Published: March 13th 2012March 11th 2012
Obsidian cut through rhyolite at Resting Spring Pass.
Well, I survived the night….. kinda. Sleeping out under a desert sky peppered with stars, planets and a harvest moon is quite an experience. However, if I were to do it over again, I would wear more than just a t-shirt and a light blanket, and I would DEFINITELY check my air mattress for holes. That being said, I woke up around 1AM, flat on the 2x4’s of the observation deck with numb toes and visible breath. It was at this point I decided to swallow my pride and head inside. Luckily, the girls downstairs made some room for me to ride out the rest of the night.
Because Sid wanted to be on the road by 9, wake-up was going to be around 0730. I decided to get up around 0600 to catch the sunrise over the mountains, pack up my gear and go for a run. And so today’s adventure began. My phone was so busy looking for a signal last night that it tired itself out and died. This was sad because I didn’t have music for my run, but more importantly I didn’t have a camera for the sunrise over the mountains. I
Alluvial fan raised on a fault
digress. A little over a mile into the run I saw a sign for a cemetery, so I made a detour (brilliant thing to do in the middle of the desert). Well, not a quarter mile up the road I hear vicious barking and see two Death Valley pit bulls in a wind sprint up the road after me. Great. I stopped (because logic tells me that outrunning them wasn’t an option) and hoped for the best! After a stare down and procession of a slow jog with only nips and slobber, I figured I was safe.
Not too much longer, Cliff, the owner of the dogs (and inconsequently part of the geology we are studying, get it? Cliff?) came out to talk to me. He was an old-timer from down south who spent some time in Vietnam. We chatted about the surrounding native lands and how he ended up there. Interesting fellow. Oh, my favorite part of our conversation is when I asked him about why he had 3 boats in his yard. His reply: “Well, Dale, to take ‘em out fishin’ I reckon. “ This seemed strange to me considering we were A.) In the middle of
the desert and B.) he had three
of them. He then explained that one of them was just a lawn ornament and he was waiting for rocks to gather around it so it would appear to have wrecked there. I didn’t have the heart to tell him that the geologic time scale and human time scale wasn’t in his favor to one day see that. Anyway, we exchanged pleasantries, directions to the cemetery, and parted ways. An interesting note from the cemetery was that most of the graves were unmarked. The few that were labeled, even the younger ones, had weathered and almost indiscernible engravings. I attributed this to frequent wind storms picking up the desert and sanding down any lasting human tribute to identity. It’s kind of sad when you think about it, but these communities are so small and isolated, that probably everyone (if there were anyone) who cared knew exactly where to find their loved ones and when they lived and passed.
After I finished my run, I grabbed some breakfast with the clan, shook a tower and we headed out. Death Valley was the destination, and it was my group’s day to lead the trip.
Halite bubbling through cooled polygonal cracks on badwater basin floor.
The way the trip is organized, we were broke into different days, each group leading the geologic excursion at a different location. Today’s destinations are going to be badwater basin, the natural bridge, Artist’s Drive and Darwin’s Falls. On our way there, my tie-job on some of the duffle bags to the roof of the Suburban experienced near catastrophic failure around 55 mph, dangling by one necessarily redundant square knot that I tied. Thankfully, Rafael had helpful students in his car that when faced with adversity, literally ran for the hills. Meg stopped the van, while Sid, who was leading the group, kept on none-the wiser. I was able to run back and rectify the situation. It was finally time for some geology!
Even though it wasn’t on our list of places, we made an impromptu stop at Resting Spring Pass. This is a geologically famous outcropping of a rhyolitic volcanic deposit. The interesting point of this outcropping is the metamorphic obsidian cut diagonally through the center (photo). This is explained by the lava at the center remaining heated for a longer period of time due to the rhyolite above and below it acting as insulation. With longer exposure
Milky white appearance across badwater looking up into the Panamint mountains.
to heat, the rhyolite metamorphosed into obsidian. The slanted appearance of the outcrop is due to reverse faulting which can be seen in the photos. Resting on top of the approximately 10ma rhyolite is the same Cambrian-aged, Bonanza King limestone we saw yesterday. My guess was that it arrived on top of the structure, again defying the stratigraphic law of superposition by the same thrusting process. However, because of the abrupt interruption of the layering, its story was different. This section of the rock had broken off from a higher surrounding mountain through normal erosional and faulting processes and came to rest atop the rhyolite.
As we are continuing on, we couldn’t help ourselves but to stop at more unplanned geology. The strict v-shaped cuts into the mountain sides is evidence of ephemeral or episodic streams that cuts into the rock during periods of heavy rain. These lead to alluvial fans, which are deposits of the sediments gathered by the water and sorted according to size, the largest being deposited closest to the base. The lifting of the alluvial fans along the right side of the basin coupled with steeper cliffs indicates a more recently active fault. (Pictures). The
A spring feeding badwater basin.
bases of both sets of mountains along the valley have concurrent and overlapping fans.
Finally, it was time to start the portion of the trip to be led by my group. Our first stop was Badwater Basin. At 282 feet below sea level, the basin is the lowest point in North America and among the lowest in the world. Its defining characteristic is the milky white floor of the expansive basin (photo). The coloration comes from the mineral halite, which has a commonly known chemical composition: NaCl. If more evidence was necessary that sodium chloride is indeed what it was, I licked it. Yup, salt. Badwater Basin is spring fed, and water can be seen along the outer edges of the basin (photo). However, with the highest evaporation potential in the world at 150” annually, and an overwhelmingly arid climate, the basin never holds water long. The explanation of why the basin is still lowering is a bit more complicated than simple evaporation and a lack of an outlet to the sea. The basin lies between two ranges (hence the entire region being referred to as “basin and range”), the Black Mountains and the Panamint Mountains. This geologic structure
lies this way because of persistent faulting in the area. The mountains are just very large footwalls being pushed up as the hanging wall, in this case, Badwater, sinks. Usually, the basins would lie at a regional base level on the water table so they would fill with water and subsequently sediments. However, with very little water to speak of, the basin is sinking faster than it can replace the altitude it is losing with sediment. Another interesting geologic process evidenced in badwater is the polygonal formations in the basin itself. These structures can be attributed to the cooling and shrinking of the basin. The contraction of the ground causes the polygonal cracks and subsequent bubbling of halite in the cracks during the crystallization process. It looks almost as if the cracks were caulked with halite.
From badwater, it was onto the Natural Bridge! Natural Bridge is a very interesting geologic structure carved out of conglomerate rocks. These rocks are lithified clasts that were once an active alluvial fan. Ephemeral streams eventually carved underneath the existing conglomerate forming the bridge. As we continued further up the trail, we came to a turtleback fault, aptly named for its shape. Looking
Class sitting on fault cutting through conglomerate
at the very base and downslope of the “shell”, we were able to put hands on the protoliths and basement rock that lies underneath all of these incredible structures. These rocks date to the Proterozoic period about 1.9Ba. (photo) These gneiss’ and chlorite schists are evidence of low, retro-grade metamorphism, a geologic process that alters the structure of the rock (in this case Milonite is the fabric) without ever changing its physical state. The most interesting part of this outcrop was the clear evidence of the 10Ma conglomerate being deposited on top of the 1.9Ba schist (photo). Also evident were active mineral drips, transported by water, coming down the rock face like hot wax (photo). On our way out, I snapped a pretty awesome picture of the sun starting to set over the badwater basin/panamint range. Like many things so far, it was beautiful (photo).
After Natural Bridge, we were off for a photo opportunity on artists drive. Geologically speaking, the place along artists drive that we photographed was a volcanic outcropping deposited sometime in the Miocene epoch (without any radiometric dating capabilities on hand, it’s hard to say for sure). From the massive pile of igneous rock, it
Another fault from top left to bottom right
is certain that the source (the volcano) was local. The vibrant colors can be attributed to oxidation, hydrothermal alteration and chemical weathering (photo). Under our feet we were able to find smaller pyroclastic debris, likely from the same period. After snapping our shots, we headed onto the next stop!
Because of the waning daylight, and the collective group need for water, we made a stop in Furnace Creek at a resort that had cell phone service, bathrooms, a live band, and….. beer! We have opted to forego the stop at Darwin’s Falls today in favor of setting up camp before we lose all of our daylight. With a great day of geology behind us, and ice cold beer in front of us, today will certainly end the same way it started; with a smile on my face.
There are more photos below