Showing posts with label parks. Show all posts
Showing posts with label parks. Show all posts

Tuesday, November 22, 2016

Titus Canyon: The Klare Spring Breccia

Klare Spring in Titus Canyon is well known as a petroglyph site (with a sign and everything); it is less well known as a breccia site and as a place to view the low-angle normal faults of the Titus Canyon fault zone (TCFZ). MOH and I were both immediately attracted to the breccia, and then—after examining it closely—we turned our attention to the various petroglyphs. (If you want petroglyphs, go here, here, or here, or to other Google-able websites.)
The breccia is the orange-brown mass of rock that MOH is inspecting intently. It's composed largely of fragments of Carrara Formation (Єc), with a few scattered chunks of gray limestone, which are presumably from either the Carrara Formation or the tectonically higher Bonanza King Formation (Єb). The upper strand of the Titus Canyon fault zone (TCFZ) cuts above the breccia, somewhere between my Єc and Єb labels, possibly at the base of the first cliff, or possibly behind and above that cliff. Rocks in this lower part look brecciated to me, but I didn't scramble up the slope to see them in person.

In fact, here are some of my ideas about the placement of the upper strand (or multiple upper strands?) of the TCFZ.
An image from Google Earth approximating the first photos.
I wasn't sure whether the two very large angular fragments of gray limestone, including the block festooned with petroglyphs, were an actual part of the tectonic breccia, or whether they had at some point slid down the cliffs and been cemented in place by the waters of Klare Spring.
Angular fragments of the Carrara Formation are healed by travertine.
The waters of Klare Spring emerge from the lower strand of the Titus Canyon fault zone, just down-canyon from the petroglyph site. The lower strand has placed this fractured, shattered, and brecciated Carrara Formation over the older Wood Canyon Formation (ZЄw, see next photo set).
Looking up canyon past Klare Spring.
I happened to shoot this pic looking eastward, back toward Klare Spring from a couple hundred yards down canyon. Once again, I had fortuitously grabbed a view of the TCFZ, this time including the lower strand that runs right through Klare Spring, and also including the upper strand (although the exact location is of that strand(s) is imprecise).
The same view with some geologic labels, including a few question marks.
The faults up the canyon (on the right) were seen in more detail in an earlier post; basically, we're looking at the upper strand of the TCFZ, which has placed the Bonanza King (Єb) over the Carrara (Єc) and some possible breccia (labeled "?"). Klare Spring is past the white car in the lower left of the photo. The lower strand of the TCFZ, which runs right through Klare Spring according to many, places the pale orange brecciated Carrara (Єc bx) over the reddish brown rocks of the Wood Canyon Formation (ZЄw). I've labeled the Bonanza King where I'm sure of it (Єb), and have left the first light gray cliff above the Єc breccia as "?". These lower cliffs, held up by rocks that appear brecciated in the first set of photos, might be composed of Carrara or Bonanza King, or even some tectonic jumble of both.

And so, we've left Klare Spring, and will continue our way down the canyon...

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
Down into Titus Canyon: We Leave Red Pass Behind (Finally!)
Scribbles
Titus Canyon: The Upper Part of Lost Canyon
Leadfield: Scams with a Side of Geology
Leadfield: Views from Old Mine Buildings
Leadfield: Geology...and a Cactus...on the Way Back to the Parking Area
Almost Titus Canyon: Is This a Fold? And... Apparent Dip with Post-it® Notes
Titus Canyon: The TCFZ, the FCFZ, and a few Other Faults
Titus Canyon: Another Look at the Titus Canyon Fault and A Scramble
Titus Canyon: We Make Our Way Toward Klare Spring

Thursday, November 10, 2016

Titus Canyon: We Make Our Way Toward Klare Spring

We're making our way down Titus Canyon toward Klare Spring, an obligatory petroglyph stop about two miles below Leadfield. On this rather short leg of our journey, we'll be seeing a hodgepodge of photos from two trips taken in two separate years, all shot within a short distance of each other not far upstream from the spring. The canyon distance of the views that our photos will show, upstream to downstream, will be about two miles (3.2 km).

Our first photo set looks back to the east. You do remember that last time, before we stopped for our little hike scramble, we had looked to the south and had seen what I think is the main strand of the Titus Canyon fault zone. We can see this same fault exposure from our current stopping point just north of a shadowy cliff. The mile-distant fault is placing Bonanza King Formation dolomite (Єb) of the upper plate over Carrara Formation (Єc) limestone and a bit of Zabriskie Quartzite of the lower plate (we can't see the Zabriskie from this angle). I’ve sketched the main strand of the Titus Canyon fault zone (TCFZ) in hachured dark blue.
As explained previously, that fault appears to wrap around to become what I've drawn in as the same fault strand, high on the cliffs in the upper right. I've postulated a lower strand, drawn in hachured bright blue. The exact position of the proposed fault is questionable, possibly higher on the hill than I've shown it, as is the formation contained within in the resulting "middle plate," which I've shown as Bonanza King. In this first photo, taken in late February of this year, things look pretty brown, because spring has just barely arrived.

The cliffs on the side of the road are captivating in that they look iron stained and possibly brecciated. I think they make a great backdrop to a photo that's very similar to the first one, but which was taken on a green spring day in early May, 2009. The creosote was in bloom, and so were some cacti and other wildflowers.
I'm not sure what rock formation is exposed in this almost-always shadowed cliff. It might be Carrara, as labeled, or it might be Bonanza King.
MOH and I wandered around this area quite a bit, checking out the wildflowers.
Here we are, a little to the north of the last spot, along an old wash channel paralleling the road, still looking to the east. 
The same photo with geologic labeling by moi.
(H/t to Dana Hunter for the "moi.")
What are we seeing here? Well, we're looking at the main strand of the TCFZ on the cliff in the distance to the east, as before, but here I've postulated an offsetting high-angle normal fault, down-to-the-north, and drawn it in with lighter blue. As for the cliffy areas north and south of the wash and road (left and right, respectively), I'm unsure of the exact location of the Titus Canyon fault. On the left, there is definite Єc in the lower cliffs, some unknown in a slope and cliffy area above that (labeled Єc?), and definite Єb near the top of the cliff (unlabeled! who let that slip by?).

Looking back to the first photo set, there’s a huge alluvial fan coming off the higher cliffs south of the road. On our most recent trip through the canyon in early 2016, I became fascinated by the massive alluvial fans within this part of the Grapevine Mountains. It looked like one hell of a lot of erosion to me—and probably all taking place fairly rapidly and fairly recently when the Grapevine Mountains were uplifted radically in the late late Cenozoic—and so I took a number of photos of fans, some that looked active, like this one, and others that looked older.
A steep side canyon area south of the road has filled with coarse alluvial debris, forming an alluvial fan complex.
A closer view of part of the alluvial fan.
A Google Earth image of the fan complex. North is not up! The magenta line on the right is the main strand of the TCFZ (extrapolated); the magenta line on the left is possibly the lower strand in this area.
Then I looked off to the northwest and took this photo after spotting the reddish alluvial fan remnant seemingly stranded high on the active fan slopes:
A reddish color in alluvium is often indicative of an older age. Rocks above the fan are all Bonanza King Formation.
I have a hard time comprehending the amount of uplift required, possibly in pulses, to create the alluvial record that can be seen within and on the edge of the mountains in the Death Valley area.
Google Earth image of our second fan complex; magenta lines are related to my idea(s) of the TCFZ.
A little bit of alluvial air-photo mapping.
The current wash (above) is obvious. What I've labeled as 'terrace 1' can be seen in the last photo as the alluvium in front of the alluvial ledge in the lower part of the photo, the alluvium I was standing on when I took that photo. Beyond that, we have the larger fan complex, including the reddish fan in the photo, which I've labeled. I couldn’t decide where to mark the lower boundaries of that reddish fan. Anyone up for some mapping?

I then turned to the west, zooming in to see what I thought might be some reddish talus, possibly small alluvial fans, high on the slope.
Reddish talus high on the slope below dark gray and reddish outcrops of the Bonanza King Formation.
It turns out that this photo shows two mapped strands of the TCFZ, although the exact location of both is somewhat in question.
Here is my best guess of the geology, taken from Niemi (2012) and Google Earth air-photo interpretation.
The mapped upper strand of the TCFZ has placed younger Bonanza King Formation rocks (Єb) over older Carrara Formation (Єc), with the Єc forming what is here a middle plate, while the mapped lower strand has placed the Carrara over the even older Wood Canyon Formation (ZЄw).

Meanwhile, back on the lower slopes:
Bloomin’ cactus!
The barrels are leaning strongly to the south. They grow faster on the shady side, causing them to lean over, giving them the nickname “compass cactus.”
These leafy green plants were everywhere.
Barrel cactus, yellow wildflowers, and ephedra (the olive green plant behind the barrel clump).
Here’s another view of the same plants, with dolomite of the Bonanza King Formation as a backdrop. The ledge on the left might be the location of the upper strand of the TCFZ, just above Klare Spring.
And that puts us in a good position to move on to Klare Spring.

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
Down into Titus Canyon: We Leave Red Pass Behind (Finally!)
Scribbles
Titus Canyon: The Upper Part of Lost Canyon
Leadfield: Scams with a Side of Geology
Leadfield: Views from Old Mine Buildings
Leadfield: Geology...and a Cactus...on the Way Back to the Parking Area
Almost Titus Canyon: Is This a Fold? And... Apparent Dip with Post-it® Notes
Titus Canyon: The TCFZ, the FCFZ, and a few Other Faults
Titus Canyon: Another Look at the Titus Canyon Fault and A Scramble

Tuesday, October 18, 2016

Titus Canyon: Another Look at the Titus Canyon Fault and A Scramble

In late February of this year, MOH and I were intent on getting down the Titus Canyon road to see the superbloom in Death Valley, which was going great guns down near Badwater. We nevertheless stopped for a hike not far downstream from the photo in my last post.
A few wildflowers bloom in front of an orange-brown outcrop of Carrara Formation limestone.
Before hiking some really steep cliffs on the north canyon wall, I looked to the south to grab a few geological photos, not realizing that besides the nice example of dipping beds, I was seeing a good example of one splay of the Titus Canyon fault zone (TCFZ).
Beds on the south wall of the canyon are dipping in a northerly direction.
In the labeled view below, we see the approximate line of one splay of the TCFZ. It has crossed the wash left of the photo (and in front of us in last week’s photo); it goes up, over, and back behind the foreground rocks (the arrow pointing the way); and it eventually wraps around to hook up with the low-angle fault on the more distant, shadowed hill. This interpretation of the location of a main splay of the TCFZ is from Reynolds, as seen in Lengner and Troxel (2008), and is also an extrapolation from Niemi’s 2012 map.
A splay of the younger-on-older TCFZ can be seen here in hachured dark blue. It is placing the younger Bonanza King Formation (Єb) above the older Carrara Formation (Єc) and even older Zabriskie Quartzite (Єz).
Disclaimers: My placement of the fault is approximate, the foreground part of the fault might be modified by a high-angle normal fault, and the cliff and hills labeled Єz may include some faulted-in Єc.
I’ve zoomed in here, just so we can see the fault exposure a little better.
The rocks above the nicely bedded section on the right (Єc) look chaotically fractured and possibly brecciated. I read somewhere that the Fe-oxide staining of the rocks is typical of the damage zone along the fault. An unpublished map that was available from NPS in 2016, has a mélange unit devoted to certain parts of the TCFZ damage zone. That unit (TfxT; description no longer available) is reported to be particularly pronounced along the westernmost portion of the TCFZ.

MOH and I had stopped at this particular point in order to go on a smallish hike—well, we actually stopped to investigate a dry waterfall, and that investigation turned into a scramble (probably Class 3).
We’re looking up a side drainage on the steep north side of Titus Canyon. The overexposed white areas are limestone that has been scoured and polished by running water and entrained debris.
It turns out that this is a decent location to view the Titus Canyon fault.
The Titus Canyon fault places the Bonanza King (Єb) over the Carrara (Єc). It is mostly (or entirely) behind the lower cliffs on the right side of the photo.
And now, for a little map comparison, before we scramble up the slickrock.
A bit of Niemi’s map, from Leadfield to Klare Spring. The UTM grid lines are spaced 1 km (1000 m; 3281 ft) apart.
A similar bit of Google Earth (GE), uncorrected for any possible skewness in orientation. The TCFZ is in magenta; other normal faults are in blue and dark blue; the Zabriskie Quartzite (Єz) is outlined in red
My interpretation of the location of the TCFZ north of the canyon is based largely on a single photo in Lengner and Troxel (2008; their Figure 6.17, p. 114).

How do these maps line up?
I’ve managed to overlay a transparent version of Niemi’s map on top of the Google Earth image.
I’ve corrected a bit of Niemi’s map where I think the labeling and coloring of a portion of Bonanza King Formation (his Єpb, my Єb) and Titus Canyon Formation (EOgtc) was accidentally switched. The overlay is not perfect: The programs I used (Word and Paint) are really not designed for precision. Nevertheless, we see some correlation between the two maps. Interestingly, the place where the two maps show the most divergence is right where Lengner and Troxel have their photo (where my magenta line does a lot of contortions). As far as ground checking of this TCFZ-modified Єb-Єc contact, it’s difficult to impossible to walk up to the fault in most places—at least not without using real climbing techniques or hanging oneself out of a helicopter on a rope!

Now we’ll get on with our hike!
A small pool of water at the base of the lower chute.
We've now walked over to the base of the waterfall, where...we find some water!
For scale, I offer a fly on the far right.
The fly is sunning itself on polished Carrara Formation, which consists here of blue-gray limestone with orange claystone partings and wavy bedding.
I’ve now scrambled up to a ledge and am looking up the Carrara cliff to the jagged outcrops of Bonanza King Formation (Єb) beyond.
The faults drawn in are mostly hidden from view by the jutting lower cliff of Carrara Formation (Єc). The TCFZ, in hachured dark blue, is offset by a high-angle normal fault in lighter blue.
I love barrel cacti!
I’ve now scrambled even higher, to stand below a second polished chute.
The third polished chute, even higher, is above a large, dry plunge pool.
This is as high as I got on this dry falls. MOH went up higher, probably to the TCFZ. I didn’t know there was a fault up there, or I might have been tempted to try to climb higher, even though I was about at the edge of my free-climbing competence. I scrambled back down and eventually found myself overlooking the first waterhole.
I stand on a ledge above the first pothole.
Right after taking this photo, I was maneuvering across a jutting portion of tear-a-pants limestone when I lost all but one point of contact and tumbled down toward the overhang above the pothole. I managed to recover on a smallish ledge. I was okay, but it really was close. That’s probably the last bit of free-climbing I’ll do! The DSLR fell also, hitting the rock I landed on, and somehow, it was also okay! (I was surprised. Possibly this is a testimony to Nikon.)

Our next stop will be a little farther downstream, closer to Klare Spring.

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

National Park Service (NPS) Geologic Resources Inventory (GRI) program, 20141114, Unpublished Digital Geologic Map of Death Valley National Park and Vicinity, California and Nevada (NPS, GRD, GRI, DEVA, DEVA digital map) [not available online - this link has info] adapted from a U.S. Geological Survey Scientific Investigations Map by Workman, J.B., Menges, C.M., Fridrich, C.J., Thompson, R.A. (2014).

Niemi, N.A., 2012, Geologic Map of the Central Grapevine Mountains, Inyo County, California, and Esmeralda and Nye Counties, Nevada [not available online]: 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: Berkeley, University of California, Ph.D dissertation, 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 [reprinted here].

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
Down into Titus Canyon: We Leave Red Pass Behind (Finally!)
Scribbles
Titus Canyon: The Upper Part of Lost Canyon
Leadfield: Scams with a Side of Geology
Leadfield: Views from Old Mine Buildings
Leadfield: Geology...and a Cactus...on the Way Back to the Parking Area
Almost Titus Canyon: Is This a Fold? And... Apparent Dip with Post-it® Notes
Titus Canyon: The TCFZ, the FCFZ, and a few Other Faults

Revised slightly 15Jun2019 for broken or dead links.

Tuesday, October 11, 2016

Titus Canyon: The TCFZ, the FCFZ, and a few Other Faults

At the end of our last post—the one about the non-fold—we came into Titus Canyon proper and were looking at this view, down the canyon and to the west.

When MOH and I passed through Titus Canyon in May 2009 and February 2016, I didn't know a whole lot about the detailed geology of the canyon: I knew the regional geology of the Death Valley NP, some detailed geology in the Beatty area, and some geologic bits and pieces for the road trip through Nevada, but I didn't know all that much about the geology along the Titus Canyon road. So, although I have some great canyon photos, a lot of the main geologic features in Titus Canyon proper were photographed by accident rather than by design. I've since come to know more of the detailed geology while doing research for the several blog posts comprising this interminably rambling and seemingly unending Titus Canyon series.

Not knowing the detailed geology means that over the years I've driven down the road and through the canyon while missing low-angle faults and a huge fold! The photos we'll see during the rest of the trip were not designed with these geologic features in mind, but because geology is everywhere, we can see portions of these features, including exposures of the several low-angle normal faults known collectively as the Titus Canyon fault or fault zone (TCFZ), which crops out in an area of somewhat more than 4 x 5 miles (about 6.5 x 8 km).
Source: Modified from part of Fig. 1 of Reynolds (1974), which was reprinted in Troxel and Wright (1976) at NPS History eLibrary. North is not up!
On Reynolds' map, I've added magenta coloring to the TCFZ and dark purple coloring to the Fall Canyon fault zone (FCFZ), the Fall Canyon fault (FCF), and what might be the Thimble fault (TF). These faults are all likely related to each other, at least broadly, and the Titus Canyon fault (zone) is explained most succinctly by Niemi (2002):
The Titus Canyon fault, an enigmatic low-angle structure, places upright Middle Cambrian strata on overturned upper Proterozoic through Middle Cambrian rocks ... .
In this instance, upright means right side up rather than overturned or upside down. Like me, Niemi cites Reynolds, both the detailed 1969 version, which I've not seen, and the generalized 1974 version (as in my previous figure). I've seen a version of part of Reynolds' detailed map in Lengner and Troxel (2008); it was particularly helpful in the Leadfield area.

Getting back to the regional map, the main splay of the Titus Canyon fault zone steepens north of Klare Spring to become the high-angle Fall Canyon fault—a single dark purple line trending nearly due north—a fault that cuts rocks at least as young as late Miocene (Niemi, 2012). On the southeast side of the upper plate of the TCFZ, a moderate- to high-angle normal fault—a single dark purple line trending east-southeast—seemingly juts out from beneath the upper plate; it's either cut by the TCFZ or merges with it, I'm not sure which. I think this ESE-trending fault is what's been called the Thimble fault (originally Reynolds, 1969; Saylor, 1991Niemi, 2002).

The rest of the dark purple faults are part of the sensu stricto Fall Canyon fault zone, a set of high- to moderate-angle normal to oblique faults that flatten with depth. Niemi (2002, 2012) explains:
This fault zone is a distinct boundary in the Grapevine Mountains, separating Cenozoic volcanic and sedimentary strata to the east  from Paleozoic miogeoclinal strata to the west [map]. Both the age and amount of displacement on the Fall Canyon fault zone are difficult to determine.
The TCFZ (we first saw a bit of it here) consists of one or more low-angle normal faults that were active during mid- to late Tertiary extension of the region (Reynolds, 1974; Saylor, 1991, Niemi, 2002 & 2012). My improvisational interpretation of Reynolds and Niemi on Google Earth—a little bit farther down in this post—is what we'll mostly be seeing in the next several blog posts.

Keeping all that in mind, let's get back into the canyon!
The first photo with some added geology.
We see a fair example of one of the main splays of the TCFZ in the labeled photo above, over on the right where the Bonanza King Formation (Єb) sits atop Carrara Formation (Єc). This example of the location of the Titus Canyon low-angle fault is from Lengner and Troxel (2008). I was having a hard time trying to place it from Niemi's map until I noticed their Figure 6.17 on page 114 (I recommend their book if you plan a trip through Titus Canyon).

From it's position on the right, the Titus Canyon fault passes in front of us and then to the left, behind the cliffs of Bonanza King. It then wraps around hills we can't see, gets offset once or twice, and becomes (I think) the upper, dark blue fault on the distant slopes. (My correlation of this upper fault with the foreground fault is largely from my interpretation of Reynolds, via Lengner and Troxel, 2008, and my interpretation of Google Earth; this particular fault is not shown on any of the maps I've seen.) I've drawn two splays of the fault system on the background hills. The lower fault as drawn, also not shown on any maps I've seen, partly mirrors Niemi's mapped Єb-on-Єc fault from the north side of the canyon. It's possible that this lower splay doesn't exist. It's also possible that what I've labeled Єb in its upper plate is really Єc, although it doesn't look that way to me (!).

Let's look at this on Google Earth (GE), where I'm storing my geologic mega-cartoon:
My current version of the TCFZ (magenta), the FCFZ and related faults (dark blue), a few other normal faults (blue), the Titus Canyon fold axis (maroon), and several stratigraphic contacts and some formation labels (modified from Reynolds, 1974, Reynolds in Lengner and Troxel, 2008, and Niemi, 2012). 
I have to admit that my interpretation of the location of the main splays or splices of the TCFZ is somewhat hypothetical. I've taken Reynolds' small scale map (here), Niemi's larger scale map (here), bits and pieces from here and there, and created my own mashup based on what I can see on Google Earth. The mashup is far from perfect, and I could change it every time I look at it. (Really, I try to restrain myself!)

As in the earlier geologic map, the low-angle normal faults of the Titus Canyon fault zone (TCFZ) are in magenta; a few possible related faults in the southeast are in dull pink. The TCFZ merges into or becomes the Fall Canyon fault (dark blue) north of Titus Canyon, and may do something similar to the southeast (also dark blue). Other faults in dark blue are part of the larger Fall Canyon fault zone (FCFZ), consisting of high to moderate angle normal to oblique faults that flatten at depth. Other normal to oblique extensional faults in are in lighter blue; some of these might be part of the FCFZ.

The bigger picture in my GE-cartoon includes the Titus Canyon fold, which we'll see more of later, with it's overturned limb west of Klare Spring. The Precambrian to Cambrian section in that area, from oldest to youngest and east to west, is Wood Canyon Formation (ZЄw) overlain by the Zabriskie Quartzite (Єz), which is outlined on the map in thin maroon lines. Above that is the Carrara Formation (Єc), which is overlain by the Bonanza King Formation (Єb). The Carrara – Bonanza King contact is marked by a thin cyan line; it's mostly seen to the west and south of the TCFZ. I've thrown in a rough demarcation line between the pre-Tertiary and Tertiary section in orange. Not drawn in are bits and pieces of the Titus Canyon Formation lying above the Bonanza King Formation, seemingly and quite possibly in the upper plate of the low-angle TCFZ. Labels on the GE image are listed below.

The Tertiary, undivided:
Tvs = Tertiary sedimentary and volcanic formations.

Part of the pre-Tertiary section:
Pz = Paleozoic undivided, including some rocks younger than Єambrian.
ZPz = Upper Precambrian and Paleozoic undivided, mostly Є and pЄ.
Єb = Bonanza King Formation (mostly dolostone with lesser limestone)
Єc = Carrara Formation (mostly siltstone, also quartzite and limestone)
Єz = Zabriskie Quartzite (thick-bedded to massive quartzite)
ZЄw = Wood Canyon Formation (a miscellaneous formation bounded by two quartzites, consisting of siltstone, quartzite, dolostone, conglomerate, and limestone)

I'd hoped to have more photos of the Titus Canyon fault zone in this post, but the geology overcame me! We'll see more next time, when we'll actually, hopefully, go on a little hike.

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., 2002, Extensional Tectonics in the Basin and RangeProvince and the Geology of the GrapevineMountains, Death Valley Region, California andNevada: Pasadena, California Institute of Technology, Ph.D. dissertation, 344 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: Berkeley, University of California, Ph.D dissertation, 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 [reprinted here].

Saylor, B.Z., 1991, The Titus Canyon Formation: Evidence for early Oligocene extension in the Death Valley, area, CA: Cambridge, MIT, M.S. thesis, 54 p.

Workman, J.B., Menges, C.M., Page, W.R., Taylor, E.M., Ekren, E. B., Rowley, P.D., Dixon, G.L., Thompson, RRA., and Wright, L.A., 2002, Geologic map of the Death Valley ground-water model area, Nevada and California: U.S. Geological Survey Miscellaneous Field Studies Map MF-2381-A, Pamphlet text, Sheet 1, Sheet 2.

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
Down into Titus Canyon: We Leave Red Pass Behind (Finally!)
Scribbles
Titus Canyon: The Upper Part of Lost Canyon
Leadfield: Scams with a Side of Geology
Leadfield: Views from Old Mine Buildings
Leadfield: Geology...and a Cactus...on the Way Back to the Parking Area
Almost Titus Canyon: Is This a Fold? And... Apparent Dip with Post-it® Notes

Tuesday, September 27, 2016

Almost Titus Canyon: Is This a Fold? And... Apparent Dip with Post-it® Notes

(This is not a fold.)
As we leave the lower Lost Canyon section of the Titus Canyon road, we're also leaving the Leadfield area. (Say goodbye!) Less than a half mile from the Leadfield parking area, the road curves rather abruptly to the left, enters a canyon with steep walls, and presents us with the view seen above. Is this a fold? It looks like one at first, and in fact that's what I thought when first rounding this same bend many years ago: "Oh, look, a neat little syncline." Beds on the south (left) are dipping to the north, and beds on the north are nearly horizontal or dipping to the south—or are they?

Actually, we're looking at a nearly uniformly dipping section of the Cambrian Bonanza King Formation; the beds are dipping about 35° to the north and look bent or folded only because of our viewpoint and a nearly right-angle bend in the canyon wall.

Let's look at this a little more closely:
Here's the non-fold with a few colored lines.
In this second photo, I've drawn a magenta horizontal line from which I've measured dip angles of the beds in the north-south section of the canyon wall. These two dip measurements of 48° and 40° to the north might be what is called the apparent dip of the beds; they definitely are not true dip measurements, which are usually taken in the field with a type of compass called a pocket transit (mine is a Brunton compass; see my first, older-model Brunton here).

NOTE: There's a technicality about apparent dip that makes me unsure what to call the inclination of beds one can see at random angles in the field or when looking at photos like the one above. True dip is measured perpendicular to strike and is always greater than apparent dip, which is measured on a vertical plane that cuts through the rock or a map at any angle other than perpendicular to strike. As we'll see below, perspective can cause the slant of beds to look shallower or steeper than the angle of true dip. I've generally called this observed or ostensible angle "apparent dip" when I know I'm not looking straight down strike (which is most of the time if I haven't lined up with the level of a compass), but it's really something else; maybe it should be called "perspective dip" "positional dip" or "POV dip".

Getting back to the photo above, I've drawn an approximate apparent dip line of 0° on the portion of the canyon wall that is running nearly east-west (on the right). Are these beds really horizontal (or even dipping back to the south, which they appear to do above the cyan line)?

In the first Google Earth (GE) image below, we're standing about at the yellow pin marked "4370 - not fold", looking southwest at the canyon wall (4370 was my original photo number). I've drawn three strike and dip symbols and one strike line on the image in magenta. I took the strike by using points of equal elevation on four individual beds that I picked out. The two symbols on the hill south of the road, herein known as DS Hill, are on individual dip-slope beds that are quite obvious in GE; these strike lines are probably the most accurate of the four. (All four lines of strike should be considered approximate.)

So, we have a strike of about N70E, or 070° azimuth. From the photo and from the dip slope on DS Hill, we know that the dip direction for three of our points is to the northwest. For the beds north of the wash, I know from driving through the canyon that these beds also dip roughly to the north or northwest; also, if they were dipping to the south, the slope would look more like the dip-slope hill south of the wash.
Our location (yellow pin) with strike-dip symbols in magenta, a set of identifiable beds in cyan, and a small fault in dark blue.
The same area, now with two dip measurements.
To measure the dip, I selected a location to the east of of the dip-slope hill that was along strike and also at the same elevation of the larger of the two strike-dip symbols on the dip slope. In the GE image below, we are standing at that point, along strike and at equal elevation, measuring the dip angle where we see the longer of the four magenta lines. Note: Only that one line really shows up in its proper orientation due to various perspective problems with Google Earth. Also note that the northwest-dipping bedding in the "fold" area—the outcrop area just above the yellow pin that corresponds to the obviously dipping strata in our photo—doesn't really look that way in GE from this angle, also due to various perspective and topographical complications.
The prominent dip slope in Bonanza King Formation beds is marked by the longer of the four magenta lines.
From the orientation and elevation I'm sitting at above, I measured a 35° dip. Doing the same thing from the west, I was able to measure a 35° dip on the dipping beds looming in front of us as we start to drive into this canyon. If we walked up to these two locations to take a strike and dip with our Brunton, we'd probably get readings within 5 degrees or so of my GE measurements, in both strike and dip. We'd get similar readings if we measured the beds on the north side of the canyon wall.

To look at this in another way, I created an analogy to our beds with a stack of Post-it® notes. The first example approximates what we see directly ahead of us, on the north-south canyon wall, as we enter the canyon (first photo).
Our multi-colored, light and dark beds are dipping about 35° to the north.
As we move around to the south and look to the north—approximating our view of the east-west part of the canyon wall—these same beds appear to be horizontal.
The apparent dip of beds is 0° as we look to the north.
If we look to the south, we see a kind of dip slope, although here I'm looking down on them from above, so they don't look as steep as they would from the canyon floor.
We look south and see a dip slope, similar to the dip slope on the south wall of the canyon (GE image #3).
It's probably worth noting that the dips I measured directly from the "fold" photo are higher than the dip I got using Google Earth. As I mentioned earlier, our perspective can cause dip of beds to vary greatly; in fact, the angle we see from changing perspectives can vary from 0 to 90 degrees, depending on our viewing angle and orientation. When looking straight into dipping beds, that is when looking perpendicular to strike, the beds will look horizontal (as we saw in Post-it® photo #2). When viewing these same beds from a point along strike, they will appear to dip at exactly true dip (Post-it® photo #1).
Another set of Post-it® beds are dipping 35° to the north (right).
As we move around in the terrain to the ESE, these same beds look like they are dipping 40° to the NNE.
Now, having moved to the SSE, the beds appear to dip 70° to the ENE.
If we look at the same stack of beds from the south, they look almost vertical. In fact they can be measured with "apparent" dips of 85 to 88° to the east.
Without having a good handle on the strike of beds while wandering around from canyon to bluff and up, over, and across the terrain, we can't really tell the dip of beds!

I did try to simulate our canyon beds with a crudely modified block of Post-it® notes. Imagine our stack of beds as above, although this stack seemingly has some thinner, almost shale-like beds in it. Now we erode a canyon or amphitheater into the beds.
Block of dipping beds with a crude canyon eroded into it.
We can easily see the dip slope on the south side of the canyon (green slope on the left). I think that because our perspective is not from within our little amphitheater or canyon, we can't really get the feel of the beds on the north wall (right) that seemingly appear nearly horizontal (photo #1). I'd have to move a tiny camera into the beds, and maybe stand it on the purple horizon lying on the thick green unit, to get the same perspective that we have in our "fold – not-fold" photo. I tried this crude Post-it® method because most 3-D block diagrams (and physical blocks) don't show a cutout that would simulate standing in a canyon with dipping beds looming all around.

Well, let's get back to our travels down the canyon!
But first... some lupine from the spring of 2009, right below the faux fold.
After we round the bend to go past the dipping beds that we saw in our first photo, it's a mere 0.2 miles to the junction with the main branch of Titus Canyon, which comes in from the north. And then, about 0.3 miles past that junction, we come to this spot, where we can see that Titus Canyon, up ahead, widens a little.

But what else can we see?
I see some wonderful rocks in a dry wash, and...
More next time!

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
Down into Titus Canyon: We Leave Red Pass Behind (Finally!)
Scribbles
Titus Canyon: The Upper Part of Lost Canyon
Leadfield: Scams with a Side of Geology
Leadfield: Views from Old Mine Buildings
Leadfield: Geology...and a Cactus...on the Way Back to the Parking Area