No, Not Excavating, But Yes, in a Canyon

One of the most remarkable characteristics of the Earth is that the rates of its interior (tectonic) and exterior (climatic) processes are approximately balanced. Erosion can dismantle mountain belts nearly as fast as they grow. …No mountain is exempt from erosion, and the steepest slopes are subject to the fiercest attacks. 

 

-      Marcia Bjornerud, Reading the Rocks: The Autobiography of the Earth

 

 

We are once again in the Dos Cabezas Mountains -- right in our backyard, so to speak, “we” being Therese and I and our dogs, Yogi and Sunny. Therese has explored part of this territory before, long ago, but it’s completely new for the dogs and me. The open-looking ground in the lower left-hand corner above is, once again, what remains of a former mining road, and our hike will take us back into the picture, past that big tree on the left and eventually deep into a canyon we can’t see at all yet. What looks like a road high above on the right, below the rocky summit, is an old mining scar, but we’re not going there. We will take what remains of the old road paralleling a rocky wash, descend into the wash where rains have washed away sections of road, and explore the canyon not yet visible – because while the land looks quite open in this initial photograph, most of what we will encounter on the ground is still hidden from view, only gradually revealed as we penetrate farther into the picture.

These massive, towering promontories, for instance, so close at hand! Did you see them coming?

The light, bright green plant in the foreground here is Mormon tea, Ephedra viridis. Early Mormon settlers to this region followed the Native American practice of making tea from the dried plant stems, for use not only as a beverage but also to treat colds. Commercial cold remedies are made from an Asian species of Ephedra; the Arizona species does not contain ephedrine, its effect derived instead from tannins.

Going is not fast or easy in a boulder-filled wash. Great forces were necessary to bring the boulders down in the first place, and yet not all monsoon floods were strong enough to keep pushing them. Sometimes the water had to go around the rocks instead, crumbling and eroding and bringing down soil from the banks of what was temporarily a stream to fill the bed with sediment and widen the whole course – except where the bed is bedrock rather than soil, and then the way remains narrow and rockbound.

 

We humans with our short lifespans and human-centric views of nature usually tend to think of erosion in negative terms, and yet structural geologist Marcia Bjornerud explains it as part of a constantly repeating cycle, the growth and erosion of mountain belts “keeping [the] planet on an even keel,” unlike other planets where volcanoes spew forth unchecked lava flows, growing and growing. “On earth,” she writes, “there are limits to growth, imposed largely by running water.” Bjornerud’s explanations and descriptions take her beneath the ocean, where sediments collect on continental shelves, but I’m sticking to the neighborhood at hand: mountains, rains, and periodically flooded washes.

 

Sunny and Yogi’s interests are even more locally focused than mine. A bone! They have found a bone! Trust those dogs always to find something thrilling – and better a bone than partially decayed rabbit carcasses or bloody deer legs left behind by coyotes!

 

I wish you could see how this boulder really looked. It sparkled in the sunlight, but my phone photo does not capture the sparkles. 

Our course has altered by about 90 degrees now, and we are getting into the canyon we wanted to explore today. These views are looking back the way we came, through that sunlight into the background and into deep shade. 

It was exciting to come upon a pool of water. 

Later at home, examining topo maps, I decided we had probably been in Walnut Canyon, and had we gone farther up we might have come to Walnut Spring. Maybe. (We saw no walnuts.) Whatever the name of this rocky slot canyon, it is not anywhere you would want to be during a summer monsoon. As our way narrowed, with massive rock walls on either side, the cowpath and/or game trail became more and more what I would call a precarious goat path. But the rocks were beautiful! --If only I knew their names! That will be in my next life, when I begin in girlhood to prepare for a career as a horseback field geologist….

Our way came out into the sun again eventually, but boulders lay thicker than ever ahead, and we agreed to turn back and call it a morning.

One main theme I have taken so far from Reading the Rocks is that the history of the earth, like the history of the universe, is a story of alternate mixing and sorting. (That, in fact, is the title of one of the author’s chapters.) Stars explode, and eventually planets and their satellites settle out of the chaos. Volcanoes erupt and jumble things again, but in time the boulders and rocks and stones sort themselves out. Tectonic plates collide and give us a new reconfiguration of land and sea. Maybe we need periodic upsets in our brief, small personal lives, unwelcome as they often are, to give us reason to reassess and re-sort, finding a new (though always temporary) equilibrium. What do you think?

 

Be that as it may, another satisfying mountain expedition has whetted my enthusiasm for further adventures off the beaten path and provided food for thought to accompany my reading.

Reading For Pleasure

 

Do you read for pleasure? For work? For information? 

 

Information, of course, as we all realize, is of many sorts and sought for many reasons. (Egad! Don’t I just sound like that boring sister, Mary, in Jane Austen’s Pride and Prejudice? Forgive me, please!) For example, friend and I were puzzling over the research findings of the newest Nobel Prize winners in quantum physics, that of “entangled quantum states, where two particles behave like a single unit even when they are separated," but a sentence my friend read to me from the New York Times over the breakfast table (she is visiting from Ann Arbor for a couple of days) only increased our bafflement: 

Measuring one of a widely separated pair of particles could instantaneously change the results of measuring the other particle, even if it was light-years away. 

 

"So," I asked, "are the changes in the particles or only in the measurements?" We quickly leapt to the uncertainty principle, which I have always liked because it points to limits of human knowledge, and I like the principle for its reminders that human understanding of the universe, however much it expands, will always remain partial, but my question remained unanswered. I can phrase it another way: Are we learning more about particles or more about measurement? 

 

If you follow the link above, you’ll see further links to what we might call (awkwardly, I admit) sub-subjects, and the one that caught my eye asked, “Does colour exist when no one is watching?” Unfortunately, the diagrams that might have answered that question (did they?) were accompanied by text in Swedish. I was reminded, though, of conversations with my beloved husband, the Artist affirming to me more than once that color exists only in the presence of light – as what philosophers call a “secondary quality,” something partly in the object and partly in our own perception. I always asked, though I knew the answer, if I couldn't turn the lights on very fast! and catch color waking up.

 

I will never be a quantum physicist.

 

Physicists and physicians, engineers and programmers need information for their work, but an author writing historical fiction also reads for information related to her work, though the work is very different in kind. She is recreating a whole world, not exploring the world of today. And writers of speculative fiction (science fiction, fantasy, dystopic narratives, etc.) create imaginary worlds, but they also need to be grounded in whatever natural, physical, and social sciences give plausibility to their imagined worlds. Presumably, those scientists and novelists are doing work they live and so find pleasure in the reading they do for information. 

Others of us are just plain curious. I read history and economics not professionally but because I crave understanding. Why are things the way they are? How did they get to be the way they are? My larger point – one of them, at least – is that reading for pleasure does not have to be only easy reading, and by no means does reading pleasure have to be limited to fiction. 

 

Here, for example, is part of a preface to a book on geology:

 

This work attempts to hold a position between textbooks and books of light reading. The formal textbook would not suit the class of readers addressed. The style of light reading would have been unworthy of the theme, and would not have supplied the substantial information here intended….

 

The method of treatment is simple. The reader begins with the familiar objects at his very door. His observations are extended to the field, the lake, the torrent, the valley, and the mountain. They widen over the continent until all the striking phenomena of the surface have been surveyed. Occasionally, trains of reasoning suggested by the facts are followed out until the outlines of geological theories emerge. The course of observation and reasoning then penetrates beneath the surface … striking fossils … nebular theory … retrospect and reflection … a relish may be stimulated ….

 

-      Alexander Winchell, Walks and Talks in the Geological Field (1886)

 

Only a few days before this book came into my hands, a geology student from Grand Rapids had visited my bookstore and found a few useful textbooks on her subject. What I wished I’d had for her, though, were some of the books on geology that, for me, stimulate relish and speak directly to the fascination so many of us find in rocks and landforms:

 

Bass, Rick. Oil Notes (1995)

Leveson, David. A Sense of the Earth (1971)

Pettijohn, F. J. Memoirs of an Unrepentant Field Geologist (1987)

 

I’ll add to that –

 

Lopez, Barry. Home Ground: A Guide to the American Landscape (2006)

 

All these books deal with material all too often presented in dry textbook style for people originally drawn to the subject, drawn outdoors, and drawn to pick up rocks and climb mountains by beauty and mystery, while these books are definitely to be read for and with pleasure.

David Grath in Texas Canyon

Note: This post could be taken as an extension of the previous post on reading subjectively. So, not a critic and not a quantum physicist!

Lake Dunes in the Desert

View across playa toward Dragoon Mountains from Hwy 186

Playa is Spanish for beach and also the term geologists use for dry lakes, such as the Willcox Playa, called Lake Cochise when referred to in its Pleistocene incarnation.  But the playa in Cochise County is not always dry. In fact, owing to a wet summer and fall, this past winter the so-called “dry lake” held more water than we ever saw in it before — bearing in mind, of course, that our personal memories here are only five years long. Right from the start, though, even bone dry, the playa exerted a fascination for us, as vast empty spaces tend to do. 

Our first year, on every trip to town, we would gaze out over that apparent void and speculate on its prehistory, straining our eyes to determine if we were seeing water or a mirage over on the far shore. The playa seemed so near and yet very far away -- and, always, utterly mysterious. 

Public access off Kansas Settlement Road

Now we learn that the section of the Sulphur Springs Valley in Cochise County (the northern end of the valley is in Graham County, its southern reaches in Mexico) has two drainage basins, Willcox in the north and Whitewater in the south, and that the heart of the Willcox drainage is the playa. Furthermore, the Willcox is a closed system, an endorheic basin, which means that water draining from the mountains down to the playa does not join ever-larger streams and rivers and make its way the ocean. Water may (and often does) evaporate or soak into the ground before ever reaching the playa, but it isn’t going anywhere else, and this kind of “unintegrated interior drainage” (Gilluly, Waters & Woodford, 1959) is typical of deserts.

View from 191 overpass, looking across corner of playa toward Willcox

Just as today’s Lake Michigan was once the much larger Lake Nipissing, what is now a playa was also once much more. An Arizona Heritage Waters website, hosted by Northern Arizona University, puts it like this: 

About 15,000 years ago in Willcox Playa, Lake Cochise reached a maximum depth of 46 feet and covered 140 square miles, maintained by the relatively cool, moist Pleistocene climate. Currently, with a mean annual rainfall of 18.5 inches per year and a mean annual temperature of 90℉, the modern playa can support only shallow, ephemeral ponds that form after heavy rains or snows. The most recent high lake level occurred about 9,000 years ago.

For more, see here. 

“It’s temporary!” Cher’s character screams at her father, when he objects that the “engagement” ring she shows him is a pinky ring. “Everything is temporary!” he memorably retorts. Ah, yes. Even mountains fail to pass the test of eternity. Ephemerality, as concept and reality, is an essential component of time, without which the world would be frozen and static.

We will not always be here. We are barely insects caught and stopped all too soon by the windshield of time, but my mantra is “We’re here now!” and so, while here, I am endlessly (note the contradiction) fascinated by what my Michigan eyes see as dunes on the Dos Cabezas Mountains side of Highway 186, miles from the extant playa in the opposite direction. 

This area reminds me of Lake Michigan sand dunes. Even the vegetation along the road looks somewhat similar — with alkalai sacaton here in place of Michigan’s marram grass — but mountainward, or “inland,” as I can’t help thinking of the land even farther from the playa, the look of the land and its vegetation is nothing like the Great Lakes region of the northern Midwest.

Farther inland and into what appear as dunes, mesquite dominates, as it does on the rangeland around Dos Cabezas. In both places occasional mesquite trees reach impressive size and stand out from their shrubbier fellows. The commonest cactus in Cochise County, cholla, is ubiquitous here, too, with foot-high cholla common and taller individuals commanding recognition. 

So it really has very little in common with the Great Lakes; however, these “duney bits,” as I can’t help calling them, continue to fascinate my mind, pulling me to them like some prehistoric, displaced mirage.

Sarah likes it, too. Of course, she likes to be wherever we are.

Of Rocks and Time and Little Knowledge

It is hardly an accident that the city of Tucson, Arizona, is home to the largest gem and mineral show in the world. The West in general is a geologist’s dream. Everywhere, earth’s bones confront the eye or lie hidden a mere scratch below the thin, poor soil. But don’t ask me much about such matters, because the little I know of Arizona’s plant and animal life is a wealth of knowledge when set against my geologic ignorance. 

There are simple, basic divisions — sedimentary, igneous, metamorphic — and the at-least-theoretical “rock cycle,” hardly as obvious or observable or dependable as the hydrologic cycle but providing an intellectual template for making some sense of stretches of time otherwise boggling to the human mind, eternities in which humans appear a few seconds before midnight on the clock of All Time. So while I read about plates and faults, veins and dikes, when I look up from my books to the mountains themselves I feel as awed by them as Moses must have been when spoken to by the burning bush. Except that the mountains are silent and still.

Rockhounds focus on smaller, transportable pieces of the mystery, on miniatures, rocks and stones rather than whole mountains, but even these small, mysterious bits baffle me. Gordon S. Fay suggests the following minimal equipment: magnifying glass, knife, penny (copper), file, small piece of quartz, small piece of unglazed porcelain, and small bottle of hydrochloric acid (The Rockhound’s Manual, 1972). Well, I have the penny! Then there are hammers and chisels, goggles and gloves, picks, rakes, shovels, and screens. Too much! I am never going to become even a rockhound, let alone a geologist.

I do, however, enjoy casual reading about geology and, to a lesser extent, about rocks, and am occasionally driven to reference books on my shelves when a different-looking rock presents itself to me out in “the field,” as it were, i.e., in my case this winter, the dusty high desert and washes outside our cabin door. Quartz is everywhere, and I hear again the words of a young geologist who remarked drily that amateurs pick up “pretty” rocks, while geologists use more demanding criteria. Well, I appreciate the “interesting” as well as the “pretty” but have nothing like the discerning eye of a geologist. 

To identify a rock, geologic engineer Fay writes, one must study its “mineral habit” and the form of its crystal (latter most often invisible to the naked eye). The phrase “mineral habit” is charming, is it not? I think right away of plants. A plant may be upright or branching or creeping or dwarf or whatever, and those adjectives describe the particular plant’s habit. Similarly, the habit of a mineral applies to its typical form.

If a particular mineral is found to occur time after time in the form of, say, a radiating cluster of needle-like crystals, we say that this is the habit of this particular mineral. If another mineral typically occurs as a kidney-shaped mass, this is the habit of that particular mineral. Thus we have mineral habit, an extremely important aid in the identification of many minerals, especially when the crystal system of a specimen found in the field cannot be determined by inspection. 

“Mineral habit” is a nice general concept, the kind of thing that should stick in my mind when whatever specifics I briefly encounter have fallen away.

Not aspiring even to amateur standing, though, I come in from my desert walk, newly found tiny rock in hand, and reach first for the National Audubon Society Field Guide to North American Rocks and Minerals because, like Audubon field guides for birds or wildflowers, this one presents photographed specimens organized by color. Is it possible I have found a bit of turquoise? Wouldn’t that be exciting? Turquoise, the Audubon tells me, 

…can be distinguished from variscite only on the basis of blowpipe tests; chrysocolla is softer. 

Okay, thanks for that variscite tip, but I won’t be doing any blowpipe tests! How about chrysocolla? A minor ore of copper, it has been found all over Cochise County, I learn, and it was chiefly copper that was mined here in Dos Cabezas back during the town’s short-lived glory days. Fay confirms, “found in copper deposits,” and gives me a test I can try with no equipment whatsoever: 

Chrysocolla usually sticks to the tongue, and this is perhaps its best known distinguishing characteristic.

How sticky counts as sticky? All I can do is try another rock and compare the two.... Okay, yes, I’d say that, compared to something else, this small blue rock does seem to stick to the tongue. And I like that kind of test -- so much less destructive to a sample than dropping chemicals on it or hitting it with a hammer to watch it shatter and fly apart. 

When attempting to identify a tree or bird or wildflower, something common to the area is much more likely than a rare bird. I would have liked my little find to have been turquoise, but here in the copper-bearing mountains of Cochise County, I’m going to bet that a blue rock that sticks to my tongue, however lightly, is chrysocolla. And since I’ve never even heard of such a rock before today, it’s been a memorable occasion for learning, just as common, weedy little corydalis, blooming now in the wash, was an exciting for me five years ago. I’m satisfied. Once again, my books have helped.

Online searches reveal other ideas. Here, for instance, I learn that chrysocolla is a "supportive goddess energy stone" that will aid me in finding the "right words to speak to aid emotional healing in others." Who would have imagined so much power in such a tiny stone picked up at random in the dusty desert?

Just Out the Door and Down the Road

This morning’s sky confirmed the forecast I’ve been seeing on my phone for several days: we’re in for a rainy day — and that’s not bad. A day of rain now and then damps down the risk of fire, a good thing in the high desert. The prediction for the next nine days following today’s rain is for mostly sun with a few clouds. Today we're in for an all-day soaker. Fine.

We made an afternoon expedition on Saturday to the spectacularly beautiful Chiricahua National Monument, where crowds I expected to see on a holiday weekend were largely absent. Absent also (and this was a real blessing) was the strong, cold wind we normally encounter up on Massai Point. Although the air temperature kept dropping as we wound our way to the 6,870-ft. peak, and we saw increasingly larger patches of snow along the narrow, winding road, sunshine was absolutely glaring when we reached the high end of the road, and on a strategically placed bench, looking out over the astonishing hoodoos, across the 40-square-mile playa and surrounding Sulphur Springs Valley to the Dragoon Mountains seventy miles to the west, we were out of even the slightest breeze and content to soak up sun to our hearts’ content.

After five years, I’m finally getting some light grip on the geology of Cochise County, Arizona, and the sky islands of this basin-and-range country. At least, I think I am, but don’t quiz me. Instead, correct me if you think I’ve gone astray. 

To understand the formation of the Chiricahua range, we have to go back twenty-seven million years and the movement of tectonic plates those 27,000,000 years ago, when the molten core of the earth was much more active and closer to the surface than it is in Arizona today. Back then a dense oceanic plate of basalt was overridden by a lighter plate of granite (the North American plate, moving west in true though still prehistoric North American fashion), and as the resulting collision (friction?) increased both rock and water temperature, the former melted as it mixed with the already molten mantle. 

Just south of the Monument (which in itself occupies only a portion of the entire Chiricahua range) are the remains of what is known as the Turkey Creek Caldera. There a magma chamber broke through the earth’s crust and spewed burning gas, ash, and lava over 1,200 square miles in an explosion estimated to be five to ten times larger than the historic Krakatoa eruption in 1883. 

Turkey Creek is so calm and quiet today that it’s almost impossible to picture the nuée ardente — scorching rain! — that flew upward from the prehistoric volcano and flowed outward at over 100 miles an hour as a burning avalanche! In time, of course, the magma cooled and hardened, forming a rhyolite bedrock over eight hundred feet thick. And that and similar eruptions were the birth of the Chiricahua mountains.

But basin and range land is not created by volcanos alone. Once the dramatic volcanic events are over and plate movement slows down, everything gradually cools, and it is then that the cooling masses of rock, slowly but irresistibly, shove against each other, faulting, tilting, and lifting some segments up, while the surrounding basins sink. The creation of Arizona’s sky islands, then — these fault-block mountain ranges that rise up from a nearly level sea (though 4,000+ feet above sea level) of grassland and desert — was very unlike that of the folded Appalachians with their more gradual slopes. 

Nor, however, is faulting, tilting, and rising the end of the story, because subsequently comes the much slower action of weathering. Wind and water (in liquid and solid form) take starring roles in the weathering story but achieve their dramatic effects at very undramatic speed.

Formed by case hardening caused by the amorphous silica left behind after precipitated water evaporates off the surface of the rock formations, pinnacles in Chiricahua National Monument were formed by the freezing and thawing of water during the last ice age approximately ten thousand years ago. 

- William Ascarza, Chiricahua Mountains: History and Nature

Sculpted rhyolite makes for stunning scenes in Chiricahua, where jointed columns of rock invite “the entry of water, instigating chemical and physical weathering.”

Less spectacular but as much a part of the geologic story as the hoodoos are “solution pans” and “slot canyons,” the latter “forty times deeper than they are wide” (Ibid.).

We do not always think about it when admiring mountain hoodoos and the other rock formations we find so amazing, but weathering is a relentlessly ongoing process, continuing in our own age, day by day. Saturday there were pockets of snow in the mountains. As sun reached some of them, that snow melted, and meltwater sought out cracks through which it could descend to creeks and rills headed for the playa. Perhaps that ultimate destination would not be reached, but water would push its way along as far as possible, carrying with it occasional small bits of rock and stone. 

And on the other side of the mountain from where we found our sheltered bench, wind was doing the work it does night and day.

Because of weathering, all the sky island peaks have been worn down from their original height, and the valleys — recipients of eroded mountain material — have gained in elevation. Today’s rain is a geologic drop in the bucket, but each raindrop, each snowflake, contributes to the cumulative effect.

The Artist and I never view Chiricahua with jaded eyes. Every visit feels like the first time, so unusual and fascinating and mentally challenging are the sights. For me, though, the presence of tall, green trees is almost as exciting as the rock formations. Down in our winter ghost town we have only mesquite and netleaf hackberry, whereas in Chiricahua there are beautiful alligator juniper, Gambel oaks, Douglas firs, and stately Ponderosa pine. We are so very lucky, we tell each other, to have all this natural beauty practically in our backyard! It doesn’t even have to be a day trip: half a day gets us there, gives us time for a walk and a picnic, and gets us back to our own Dos Cabezas, which are, literally, in our backyard, so that coming back home at the end of the day is never a disappointment.

Back in Michigan, where we live maybe a mile from the glory of Lake Michigan, we don’t see the water from our windows, but neither do we pay lakeshore property tax or worry that rising lake levels will carry off our home. The closest road to the Lake is private, so we have to take a little ride to get to a beach, but it isn’t all that far, and on mornings after stormy, windy nights we can hear the waves from our front door. Thus it is well within our reach, that glory — even closer than it was when we lived in Kalamazoo and I occasionally needed a 100-mile evening round trip so I could walk on the beach to unwind after a day of work at a job I did not love.

I was lucky even in my girlhood, when the house my parents bought for our move from South Dakota to Illinois was on the last street of a subdivision, out beyond the city limits, with a working farm across the road to the west. How hungrily and greedily and gratefully, too, I watched thunderstorms and sunsets in that open expanse from our enclosed front porch! 

South Dakota, Illinois, Michigan, Arizona. Fields, lakes, desert, mountains. Just outside the door or maybe a little way down the road, open spaces and natural beauty have always helped me breathe deeply and filled me with peace.

Sources: 

1. Ascarzs, William. Chiricahua Mountains: History and Nature (Charleston, SC: Natural History Press, 2014)

2. Gilluly, James; A. C. Waters; & A. O. Woodford. Principles of Geology, 2nd ed. (San Francisco: W. H. Freeman & Co., 1959).