Tuesday, July 26, 2016

Down into Titus Canyon: We Leave Red Pass Behind (Finally!)

We will leave Red Pass shortly. Be sure that you've looked around: Take your last look eastward toward White Pass and Titanothere Canyon. And be sure you've gotten your fill of the hoodoos above the pass. What we'll do right now, before sliding down into the eastern reaches of Titus Canyon, will be to take one last look ahead, this time with binoculars, a zoom lens, or a spotting scope. We’ll look in the direction of Leadfield, where we can begin to see the broad fold above the ghost town.
Our zoomed in view.
I said in an earlier post that you could see the westernmost, still-standing cabin at Leadfield if you know where to look. It sits at the end of an old trail below a broad fold in the Carrara Bonanza King Formation. I have to admit that I didn’t spot this until I saw it enlarged on another website and confirmed the sighting on Ron Schott’s gigapan from Red Pass. Did you spot the cabin?
Well, there it is. Check the snapshot of the cabin on the gigapan if you're not convinced.
Before we move on, we'll take a look at the geology. As in several previous posts, the map symbols I'll use, along with the mapping (faults and contacts), are primarily from Niemi (2012) with a little bit from Reynolds (as shown in Lengner and Troxel, 2008; a tiny version of his map is shown here). These symbols are listed in an earlier post.
This matches the wide-angle photo more than the zoomed photo, but enough of that: The symbols jump around too much in Google Earth.
Essentially, we have several groups of ash-flow tuff sheets erupted from the Timber Mountain caldera back in the Miocene (Td, Tm, and Tc) lying on intermixed or intercalated volcanic and sedimentary units (Tw, the Wahguyhe Formation and Trp, the Rhyolite of Picture Rock, which consists of latite flows). The Tw-Trp mix rests on top of the dominantly sedimentary Miocene Panuga Formation (Tg, formerly the upper part of the Titus Canyon Formation) and the sedimentary Eocene to Oligocene Titus Canyon Formation (EOgtc). A megabreccia subunit composed of limestone clasts from the Bonanza King Formation forms irregular masses in the lower part of the Titus Canyon Formation. The megabreccia is shown here as Mbx; I've approximately outlined a few of the masses below. You can also see a bit of the Cambrian Carrara Bonanza King Formation [it should be labeled Cbl, not Cc] in the folded rocks sitting just above the old site of Leadfield, which, besides that one cabin, really isn't visible yet. I haven't drawn in all the contacts (in cyan): I've left a few to your imagination.
The zoomed-in photo with some geology added.
There are a number of faults in this area, and I've only shown a few (in dark blue) on the photo. Unfortunately, one of the major ones, labeled "Fall Canyon Fault Zone" (FCFZ) on Niemi's map, is really kind of hidden at this angle. I've indicated part of it in a heavier blue line, with an arrow to indicate that it's wrapping around the topography to head up toward the upper part of Titus Canyon. Please check out Niemi's map to see the complexity of the FCFZ. By the way, that upper part of Titus Canyon is kind of hidden between the closer Tw section on the right and the more distant Tw + Trp section closer to the center. It's hard to spot the canyon in my photo. Many of the other faults I've shown have low apparent dips in the photo merely because of the angle of our view. They are normal faults, as far as I know, probably of high to moderate angle—or even of low angle, at least at depth.

Now that I think about it, I'm going to have to go ahead and show this next photo, also taken from Red Pass, just so you can see the FCFZ better. Also, the upper part of Titus Canyon can be visualized more easily. I'm not sure which blue line represents the fault best: One is essentially from Niemi (2012); the other is from Reynolds (as shown in Lengner and Troxel, 2008). And both lines are what I've chosen using Google Earth, so a lot of interpretation has transpired. Both faults as drawn may be strands of the same fault. That is, to me they both look like something "fault-ish" in Google Earth. The fault on the left (west) cuts reddish and greenish beds of the EOgtc on the west. The fault on the right has light colored rocks (cream, pale greenish yellow, or light yellowish gray) of the Tw on the east (right). I'm really not sure what formation the rocks in the middle belong to, but I am sure this means that another field trip to the area is warranted.
"Lost Canyon" in the foreground; upper Titus Canyon (indicated in red) between two volcanic ridges; FCFZ in blue.
Going down the hill from Red Pass, we are finally in the greater Titus Canyon drainage area. This particular canyon is unnamed, although Lengner and Troxel call it “Lost Canyon,” using a name they say was used by Reynolds  (presumably in his 1969 dissertation), and which they also found in a report from the 1920s. Niemi used “Lost Valley” for the same area, a name that was reportedly used for the northern arm of Death Valley. I'm favoring "Lost Canyon" at this point.

Let's drop on down! The road twists and turns quite a bit, but otherwise isn't too bad. A little ways down the hill, we get a good look at this unnamed hill, herein called "Tc Hill" for the geologic formation capping the hill.
This hill is really quite colorful, and some photos I've seen of it at sunrise or sunset make it look even brighter.
I've got several sets of thin cyan lines in this next photo, and a slightly thicker cyan line at the very approximate contact between the Tc (Crater Flat Group tuffs) and the underlying Tw (Wahguyhe Formation sedimentary and volcanic rocks). The thin lines represent what look like individual beds within the formations. The yellow line outlines a talus mass or slump block.

Updated [27-28Jul2016]: The Tc-Tw contact should probably be considerably higher on the hill, putting most or all of the greenish rock into the Tw, and possibly the whitish layer just below where the rock turns pinkish to reddish orange upward. And though the line is based directly on Niemi's map, the contact doesn't really match the way he shows his contacts drawn on two aerial photos of the area (Fig. 7 and 8).
Tc Hill and the approximated Tc-Tw contact.
Now, below, I've added one strand of the FCFZ, and a couple small offsets in the cliff face. Now you see why I added the marker horizons!
Tc Hill with FCFZ and two minor normal faults added. All faults shown are down-to-the-east (right).
Although I've labeled the lower greenish rocks as Tw (that's what they appear to be on Niemi's map), it's possible that they are part of the Tg or EOgtc.

Well, that really about does it for this time! We're in the upper part of Lost Canyon, winding our way toward Leadfield. The worst part of the road (unless it has been washed out or is in any kind of flash flood situation) is waiting for us up ahead around a sharp bend. From here to Leadfield, we'll be driving mostly on the Titus Canyon Formation. I'm pretty sure that this latter fact means that this part of the road can get nasty in a rainstorm.

A Couple 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.

Location map

Related Posts:
The Approach to Titus Canyon: Tan Mountain
The Approach to Titus Canyon: Up and over White Pass
The Approach to Titus Canyon: To Red Pass
The Approach to Titus Canyon: Just Below Red Pass
A Hike at Red Pass, Titus Canyon Road, Death Valley, CA
Titus Canyon Road: A Little History and a Few Maps

Tuesday, July 19, 2016

Titus Canyon Road: A Little History and a Few Maps

Now that we've arrived at Red Pass, and we've even taken a little hike, let's stop, absorb the view, and reminisce a bit.
The view west from Red Pass.
My experience with Titus Canyon probably dates to the early or mid 1980s when I was working for Former Mining Company down in the Mojave Desert of California. At that time, my minerals exploration work consisted of operating and running reconnaissance and project work, the latter of which generally consists of geologic mapping, surface sampling (rocks, soils, stream sediments), an occasional geophysical survey or two, and drilling (back then, all the drilling I did as part of gold exploration and evaluation was RC drilling, see more here).

Over the years, I've used the road into and through Titus Canyon mostly to get from here to there by way of a more scenic passage, a route that runs close to the geology (sometimes within arms reach). This alternative course can't really be called a short cut because the main roads into the Mojave, 95 and 395, are usually more direct and almost always much faster. Because of Titus Canyon Road's relative inefficiency in getting me to my destination, I haven't driven it more than a handful of times over the past three-plus decades, and two out of those maybe 5 to 6 total times have been within the last ten years. Back in the day—when I took this out-of-the-way "short cut" mostly from Beatty, Nevada, to Baker, California, when I was likely heading for Baker (yikes!), Barstow, or Ridgecrest—I generally drove the road alone in a half-ton, 4WD Ford pickup truck with a regular cab and full length bed. (I may have driven the road once or twice with a field assistant as passenger...maybe.)
“Short cuts make long delays.”
J.R.R. Tolkien, The Fellowship of the Ring
My present-day impressions of the road and canyon are probably heavily biased by whatever state the road was in back then, and perhaps they are affected by the relatively long wheelbase of the truck I was driving. At least in my imperfect memory, Titus Canyon Road (the TCR) was largely untraveled back then, meaning that on the entire one-way trip (which, like I said or implied, I usually made as quickly as possible with very few stops because I was on my way to a destination still a few to several hours distant) I doubt that I saw as many as four vehicles—and I really don't remember seeing more than one or two. In other words, the TCR was a back road that few people knew about, or if they did, they didn't bother to use it. The road was only for true Death Valley or Saline Valley aficionados (the road to Saline Valley is a real 4WD road, one not to be scoffed at, while the TCR rarely requires 4WD, depending on one's vehicle and off-road skill level).
As you know if you've been reading my recent Death Valley blog series, the last time I went down the TCR was with MOH back in late February of this year. There were several vehicles parked at Leadfield when we arrived, and there were many more vehicles quite a ways behind us (I was driving relatively fast on the road, once again trying to make it through to reach a particular destination: the superbloom down near Badwater). I just don't recall the road being so heavily traveled back in the 80s, when I probably would have been on it mostly in December through May at the latest.
“I met one other fella' on the trail...”
Ronald Swartley, 26 'spilling' miles to Death Valley, Am Motorcyclist (1978)
Note: I would personally hesitate to drive the road from mid May through sometime in October, November, or December (depending on the local weather) without a SPOT, which of course we didn't have back in the 80s. An equivalent type of safety backup back then might have been a car phone, although I personally had very poor luck with such a device in the late 80s down near the fairly populated (by Nevada standards) area of Victorville, Apple Valley, and (ugh!) Lucerne Valley (link to a great description of the seedy place at the Urban Dictionary; matches my remembrances of that sh**hole to a T).

My memories of the TCR center mostly around the awe-inspiring views from the heights of Red Pass and the incredible twisting, winding, and dropping of the road into the valley at Leadfield. The curves seemed tighter in a full length pickup than they do in a Jeep (or the current road is wider). My clearance over the rocks on the final steep pitch approaching Leadfield has always been fairly good, but I may have had to dodge them a little more assiduously back then (I wonder if the road was maintained as frequently?). Most recently, I've been surprised both times at the length of the first section of the trip, from the pavement of Nevada S.R. 374 to the apex of Red Pass. Oh, and of course the slot canyon near the end has always been fun. It's become quite a popular hiking area, something I don't really recall from earlier days, either. Another Note: the NPS say the Titus Canyon road is the most popular backroad in Death Valley National Park.

A cabin at Leadfield.
I regret, once again, that I haven't ever stopped to get a photo of the worst section of the road, the bedrocky part where you have to dodge a few rock masses sticking up out of the road in quite an inconvenient fashion, but I'm usually too busy driving...and dodging...and then it's over.

While doing a little research for this rambling post, I stumbled across a factoid previously unknown to me. As recently as 1978, Red Pass was known by some, including the National Park Service, as Bloody Gap—presumably because of the red color of the rocks rather anything because of anything nefarious in its history. I first noticed Bloody Gap being used in the caption of this old postcard [no longer available]. It was mentioned in this descriptive bit about Leadfield in Desert Magazine (1968), in this L.A. Times article (1969), and in this American Motorcyclist story (1978). The USGS, however, doesn't list Bloody Gap as an alternate name for Red Pass.

On my way to finding every mention of Bloody Gap that I could (including a few more links to selling old postcards on Ebay or what-have-you), I looked at old maps to find Bloody Gap, and also to see if another old name for part of the canyon, "Lost Canyon," was ever published.

By 1954, the TCR was shown as one way.
1954 Death Valley 1:250,000 sheet, courtesy USGS
And in 1961 and 1964, Titanothere Canyon was shown as "Titanother Canyon."
1961 Death Valley 1:250,000 sheet, courtesy USGS.
In 1985, the 30x60 Saline Valley map showed Titanothere Canyon (with an "e" at the end) and Red Pass. No Bloody Gap. No Lost Canyon. There was, however, quite a gap in map making between 1964 and 1985!
1985 Saline Valley 1:100,000 sheet, courtesy USGS.
For reference, here's a bit of the most current 7.5' topo map with everything as we know it today:
1988 Thimble Peak 1:24,000 map, courtesy USGS.
We'll be dropping from Red Pass into the eastern branch of Titus Canyon next time.

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

The Approach to Titus Canyon: To Red Pass

The Approach to Titus Canyon: Just Below Red Pass

A Hike at Red Pass, Titus Canyon Road, Death Valley, CAcu

Friday, July 15, 2016

Things You Find in the Field: An Old Outhouse

MOH and I were driving around several years back—after we had completed some field work with some former Former Mining Company employees—when we came across this old outhouse with a nicely carved crescent moon in the detached door. With an old, probably 1-2 megapixel camera, we took pictures of each other sitting inside the outhouse.
Blurrified photo of myself. Likewise one of MOH (not shown).
Some time later, probably near the end of that same year, we decided to make up some original Xmas cards. This was back in the Windows 98 era (I think), and we had a desktop computer and an off-brand card-making program.
This is about what the finished product looked like, after some cut and paste and very basic photoshopping. Blurrification for this post done more recently.

Tuesday, July 12, 2016

A Hike at Red Pass, Titus Canyon Road, Death Valley, CA

Arriving at Red Pass, which has a couple wide spots for parking, you're about half way down Titus Canyon Road (TCR), and only now are you about to enter the Titus Canyon drainage. Of course, half way depends on how you look at things. You're about half way, as the crow flies, from beginning to end of the TCR, including the western part down the alluvial fan to Scotty's Castle Road; you're less than half way, as the crow flies, from the eastern range front to the western range front; and you're more than half way, as the crow flies, from leaving pavement on the east end to exiting the narrow part of the canyon on the west end. I usually think of the road that last way, but any way you cut it, Red Pass is a good place to stop, get out, look around, take a few photos, and go for a hike. That's what MOH and I did back in early May, 2009.
I know of two trails beginning at Red Pass. The first trail, south to Thimble Peak, has a Class 3 scramble near the top that sounds awful to me (though it doesn't look too bad here). Maybe on our next visit, we'll explore climbing the peak from the west side, rather than the usual east side, or maybe we'll hike the trail part way.

You can't see Thimble Peak from Red Pass, but here's a photo of the peak, way over on the left, taken from White Pass.

The second trail leads up to the hoodoos and rock formations that sit immediately above the pass. I'm not sure if this trail does anything more than wander up to and around the rocks and hoodoos in the Panuga Formation (formerly the Green Conglomerate facies of the Titus Canyon Formation), but I took our hike as an opportunity to walk out to the red ledge that had been visible for miles. I had suspected that the ledge might be a tuff bed, but knew that without a field inspection I'd just be guessing.
The main rock formation, as seen from the east. This oddly shaped mass of eroding conglomerate is sometimes called "Quail Rock."
Here's the red ledge we've seen in two past posts.
We already know the red ledge consists of a crystal tuff marker bed, but MOH and I didn't know that at the time of our hike. Because I'm really not giving anything away, here's a labeled version of the photo, with map unit symbols once again from Niemi (2012).
The Wahguyhe Formation (Tw) overlies the Panuga Formation (Tg), which contains the reddish marker horizon that consists of a crystal tuff (xtl = crystal).
Let's get a little closer.
You can see a very light brown layer near the base of this part of the light brown weathering, massive-looking ledge.
For scale, we've got some smallish plants, including a red-flowering one.
And here's the lighter layer seen up close with field boot for scale.
It turns out that what we're seeing as a lighter-colored layer is a more crystal-rich portion of the tuff bed. I've zoomed in on this below. A finer-grained, fairly crystal-poor, biotite-bearing section lies above a coarser-grained, crystal-rich section.
My fingers are about at the upward transition from crystal-rich to relatively crystal poor.
I'm not sure exactly what kind of tuff this is, although I suspect it's an airfall tuff, possibly reworked in places. I would have needed a bigger hammer and willingness to break rocks in a National Park to have figured things out better. I also would have prefered a cooler day.

And that's about the end of this little hike. Before leaving, let's zoom in for one last, closer look at Quail Rock.
We can see definite layering with coarser and finer layers, and a texture that looks like lithified fanglomerate. Next time, I'll hike higher on the hill so we can take a closer look (and get better scale).
I like the faint cloud texture, which reminds me of microcline twinning.
After hiking back down to the parking area, we can walk over to the western edge of the road and finally look into the easternmost reaches of the Titus Canyon drainage. We'll see more of this next time. In the meantime, you can explore this gigapan, by Ron Schott, which looks west from Red Pass from about this same vantage point.
Where's the Leadfield cabin?
You can see the farthest cabin at Leadfield from Red Pass if you know where to look. And although it's very difficult to pick out in my photo (in the cropped version, above, it consists of just a few pixels), you should be able to find it on Ron's gigapan. Try it! In case you can't find it, I'll point it out next week!

A Couple 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.

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
The Approach to Titus Canyon: To Red Pass
The Approach to Titus Canyon: Just Below Red Pass

Wednesday, July 6, 2016

Approach to Titus Canyon: Just Below Red Pass

We're now about two thirds of the way up the hill toward Red Pass on the Titus Canyon road, a one-way road that runs approximately east to west from Nevada into California, starting not far south of the ghost town of Rhyolite. On this short section of our safari, we'll see some Titus Canyon Formation, although no more outcrop shots, sorry; we'll see some What-Used-To-Be Titus Canyon Formation, now Panuga Formation; and we'll see a bit of what lies above the Titus Canyon and Panuga Formations. Although there were a few places on the hill to pull over, I ended up taking most of these photos from the middle of the road: There was no one behind us for at least a half a mile or so.
We're looking northeasterly toward some distant hills capped by Miocene ash-flow tuffs. But it's really the closer rock formations that we're interested in.
The map symbols I'm using are from Niemi (2012):
Tm = Miocene Timber Mountain Group (ash-flow tuff)
Tp = Miocene Paintbrush Gp (ash-flow tuff)
Tc = Miocene Crater Flat Gp (ash-flow tuff)
Trp = Miocene Rhyolite of Picture Rock (rhyodacite to latite flow rock)
Tw = Miocene Wahguyhe Fm (sedimentary and volcanic rock)
Tg = Miocene Panuga Fm (conglomerate, sandstone, and minor tuff)
EOgtc = Eocene-Oligocene Titus Canyon Fm (various sedimentary facies)
The same view, labeled. (We've already seen this cliff from another angle and from a distance, here, so this should be somewhat familiar.)
The main items to note in the labeled photo are 1) the hill of reddish Titus Canyon Formation (EOgtc) in the foreground, 2) the low, greenish cliffs of Titus Canyon Formations down the small wash, 3) the fault separating the Titus Canyon from the greenish slopes and cliff of the Panuga Formation (Tg). We can't actually see the fault from where we're standing because it runs behind the low rise of greenish Titus Canyon Formation rocks; I've drawn it in anyway. The Panuga includes a reddish crystal tuff at about midpoint (labeled in this photo, not in the next). I've labeled the background formations without marking the contacts: I'll leave those to your imagination. The Timber Mountain Group rocks (Tm) are probably just the uppermost, dark-brownish hill-capping units; the lighter brown Paintbrush Group tuffs (Tp) above the thicker, tan to red Crater Flat Group (Tc) tuffs are actually quite thin.

I'll be calling the cliffy hill on the left "Tw Hill" because it's capped by Tw. All of the greenish rock on Tw Hill used to be part of the late Eocene to Oligocene Titus Canyon Formation. Now, only the very lowest greenish rock, exposed in the low cliff just down that little wash in the foreground, is Titus Canyon Formation. Beyond that—and past at least one fault or past a broad fault zone—the greenish rock on the slopes and in the cliff, above and below the thin reddish layer bisecting the hill, is part of the Miocene Panuga Formation. What changed? Surely the rocks didn't actually change in age from Oligocene to Miocene!

Well, what happened was some regional correlation of key stratigraphic horizons and a bit of renaming. Firstly, the entire Green Conglomerate facies, formerly of the Titus Canyon Formation, was reassigned to the Panuga Formation (Snow and Lux, 1999), the main reasons being, as I understand them, that 1) it lies on an unconformity formed on the Variegated facies of the Titus Canyon Fm, and 2) clast composition changes across the unconformity, such that the Panuga contains some clasts of Tertiary volcanic rocks, whereas the layers below don't. Also, the reddish layer in the middle of the cliff is (I think) the crystal tuff that was correlated to the 15.7 Ma Tuff of Unconformity Hill by Snow and Lux (1999), giving that portion of the section a Miocene age.

MOH and I drove a little farther up the hill. Not far below Red Pass, I took another opportunity to take a picture of Tw Hill: I wanted to get a good shot of the reddish layer, because we had hiked up to it in 2009.

Before going on, I'm going to break a general rule of mine and say something about the quality of the photos. The greenish rocks in the area, which are in both the EOgtc and the Tg, are a relatively unusual color of green for rocks, a color that I've found hard to capture accurately. You can see the difference in color balance between my first and second photos The first was taken in 2009, when a lot of green plants were growing; the second was taken in 2016 before many plants had popped their heads out of the ground—and the plants have something but not everything to do with the difference. For further color comparisons, check out photos of the same area at Geotripper (also 2016).
Another view of "Tw Hill."
And by now, we all know what that pile of rocks is, right? Yes, it's Tw on Tg on EOgtc (with a crystal tuff in the middle of the Tg).
There's a major fault between us and Tw Hill, one that, perhaps, first appeared in maps by M.W. Reynolds (1969, 1974). Reynolds' original 1969 map is not available online, but a small portion of the map is included in a book by Lengner and Troxel (2008), a book that explains the geology and natural history at Leadfield and along the Titus Canyon Road (I highly recommended it!). This fault (the one dashed in above) is marked on Niemi's map as "Fall Canyon Fault Zone" (FCFZ). The reason I've questioned this name in the photo is because to the west in Fall Canyon, Niemi labels a single fault "Fall Canyon Fault." I didn't really find a clarification of this in the report accompanying his map. He does say that the fault zone basically separates the Paleozoic section to the west from Cenozoic section to the east. In a broad sense, several large and small faults combine to accomplish this separation east of Fall Canyon; perhaps all or a few of these are considered part of a larger FCFZ. In other words, perhaps the FCFZ is the broader fault system I've emphasized roughly below in blue:
This colorful map is modified from a small portion of Fig. 2-26 in Ridgway, et al (2011). The Titus Canyon and Panuga Formations (labeled Ts) are in yellow; Tertiary volcanic rocks are in orange; Cambrian rocks (and some Ordovician?) are in pink. Most of the labels are irrelevant to us. The actual Fall Canyon Fault is the one I've marked in blue that is farthest to the west. It joins southward with a low-angle fault or fault system: the Titus Canyon Fault, which squiggles around quite a bit. All of these faults, as I understand them, are related to extensive Tertiary extension that also formed the Boundary Canyon detachment fault, which outcrops mostly south of the Daylight Pass Road (Reynolds, 1974Saylor, 1991).

Either way, there are several faults, possible faults, and linears that can be identified in the area of Red Pass and Tw Hill. A few of these can be seen in the two labeled Google Earth images below:
Some faults and possible faults in the general Red Pass area. The only contacts I've left in are ones between the Tertiary sedimentary formations and the overlying volcanic formations (i.e., between the Tg and Tw).
Now, for a moment, I'd like to focus in on the arc I've emphasized below in sprayed cyan. This is a portion of the fault or fault zone labeled Fall Canyon Fault Zone by Niemi. I show more than one possible trace, partly because of the inexactitude of my method of transfer to Google Earth. Zoom in above to see that there is more than one possible trace; the two to the north are from Reynolds and Niemi, the two main ones to the south are from Reynolds (and maybe Niemi's trace is the same as his), and a linear I picked out from Google Earth. If I do a three-point problem [Wayback Machine] on this fault near Red Pass, I get dips to the northeast of less than 30 degrees! Well, it may bend and curve a bit, as many faults do, so maybe that's not an accurate representation of the overall dip angle, but it appears to be a low-angle fault, at least in part. This might be a low-angle normal fault, or it might be one of the oblique-slip faults of the area (Saylor, 1991). Lengner and Troxel (2008) allude to a low-angle fault running about where I've drawn the sprayed line east of my arc, below, possibly running toward (and beyond??) White Pass. These all may hook up at depth with a regional low-angle fault (or faults), which may or may not be the Fall Canyon Fault itself, which is said to flatten rapidly at depth (Fridrich and Thompson, 2011), or the Boundary Canyon detachment, which has been hypothesized to hook up with the Bullfrog detachment (Saylor, 1991).
A sprayed arc along the low-angle fault cutting across Red Pass (FCFZ?) and a sprayed line along the trace of a possible low-angle fault between upper Titanothere Canyon and White Pass.
Now, back to the rocks!
I've zoomed in to a portion of the crystal tuff in the middle of the Panuga Formation (Tg) on Tw Hill. We'll see this up close, next post.
The contact between the Tg and overlying Tw is marked by an abrupt change in color and increase in erosive resistance.
Looking back to the east toward White Pass.
I'd like to note that in the last post I stated that the dark rocks, which are in the center of the above photo, look more like Bonanza King Formation than the Carrara shown on Niemi's map. What we actually have—I finally realized—is dark, reddish brown Zabriskie Quartzite (the thick, cliffy ledge to the right of center, dipping to the north, or left) overlain by the slope-forming, lighter reddish brown Carrara Formation. Above that, just left of center, there is a small jumble of dark gray rocks. This is megabreccia composed of Bonanza King Formation fragments; the megabreccia, a mappable unit, is generally considered to be part of the Titus Canyon Formation.

And with that, we'll zip up the rest of the way to Red Pass.

A Few References:
Fridrich, C.J., and Thompson, R.A., 2011, Cenozoic tectonic reorganizations of the Death Valley region, southeast California and southwest Nevada: U.S. Geological Survey Professional Paper 1783, 36 p. and 1 plate.

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.

Reynolds, M.W., 1969, Stratigraphy and structural geology of the Titus andTitanothere canyons area, Death Valley, California [Ph.D. thesis; not available online]: Berkeley, University of California, 310 p.

Reynolds, M.W., 1974, Geology of the Grapevine Mountains, Death Valley,California; a summary, in Death Valley region, California and Nevada, Geological Society of America Cordilleran Section, Field Trip 1 Guidebook: Death Valley Publishing Company, Shoshone, California, p. 91–97.

Ridgway, Kenneth, Stamatakos, John, Gutenkunst, Michele, and Dubreuilh, Philippe, 2011, Stratigraphic analysis and regional correlation of Oligocene and early Miocene strata in the Yucca Mountain area, Prepared for U.S. Nuclear Regulaatory Commission contract NRC-02-07-006: Center for Nuclear Waste Regulatory Analyses San Antonio, Texas.

Saylor, B.Z., 1991, The Titus Canyon Formation: Evidence for early Oligocene extension in the Death Valley area, California [M.S. thesis]: Massachusetts Institute of Technology, Cambridge, 65 p.

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 [Google Books].

Location map

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