|(This is not a fold.)|
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.|
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.|
|The prominent dip slope in Bonanza King Formation beds is marked by the longer of the four magenta lines.|
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.|
|The apparent dip of beds is 0° as we look to the north.|
|We look south and see a dip slope, similar to the dip slope on the south wall of the canyon (GE image #3).|
|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.|
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.|
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.|
But what else can we see?
|I see some wonderful rocks in a dry wash, and...|
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!)
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