Rock and Light: The Primal Elements of Death Valley, Monochrome Edition

Sorry for going all pseudo-Ansel Adams on you all. I was playing with the photo-editing program with the pictures that I used in yesterday's post, and at one point I switched to black and white. I'm enchanted by the colors of our planet, but it is easy to forget that features can often be better discerned in monochrome photos.

It's almost as if the blinding sun, so unexpected, blinded me to the textures and depth of the rocks revealed in the slopes of the northern Black Mountains of Death Valley National Park.  Monochrome imagery is something that really has only existed since the advent of photography, and its value today is in the unexpectedness of the image. We expect color, but it's not there. As Wikipedia (the ultimate authority) would put it, monochromatic images "are not direct renditions of their subjects, but are abstractions from reality". And yet, science illustrators often prefer to show objects of research in black and white, or even as drawings to emphasize the ultimate reality of their findings.

It occurs to me that monochrome images do have an impact on the human psyche, and it exists at a very fundamental level. Our vision at night is monochrome, and humans evolved with a certain primal fear of the darkness. One can't see approaching predators in the dark, and in low light one would be highly attuned to noticing small changes or movement in one's field of vision. Black and white images capture our attention in a way that color images just can't.

In any case, I was mainly looking for an excuse to put up some pictures that I found interesting. Badlands topography has always been a good subject for black and white photography because of the strong contrasts between light and shadow, and the Furnace Creek Formation is the ultimate expression of badlands.

Stepping From a Valley Floor into a Mountain Range: Travels in Death Valley

To me, one of the most stunning things about exploring Death Valley is the abruptness of the landscape. There are no gentle transitions. You are either on the valley floor, or you are on a mountain. There is no in-between. I'm hard put to think of another place in the world where you can stand on a valley floor and place your hand on a mountain slope. It's just usually not the way of things.

But Death Valley is like that. The main valley is more than a hundred miles long, and 10 or 15 miles across. It's a place of wide open vistas that extend for miles. But if you approach a mountain range like the Black Mountains between Badwater and Furnace Creek, you walk up the gentle slope of an alluvial fan, and then you are stopped by the mountain. Because of the active fault scarp, it rises like a wall straight up out of the ground.

We had come down onto the floor of Death Valley after looking at the diversion of Furnace Creek into Gower Gulch, hoping to get some insight into the effects of flooding a small canyon with the debris and mudflows from a drainage area of 170 square miles. It was pretty awe-inspiring. In the 70 years since the diversion, Gower Gulch had scoured its channel through the Black Mountains, and eroded a deep channel into the surface of the Gower Gulch fan. There's a 25 foot high dry waterfall at the entrance to the canyon, but a trail clings to a narrow terrace of the old alluvial fan to the left (above). It's not hard to explore the narrow canyon above.

There was still a thin stream of water flowing through the canyon, a small remnant of the flash flood that had thundered through the canyon the previous night (Death Valley had just experienced a night of record rainfall for the date, 0.62 inches; of course we were camped out in the open). The debris had covered the highway just downstream.

It's a steep and rugged canyon, one of many that begs exploration by curious people. Treasures are to be found in these canyons...old mines, colorful rock exposures, fossils, and elusive life: Bighorn Sheep maybe, or a Kit Fox. Who knows?

In the end, it's all about the landscape itself. Naked rock exposures and faults. Alluvial gravels. Stepping from a valley floor into a mountain range in one step. There's no place in the world like this...

Travels in Death Valley: the Strange Story Told By a "Rock"...

A beautiful collection of colorful rocks lie scattered across the surface of an alluvial fan in Death Valley National Park a few miles south of Furnace Creek. There is a piece of vesicular (full of holes) basalt on the lower right, next to a piece of gray limestone. One might be just 10 million years old, while the other may be 300 million, containing the remains of long dead and extinct organisms. At the top left, a piece of orange-brown sandstone, possibly deposited on an ancient ocean shoreline, or maybe a lakeshore in a long-ago desert, maybe even a sand dune. Perhaps a piece of granite is in there somewhere, a rock that cooled four or five miles deep in the crust. What a long journey it had before it was exposed by erosion and carried down the desert wash! And then there is...wait...what is that at center left? That's no conglomerate! Well it sort of is, but isn't natural is it? That's a piece of pavement. What's going on here?

It's not a story that appears on National Park Service interpretive signs, and in fact I think the park service would rather that people not explore the particular canyon at all. It's sort of unstable, as in vertical walls made of loose and cracked chunks of claystone. And like the piece of asphalt pavement on the alluvial fan surface, it's not natural either. This canyon didn't exist 75 years ago.

Gower Gulch used to be a minor drainage in the Furnace Creek Formation badlands near Zabriskie Point which debouched onto the floor of Death Valley, forming a small alluvial fan. Badwater Road crossed the fan, which consisted of mostly fine-grained materials like silt and clay.

The problem is that nearby Furnace Creek drained a much larger region than Gower Gulch (170 square miles versus 2 square miles), and was prone to violent flashfloods and mudflows that damaged facilities at the Furnace Creek Resort about five miles downstream. Around 1941 someone thought to blast through the low ridge that separated Furnace Creek and Gower Gulch, forcing the entire drainage to flow through the badlands and onto the Gower Gulch fan downstream. The diversion caused profound changes upstream and downstream.

At the diversion point (above), the flash floods cut through the soft siltstone and shale like a hot knife through butter, cutting 40 feet or more in seven decades. The floods carry a heavy load of coarse-grained debris and gravel that acts as an abrasive on the channel floor. The canyon changes year to year as each flashflood causes slopes to be undercut, causing rockfalls and slope failures.

It's upstream where serious damage to the road occurs. The diversion caused a sudden steepening of the Furnace Creek channel, and the faster moving floods have eroded the channel in an upstream direction, a process called headward erosion. The deepening of the channel is apparent as far as two miles upstream, and in numerous places it has encroached onto Highway 190, washing away some of the pavement, and incorporating the fragments into the alluvial fan deposits downstream (as in the first picture above).

Downstream, the road damage occurs in a different way. The alluvial fan used to receive fine-grained silt and clay in relatively minor floods that did little damage to Badwater Road. Now the flashfloods are on steroids, so to speak, with more water, more debris, and far more speed. Badwater Road is regularly overwhelmed, as it was on the day we visited, with mudflow deposits. Boulders can sometimes be sizable. For example, check out the two fragments on the fan in the picture below. How big do you think they are?

Here's your answer: pretty big.

Death Valley is a monument to geologic changes over billions of years, but it is also a dynamic environment where geologic change happens on a daily and yearly basis as well. We saw plenty of evidence during our February trip.