The Answer to Sunday's Mystery Quiz...And Where I'm Headed Tomorrow

The answer is: Death Valley National Park!

I admit that I was trying to be a bit deceptive with my pictures. Many people have a stereotypical image of Death Valley that includes salt flats, sand dunes, and miners with their burros tramping over barren desert mountains. Those things are part of what Death Valley is, but there is so much more.

I mentioned in Sunday's post that Death Valley is possibly the most geological park in the entire National Park System. The reasons for saying this include what I pointed out before: "the park contains rocks from every major era, ranging in age from as much as 2.3 billion years ago, including perhaps the most complete Paleozoic sequence of rocks found anywhere (something like 20,000 feet of Paleozoic rocks, including formations from each period), rocks from the Mesozoic (including plutonic granitic rocks), and a sequence of early Cenozoic sediments known for their mammalian fossils. The youngest rocks in the park may be only a few hundred years old."

There are other superlatives that can be added: the lowest point in the western hemisphere, the hottest temperature ever recorded on planet Earth, the driest place in North America, and features like the mysterious sliding stones of Racetrack Playa, the strange "turtleback" faults and metamorphic core complexes, Lake Manly (the freshwater lake that filled Death Valley 600 feet deep during the ice ages), and four species of fish (!!) including possibly the most endangered vertebrate species on Earth, the Devils Hole Pupfish.

There's more: the Ubehebe Craters, classic maar volcanoes that may have exploded only a few centuries ago, the badlands topography of Zabriskie Point, the Badwater salt pan, evidence of previous Death Valley type grabens that formed 15-20 million years ago, Neogene tuff deposits recording a wave of rhyolite eruptions across the American West, and the iconic sand dune fields.

As I said before, the park is so extensive and intricate, one could explore it for years and always find new treasures. If you are curious, the top picture is a view towards northern Death Valley from the lower end of Titus Canyon. The road through Titus is an epic adventure where one drives not over, but through a mountain range. The second picture is from the deepest part of the canyon, where the walls rise 3,000 feet, providing a Grand Canyon kind of feeling.

The third picture is one of the unexpected pleasures of exploring Death Valley. In the newer part of the park on the western side of Panamint Valley there is a permanent spring system and a 20 foot high waterfall. Darwin Falls is only a mile of hiking, and is a pleasant contrast to the barren desert.

The last picture is Mosaic Canyon, a better known part of the park, but a place with strange secrets. The mosaics are breccias and conglomerates that have been plastered to the sides of the canyon, but structural geologists seek out the exquisite structures revealed in the yellowish Noonday Dolomite of latest Proterozoic age. Callan Bentley of Mountain Beltway recently posted some neat shots of the folds in the lower canyon.

So that's where I'm taking 25 or so students tomorrow. It's hard for me to think of another single park or region that offers so much geologic diversity in one place.

Of course, you may have a different opinion...is there a place in the world that has more geologic diversity than Death Valley? I would love to know what you think!

Death Valley Days: The Fourth Day - The Long Road Home

Day dawns on the Cottonwood Mountains west of Stovepipe Wells. We've got about 400 miles to reach home, but we weren't going to let that stop us from doing a few last minute stops at Death Valley National Park. We've spent three days exploring the region (here, here and here), successfully avoiding the worst of California's storms this last weekend, and seeing some wonderful geology.

Tucki Mountain is an immense edifice rising 8,000 above our camp at Stovepipe Wells at sea level. The shape of the mountain is reminiscent of a turtleback fault, and it may in fact be an incompletely exposed metamorphic core complex (I would love to hear from the structural geologists about it). Mosaic Canyon is a deep gorge on the north flank that narrows down to a twisting labyrinth in its lower reaches. It is a main tourist stop, but most visitors never notice the spectacularly exposed structural features.

Just a short distance up the canyon from the parking lot is one of the best exposed examples of a normal fault I can imagine. Laura is resting her back on the headwall and sitting, more or less, on the footwall. The different colored layers show that the headwall dropped relative to the footwall, indicating extensional stress.

A little further up the canyon, the so-called 'mosaics' appear, chunks and pieces of canyon alluvium that were lithified, glued to the canyon walls, and exposed by continued downward erosion of the canyon. The photo above would serve as a perfect example of the appearance of an angular unconformity (a buried erosion surface with tilted rocks beneath and horizontal layers above), although the specific relationships here stretch the definition a little bit.

Paul was describing a large recumbent fold in the upper part of the narrows. These rocks have undergone an astounding amount of deformation, having been twisted into tight folds multiple times.

We made our way down the canyon for one last restroom break and chance for curios and t-shirts, and starting winding our way up into the Panamint Mountains for a last look at the valley. The road down the Mosaic Canyon fan provided a marvelous view of the Death Valley Dunes (Mesquite Dunes). Contrary to many people's stereotypes about deserts, dunes are a relatively rare part of the landscape in a place like Death Valley. Powerful winds blow the sands off the alluvial fans and down the long valleys until some flank of a mountain range interrupts the flow of the wind. The sand is deposited and shifts back and forth in the wind eddies. The highest of the dunes reach 150 feet or so. They are especially fascinating at night and in the twilight hours. In the morning the surfaces are covered by trackways of insects and animals. Most people don't realize they have seen the dunes; they were a stand-in for the Star Wars planet of Tantooine (the Dante's View panorama of Death Valley was used for the setting of Mos Eisley).
The interruption of the fan in the far distance is the trace of the Furnace Creek fault, a strike-slip fault that follows the base of the Funeral Mountains on the skyline. Death Valley hasn't been historically active as far as earthquakes go, but there are many signs that the faults are quite active.
We drove up the gravel road to Aguereberry Point. The gentle rolling landscape gave little indication of the jagged cliffs just over the ridgetop. These hills give some indication of the topography of the region prior to the formation of the deep fault grabens of Death Valley and Panamint Valley. They were preserved as the mountains rose and valley collapsed, but in the fullness of geologic time, the hills will be breached by headward erosion and will disappear.

We topped the ridge at 6,000 feet and arrived at Aguereberry Point. Being at the end of a gravel road, it receives far fewer visitors than Dante's View, but it is no less spectacular. One stands beneath the flank of 11,049 foot Telescope Peak, and has a sweeping 270 degree view of Death Valley, the Panamint Mountains, the Inyo Mountains, and the Sierra Nevada in the far distance. At our feet was the massive alluvial fan of Furnace Creek, the location of many of the park's tourist facilities.

The salt flats of Badwater and the Black Mountains fill the view to the southeast. In the foreground are tilted Paleozoic sediments, carbonates and sandstones that were deposited in shallow seas, but ultimately accumulated to depths of many thousands of feet. We were standing on quartzite that was once a beach in Cambrian time 500 million years ago. We could see the burrows made by countless worms in the tropical climate.

Finally the last geology stop was complete, and we hit the long road home, via Trona, Ridgecrest, Bakersfield and Fresno. It was a good trip! I hope you've enjoyed the virtual tour.

Death Valley - A land of many treasures

And very few of the treasures are of the monetary kind. Mosaic Canyon, at the north end of the Panamint Mountains is a treasure trove of learning opportunities at all levels. In the picture above, students witnessed a rare sight of flowing water in a desert wash (after an overnight soaking in our campsite; no one really cared, it was the last day). We could watch the pebbles rolling down the channel, and it was easy to imagine one of the large flash floods that have carved the intricate narrows just upstream.

The canyon walls are adorned with the "mosaics", chunks of yellow dolomite marble that were once cobbles in the stream bed. They were later cemented, and then eroded by later floods. Understanding their origin was the goal of the student projects while they wandered up-canyon.

The canyon lies at the edge of a metamorphic core complex, Tucki Mountain, and numerous faults are visible on the walk up the canyon, including one of the sweetest pictures of a normal fault one could ask for.

The yellowish rock forming the canyon wall is the late Proterozoic Noonday Dolomite, a carbonate shelf deposit recording the subsidence of the recently rifted passive margin of the western edge of North America. At first glance, the rocks appear simply tilted, but closer observation reveals complex folding patterns.