Posts Tagged ‘Sandstone’

Exhilaration & Loathing

Tuesday, April 17th, 2012

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  Organic. That’s the word I gravitate towards when I think of the landscape of southern Utah. A myriad of canyons, incised into bands of vermilion, mauve, ivory, ochre and chocolate — rocks from the depths of time in living color.

  It’s a fractal place, if there ever was one. Big gorges branch into smaller gorges. They, in turn, divide into even smaller canyons, subdividing and subdividing, right down to the seemingly microscopic level. Life forms of all sizes cling to those tributaries, however big or small, as those very furrows are the arteries of water, the lifeblood of this high desert plateau. The panorama is rumpled, folded, and convoluted like some kind of living tissue, like a dissected brain of gigantic proportion.

  Just recently, I drove north along one such magnificent artery: White Canyon. There the road skims over surrealistically-shaped Permian sandstone ledges, and I was just beginning a long awaited August vacation. I looked from my speeding vehicle down into the winding chasm I was paralleling, hoping to catch sight of some ancient Anasazi ruin, that (of course) no one had ever noticed before.

  That highway, which runs between the “middle-of-nowhere” towns of Blanding and Hanksville, is among the most inspiring drives I have ever seen. That I could spot some prehistoric cliff structure was not impossible. There are plenty in those canyons. There used to be a lot more.

  I crossed several bridges, looking down into overgrown streams below. Even there, the rich smell of murky stream water in the hot sun reminded me of the life-giving power barely flowing beneath the steel girders. A cobalt sky overhead only accented the scene. Now the road wound up and up, away from the water, through immense vertical cuts in the rock strata, blasted and carved away to oblige the road — as if to enforce upon us all the fact that humans can do anything once they put their minds to it.

  High above the Colorado River, the biggest artery in the plateau, is one of the most expansive viewpoints anywhere. I got out of my car, as I always do at that spot, ready to bask in the vista for a few moments. I walked over to the edge, and looked down.

  Unprepared for what I saw, I gasped (it was only a short one), and then a big, wide smile started to break across my face. I almost started to jump up and down with delight. There you go, boys. Try water-skiing on that. What goes around, comes around.

  Far below, where wakes from motorboats and “personal watercraft” once crisscrossed Lake Powell, lay mudflats. Miles and miles of mud, baking in the sun. I couldn’t believe it. In all my years of driving back and forth across the American West, I had never seen anything like that. I thought again of that idea of “humans being able to engineer anything”. Now, really?

  Do we really think we can just remake Earth’s surface without consequences?

  There is probably no greater symbol of the defacement of the American West than “Lake” Powell — actually a reservoir. It is formed behind Glen Canyon Dam, the concrete wall that stands further downstream in the way of the once relentless Colorado.

  And there is probably no greater insult to a true nineteenth-century American legend, the first explorer of Glen Canyon, than to have his name affixed to what he surely would abhor. John Wesley Powell must be rolling over in his grave, smiling, too, at the cubic miles of mud and silt accumulating in Glen Canyon, and he would probably say to us now, “I told you so”. At least he got to see its splendor. So the symbol is not a mark of progress, after all. It is a symbol of hubris, indeed, even death.

  In my picture, you can see what looks like a long, sloping runway above the mudflats, below the cliff. That is the huge boat launching ramp of the now-closed Hite Marina. Or was the ramp, I should say. The reservoir is almost 100 feet below “full pool”, and therefore lies hundreds of feet from the bottom of that ramp.

  A result of drought in the West, this situation will almost certainly get worse, for the foreseeable future anyway. Combine that with the fact that when you block a river as muddy as the Colorado, lots of silt drops out of suspension, and it starts to build up. All of that grayish sludge you can see now is covering a lost world.

  These realities will render Glen Canyon Dam useless — for either storing water, or for generating electric power. Somehow, people just don’t get it — how fast it is happening here. Those motivated by politics would have us all believe that dismantling the dam is some wacko idea, selfishly promoted by those awful environmentalists. That the aforementioned are so skilled at calculated nuance and misinformation does little to dismiss the facts.

  The Colorado River averages a sediment load of about 100 million tons a year. That’s about 30,000 dump truck loads every day. And as of the time of this writing, the reservoir is dropping about one foot every nine days! The drying-up of the reservoir, coupled with the filling-in by silt, means that it is losing on both fronts: from the top down, and from the bottom up. If you don’t believe me, drive there and look for yourself.

  Beneath that mud and what’s left of the water, are countless archaeological ruins, and the remains of the most intricately beautiful canyon on Earth. By most estimates, present climatic conditions will actually worsen, causing an increase in the rate of the water level’s decline.

  Eventually, the silt accumulation will start to block the dam’s outtake portals, making operation of the power generators unsafe. And by then, even more irreplaceable canyon beauty will be lost to the muck.

  In recent publications, I have written about the modification of Earth’s geology by humans, and how it can be either good or bad. This modification (Glen Canyon Reservoir began filling in 1963), will go down as one of the most calamitous and short-sighted ever.

  If for no other reason, Glen Canyon Dam should be demolished, and what’s left of its reservoir drained, as an admission of our arrogance and conceit in living with nature. Let life return to the landscape.

  If we had real vision, and cared at all about people yet to come into this world, we would leave them something of magnificence and meaning, not the entrenched wasteland that is inevitable under current policy.

A Hard Place

Saturday, March 17th, 2012

These ancient ruins cling to resistant vertical cliffs, either avoiding something, or in hope of something.

  You’ve all heard it before. You know, the line about how tough things are, the line about an impossible situation, about being “between a rock and a hard place”.

  It was a warm spring day, and I had just about had it with the climb up a steep, brushy, wooded slope, if you want to call it that. It was more like a tangled obstacle course, except that it seemed nearly vertical, and the loose soil beneath my feet made getting up through it even more frustrating, as it was two steps forward, slide back one.

  Annoying little bugs swarmed around my face and ears, but they kept me company and gave me something to yell at. They were the only creatures, I’m sure, that would have thought my sweat- soaked shirt and hat smelled nice. I was beginning to wonder if it was worth it, if all this work made any sense. It would be easier to turn around, and go back to the car, now miles down the deep canyon. My heart was pounding. I was trying to find some ruins.

  I was well into the rugged Sierra Ancha (in Spanish, “wide mountains”), about 75 miles northeast of Phoenix. This remote range is one of the least explored archaeological areas in Arizona, and it is not hard to understand why. Deeply-incised canyons cut through massive layers of rock, and these in turn are coated with all kinds of thick vegetation – tall pine woods at the summit, right on down to the cactus-strewn canyon floors.

  Rattlesnakes abound, and who knows what other dangers, too – maybe the emotional ghosts of those who lived here and built my goal about 700 years ago. Whatever caused people to live in such a place must have been an intensely emotional thing, and I imagine that that emotion was fear.

  And then I saw them. Right above me was one of the most spectacular sets of cliff-dwellings I had ever seen, there literally clinging to the massive rock cliffs above. They looked like they had just grown there, right out of the stone. My mind flashed on the connection between life and rocks, and here was another example. Only here it was humans that grew this place in the rocks, and I knew there were more such spots around that area, too. The rocks offered protection.

  The Sierra Ancha are so rough and craggy because most of the rock there is very hard and tough, and consequently very resistant to erosion. In the area of these Anchan Culture cliff-dwellings, quartzite and limestone are the order of the day.

Massive quartzite in the Sierra Ancha.

  Quartzite is a metamorphic rock, meaning that the original stone has been changed by heat and pressure, in this case altering an old sandstone formation (left-over beach sands, possibly) into a much more durable rock unit.

  Limestone is a rock, also very unyielding, precipitated out of oceanic waters, and forms vertical cliffs in a lot of places where it occurs.

  Both of these rocks point to a time when this part of what we now call Arizona lay along the shores of ancient seas lying to the west and south. It was not North America then, and what we now see as our landscape would then have been around a billion years into the future.

  These rocks are collectively known to geologists as the Apache Group. Higher up in their section, you can also see layers of dark basalt, a volcanic rock that erupted way back then in various places, as the old setting went through some convulsive times.

  Equivalent rock formations are found in and below the bottom of the Grand Canyon, and there they are approximately 5000 feet lower in elevation than they are here, there near the Colorado River itself. Therefore, the rocks above that point, most all of those colorful layers now seen in the walls of the Grand Canyon, were once on top of the Sierra Ancha as well.

  Because of massive uplift of the region, the younger rocks are now gone, and the innards are exposed.

  You can see these same rocks when you wind your way up State Route 288 (also known as the Young Road) from the valley floor, near the Salt River and Roosevelt Lake, to the upper reaches of the Sierra Ancha, near Aztec Peak, on the way to the small town of Young. In this stretch, you are going up through time.

The Sierra Ancha, along the left skyline, appear deceptively gentle. Roosevelt Lake is in the foreground.

  My distress at the sweaty work-out turned to delight; my desperation turned to awe. Tough places, tough rocks, I mused. The Apache Group is still there because it is so hard to get at, and in turn, the dwellings of the ancients remain tucked within its depths, mostly untouched, for the same reason.

  That the inhabitants of these ruins chose to live, and die, between the difficulties of the nearly impassible terrain below and the sheer walls of stone, demonstrates the incredibly fine line of life to which they clung, and the tenacity of nature itself.

LandMark

Monday, November 14th, 2011

Camelback Mountain, in Phoenix, Arizona.

  Ask yourself which natural rock formation has come to symbolize Phoenix? Which one actually represents our city?

  Most people would say Camelback Mountain. Everyone here knows Camelback. Tourists from afar know of Camelback. And even those who have never been to Phoenix have somewhere heard that name, or read it.

  Rising almost out of the middle of the metropolitan area, it gives personality to our city. Like an actor who works best when able to “play off” of a certain other character, Phoenix has that statuesque mountain. More than just a prop, it is, many would say, the centerpiece of our stage in the world.

  If you are new to the Valley, or have just never noticed, when viewed from the south, the mountain’s profile does bear a resemblance to a reclining camel. You can see the head and neck on the west end, and the higher “hump” of the camel is the eastern part of the peak.

  Now since we are in the American Southwest, a camel would seem to be a figure unlikely envisioned in anything local. But there were camels in Arizona in the 1850’s—they were imported by the US Army, and used briefly for transport. That experiment didn’t work out very well, but since a camel’s association with the desert is almost a primeval thing, a sort of camel’s “essence” remains here.

  Few other cities in the world have such prominent, singular, natural monuments within easy reach. Rio de Janeiro, with its Sugarloaf, is one contender; or Capetown, South Africa, with its captivating Table Mountain. The Rock of Gibraltar certainly comes to mind, but it sits at the gate of the Mediterranean Sea, and is not really in a large city. And Ayers Rock, Australia? Well, it’s out in the middle of nowhere.

  Identity is a key factor in one’s psyche, and identification with landscape goes way back to when humans were just figuring out the world. For ancient Native Americans, the association with landscape was a given—for most of us in the modern-day world it is just a distant memory. But it is lodged deep in our minds somewhere, and without it we might as well live in underground bunkers, or windowless, modular structures without end.

  I feel sorry for space-station colonizers of the future, for they will never know the wonder of gazing up at a big, beautiful rock that can be seen for miles and miles, knowing that it is right in their own backyard, and that they can walk right on up it if they like.

  Although many don’t know it as such, Camelback Mountain is just one of the peaks in what are called the Phoenix Mountains. They cut our city roughly in half, and run from Moon Hill, on the northwest end (near I-17), to Camelback itself on the southeast end. North Mountain, Shaw Butte, Squaw Peak, and Mummy Mountain are some of the other well known prominences in the series.

  The whole group is what is known as a fault-block range. The Valley of the Sun owes most of its general appearance to a particular episode of geologic activity called the Basin and Range Disturbance, which ran from around 15 million years to about 8 million years ago.

  That span of time is a very recent part of Earth’s history, and so our setting is really one of geologic youth. The rocks which make up many of the mountains and features around us are very, very old, but they have just been recycled into the shapes we see now, that’s all.

  During that episode, the crust of our planet here stretched out and broke into pieces which run for miles and miles in more or less parallel orientations. With that activity, and because of gravity, some of those slabs started to settle down, alternating in a fashion with blocks left standing in between— the Phoenix Mountains are one such block. Millions of years of erosion then sculpted that high ground into the picturesque shapes we see now, one of which looks like a very tired camel.

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  The Valley’s “look” is very much due to “fault-block” mountains, like the Phoenix Mountains. The McDowell Mountains and the Sierra Estrella are also such ranges. But, there is another significant piece of the story of our setting, though, and that has to do with why our Valley floors appear to be so flat. In this case, I will also use Camelback Mountain to illustrate the point.

Camelback Mountain, from the summit of Squaw Peak, in Phoenix, AZ.

  The second picture here was taken from the near the summit of Squaw Peak, looking to the southeast. In it, Camelback Mountain has a shape very different from that in the first photo, where the “reclining camel” can be seen. In the forefront of this image is a ridge of the ancient metamorphic rocks of the Phoenix Mountains, on Squaw Peak.

  But behind it, you can see a small, level valley filled with the growth of civilization—a patchwork of cross streets lined with houses, buildings, landscaping, light poles and wires, and other signatures of humanity. On a mammoth scale, it looks here so much how like a colony of mold might appear in an old, forgotten bowl of Jell-O still open in your refrigerator, a dish with an uneaten piece of fruit left sticking out of the dessert’s firm surface. The mold relentlessly multiplies against the chunk’s base, ever struggling to breed its way up the sides of the lump.

  Similarly, Camelback rises out of that swale—its profile now a rugged, majestic pyramid— accenting the flatness all around it. The vast Sonoran Desert stretches out in back, for many, many miles.

  This view of Camelback Mountain alone, in my mind, makes the “workout” trek up Squaw Peak worth it. Just drive to the Phoenix Mountains Preserve, north of Lincoln Drive, park in the massive parking lot, and start up. For most, it will be slow going, but you will have lots of company. I have read that this hiking route is the busiest trail in North America, and it will indeed seem that way as you make your way up and down along with hundreds of other people, some young, some old; a few running, most walking, taking in the view.

  So why then, given that Earth’s crust is so broken up by the faults that delineated the Phoenix Mountains, is the surrounding landscape so flat? Shouldn’t we see a wilderness of canyons and gorges, and not the gentle valley floor that so readily harbors life and our comfortable, enviable world of greenery and strip malls?

  It’s that old, never ending story of “what is up, must come down”. Over the past ten or fifteen million years that our friend Camelback has been looming above the down-dropped blocks of rock once attached to its flanks, its slopes have also been eroding on a less exaggerated scale—a little bit here, a little bit there, day by day.

  All that sand, gravel, and clay has had to go somewhere, and where it ended up is simply down-slope in the deep basins surrounding Camelback Mountain, the Phoenix Mountains, and all the other ranges in our scenic part of the world.

  Over those millions of years, all of that eroded material—which geologists loosely call alluvium—has accumulated greatly in the Valley of the Sun and many other valleys of southern Arizona. Between all of the mountain ranges around here are deep, deep trenches. The actual bedrock surfaces of many of these basins are way below sea level, and many are thousands of feet below the surrounding landscape.

  That is why the land, out of which rises Camelback Mountain and the other peaks of the Phoenix area, is so flat. It is like a calm ocean of sand and gravel, barely rippling against the ranges, not revealing what lies beneath. What we see above it are simply the very tips of the mountains, in the same way that icebergs only show a small part of their true mass above the water’s surface, belying the real nature of what is unseen.

  In the case of our Camelback, it looks in my picture like it is separated from the rest of the Phoenix Mountains by the flat area, but “below the deck”, it is not. Down there, and here not too far down, underneath those houses, roadways, and trees, is the bedrock that connects all of the Phoenix Range together. Off to its south, and to its north, the fill material is much, much deeper.

  Thankfully, there is lots and lots of that alluvial fill, and those filled-in basins are wide and voluminous, for they hold vast amounts of groundwater—enough to keep that “growth” of civilization going for decades to come.

*******

  There is yet one more part of Camelback’s story—one missed by even the many hundreds of hikers who ascend its slopes daily: that of its role as an ancient sacred spot, where for centuries humans came to connect with their surroundings, or perhaps disconnect from them.

The Grotto in Camelback Mountain.

  Tucked low into the northern side of the rugged and strangely-shaped rocks of its western end, is a large cavity—a shady, cool cave that looks like it might have been designed as a band shell—a prehistoric amphitheater which even way back then was recognized as prime real estate.

  From inside it, the view to the north expands to include the Phoenix Mountains and Squaw Peak. Yet, there is a sense of enclosure, security, and especially of harmony. It’s not just because you are mostly surrounded by solid rock, offering safe haven from any attacker that might want to sneak up on you. No, it’s the feel of the setting that you notice. It feels rejuvenating.

  Many people are under the impression that primitive peoples thought of caves like this one simply as shelter. I would argue the opposite. The Hohokam people who lived in our valley up until around 1450 CE (current era) didn’t need shelter. They already had well-developed pueblos all over the area, as well as vast farm fields, extensive trade routes, and an elaborate culture. Indeed, they had other uses for such special places—what some would call magical places.

  The Camelback Grotto is one such spot. While standing in it, with the rocky, orange-brown, half-dome shaped ceiling some forty or fifty feet overhead, I couldn’t help but notice a close ridge of similar reddish sandstone and conglomerate a hundred yards or so out in front of the opening.

  The more distant mountains are off to the left—the ridge itself interrupts that background range as a natural sculpture of rounded and cave-riddled rock that looks organic, like a growth blooming up from the flat valley floor just below. That arrangement of rock not only adds to the feeling of the place—it is integral to it.

  The Grotto in the rocks of Camelback Mountain was formed by weathering and erosion. Those relatively soft sedimentary layers on Camelback’s west end have all been shaped by the same processes that also formed the scenic redrock buttes in nearby Papago Park, and in fact, they are part of the same geological formation.

  (The first photograph above was taken from the Papago Park area, near McDowell Road, looking north towards Camelback Mountain. The red rocks and buttes of Papago Park also stick out of the Valley’s alluvial fill—only they are lower in elevation and therefore less imposing. When such smaller formations poke up through the surrounding alluvium, they are called inselbergs.)

  It is possible that some of the opening’s shape has been modified by humans, but if so, not in noticeable fashion. As elsewhere on the mountain, the conglomerate unit contains small to massive chunks of much older, angular granite—evidence that these rocks resulted from very violent forces some twentyfive or thirty million years ago. It is serendipitous that such chaotic stone has evolved into the serene site it is.

  Why above do I say “connect”? Because that means changing a state-of-mind. Why do I say “disconnect”? Same thing: that means changing state-of-mind. It’s the change of mind that counts. The alteration of state-of-mind creates a sense of just being there, being absorbed in the present.

  Ancient Indian peoples looked at the landscape as part of their being, not just as something to utilize economically. It was not outside of them—it was part of them. Landscape exerted force on their daily lives, and influenced them in ways most of us just do not get or understand. Some places had the ability to amplify or modify those forces and influences, and the Grotto is one of those sites.

  The Camelback Mountain Grotto has been known to Phoenicians since around the time our city was established. People then visiting the cavern found and noted artifacts such as decorated, short, cane reeds. There were also lumps of salt, shell beads, small bones, arrowheads, and skyblue turquoise.

  But the reeds were particularly intriguing. They appear to have been ceremonial or ritual objects containing plant material, and were embellished with inked-in figures or marks. Wrapped around the outside of many of them was cloth fabric, and they were often found in bundles of four. Incense? Cigarettes? Who knows? Besides being a spiritual setting, maybe the Grotto was a party place, too.

  More than just a landmark, Camelback Mountain has been a special place for at least a thousand years.

  We are fortunate that it still is.
 

What’s the Angle?

Wednesday, June 15th, 2011

Tilted rocks in Papago Park, in Phoenix, Arizona.

  Weirdly-shaped rocks. I’ve heard that phrase over and over again, mostly from tourists. Wondering why the rocks look like they do, those visiting the Valley of the Sun notice them immediately, as those formations are almost right next to the airport where the visitors have just arrived.

  The pinnacles stuck in my mind, too, on my first visit to Phoenix, many years ago. Brightly orange in the setting sunlight, there was something about their curvy, pointed look, all filled with voids and cavities: they seemed like frozen flames rising from the flat desert floor.

  The Papago Buttes, we call them. They are the centerpiece of Papago Park, one of the City’s thoughtfully planned expanses of preservation in what otherwise surely would be yet more endlessly repetitive housing tracts, strip malls, and asphalt checkerboard development.

  What people first notice about the buttes are the caves and the holes in the rock. In geology-speak, those are called “tifoni”. I looked up that word, and it means “typhoons” in Italian. I’m not sure why or how those storms made it into the lexicon of geology, let alone in Italian, but maybe that’s a subject for another day.

  As for the openings themselves, they are caused by differential weathering and breaking-down of the host sandstone and conglomerate (which is a rock composed of different-sized stones and particles, sometimes called “puddingstone”).

  But there is more here of which to speak. The structure of the buttes, or the way in which they connect to the rocks underneath, is one of the more interesting facets of the geology here.

  In other writings, I’ve previously described to you the nature of the rock surface underlying our valley — an amazingly deep, rugged trench in the Earth’s crust. The buttes are just the tips of some craggy peaks that are almost completely buried by the sand, gravel, and salt beds that fill the valley and give its floor such a flat appearance. They poke through the surface in Papago Park just enough to make a great backdrop for the Phoenix Zoo, and the Desert Botanical Garden.

  Drive along Galvin Parkway near the Zoo, or better yet, take a walk around the Hole-in-the-Rock area in Papago Park and look over at the prominent tall butte, just to the northwest. You will notice there, I hope, that the reddish sandstone and conglomerate is layered, and that the layers are slanted steeply to the southwest.

  Recall also, that I told you about the South Mountain Metamorphic Core Complex (I just love that phrase — it’s got such an academically-sounding, yet melodic, ring to it.) in my previous essay, “Name That Tune”.

  I explained there how the broad, arching dome of South Mountain was pushed up from the heated, plastic rock of our planet’s crust around 25 million years ago. Though the rock was hot and soft down deep, it had to push through higher layers that were cool and rigid. Some of those layers are the orange rocks that make up the Papago Buttes.

  Rigid rocks don’t bend, of course. They break. And when they broke, in this case, they had to “get out of the way” of the emerging dome, part of which we see now as South Mountain. In making way for that uprising mass, they couldn’t just simply slide out sideways, as they were confined by other rocks in the same layer, and rocks behind, above, and below those.

  You might be thinking that South Mountain is quite a distance from Papago Park, so why the problem? Geologically, of course, it is not. And at depth, down there below the fill material in the valley, their rocks are physically connected. When the rock layers broke from the pressure below, they could only break up into fragmentary pieces or slabs, looking something like how a deck of playing cards looks when it is unevenly pushed from the side, splaying the cards into a skewed stack.

The Papago Buttes, with Camelback Mountain in the background, highlight the Phoenix Zoo's Lake, in this view.

  Now imagine those cards as the rock slabs, first breaking into pieces, then standing up, while tilting back and away from the imposing mass coming up from below. That’s what you see at the Papago Buttes, and in my accompanying picture. The tilt can even be seen at Tempe Butte, next to Sun Devil Stadium, even though that is a different type of rock. All of the rock layers are tilting away from South Mountain.

  Theoretically, other rock layers hidden beneath us also tilt away from South Mountain, making it the center of a giant bullseye, of sorts. Those inclined layers strangely reveal one more chapter of the ongoing story written in the rocks all around us.