Thursday, June 27, 2013

Yeah, I'm Still Here (and there, and everywhere): SUPER MOON!

Hey world! I'm still here...and there...and it feels like everywhere, and we are having a great time exploring the geology of the Colorado Plateau. This has been one of our cooler trips ever, with spring-like temperatures (and windstorms), so we are enjoying it as much as possible. Since the last post, we've been to Grand Canyon, Cedar Mesa, Mesa Verde, Arches, Canyonlands, Capitol Reef and lots of other wonders. We are actually just two more days from being home.

I know the SUPER MOON was overblown, as usual, but a full moon rising at Arches National Park is nothing to sneer at. It was gorgeous, and if you want to see it supermoon style, you just up the zoom on the camera, and voila!

A morning or two later, we could watch the moon setting among the Entrada Sandstone cliffs...
Lots of pictures, lots of adventures in geology to talk about. We'll see you in a few days!

Monday, June 17, 2013

The First Stage of our Journey: Basic Principles

We are into our third day on our journey through the Colorado Plateau, and yesterday we actually reached the plateau. We needed to get out of the Central Valley, cross the Sierra Nevada, and then make what once was a terrifying traverse of the dreaded Mojave Desert. My family recounts the difficulty of driving the Mojave in the immediate aftermath of the Great Depression, with long steep grades on Route 66 that were driven primarily at night for fear of overheating the radiator system of the old Ford. It was of course worse for colonists in covered wagons. To the Paiute people, it was simply home.

For us it was a pleasant drive (for once), as we had cooler weather than normal, and no serious accidents on the highway causing delays. We had the time to explore one of my favorite teaching sites in the region, Rainbow Basin National Conservation Area.

The basin exposes the colorful beds of the Miocene Barstow Formation, and the rocks have a rich record of fossil discoveries, including early species of elephants, horses, camels, bear-dog ancestors, cat ancestors, and even multitudes of insects and arachnids. But best of all, it is a place to learn the basic principles of geology.

We talked about Steno's principles of stratigraphy and cross-cutting relationships, and the students set about telling the sequential story of the outcrop seen above. Can you do it? Can you lay out a sequence of events that tells the story of how this rock came to be the way it is? I'm glad to say the students did pretty well, especially since this exposure is our SLO exercise (student learning outcome).
I'll post again when I get a chance!

Friday, June 14, 2013

On The Road to the Back of Beyond...

 There are places I remember
All my life, though some have changed
Some forever not for better
Some have gone and some remain 

These Lennon/McCartney lyrics hit me every time I set out on the road to the Colorado Plateau, which is both a geologic classroom, and a sort of spiritual center of my Universe. The deceptively barren desert is full of life, and at the same time full of ghosts. Some parts are so familiar to me that I can feel the texture of the sandstone in my imagination, and other places, many places, are yet to be discovered.

Change has happened out on the plateau over the years. Former gravel roads are paved over, cities have grown, others have become smaller. Geological changes are happening too, the ever-present erosion and occasional rock falls, and other more subtle changes brought about by a decade of drought. Is the change permanent? I suspect it is.
The rocks and soil that form the framework on which all life thrives is passive. It has been witness to millions of years of change, and an ever-changing parade of life forms. The trail above was cut out of a separation plane on a sand dune that was trod on by reptiles and insects 200 million years ago. The sand grains were eroded from a mountain mass hundreds of millions of years older. We are brief visitors on this land before our atoms get scattered and recycled.

For the next two weeks I get to play the role of mentor to a group of students who will be seeing this landscape for the first time in their lives. I don't know who will learn more, them or me!

I'll be missing in action for a few weeks, but I will sign in when I can.  Gaelyn, hopefully we'll see you on the 17th or 18th! 

Thursday, June 13, 2013

A Tale of Two Arches, But Not in Arches

Travelers in the southwest might get the idea that arches can only be seen in Arches National Park in Utah. It's true that Arches National Park has the largest concentration of arches in the world, and the world's longest arch is found there, but arches have formed all over the Colorado Plateau. I saw two notable examples last week, and they can be seen in today's post.
Grand Staircase-Escalante National Monument has a rather spectacular version of one in Grosvenor Arch, about eight miles east of Kodachrome Basin State Park. The cliff is composed of Henrieville Sandstone (Jurassic in age), with a capstone of Dakota Sandstone from the Cretaceous Period.
It used to be called Butler Arch, but an expedition from the National Geographic came through the area in 1949, and they pulled strings to rename it after their boss. The biggest of the two arches is about 152 feet high, and 100 feet wide.

We heard an ungodly screeching all around us while at the arch, and it didn't take long to find the noisemaker: a bunch of cicadas. They look like horrifying beasts of Hades, but are essentially harmless.
Driving west from Grosvenor, we passed a nice viewpoint of Wiggler Wash, where the creek cuts through a fold, exposing the Entrada Sandstone and Henrieville Sandstone. The pink cliffs of the Aquarius Plateau can be seen in the far distance.
This was a tale of two arches, but I actually didn't mean the double arch of Grosvenor. The next morning we were at Bryce Canyon National Park, another place where arches form readily. One of them can be seen from a pullout in the southern part of the park. It's called Natural Bridge, but as the signs and irritated geologists will tell you, bridges span creeks, while arches form by other means. But it's pretty neat in any case.

My posting will be very spotty over the next two weeks. I had so much fun on my one week exploration of Grand Canyon, Bryce and Zion that I am headed back out there again, this time with two dozen students. We're making a huge loop through the plateau country, with no wi-fi motels, and rare access of any kind. I might actually have to breath the air, hike around for entertainment, and gaze at stars at night. I'll try to maintain a positive attitude!

Wednesday, June 12, 2013

The Three Stages of Hoodooism....

Some folks make a big miscalculation if they visit Bryce Canyon National Park. They seem to believe that if you've seen one hoodoo, you've seen them all. They may be in a hurry, and thus hit the one famous overlook, like Sunset View, or Inspiration Point, and head out to Ruby's for lunch, and then on to Zion. They miss out. There is a twenty mile long park road that has a dozen or more stops, and once you know what to expect, you can enjoy the sometimes subtle and sometimes obvious differences.
I mean, this is hardly memorable at all, right?

Here's what I am getting at...there are unique sections of the park that reveal differences in the degree of erosion that has eaten away at the edge of the plateau. The Silent City, in the most visited and most photographed part of the park, is a vast expanse of countless hoodoos, and there is no place quite like it in the world. But the formation of which it is made, the Claron Formation, is present over thousands of square miles in southern Utah. Why aren't there dozens of valleys out there just like this one?

It has to do with the degree to which erosion has reached the underlying Cretaceous layers. In the northern stretch of the park, around Fairyland View, headward erosion of the Paria River has only begun to attack the Claron, and essentially only the "tops" of the future hoodoos are sticking out.
Fairyland is colorful and beautiful, but it is mostly lacking in the tall hoodoos that characterize the Silent City in the central part of the park. The incision caused by the occasional flash floods just hasn't cut very far into the freshwater limestones of the Claron Formation. As time goes on, the gullies will become deeper and deeper, and the hoodoos will reach their zenith in height and relief.
In the diagram above, note how the deepest slot canyons have almost reached the underlying Cretaceous sediments. The sediments include weakly consolidated sandstone and siltstone that is easily eroded. Once the contact has been reached, the hoodoos will rapidly disappear. Until then, the scenery is spectacular! The Sunrise, Sunset, Bryce, and Inspiration viewpoints in the central part of Bryce Canyon National Park are truly incredible places to learn about hoodoos. The hikes into the depths of the slot canyons, especially Wall Street, are memorable.
The southernmost part of the park, at Yovimpa and Rainbow Points, represents the last stage in the disappearance of the hoodoos. The Claron Formation only makes up part of the cliff face, and only a few hoodoos are evident.
Most of the hoodoos may be gone from the valleys below, but Rainbow and Yovimpa Points are at the highest point in the park, and the view from each point covers thousands of square miles of plateau country, including the heart of Grand Staircase-Escalante National Monument, and far off in the distance, the Kaibab Plateau and the Grand Canyon. On this recent trip, we could make out the snowy peaks of the Wasatch Front to the north, many miles away.

Bryce Canyon deserves a leisurely exploration. It's not a place to rush through...after all, if you disrespect the petrified beings of the Silent City, you might suffer a "hoodoo curse"!

Monday, June 10, 2013

What Is Your Favorite Volcanic National Park?

So many great choices! Would it be Rainier? Crater Lake? Lassen? Hawaiian Volcanoes? Haleakela? Yellowstone? Zion?

Wait a minute...Zion? Since when does Zion National Park have volcanoes? Since about 125,000 to 1.4 million years ago, actually. The western edge of Zion includes the Hurricane fault zone and a series of associated basalt flows and cinder cones. Firepit Knoll (above) and Spendlove Knoll (below) are two nearly symmetrical cones dating to around 220,000-310,000 years ago.

The park also has an outstanding example of an inverted stream. A flow filled North Creek and erosion removed the surrounding softer rock, leaving the former stream bottom as a prominent ridge.

It's a bit tricky to see, but cliffs drop off both sides of the road, which was built on the surface of the basalt flow. From higher up, the ridge is more obvious (below). The flow emanated from the Firepit/Spendlove Cones.

Where are these features, and how do they get missed by 95% of the park visitors? They can be viewed by following Kolob Terrace Road to Lava Point. The park brochure mentions the road, but I guess there are so many exciting things to see down in the canyon that folks don't set aside enough time to explore this road into the high country. It's both a shame and a blessing.

A blessing because I don't like crowds, but a shame because people are missing out on a very scenic and geologically interesting road. The road climbs 4,000 feet in 21 miles from the village of Virgin to Lava Point, one of the highest points in the national park. On the day we were there last week, the temperature dropped from 104 degrees in the valley to 78 degrees at the lookout. Aspen trees lined the last mile of the drive (most of the road is paved, except for this last bit, but the road is smooth).

The road begins in the Triassic Moenkopi Formation, and quickly ascends the lava flows to exposures of the Jurassic-aged Navajo Sandstone. This is the same unit that forms the spectacular cliffs of Zion Canyon. Without the vertical canyon walls, the Navajo weathers into a bewildering variety of beehives, castles, spires, domes, and whatever else your imagination conjures up.

The road crosses the park boundary several times, and passes through beautiful park-like meadows.

At road's end, we discover why the spot is called Lava Point. Columnar basalts form a cap on the edge of the plateau. At nearly 8,000 feet, the area is covered in a fir and aspen forest.

In a meadow near Blue Springs Reservoir, I caught a horse hanging out with a little friend catching flies on his back.
The cacti were in bloom here and there.
And then there is the view! From this vantage point, we can look into the deep canyons of Zion, and beyond to the Kaibab Plateau and the Grand Staircase. The view also extends to the high plateau country to the north.

There is a small campground set a few hundred yards from the edge of the plateau. There were a few people camping there, and all of six other cars at the viewpoint. It was cool, shady, quiet, and beautiful; a distinct contrast to the normal tourist haunts in Zion Canyon.
Give it a try next time you are in the region. And don't forget the Kolob Fingers, the other outlying, lesser-known part of Zion National Park.

Sunday, June 9, 2013

A Stroll Through the Gateway to the Narrows of the Virgin River

I bet no one has ever thought to take pictures of this place before! Or not. The Gateway to the Narrows trail is only the most popular trail in one of the most visited national parks in the system. I often try to describe places off the beaten path, but sometimes it's fun to catch these popular spots and be reminded why they are so famous in the first place.

Zion National Park is the ultimate exposure of the dramatic Navajo Sandstone, which formed in early Jurassic time as a widespread "sea" of sand dunes extending from Wyoming to Arizona and Nevada. The formation is more than 2,000 feet thick at Zion, where it forms vertical red and white cliffs.

The cliffs have been exposed by the rapid incision of the region by the forks of the Virgin River. Where the river has reached the underlying Kayenta Formation, mass wasting and erosion has caused rapid cliff retreat, forming a wider valley with a flat floor that allows for the development of tourist facilities (the campgrounds and visitor centers and such). Things change at the upper end of the valley where the river is flowing exclusively in the Navajo Sandstone. The canyon is 2,000 feet deep, but in places is only a few feet wide. The Narrows of the Virgin River is a stunningly beautiful place.

At road's end at the Temple of Sinewava, an easy 1 mile paved trail provides access to the narrows. That's where I was the other day.
It is one of the more crowded spots in the park, but the mess is mitigated somewhat by the wise decision of the park service a decade or so ago to ban cars from the upper canyon. Today, the only engine noise comes from a tram every ten minutes or so. The hikers jump out, disperse, and it is quiet again.
When the lower canyon is stewing in the desert heat, the Gateway is cool and shady (no wonder it is popular). Water seems to be everywhere, in the river itself, and dripping out of the canyon walls. The Navajo Sandstone is quite permeable, but the underlying Kayenta Formation is not. Springs are often found at the contact between the two, such as at the "swamp" (our friends on the trip from the southeastern states probably snickered a bit about the name; at least we didn't have to worry about crocodiles...).
The lush greenery attracts plenty of animals, including a national park deer (i.e., they graze right next to the trail and pose for pictures).
 The springs emerging from joints in the rock produce beautiful hanging gardens with flowers of all kinds.
 The columbines are my perennial favorites...
 As the sun climbs higher in the sky, the walls of the canyon are reflected off the Virgin River.
For all the crowds, it is a beautiful and serene place.The paved trail ends at the entrance to the Narrows of the Virgin River. One can don some water shoes and explore upstream for miles. Or take a road to the isolated north end of the park and backpack downstream through the narrows. Or one can just sit somewhere and listen to the river and the birds.

More on Zion in the next post!

Saturday, June 8, 2013

A Dam Big Shame, and Things Lost and Gamed...

A different "Paradise Lost"...

It just doesn't get much better than this, to stand on the brink of a high cliff in the barren desert, and to see a stream of life-giving water in the depths below. Of course, if you are in trouble and dying of thirst, you are pretty well screwed, since the cliffs are pretty much unclimbable! There is a story behind the dramatic appearance of the river in the photo. It not a genuine river anymore, not exactly. It is a blunt instrument, wielded badly.

Glen Canyon Dam was built between 1957-1964 after a contentious environmental battle over whether national parks (Grand Canyon – Bridge Canyon dam) or National Monuments (Echo Park dam-Dinosaur National Monument) should have reservoirs extending into their boundaries. Glen Canyon was at the time protected by neither designation. The dam is 710 feet high (216 m) and 1,560 feet (475 m) wide, with a volume of 5,370,000 cubic yards (4,110,000 cubic meters) of concrete. It is anchored in Navajo Sandstone. When full the lake is 186 miles (299 km) long, with 1,960 miles (3,150 km) of shoreline, and a total capacity of 26.2 million acre feet (equivalent of two years of the average flow of the Colorado River). The lake is a popular national recreational site today, but Glen Canyon was once one of the most beautiful valleys along the Colorado River. Unfortunately, when the dam was completed, only a few hundred people had floated down the river to see the stunning canyon (and therefore explaining my title of things "lost and gamed"; the dam was built here by threatening to put dams elsewhere).

After construction was completed in 1964, the lake slowly filled (since water use downstream did not cease, only surplus water was used to fill the lake) and did not reach capacity until 1980. In 1983, the dam came perilously close to failing due to a major flood and design errors. Instead of using floodgates and spillways at the top of the dam for emergency drainage, designers utilized the diversion tunnels used to channel the Colorado River around the dam site during construction. They proved woefully inadequate to the task in 1983 as cavitation caused the walls of the diversion tunnels to rip out. In places the powerful flow of water cut 32 feet (10 meters) into the soft Navajo Sandstone and threatened the structural integrity of the dam itself. The diversion tunnels had to be shut down, and the lake threatened to flow over the crest of the dam in an uncontrolled fashion. This could have led to catastrophe, as such uncontrolled flow could have eroded and weakened the sandstone abutments of the dam. Failure of Glen Canyon dam would have led to the domino-like destruction of other large dams downstream, and the decimation of the water-supply infrastructure of some thirty million people. The disaster was averted by the construction of an 8 foot high dam of wood flashboards that held back the water long enough for the flood to subside. The structural integrity and survival of the dam came down to about one inch...the distance between the water level and the top of the flashboard dam in 1983.

Dam engineers are confident that modifications to the spillway tunnels will allow the dam to withstand future flooding events, but other concerns have become prominent. The southwest has been suffering an extended drought, and lake levels in recent years have become perilously low, threatening to turn Lake Powell into a “dead pool” incapable of producing electrical energy. In 2013 the lake was filled to less than 50% of capacity. Some water experts suggest that the lake may never be able to fill to capacity again, in part from drought, climate change, and upstream diversions of water.

Back to that photo at the top of the isn't the whole story. The spot is called Horseshoe Bend, and it lies just a couple of miles downstream of Glen Canyon Dam. It is an entrenched meander, which developed when the land was uplifted, while the originally sluggish winding river started cutting downward instead of laterally. The rainbow-like pattern of red rock and green-blue water is an artifice of the reservoir. Unlike the olden days when copious amounts of silt caused the river to flow red, the water draining from the lake today is transparent and cold, in the 40-50 degree range. For a river in a hot desert, this is extraordinary. The ecosystem of the river evolved in different conditions than this, and species are sensitive to the new regime. Natural species of fish, amphibians and insects are in a difficult situation. For we humans it is ironic that river rafters have look out for hypothermia in their crews if people get dumped in the river on a day when the temperature is over 110 degrees.

So the view is just stupendous, but sobering at the same time. It can be reached by a short 3/4 mile long sandy trail from a parking lot on Highway 89 just 4-5 miles south of Page, Arizona. The highway is closed because of a serious landslide farther south but is open to the parking lot. It is well worth your time if you are ever in the region.

Thursday, June 6, 2013

What to do? Playing the Slots (Canyons, that is)

One of the most beautiful sights you will ever see is a slot canyon on the Colorado Plateau. Formations like the Navajo Sandstone are good cliff-forming rock layers, and yet they are easily eroded under the right circumstances. Flash floods carry a lot of abrasive sediment, and they work quickly to turn the slightest crevice into an intricately winding maze that can be dozens, even hundreds of feet deep and only a few feet wide.
Add to the maze-like labyrinth the glow of the fierce desert sun, and the rock seems to glow. Exploring a slot canyon can be an exercise in spiritual awareness.

Antelope Canyon near Page, Arizona on the lands of the Navajo Nation is regarded by many to be one of the finest slot canyons in existence. The gulch that formed it drains a region of many square miles, and flash floods can deliver tons of sand in a matter of minutes in water/mud twenty feet deep.

 We traveled through it yesterday, and I wanted to share some of the photographic results....
Antelope Canyon embodies a sort of perfection of form and light...the crossbedding structure of the ancient sand dunes adds wonderfully to the texture.
 And the darkness contrasting with the light presents a wonderful challenge to the photographer.
As our visit continued, the sun rose higher, casting more beams of light in the greatest depths of the gorge.

It was just as perfect a moment of spiritual peace and recognition of the paradox of chaos and order in the Universe that one can imagine. Except for one thing. One really important thing...we had to pay a pretty penny for the privilege, and we were conducted through the canyon like cows being herded onto a cattle train...and thus comes the paradoxical question: What to do about it? How to find some way of centering the spirit and finding the peace and solitude so many of us covet?
Well, I suppose you seek out the ragged little sibling canyon that isn't so perfect. Maybe a part of the Navajo Sandstone that has been broken and jointed by the compression of the Earth's crust. Maybe a canyon carved not by mushes of sand and mud, but battered by boulders of solid chunks of rock. A canyon with unstable walls that can collapse and fall without warning.
Maybe you seek out a canyon like Cottonwood Wash in Grand Staircase-Escalante National admission fee, no guides, no people, just quiet.
 And a different kind of beauty: a hard edged beauty. Not as colorful, but full of character.
So, really: how do you choose? Perfection, but with crowds and cattle prods? Or a roughhewn rugged beauty with intense solitude and serenity?
 For me it is no contest...solitude wins out every time. But there is the other solution to the quandary...
 You do both! And that is why yesterday was a great day....
I know of lots of other slot canyons out there. What are your favorites?