We'll climb up Red Pass next time. While you're waiting, check out this great gigapan by Ron Schott, which looks like it was created at about the same spot I took the last photo.

A Few References:
Lengner, K., and Troxel, B.W., 2008, Death Valley's Titus Canyon & Leadfield ghost town: Deep Enough Press, 175 p.

Niemi, N.A., 2012, Geologic Map of the Central Grapevine Mountains, Inyo County, California, and Esmeralda and Nye Counties, Nevada: Nevada, Geological Society of America Digital Maps and Charts Series, DMC12, 1:48,000, 28 p. text.

Snow, J.K., and Lux, D.R., 1999, Tectono-sequence stratigraphy of Tertiaryrocks in the Cottonwood Mountain and northern Death Valley area, Californiaand Nevada, in Wright, L.A. and Troxel, B.W. eds., Cenozoic basinsof the Death Valley region: Geological Society of America Special Paper 333, p. 17–64.

Location map

Related Posts:
Beatty: Old Buildings, A Fold, and Onward toward Titus Canyon

The Approach to Titus Canyon: Amargosa Narrows, Bullfrog Pit, and the Original Bullfrog Mine

Mineral Monday: Close-Ups of Bullfrog Ore from the Original Bullfrog Mine, Nevada

The Approach to Titus Canyon: Tan Mountain

The Approach to Titus Canyon: Up and over White Pass

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