Volcanoes in the Mist (and underground): Travels in Death Valley

The Inyo Mountains, in any other setting in the world, would be considered a major mountain range, preserved as a national park perhaps, and celebrated as scenic wonderland. But just like an accomplished sibling overshadowed by a more famous brother or sister, the Inyos lie across the valley from the most spectacular part of the Sierra Nevada, and south of the higher White Mountains. For better or worse (mostly better), only a few roads penetrate the range, including the main western highway into Death Valley National Park, State Route 190. That was the road we followed on our recent exploration of Death Valley.

As was noted in the previous post, we attempted our trip during the Bombogenesis storm that wreaked havoc across Southern California. This kind of storm can often result in disaster as highways get closed or damaged by landslides, but we were lucky and were able cross the Inyo Mountains and Darwin Plateau without problems. But we did get the opportunity to see some great geology, and even were able to add a new stop to our itinerary (because we missed a different one, but I'm not complaining).

Our first sight as we approached the mountains was the snow covering the desert peaks (first picture above), a hint to the seriousness of the storm we were challenging. The tilted rocks are Paleozoic-aged (300-550 million years) limestone layers. They recall a time when California was very different, completely submerged under a shallow tropical sea. We would be seeing more of these fascinating rocks later on. The road crossed the flat uplands of the Darwin Plateau, and then plunged down a steep incline towards the Panamint Valley.

We actually had fog in this arid environment, since the clouds were crowding against the edge of the steep mountains. As we passed the Father Crowley Vista Point, the clouds briefly parted and we had a view into the deep gorge of Rainbow Canyon. At this point, the slopes and flats are covered with basaltic lava flows ranging in age from 8 to 4 million years old. The immediate question becomes, why volcanoes? Why right here?

In a sense, volcanism is possible almost anywhere on the planet. It's not that there is magma everywhere, but that a hundred miles beneath our feet there is a zone, the asthenosphere, where the rock is almost molten, but not quite (perhaps 5-10% liquid). To melt this rock and create volcanic activity would require raising the temperature (as happens at hot spots like Hawai'i), or releasing pressure (pressure keeps the rocks from melting in the same way that pressure cookers prevent water from boiling). There aren't any hot spots in the immediate vicinity, but the crust across the Basin and Range Province has been stretched and thinned, allowing pockets of basaltic magma to form and rise into the rocks above, often following fault zones to the surface.

Although we couldn't see it through the clouds, there are basaltic lavas across the Panamint Valley that are of the same age and the same exact composition as those at the vista point. In addition, the rocks across the deep valley have no obvious source (the picture below is from last year, a decidedly drier trip). The best explanation for these rocks is that the lavas flowed across an original surface that was later broken up by faulting when the Panamint Valley formed. Since the youngest volcanic rocks are just 4 million years old, the Panamint Valley is younger still. The Panamint Valley is more than a mile deep and 65 miles long! That's a lot of geologic activity in a short period of time.

Looking across the Panamint Valley towards Hunter Mountain. The dark rocks on the left summit area are identical to the rocks at Father Crowley Vista Point.

We made a stop along the road descending into the Panamint Valley to check out some spectacular exposures of the dikes and sills that once fed the eruptions of the basaltic lavas (most years we are in too much of a hurry to get a camping spot at Stovepipe Wells). The magma was following whatever weakness in the surrounding rock that could be exploited by the molten rock. In some cases, vertical fractures allowed the magma to rise, forming dikes. In other cases, the molten rock flowed between limestone layers, forming sills. This extraordinary roadcut (below) showed textbook examples of both kinds of intrusions in the same outcrop. The usually black basalt has been oxidized (rusted) to produce the strange reddish-brown color.

There's a saying that one should never blindly sit on the ground in the desert. There are just too many things with fangs, stingers, or spines. The barrel cacti were looking to grow quickly in these rare wet times!

We headed down the highway. We had reached Death Valley National Park, and we faced whatever Bombogenesis was going to throw at us...

So, Besides Fish, What's the Last Thing One Would Ever Expect to See in Death Valley National Park?

It's one thing to find that a number of fish species survive within the boundaries of Death Valley National Park, which preserves the hottest and driest desert in North America. But sure, springs will persist in many dry environments. But a permanent, year-round waterfall? Yes, there is one in Death Valley National Park.

When Death Valley was changed from a national monument to a national park in 1994, the boundaries were vastly expanded, and came to include a portion of the Darwin Plateau at the south end of the Inyo Mountains southeast of Owens Lake. Part of the reason this area was included was the presence of a permanent stream, and its importance as a wildlife area. And there was Darwin Falls as well.

The falls are a short walk up a canyon just upstream of the Panamint Springs Resort on Highway 190. Indeed the water at Darwin Falls isn't just for the wildlife. A pipeline runs the length of the canyon providing the precious liquid to the resort as well.

There is some excellent geology exposed in the canyon walls on the way to the falls. One example is this excellent exposure of a dike, an intrusion that cuts across the sedimentary layers. There are nice examples of jointing in the granitic rocks exposed a little farther upstream.

Then comes the unexpected thickets of vegetation and the sound of trickling water. The trees are so thick it is a little tricky getting a clear shot of the lower falls. The falls are about 20 feet high, pretty small by any standards, but we are talking about a desert environment here. I understand several other falls are present upstream for a total drop of 80 feet or so.

These pictures are from 2008. I've only made it to the falls the one time, but I'd like to get up there again, maybe when the sun hasn't practically set! Thanks to commenter "twoeightnine" for jogging my memory about this extraordinary place in Death Valley!

The

Another Cool California Roadcut: Dike and Sill on Highway 190 near Panamint Springs

Dike (vertical brown rock) and sill (horizontal brown rock) along Highway 190 near Panamint Springs

I've been working through my memories of beautifully instructive roadcuts in California. Some, like the Big Pumice Cut and the Charlie Brown Outcrop, are quite famous to geologists and generations of field studies students. Others have received less attention, and today I'm showing a particularly nice spot to learn about the difference between a dike and a sill.

A dike is an intrusion of molten rock that is tabular (thin, but deep and wide, as it fills fractures in the rock), and discordant (it cuts across rock layers). A sill is also tabular, but it is concordant, meaning it squeezes between layers rather than cutting across like a dike.

Highway 190 provides access to Death Valley National Park from the west at Lone Pine and Olancha. It travels around the south edge of Owens Lake, and then crosses the Darwin Plateau before beginning a steep descent into the Panamint Valley. From there it crosses the Panamint Mountains at Townes Pass and enters into Death Valley.

The Darwin Plateau is capped with multiple layers of basaltic rock covering a sequence of Paleozoic limestone layers. Midway down the stretch between the turnoff to Darwin and the resort of Panamint Springs there is a spectacular exposure of a dike and a sill in the same roadcut. The basaltic intrusion has been weathered to an orange-brown color. The Paleozoic-aged limestone is gray and has clearly delineated layering that makes it a straightforward exercise to distinguish the two types of intrusions that cut through it.

I wish I could say that this is a favorite stop on our way to Death Valley, but unfortunately we are usually running late by the time we reach it late in the afternoon on our way to Stovepipe Wells. It is a marvelous example of both kinds of intrusions.

The Harrowing Journey to the Valley of Death (21st Century Style)

When is the next bathroom? Will there be flush toilets at the campground? What about showers?

Geology field tripping in Death Valley National Park in the modern era is a far cry from the adventures of centuries past, specifically the 19th and 20th (the earth scientists living among the Native Americans in past centuries left no record, but they no doubt knew which rocks and minerals were valuable for tool making). In the 19th century the "earth scientists" were the few itinerant miners and prospectors looking for other kinds of valuable minerals, especially gold and silver (though the most valuable finds were probably the borates and talc). Just getting to the gigantic blank spot on the map was a challenge, and surviving in the harsh climate was a gamble.

At the beginning of the 20th century, access was improving, and rough dirt roads coursed up many of the valleys and crossed the less rugged passes of the mountain ranges. These roads were utilized by the first of the university-trained geologists who undertook the daunting task of mapping the Death Valley region. It wasn't that the rocks weren't exposed well. They offer some of the best exposures to be found anywhere. But the Basin and Range Province is so vast the few individuals who first worked in the region were limited simply by time and mortality. There was hardly enough time in one life to see it all!

By the 1930s, mining roads made for much better access, and the designation of Death Valley as a national monument by Herbert Hoover in 1933 led to increased tourist traffic. The mines began converting their hospitality facilities to tourist destinations, particularly at Furnace Creek. Paved highways allowed for quick trips out of Las Vegas or the Los Angeles region, and Death Valley began to feel just a little bit "urbanized". But not really. It can be easy to forget that this land is still the same harsh climate that it's been for the last few thousand years since the end of the ice ages. The heat and dryness can still lead to heat stroke and dehydration, and all it takes to bring one to the edge of mortality is a blown radiator hose or flat tire.

And so it was that we were making our way into the "Valley of Death" for our geology field studies class a couple of weeks ago. We had already searched for fossils at Sharktooth Hill, learned the basics of stratigraphy at Red Rock Canyon, and explored a dry ice age waterfall at Fossil Falls, but it was time to head east out of the Owens Valley and into one of the most isolated regions of the lower forty-eight states. We first crossed the relatively muted topography of the Darwin Plateau at the south end of the Inyo Range (top picture), and then took the Mr. Toad's Wild Ride down the steep highway to Panamint Springs and Panamint Valley. We made a short stop at the Father Crowley Vista Point (above). This site used to be a wide dirt lot on the side of the highway, but has been developed into a formal vista point with a simple toilet facility and protective fencing (gotta keep them tourists from falling over the cliffs...). The view is stupendous, with an excellent vista of the Panamint and Cottonwood Mountains across the way. There are complex relationships between the rocks of the Panamints, which are hinted at in the picture below, where dark flows of basaltic lava cover intensely folded Paleozoic carbonate rocks. The hill beyond exposes a granitic pluton.

The bottom of Panamint Valley holds more recent geologic phenomena, including the Panamint dune field and a fault scarp along the mountain base (the sunlit terrace)....

 ...and Panamint Dry Lake (below). Telescope Peak, the highest point in the park at 11,049 feet, is often graced by snow during the winter months. On the other side of the Panamint Range is Death Valley itself, which in large part lies at a depth of several hundred feet below sea level. Not many places around the world have such great relief.

From the Panamint Valley at about 1,000 feet we began climbing to cross the Panamint Mountains over Towne Pass at 4,956 feet, and in the setting sun we followed the long grade down the alluvial fan system to Stovepipe Wells at sea level. We pulled into the campground at dusk under a beautiful fiery sky.

 As the western sky faded, the light grew in the east as the full moon rose above the Funeral Range.

We had reached the Valley of Death, and it was a beautiful place. And there were flush toilets and showers!