Every morning, the sun emerges from below the rusty basalt ridge to the east and reveals a desert landscape. Sunlight passes down the sandstone faces surrounding the campsite, falling across layers of burnt red and columns of rock, finally settling on our tents at the base of the cliffs. The transition from the desert’s cold wind-blown nights to blistering hot cloudless days begins. By 7:15 am the temperatures in the tents become uncomfortable. This prompts the escape from my down sleeping bag. Yesterday’s shirt inverted becomes today’s, a shake of my sweat encrusted malodorous socks empties loose sand, and I re-lace my sun-bleached boots.
I join the other members of the field crew at the picnic bench in the center of the campsite for discussions of today’s objectives over peanut butter and oatmeal. Today will be another day of measuring stratigraphic section. That is what we have come here to study: the lines in the rock.
We arrived in the Mojave Desert two weeks prior in the first week of May, driving west from Ann Arbor, across the great plains, the Great Basin, and through Las Vegas. When we reached Nevada, we were greeted by rows of mountains—north south trending ranges separated by series of parallel basins. Crossing basin and range and basin and range, we sped past Joshua Trees and Creosote bushes at 70 mph, watching fields of solar panels and wind turbines feast off of the desert’s extreme conditions. We continued across the mountain ranges towards Red Rock State Park in the Mojave Desert of California.
These were my first views of the desert and America’s southwest. I joined the Badgley Lab from the University of Michigan for their summer field season. Led by Catherine Badgley, professor in the Department of Ecology & Evolutionary Biology and current director of the Residential College, her two graduate students and post-doc were bound for California to revisit old sites, sort through museum collections, and explore a new formation. Fabian Hardy, a graduate student paleontologist, was embarking on his first trip to his field site to investigate the response of mammalian diversity to changing climates and topographies. I joined Fabian for his field season within Red Rock Canyon State Park, where the Dove Spring Formation documents millions of years during the Miocene Epoch. In this period, warmer climate and active tectonics caused immense biological change throughout the southwest. These geological, environmental and ecological changes have been preserved in the strata of rocks. Over the past century, paleontologists have uncovered diverse assemblages of rodents, along with fragments from ancient bear-dogs, carnivorous cats, camels, horses, and elephant-like mammals. By placing this extensive and transitioning sequence of fossils within a larger ecological context, Fabian seeks to understand the mechanisms that affected mammalian diversity throughout the Mojave.
After exploring and troubleshooting for weeks, we are in the final days of this year’s field season. We have crisscrossed the ridges within the Dove Spring, continuing our slow march northwest and forward through time. Now there are only a few gaps in the section, a few hundred thousand years of history still preserved in rock. The next few days are an effort to complete our record of the formation. After eating oatmeal over today’s map, we lather on sunscreen and drive to the uppermost part of the section beneath the blazing sun. We snake through the wash and park along an ATV path and follow trails carved by water to the final and youngest part of the section. The finer sandstones, red rocks, and basalt ridges from the previous millions of years are capped by conglomerates formed from the cobbles and pebbles of the rising Sierras. When we reach yesterday’s final point, we begin another day of measuring sections of rock.
One-and-a-half meters and thousands of years at a time, we measure the layers. With each step, I align the compass at the top of the metal Jacob’s Staff, lean to the rocks tilt, and sight my next step. Fabian characterized the surface, documenting the lines in the rocks, the types of the sediments, lenses of ash, and pounding at the earth with his hammer for samples of ancient organic material—all contributing elements to his unraveling understanding of the paleoecology of the region.
I take the rock samples and toss them in my backpack. The bags of sediment accumulate, crushing our PB&J lunch once again. As the sun reaches its apex, we stop for lunch to salvage what’s left of crumbling potato chips and sandwiches and eat below the meager shade of a Joshua Tree. It’s been over a week since our last shower, and the duct tape patches on our pants are beginning to fail. The past weeks we have slept through torrential spring thunderstorms, endured the desert’s sandy wind, worked below the blazing sun, and saved ourselves from heat with water guns. We get back on our feet and continue working for only the promise of lemonade, our last bottle of salsa, heaps of pasta, and yesterday’s leftovers back at camp.
All around us, burnt faces of rocks sculpted by water are an indication of the forces that built the topography of the Mojave. Beginning tens of millions of years ago, the Great Basin began to spread apart, building mountain ranges and carving basins into the landscape. To the West, the Sierra Nevada Mountains rose. These faces of exposed rock are a product of that extension, composed of sediment from eroding uplands and transported by ancient waterways. The faults that cross the walls of rock, offsetting the continuous layers is evidence of their continued movement. What today appears as an arid desert eternally baked by sun, was once speckled by lakes and crossed by rivers, forests, and grasslands in the Miocene. In the Mojave, these histories are preserved and presented in astonishing detail and scope. Standing there, looking at the rock and attempting the grasp the massive and inhuman spectacle of this place, I want to understand it all. To look at the rock, track the bends in the layers, to relive the extension and formation of mountains and basins, to recall stories of forests, rivers, marshes, and lakes, and to see camels, horses, bears, and cats across the landscape in the evidence of bone fragments.
On our last night in the Mojave, I climb the sandstone buttes behind the campsite to view the stars. Preparing my sleeping bag on the flat bed of resistant sandstone deposited millions of years ago, car headlights from CA-14 illuminate me, sitting within another epoch, with unknown histories all around me recorded in the rocks. Stories of mountain building, river systems, and forests, with oceans and other annals preserved further below. It is only within the last million years that climatic changes morphed the desert landscape of the Mojave we know today. The modern alluvial fans, playas, sediment faces, and the flora and fauna they support are the product of a mere moment in geologic time, and me, only a transient observer in this changing landscape living with an illusion of permanence. In millions of years, this place will have transformed again, morphed to new shapes with different climate and species unknown to us.
Like a brief candle in the dark, the headlights move on, leaving me alone with the silhouette of rocks above, the night sky, and a reminder of the ephemeral existence of species, ecologies, and ourselves, all within the remarkable persistence of life on earth.
About the author:
Ethan VanValkenburg is a second-year undergraduate in the Residential College pursuing a degree in Ecology, Evolution & Biodiversity from the College of Literature, Science, and the Arts. He has enjoyed the RC’s repertoire of writing classes and hopes to continue to combine his fascination for science and ecology with his passion for writing. This summer, his interests in research, ecology, and geology led him to California’s Mojave Desert with Catherine Badgley and the Badgley Lab where he carried rocks, saw his first desert, and explored the ancient past of the Dove Spring Formation.