Body Dysmorphic

When I was a kid, growing up on the farm in Southern Idaho, I would run barefoot down the dirt lanes and ditch banks that lined the fields. The dust on the lanes, especially in high summer, was white and fine as bleached, sifted flour. It coated my skin and made it look chalky. But when I swam in the Snake River, my feet sank into sucking, stinking, black mud. Since the rimrocks that soared above the fields were black, and since the giant boulders that protruded from the sides of the hills were also black, as I got older it seemed clear to me that all lava rock was black.

My mother, a voracious reader of everything from People Magazine to Pulitzer Prize-winning novels to literature on the region’s archeological and geological history, told me the black rock around the farm was called basalt. When we traveled to my father’s Mennonite boarding school reunions outside of Portland, Oregon, we drove through the Columbia River Gorge, where I noted the same kind of rock as on our farm in the same kinds of formations, soaring, spectacular cliffs and chunky black boulders.

Then, in my first year of college on Washington’s Puget Sound, I learned where the Columbia River Gorge’s basalt came from. Our instructor, who wore hiking boots to class and who reminded me of a more gray-complected (he may have been a smoker) Chuck Norris, told us about the runny basalt flows that erupted, again and again, from vents along the borders of Oregon, Washington and Idaho, and flowed westward down the slight slope to the sea. I seem to remember him painting a vivid picture of lava like scalding molasses seeping across thousands of square miles, inexorable and terrifying.

The Columbia River Basalt Group flows were thought to have moved at a maximum rate of about three miles an hour, my geology instructor said. If you were a deer or a bear, you could certainly run faster than that. But, the instructor added, could you do so for hundreds of miles without stopping for rest? Could you outrun this sidling death as it made its way to the Pacific?

My more macabre, late teenage sensibilities latched onto this idea. Like many white, highly-literate, upper middle-class young women of the nineties, I was significantly influenced by the fashion of viewing sickly-looking, pale creatures as the pinnacle of beauty. Any character introduced by the Brontë sisters, say, or even the Brontë sisters themselves, wandering the moors (high desert) and wringing their hands, their elegant limbs weighed down by heavy, Victorian skirts, their cinched corset stays clamping off their diseased airways, causing gasping that looked either religiously ecstatic or orgasmic, depending on your viewpoint-all this held great appeal and dovetailed nicely with the idea of the Columbia River Basalt Group flows. What was a slender-limbed, delicately-boned deer running from inexorable lava but Emily or Anne Brontë fleeing the suffocating creep of tuberculosis?

(Here comes a helicopter, ready to swoop down and save her from the encroaching lava…No! Don’t let it! How beautiful and noble the suffering, when she succumbs at last to that inching death! How much more beautiful the destruction of her graceful form, than grotesque, banal living!)

Even in college, it seemed easy to assume that, since the basalt formations I’d seen in coastal Oregon and Washington looked the same as those I saw around our farm in Southern Idaho, the two areas must have formed in a similar way. In the way of some assumptions, the idea hardened into fact in my mind. If I’m being honest, both my childhood and young adult minds would have done anything to link the western Columbia River region’s verdant land of rain and massive rhododendrons to the barren, godforsaken landscape on which I’d grown up. It seemed decadent and other-worldly, to be surrounded by beautiful, civilized plants that needed no encouragement to sprout. In contrast, anything green that grew on Southern Idaho’s high desert had to be painstakingly nurtured to life with luxurious amounts of water and phosphoric fertilizer.

It wasn’t until I was much older and researching the geology of Southern Idaho for myself that I realized the white dust that permeated the valley where I grew up, and not the black basalt rock, was a truer indicator of the region’s geological history.

The basalt rock I saw around me, in fact, formed only the thinnest of skins across Southern Idaho’s middle and eastern Snake River Flood Plain. Underneath it, and the source of the white dust I’d daily run through as a kid, was a thick layer of another kind of lava rock, called rhyolite. The rhyolite came from a series of so-called “super-volcanos,” also variously known as “super-eruptions,” or even, by certain geologists with a colorful bend of mind, “monster volcanos.” These volcanos, which happened at intervals of about 600,000 years, starting about 17 million years ago, were the most catastrophic kind imaginable, the likes of which have never been seen in recorded history. The monster volcanos did not burble or squirt voluminous, seeping quantities of runny lava that flowed obediently to the sea, like the basalt flows that formed the Columbia River Gorge. Instead, anything within a hundred miles of each super-eruption would have quickly died in the resulting pyroclastic flow (burning ash and red-hot steam). Subsequent ash fall would have coated a much larger area from its eruption site in Southern Idaho, thousands of square miles, blocking sunlight, covering the ground in ash drifts several feet deep, and causing slow suffocation in plants and animals. The immeasurable loss of life would have continued during the weeks and months after the initial eruption.

Scientists know about the ferocity of the volcanos that formed Southern Idaho’s middle and eastern Snake River Plain because they have found hundreds of sites in the continental United States and Canada where ash and other debris from these massive eruptions was deposited within the geological strata over the eons. Some sites are as far from Southern Idaho as Texas or Nebraska.

If you’ll permit me a gross analogy, it’s kind of like throw-up. Sometimes you have a stomach bug that produces rivulets of vomit easily directed at, and confined to, the toilet or whichever receptacle you’ve designated to hold it. And sometimes you have a bug that produces vomit on the scale of a resurgent, rhyolite volcano. That vomit comes out at such pressure it squirts across the room, painting furniture and walls. Places you didn’t even know vomit could travel to, behind picture frames and on the backside of the washing machine, for example, end up smeared with the horrible stuff, such is the force with which it was ejected (obviously I have kids).

And what was left on the Snake River Plain after these massive rhyolite eruptions? Shouldn’t there be some sort of crater or caldera?  When you look at a volcano like Mt. St. Helens, for example, you see a kind of decapitated mountain. It fits with our idea of what volcanos look like.

The massive, rhyolite volcanos that formed the Snake River Flood Plain did leave calderas, but they don’t look like the calderas of a stratovolcano like Mt. St. Helens. For one thing, the latter eruption was far more recent, and thus not subject, like the super-eruptions of Southern Idaho, to eons of subsequent geological processes. Also, the two volcanos were of a different kind and vastly different scale. The caldera at the top of Mt. St. Helens is one mile wide and two miles long. The calderas on Southern Idaho’s Snake River Plain, in contrast, are tens of miles wide. If  a lay-person (like me) went out on the desert south of Boise looking for a caldera, I probably couldn’t spot one, in part because I might be standing inside it.

A lot of the destructiveness of the so-called “super-volcanoes” that formed middle and eastern Southern Idaho can be attributed to the kind of lava that erupted from them. I really can’t describe rhyolite lava better than the authors of Roadside Geology of Idaho, David D. Alt and Donald W. Hyndman.

Here are some samples of their rhyolite descriptions, all from page 241 of Roadside Geology of Idaho (published 1989):

“Although rhyolite ash looks harmless enough in its pastel shades of pale gray, yellow and pink, the eruptions that produce it are extremely violent, extraordinarily dangerous. Molten rhyolite magma combines the volcanically perilous properties of high viscosity and a burning thirst for water.

“In fact, rhyolite magma is so viscous that it has a consistency almost like that of modeling clay; it hardly seems believably liquid.”

“…steaming rhyolite magma expands internally as it erupts, like rising bread, but so rapidly that it explodes like a grossly-oversized and overheated steam boiler.”

The authors describe large masses of molten rhyolite magma beneath Yellowstone Park that cause the ground to bulge like, “slowly growing tumors.” Elsewhere they describe how, “Glowing clouds of finely shredded rhyolite lava suspended in red hot steam boil out of the devil’s cauldron of a collapsing caldera…”

The descriptions like these found here and elsewhere, by other authors, which I first came across in my late twenties, seemed to finally drive home the idea that, much as I would have liked to grow up on a gentle, bucolic landscape, formed by more easily-conceptualized geologic processes, I did not.

I am not Joan Didion, I’ll tell you right now. I am not elegant or subtle, and any great truth I might say or write is stumbled upon purely by accident, after much fumbling and falling down. I am a strong woman, tall, shaped like a T-Rex, with small arms, thickly-muscled thighs and a wide ass. I am irritable and sad and haunted by things from my own past and pasts before mine. My teeth are big and long, like a horse’s, and tiny spit bubbles form on them sometimes when I talk, especially if I am excited. Sometimes, after I visit the farm, it takes me several days to realize my shoes smell like cow shit. Would that I could trip through tendrils of green ferns and lilies of the valley, but I’ll have to do with sagebrush and white dirt.

Sources I used to help make this entry factually correct (I take full responsibility for any factual misunderstandings or errors, and also for the vomit analogy):

-Mastin, Larry G.; Van Eaton, Alexa R.; Lowenstern, Jacob B. “Modeling ash fall distribution from a Yellowstone supereruption.” AGU Advancing Earth and Space Sciences Geochemistry, Geophysics, Geosystems. Volume 15. Issue 8, August 2014, pp. 3459-3475.

-Resurgent Calderas, Valles Caldera National Preserve, Yellowstone National Park. (2023). National Park Service. https://www.nps.gov/articles/000/resurgent-calderas.htm#:~:text=Boulder%2C%20Colorado.%5D-,National%20Park%20Resurgent%20Calderas,Valles'%20caldera%2Dforming%20eruptions.

-Cascades Volcano Observatory. (2023). Columbia River Basalt Group Stretches from Oregon to Idaho. USGS Science for a Changing World. https://www.usgs.gov/observatories/cvo/science/columbia-river-basalt-group-stretches-oregon-idaho

-Mount St. Helens Fact Sheet (copied by permission from publication of Mount St. Helens National Volcanic Monument and Gifford Pinchot National Forest). (2024). Oregon State University. https://volcano.oregonstate.edu/mount-st-helens-fact-sheet.