The Real Jurassic Parks: Arches National Park, continued. And an Eminent Threat.

I didn't really mean to leave everyone hanging in the Jurassic during our months-long tour of the geology of the Colorado Plateau, but I am easily distracted by things like work and politics. I want to at least make it out of the Mesozoic era before Thanksgiving, so I am picking up the thread where we left off on Oct. 17 with a visit to Arches National Park.

The stratigraphy of the park is relatively straightforward: the visible scenery mainly includes the Navajo Sandstone, the Dewey Bridge member of the Entrada Sandstone, and the Slickrock member of the Entrada. The Navajo Sandstone has a huge role in the scenery of other parks on the Plateau (see discussions here), but is mostly muted here. It is familiar to park tourists as the "petrified sand dunes" that can seen along the road in the south part of the park, and the very dramatic white rock along the park entrance road. The Dewey Bridge member is a "crinkly" layer of sand, silt and gypsum at the base of many of the arches. The reason for the deformed layers is unclear. One intriguing proposal is that a nearby asteroid impact distorted the layers (Upheaval Dome in Canyonlands National Park is the proposed impact site). Most of the arches occur in the Slickrock member, a cliff-forming layer that is obvious throughout the park.

The origin of the park's famous arches (there are hundreds) is tied to the salts of the Paradox Basin discussed earlier in this post. The salt beds are thousands of feet thick, and when placed under pressure, can slowly flow upwards through the overlying rock, forming domes and anticlines (upward pointing folds). Over millions of years, erosion removed thousands of feet of overlying sediment, and the salt was close enough to the surface to be affected by groundwater: it was dissolved away. The tops of the folds collapsed inwards, and the Entrada Sandstone was fractured (jointing) into a series of parallel fins. A large northwest trending anticline crosses the park; most of the arches occur along the flanks of the anticline.

The top of the fins are exposed to the arid desert climate, where the rock dries quickly following the infrequent storms. At the base of the fins, where the rock is buried by soil and loose sand, the rock may stay moist much longer. This leads to the solution of the cement holding the sandstone together, and the fins start to weather from below. Eventually a small window may open up, and falling slabs of rock enlarge the opening. The largest arch, Landscape, has an opening the length of a football field. Unfortunately, it is so thin and fractured that it may not last our lifetimes (it is in the third picture of the day). A large chunk fell about fifteen years ago. Wall Arch, another arch in the same area, just collapsed last summer.

Today's first photograph shows a small arch in the vicinity of Delicate Arch (a corner of Delicate is visible on the left side). The foreground includes tilted layers of the Entrada where they collapsed into the salt anticline. The La Sal Mountains can be seen in the distance.

The second photo shows my nomination for one of the most dramatic trails in existence, the one that leads to Delicate Arch. This is definitely a case where the end of the trail is not the main attraction; the whole trail is a treat, from one end to the other.

Unfortunately, politics and politicians don't stop politicking, elections or not. Arches, like the Grand Canyon is being threatened by the possibility of gas drilling just outside the park boundaries. The outgoing administration seems to be trying to run a fire sale on leases before they leave office in January. It is especially irritating that the Bureau of Land Management seems to be trying to fly under the public radar in their announcements. More information on the issue (and maps of the proposed leases) can be found here.

The Real Jurassic Parks: Goblin Valley and the Entrada Sandstone

This paleogeographic map is courtesy of Ron Blakey at Northern Arizonal University

Welcome to one of the most unusual (and most isolated) parks in the American Southwest, Goblin Valley State Park. It is located in south-central Utah, miles from anywhere (the relative metropolis of Green River, population 973, is about 50 miles away). It is a fine introduction to the Entrada Sandstone and Summerville Formation, two of the more scenic layers within the San Rafael Group.

In the latest part of the middle Jurassic (around 165 million years ago) huge changes were taking place across the American west. A subduction zone had formed off the coast of California, and compressional forces had caused the faulting and uplift of a range of mountains across Nevada. A shallow sea occasionally extended into the region from the north, leaving vast deposits of mud, silt and sand deposited in tidal flats, while in other areas river floodplains and desert dunes predominated (the region still lay across the subtropical belt, much like the Sahara today). The sediments, which have a distinctive red-brown color, are known today as the Entrada Sandstone.

In other regions, the Entrada is primarily a cross-bedded sandstone that forms distinctive cliffs, but here at Goblin Valley, the formation is more variable, with alternating layers of sand, silt and shale that erode in a differential manner, forming slopes and ledges.

The Goblins are short spires called hoodoos, which resulted from the erosion along joints and fractures in the rocks. If you are a fan of the movie "Galaxy Quest", will immediately recognize the park, and will probably be looking for cute little purple cannabilistic space aliens and immense rock monsters. You will probably be disappointed in your search, but your imagination will probably conjure up even more fantastic creatures as you wander through the goblins.

The park includes a unique campground that is nicely developed with showers and flush toilets but very little shade (there is a nice group campsite too). During the summer we make a point of arriving in the late afternoon when the sun is approaching the western horizon. The views east are expansive, and few parks in the American west offer better star-gazing. The San Rafael Swell, a huge monocline, lies just to the west. The Henry Mountains, one of the last mountain ranges in the United States to be given a name, lie just to the south. Reaching over 11,000 feet, they are a series of laccoliths, a unique type of mushroom-shaped intrusion, almost, but not quite volcanoes (although volcanoes may have once existed above them). The region is also a great place for seeing pronghorn antelope!

The Abandoned Lands...A Journey Through the Colorado Plateau: A day in the canyonlands, Part 2

In the last post, we saw the sun rise over the Canyonlands region of the Colorado Plateau, an area that includes Arches and Canyonlands National Parks and Dead Horse Point State Park. We saw all three on this one extraordinary day.

We woke up and Devils Garden Campground in Arches, and in the relative cool of the morning we followed the trail out of Devils Garden to see the largest natural span in existence: Landscape Arch. At 290 feet, the span is as long as a football field.

If you haven't ever seen Landscape Arch, you should bump it up to the top of your bucket list, because I don't think it is going to persist much beyond our collective life times. Since 1991, slabs measuring 30, 47 and 70 feet have dropped off the thinnest part of the arch. The trail under the arch was closed years ago for fear of rocks falling on visitors. The folks at Wikipedia think that it might mean there is less weight being supported by the arch, but I think that the math is increasingly working against the continued existence of the sandstone span.

Some of the students who were on the trip might not remember the moon lurking underneath the arch that day. I'm cheating just a little, pulling up my favorite shots from the 2008 trip, since I actually walked a different trail that morning. I was headed to Pine Tree Arch, which is on a short spur trail off the walk to Landscape.

Because of the unique geological circumstances of the Paradox Basin, the park contains the highest concentration of arches on the planet. Most of them occur in the Jurassic Entrada Sandstone, a relatively uniform dune sand that formed in a tropical or equatorial coastal region. The Entrada lies above salt layers that developed in the Paradox basin (a large isolated bay complex that occasionally was cut off from the ocean and dried up) in late Paleozoic time. Salt deforms easily under pressure, and has pushed the overlying rocks into a series of anticlines (upward pointing folds in the rock). When the salt began to interact with groundwater, the salt dissolved and the top of the anticline collapsed inwards, stressing the overlying Entrada, and causing a series of parallel joints to form, like those in the picture above, at the start of the Landscape Arch Trail.

The raven apparently supports an alternate hypothesis of arch formation.

Once the fins develop, precipitation is directed preferentially into the sand-filled joints and fractures, and the constant soaking of the sandstone at the base of the fin causes the solid rock to lose cement at a higher rate than the higher parts of the fin. Eventually a small opening occurs, and slabs of rock fall out, enlarging the arch over time. The arches grow until they collapse, an event that is fairly common, even in human times of reference. Several dozen arches have collapsed since 1971 according to some web sources, but I can't find any original confirmation for the number (that's out of 2,000 arches in the park). It's not that we are running out of arches, though; new ones are forming too.

Pine Tree Arch is an attractive little span with a nice view through the opening. One thing about Landscape Arch is the difficulty of getting a good angle on the sky. There is a cliff behind Landscape, and the closed trail prevents access for views upward. I found Pine Tree far less crowded and more intimate, even though it was only a few hundred feet from the main trail.

We finished our hike and returned to the vans. We headed to the Windows Section of the park, and the heat...well the heat descended on us like a blanket. Just look how the gang fought for the pitiful amount of shade at our lecture stop!

Next, an Indiana Jones adventure! This is a continuing series about what I've called the Abandoned Lands of the Colorado Plateau. It's kind of hard to be describing a very crowded national park as an abandoned place, but it was abandoned already by the Native Americans, the original ranchers, the uranium miners, and when the price of oil becomes prohibitively expensive, I worry it will be abandoned by our society as well. In the meantime, it is a place of beauty and inspiration.

I Guess "Fujicolor Basin" Just Didn't Have That Ring To It: Exploring Kodachrome Basin State Park

I'm not a real fan of corporate name sponsorship. I simply can't keep up with the names of Candlestick Park and whatever they're calling the stadium where the Lakers play in Los Angeles. When one hears the name of the little-known state park in Utah, it sounds like another case of corporate sponsorship gone crazy. But as I understand it, the story of the naming of Kodachrome Basin State Park was a bit more nuanced.

It's funny how a name can change the meaning and significance of a place. A hundred years ago, only a few ranchers and local Native Americans had ever even seen Kodachrome, and the ranchers referred to it as Thorny or Thorley's Pasture (I'm operating off dim memory here), and the beautiful valley was quite literally unknown to anyone from outside the region. In the late 1940's an exploration party from the National Geographic Society came through the region (imagine still exploring the United States only half a century ago!), and they were impressed with the scenery. They used their influence to rename nearby Butler Arch for their director (the arch is now called Grosvenor Arch). They gave the basin its name for the vivid color for a new bright film variety from Kodak. The article in National Geographic brought a lot of attention to the region, and tourists started seeking it out.

I must say I don't get corporate thinking sometimes either. Apparently Kodak was not happy with the copyright infringement, so when Utah sought to make a state park out of the basin, they called it Chimney Rock State Park. Kodak finally wised up and realized what a free marketing opportunity  they had, and consented to calling the park Kodachrome Basin. Over the years they have provided some support to the park. The park has outlasted the product; Kodak produced the last roll of Kodachrome film in 2009, and the company is struggling to survive in the digital age.

The park has two main attributes: the colorful Jurassic sedimentary rocks, and the strange columnar towers called sedimentary pipes. The sediments are mostly members of the Entrada formation, which is responsible for some spectacular scenery in other parts of the Colorado Plateau, most notably at Arches National Park and Goblin Valley State Park. The bright orange layers are the Gunsight Butte member, while the high white and red striped cliffs are the Cannonville member, and the light tan layers are the Escalante member. The highest cliff ramparts are composed of Cretaceous Henrieville and Dakota sandstones.

Lower parts of the basin expose Jurassic Carmel formation, most notably the Winsor member. The odd pipes occur mostly in the Winsor member, and the overlying Gunsight member of the Entrada.

The sedimentary pipes are one of those interesting mysteries that crop up in geology every so often. They are composed mostly of a slurry mix of sediment from the lower members of the Carmel, and penetrate the Entrada. There are around four dozen of them in and around the park, and they range in height from 6 feet (2 m) to 170 feet (52 m). They are composed of more highly cemented rock, so as the sediments are eroded away from around them, they end up standing out. It has been suggested that they are the result of hot spring activity, and that they might have been pathways for geysers (some have suggested that the park is sort of a Yellowstone in reverse). This is an intriguing and imaginative idea, but what was the source of the heat? There are no magma intrusions in the immediate region, and in other parts on the Colorado Plateau where intrusions do occur, such pipes aren't found (that I know of).

Another possible explanation is that the pipes are liquefaction features, places where water rushes towards the surface from saturated layers below during the shaking from earthquakes. I've liked this explanation in the past, since there are a few major fault zones just a few miles away. But researchers say there is a time problem. The latest studies suggest that the pipes are very old features: they don't penetrate the overlying Henrieville sandstone, and are therefore probably Jurassic or early Cretaceous in age. The faults in the region didn't become active until less than about 15 million years ago. I still like this explanation though...everyone knows that one's favorite hypothesis has to be the right one...I think.

The most recent suggestion is that the pipes formed from lenses of groundwater trapped in sabkha deposits, layers of evaporites like salt or gypsum along arid environment shorelines, which formed the Paria member of the Carmel formation. As younger sediments were laid down on top of the older layers, the pressure grew in the groundwater deposit, and water squeezed out, following the path of least resistance, generally upwards. This model has the virtue of being supported by most of the evidence...but I repeat the end of the last paragraph.

The park is a pleasant place to explore. In addition to the colors and unusual pipes close at hand, there are beautiful vistas to be had. On our reconnaisance trip a few weeks back we hiked out to Shakespeare Arch in a remote corner of the park. The short trail included panoramas of the White Cliffs to the southwest, the high cliffs of Navajo sandstone found around Carmel Junction and Kanab.

To the west, the pink strip on the horizon is the Claron formation, the Pink Cliffs of Bryce Canyon National Park.

We could also look up the slope to Kodachrome Basin itself. All in all a very colorful landscape.

The state of Utah has worked hard to make Kodachrome a destination for campers. The small 28 unit campground has flush toilets and showers. They sell firewood. And get this: when we arrived at our campsite, it looked like someone had raked our campsite. Feng shui in the wilderness! There is a small general store, a few rental cabins, and a new visitor center. If you have a large group, you can reserve one of two group campsites: the older Oasis site has been a favorite of ours for many years. The Arches site is newer, but is in an isolated corner of the park, with fewer facilities. I've had many commenters say that Kodachrome is their favorite campground on the Colorado Plateau. I put it near the top of my list, too.

We'll be stopping at Kodachrome during the AAPG tour that I am leading in July. If you want to join us, get the information here.

Get the park brochure here: http://static.stateparks.utah.gov/docs/kbspNewsBrochure.pdf

An excellent resource: Baer, J. and R. Steed. 2010. Geology of Kodachrome Basin State Park, Kane County, Utah. In Sprinkel, D.A. et al (eds.), Geology of Utah's Parks and Monuments, Utah Geological Association Publication 28, 3rd edition. Salt Lake City: Utah Geological Association, 467-482.

Shakespeare Arch is one more attraction in an already attractive place. It's at the end of pleasant half mile hike.

The Real Jurassic Parks: Kodachrome Basin (and a great resource!)

Back on the (virtual) road with our exploration of the geology of the Colorado Plateau, and the current series on the REAL Jurassic Parks. In our last post we were chasing "Galaxy Quest" rock monsters through Goblin Valley. Today, we are seeing another of the little-known gems of the Plateau country, Kodachrome Basin State Park in southern Utah. Kodachrome is another park that puts the Entrada Sandstone on prominent display along with something like four dozen unusual formations called clastic pipes.

These enigmatic features jut through the Entrada Sandstone, and being better cemented than the surrounding rock, they tend to stand out as towers tens of feet high (the highest are more than 100 feet). They are mostly composed of breccia and sandstone. Their origin is unclear, although there are plenty of well-considered hypotheses including cold and hot springs, earthquakes, overburden pressure, and UFO's (they always have something to do with weird things out here). I have no particular expertise to judge, but I have to note the presence of several major fault zones in the immediate vicinity, and can easily imagine an origin rooted in liquefaction effects (this statement acknowledges the fact that we can see the things we know about and can miss evidence favoring things we know nothing about...).

Some of the pipes are exposed in their original matrix of Entrada, as can be seen in the second photograph. Notice how the strata form a graben or syncline in the area adjacent to the pipe.


Why the unusual name? Aren't there trademark restrictions or something on such blatant commercialism? Actually, the name was given to the basin in 1949 by the National Geographic Society following an expedition in the region. Yes, an expedition. Even today, the area remains one of the most isolated corners of the lower 48 states. They were using the newfangled color film, and were inspired by the intense coloration of the rock (for those of us too young to remember, there was a time before digital cameras....). The basin became a state park in 1962, and was called Chimney Rocks for fear of trademark infringement or something, but Kodak recognized good PR, and happily let the state keep the name. They have even sponsored park brochures (in color, of course).

If you are leading a field trip through the region, and find nearby Bryce Canyon too crowded and noisy, consider Kodachrome as an overnight stop. There are two nice group campsites, and a good shower facility (we of the long trip persuasion have to remember the basics....). A network of short trails explores the park, and a short drive east reveals the spectacular Grosvenor Arch. A longer gravel road (Cottonwood Canyon Road) travels south along the Cockscomb Monocline, emerging near Page and Glen Canyon Dam. It's a great drive...in dry weather. Don't try it after storms! The Utah State Parks website for Kodachrome can be found at http://stateparks.utah.gov/parks/kodachrome/.

BTW, geology road guides for all state and national parks in Utah can be accessed at http://www.utahgeology.org/uga29Titles.htm. These are PDF's of the first edition of the truly excellent book Geologic Road, Trail, and Lake guides to Utah’s Parks and Monuments, P.B. Anderson and D.A. Sprinkel, editors (Utah Geological Association-29 Second Edition, , 2004, CD-ROM, $14.99. Available at the DNR Map and Bookstore, http://mapstore.utah.gov/ ). The roadguides are a companion to the very comprehensive Geology of Utah's Parks and Monuments, also available from the Utah Geological Association.

Vagabonding Across the 39th Parallel: Sun and Rock in Arches National Park

Last summer we set out on a vagabonding journey that roughly followed the 39th Parallel across the western states of Nevada, Utah and Colorado. By vagabonding, I refer to the set of loose rules we followed to not plan more than a day or two in advance, and try to see as many new sights as we could see. We ultimately made it to Rocky Mountain National Park, and now after 10 days on the road, we were headed west, slowly returning home to California.  Our winding road brought us to the town of Moab, Utah, and Arches National Park. We were now on the Colorado Plateau, a vast area of the earth's crust that was stable for hundreds of millions of years, but in recent geologic time has been uplifted and deeply eroded by the Colorado River and her tributaries.

I've been to Arches National Park a great many times, but almost always with a large group of students. A group necessitates some serious planning, and our trips usually include the same three places: a hike to Delicate Arch for the sunset, a hike to Double Arch, and a hike to Landscape Arch, the largest in the park (and probably in the world). On this particular day, our new experience was stopping and sitting at one of the less iconic viewpoints. Literally sitting, for a rather long time. We had a picnic dinner, and just experienced the desert while the sun set behind us. 

Before settling in, we made a quick circuit past the La Sal Mountains overlook and the Windows Section. The La Sal Mountains are outside of Arches National Park, but provide a spectacular backdrop to arches and fins that make up most of the scenery in the park. The mountains have an unusual origin. They are not quite volcanic in origin (although volcanoes almost surely existed here, but have been eroded away), but instead are formed of intrusive rock that reached shallow depths in the crust, wedging and bulging up the sedimentary layers that lay above the molten rock. The intrusions are called laccoliths. The mountains rise to 12,000 feet, and are often snow-covered, even in early summer.

The Windows Section contains several large arches, including Double Arch, made famous by the opening scenes of Indiana Jones and the Last Crusade. There is no deep cave up in the alcove, and no Coronado's Cross, though. Just a spectacular double arch. It's big; click on the photo below and look for the people walking under the arch.

The Windows Section is a good place to learn the stratigraphy of Arches National Park (see the picture below). There are three important sedimentary layers that are fundamental to the scenery, all Jurassic in age. The Navajo Sandstone is the preserved remains of a vast dune sea (an erg) that developed along the western edge of the supercontinent Pangea. It makes up much of the spectacular scenery at other parks like Zion and Capitol Reef, but is less visible in Arches. It makes up the lighter-colored layer at the base of the slope in the picture below.

The layers atop the Navajo Sandstone are two members of the Entrada Sandstone: the Dewey Bridge member and the Slickrock member. The Dewey Bridge formed in a tidal flat environment and has variable layers of siltstone and sandstone. It is easily eroded, which allows it to undercut the harder Slickrock member, causing the cliffs and fins in which the arches are developed. It often has a wavy "crinkled" aspect that has led some geologists to speculate that the layer was affected by the nearby impact of an asteroid at Upheaval Dome. The speculation is controversial, but the explanation appeals to me simply on the scale of grandeur and in thinking outside the box.

The cliffs at Arches are made of the Slickrock member of the Entrada Sandstone. The formation preserves sand dunes that developed along the coast of Pangea (much like the Navajo Sandstone). The arches form most often in the Slickrock member. I wrote about the formation of the arches in my series Time Beyond Imagining. Here is a short excerpt:

"The origin of the park's famous arches (there are hundreds) is tied to the salts of the Paradox Basin. The salt beds are thousands of feet thick, and when placed under pressure, can slowly flow upwards through the overlying rock, forming domes and anticlines (upward pointing folds). Over millions of years, erosion removed thousands of feet of overlying sediment, and the salt was close enough to the surface to be affected by groundwater: it was dissolved away. The tops of the folds collapsed inwards, and the Entrada Sandstone was fractured (jointing) into a series of parallel fins. A large northwest trending anticline crosses the park; most of the arches occur along the flanks of the anticline.

The top of the fins are exposed to the arid desert climate, where the rock dries quickly following the infrequent storms. At the base of the fins, where the rock is buried by soil and loose sand, the rock may stay moist much longer. This leads to the solution of the cement holding the sandstone together, and the fins start to weather from below. Eventually a small window may open up, and falling slabs of rock enlarge the opening."

The sun was sinking lower towards the horizon. We sat in the silence and ate our sandwiches; a few cars stopped briefly and people stepped out to see what we were looking at, but they were mostly in a hurry to be someplace else.

Arches is an elemental place, as most desert landscapes are. There is sunlight, and there is rock. Everything else is secondary, the plants, the animals, the people. If you are caught in the open on a hot summer day, the elements are perilous. Survival is a crapshoot. In our insulated existence, the crapshoot becomes a source of great beauty, especially as the sun sinks and the searing heat dissipates. The rocks glow, and then slowly fade to darkness.

Our minds see meaning in the random shapes of the rocks, and we make stories of their origin. Some stories involve myths and heroes, while others involve jointing and frost wedging. I enjoy both kinds. What do you see here?

The fire in the sky died away, and stars emerged in the darkness. We gathered our things and drove back into town.

A Land of Strange Standing Stones, Part 2: Kodachrome Basin State Park

There was a time not all that long ago when there was a part of the United States mainland that was still considered terra incognito. It was in 1948 that National Geographic explored this region and called it not a tour, but an expedition, complete with jeeps and supply caches, and explorers who gave new names to features, even though many of them already had been named by the resident ranchers.

Kodachrome Basin State Park (once called Thorley's Pasture) in southern Utah showed up at the end our our 40 mile gravel road journey through what I called a land of strange standing stones (it's also accessible from the north by a paved road out of Bryce Canyon National Park). For the second time in a day we were treated to the strange sight of vertical pillars of stone, but these had an origin quite unique from the spires along  Cottonwood Wash Road. It's an origin so unique that geologists haven't quite decided what it actually is.

The spires, called sedimentary pipes, are composed mostly of a mix of sediment from the lower members of the Carmel Formation that have penetrated into the overlying Entrada Sandstone. There are more than five dozen of them in and around the park, ranging in height from 6 feet (2 m) to 170 feet (52 m). They are composed of a more highly cemented rock, having been exposed as the surrounding sediments were eroded away It has been suggested that they are the result of hot spring activity, and that they might have been pathways for geysers (some have suggested that the park is sort of a Yellowstone in reverse). This is an intriguing and imaginative idea, but what was the source of the heat? There are no magma intrusions in the immediate region, and in other parts on the Colorado Plateau where intrusions do occur, such pipes aren't found.

Another possible explanation is that the pipes are liquefaction features, places where water rushes towards the surface from saturated layers below during the shaking from earthquakes. I like this explanation, since there are some major fault zones just a few miles away. But researchers say there is a time problem. They say that the pipes are very old features: they don't penetrate the overlying Henrieville sandstone, and are therefore probably Jurassic or early Cretaceous in age. The faults in the region didn't become active until less than about 15 million years ago. Maybe.

The most recent hypothesis is that the pipes formed from lenses of groundwater trapped in sabkha deposits, layers of evaporites like salt or gypsum along arid environment shorelines, which formed the Paria member of the Carmel formation. As younger sediments were laid down on top of the older layers, the pressure grew in the groundwater deposit, and water squeezed out, following the path of least resistance, generally upwards. This model is interesting, but has it been seen in other settings? Some of the petroleum geologists that have traveled with us find this to be a  plausible explanation.

But aren't mysteries great? Like the origin of the Grand Canyon, science thrives on unanswered questions. It's a fascinating place to visit and explore.

The sediments in which the pipes occur are mostly members of the Jurassic Entrada formation, which is responsible for some spectacular scenery in other parts of the Colorado Plateau, most notably at Arches National Park and Goblin Valley State Park. The bright orange layers are the Gunsight Butte member, while the high white and red striped cliffs are the Cannonville member, and the light tan layers are the Escalante member. The highest cliff ramparts are composed of Cretaceous Henrieville and Dakota sandstones, last seen at Grosvenor Arch.

For more information...

Get the park brochure here: http://static.stateparks.utah.gov/docs/kbspNewsBrochure.pdf

An excellent resource: Baer, J. and R. Steed. 2010. Geology of Kodachrome Basin State Park, Kane County, Utah. In Sprinkel, D.A. et al (eds.), Geology of Utah's Parks and Monuments, Utah Geological Association Publication 28, 3rd edition. Salt Lake City: Utah Geological Association, 467-482.

Where are the Ten Most Incredible Places You've Ever Stood? My Number 9: Frame Arch and the Delicate Arch Trail

It's the journey through the Ten Most Incredible Places I've Ever Stood! As I explained in the last post, the list is subjective, and everyone's list will be different. I'm pleased at the response of many of you already listing your most incredible spots in the comments, and on my accounts at Facebook and Google+. I'm looking forward to seeing more! My own list is not in any particular order, other than my choice for number one. Folks will perhaps not be surprised to see that I selected the picture above for my number 9; it's the cover photo from my Geotripper Images website where I've posted a lot of my geological pictures for use in educational/academic projects. It is a view of the La Sal Mountains through Frame Arch at the end of the Delicate Arch trail in Arches National Park.

In the years before PowerPoint, I started all of my geology classes with a set of slides (this was an ancient technology that involved "carousel trays", "slide projectors", and "film") to introduce the students to the world as it is revealed by geological processes. The first picture was always this stretch of trail just short of  Delicate Arch. I chose it because it symbolized so much about the wonders revealed in the incredible history of our planet.

The trail is cut into a formation called the Entrada Sandstone, a layer composed mostly of  windblown sandstone as well is silt and mud in some areas. It once was a system of sand dunes near a coastal delta and estuary during the Jurassic Period around 140-180 million years ago. The trail surface is a natural separation along the surface on one of the dunes, so by walking on this trail we are striding on the same surface that dinosaurs, ancient mammals, and arthropods walked on many millions of years ago. We know that these rocks were buried deeply by thousands of feet of overlying rock, but they were pushed upwards by vast salt domes rising from older formations below. The doming effect split the rocks into linear fins, and the arches developed from weathering and erosion at the base of fins.

At one viewpoint an observer can appreciate the variety of depositional environments that led to the formation of the colorful Entrada rocks, the vast amount of time that the rocks lay buried in the crust, the immensity of earth movements that brought the rocks back to the surface, and the intensity of erosional processes that shaped the rocks into what they are today. And one can walk on a surface that may very well have been a trackway for a dinosaur many eons ago.

But (like they say in late-night television ads), there's more! Although many people use Frame Arch to frame Delicate Arch, I chose to emphasize the La Sal Mountains instead (the top photo). The La Sals represent the role of magmas in earth processes. The mountains are composed of intrusive rock that reached close to the Earth's surface about 25 to 28 million years ago. Some may even have erupted out in volcanic eruptions, but the rest of the rock formed into mushroom shaped plutons called laccoliths. The dioritic rock proved more resistant to erosion than the surrounding shale and sandstone, so the peaks rise 6,000 to 7,000 feet above the plateau surface. The highest peaks in the La Sals reach nearly 13,000 feet above sea level.

It's a scenic, even iconic spot for photographers and park visitors, but what makes this one spot special to me? It's the unique experience of each visit. It's been my privilege to visit this spot perhaps a dozen times in the last 30 years and every time it has been an awe-inspiring journey. We usually head up the 1.5 mile trail in the late afternoon in order to catch the sunset on Delicate Arch. Quite often there is a raucous crowd, and some moron always feels a need to go stand under the arch for an inordinate period of time, prompting shouted complaints from the large group of photographers on the ridge top. Frame Arch becomes the special spot at that point because there is only myself and a few of my fellow travelers. We don't hear the chaos and mayhem at Delicate Arch, and we can just sit and appreciate the changing colors and deepening shadows.

Once or twice we've been doused with a summer rainstorm, and in one particular year we took shelter under the arch and gloried in the lightning and crashing thunder, and watched as the dry sandstone transformed into a series of waterfalls and white cascades. It was one of the most cherished moments of my life. We assumed that the storm would obscure the sunset, but as quickly as the storm hit, it dispersed and the sunshine broke through to highlight the La Sal Mountains in the far distance.

One more reason that this spot is on my incredible list is because of the ephemeral nature of Delicate Arch itself. It may not last my lifetime. The arch is only a foot and a half thick at one point, and there are valid fears that it could collapse in the natural order of events. Of course, humans may help it along; I've heard of at least one episode in which a man attacked the arch with an axe. Then again, it could last another thousand years. Who knows? In the meantime it is a magic place.

Once before I pass on I would like to see it in the snow.

Time Beyond Imagining

Still decompressing after a "long" trip of two weeks through geologic time on the Colorado Plateau. It is always difficult to comprehend the contrast between the hours and days of one's human existence with the millions and billions of years that characterize the geologic history of our planet and Universe. I expect to follow this theme in my blogs for a few days as I sift through the pictures of our journey.

The unusual view above comes courtesy of astronomical lunar cycles and Landscape Arch in Arches National Park. The arch has an opening nearly as long as a football field, and is only 6 feet or so across at the thinnest point. It is rather a wonder that the span still stands, and the future prognosis of the arch is probably measureable in human, not geologic, terms. A large chunk fell from the span around 1991.

The arches in the park are formed in the Slickrock Member of the Jurassic Entrada Sandstone. The unit has been pushed upwards by bodies of mobile salt from the late Paleozoic Paradox Basin. The upward pressure in the salt anticline has fractured and jointed the sandstone into a series of "fins", long narrow walls of rock. The base of the fins lie in the Dewey Bridge member of the Entrada (or Carmel), which is easily eroded, allowing a small window to form at the base of the fin. Chunks of rock fall from the window, until an arch develops. There are hundreds in the park.

Accretionary Wedge #56: Because Every Picture of the Earth Tells a Great Story

Andrew Alden at About Geology is hosting this month's Accretionary Wedge, and the topic is landscape topography through the eyes of a geologist:  

Once upon a time, you took a picture of something that lots of people photograph. However, because you are a geologist, it didn’t turn out the way it does for most people. Show us that picture, tell us what you see in it, and tell us about the way you take pictures.

No matter where you go, no matter where you are, there is a story to be told by the rocks. And ultimately, no matter how dull the scene might appear, the story is fascinating. These are the first words that I utter in every class I teach, and I cannot look at a landscape, any landscape, without wondering what lies beneath. And sometimes the scenes are far from dull.

To many, the story to be told by a picture may be "I was standing in front of some scenery". Few geologists can ever see a landscape that way. The picture above is one of my favorites, because such a rich history is encapsulated in the small frame of the photograph.

We are standing in a small arch located in Arches National Park in Utah, which actually happens to be called Frame Arch. The view extends across the fault graben of Salt Creek Valley to the distant La Sal Mountains. The reddish rock is the Entrada Formation, a sandstone deposit that developed in the tidal zone of a coastline in Jurassic time. Dinosaurs once climbed coastal dunes in this spot where I stood snapping a picture.

The rocks are tilted because there is a huge body of salt beneath the surface. Water trickling down into the fissures and joints dissolved away the salt near the surface, and the Entrada layers collapsed into the void.

The La Sal Mountains in the distance are volcanic, or to be more correct, laccolithic. The high peaks are made of the more resistant rock that squeezed between and inflated the space between sedimentary layers. Later on, the rocks were lifted up and the overlying layers were eroded away. The eroded mountains are the hearts of ancient volcanoes.

How did this photo "turn out different"? It's because I was more or less ignoring the reason this opening in the rock was called Frame Arch...just to the left in the distance, you can see the slightest opening to what may be the most famous arch in the world, Delicate Arch. It's the symbol of the park, and almost everyone climbs up to Frame Arch uses it to frame Delicate (below). But the geologist's eye takes in more than icons.

Thanks, Andrew, for hosting the Accretionary Wedge this month!

The Abandoned Lands...A Journey Through the Colorado Plateau: The Joys and Perils of Serendipity on the Lisbon Valley Anticline

When traveling with 35 students, one must plan each day carefully. You have to be cognizant that everyone does not operate on the same bladder timing plan, that people on the trip have different metabolisms, that every stop has the potential of becoming a long delay. One tries at all times to keep to a carefully planned schedule with highly calibrated rest stops at appropriate intervals, and academic stops are structured so as to enhance the learning experience in line with the course learning objectives and previous successful academic outcomes.

And sometimes you just have to say screw it all and try something totally different.

We were well into our journey into the Abandoned Lands, an exploration of the Colorado Plateau, and we had crossed the Utah state line and were driving north on Highway 191 towards Moab and Arches National Park. We were leaving the lands of the Ancestral Pueblo people, and were coming into a region with a general paucity of obvious archaeological remains. It is a land of barren rock where water is scarce and survival difficult without the niceties of modern technology. It is the realm of the geologist.

The region between Moab and Monticello is a complex mix of anticlines, faults, and laccolithic intrusions. The combination of these structures has led to the formation of a variety of ore bodies, and the history of this landscape is tied mostly to the search for those ores, by ancient peoples as well as modern prospectors.

As we drove north we passed Church Rock, an outlier of Jurassic Entrada Sandstone. The Entrada accumulated in coastal sand dunes and muddy estuaries along a western sea. Conditions were quite arid at the time, as it was situated in the subtropics, much like the Sahara Desert today.

The plan was to make a sensible stop at a roadside rest area and continue on to our camp for the night at Arches National Park. But I was looking at the highway maps and geology road guides, and I found myself asking "why don't any of these guides say anything about Highway 113 and the uranium mines out in the Lisbon Valley Anticline?" Yes, sometimes we think that way. So, I got on radio and said we were turning onto Highway 113 to simply see what was there. It was serendipity...

I turned onto this road, which really did have kind of an abandoned look to it. As mentioned previously, I had no guides, and I had never been on the highway before, but I knew that somewhere in the ridges ahead was the fabled and deadly Mi Vida Mine, discovered by Charlie Steen in 1952.

Charlie Steen looms large in the legends of the "uranium frenzy" that gripped the Colorado-Utah borderlands in the late 1940s and early 1950s. Uranium and vanadium had been mined in the region intermittently during the early part of the century, but production was limited. It was the invention of the atomic bomb, the Cold War, along with a recession following World War II that left thousands of soldiers in the unemployment lines that led to an unprecedented migration into this barren region. It was also the first government-sponsored mining boom, as the bureaucrats promised to maintain a minimum price for uranium for at least a decade.

Charlie missed out on the draft for medical reasons, but went to work in the oil industry. By behaving just like a geologist, he got himself fired for insubordination and could not find employment anywhere in Texas. Hearing of the uranium rush, he piled his young wife and four very young sons into a surplus jeep, mortgaged his mother's home for $1,000 and headed north into the Utah Canyon Country. As a geologist, he had some ideas about where the yellow carnotite uranium ores might be found, and his ideas were viewed with amusement by his colleagues. But he sunk the last of his dollars into a drilling rig and set up on the limb of the Lisbon Valley Anticline. For months his family subsisted on poached venison stew and cereal while he drilled the 200 foot hole.

And the drill bit broke off...

He was beat. There was nothing in the hole but some kind of black coal-like material, not the bright yellow carnotite that everyone was looking for. He had samples of the black stuff in the back of the jeep when he rode into Moab for the maybe the last time.

Did I mention that Steen couldn't even afford a Geiger Counter? According to the stories I've read, he either grabbed someone with a counter to test his samples, or someone walked past his jeep with a Geiger Counter that happened to be switched on, but in any case the counter went crazy. The black stuff turned out to be pitchblende, the richest ore yet discovered on the Colorado Plateau. The layer was 70 feet thick. In a short moment, Steen went from the poor house to Boardwalk and Park Place. He named the mine the Mi Vida ("My Life").

By most accounts, Charlie Steen was generous with his new-found riches, donating to many charitable causes in the Moab area, and he apparently threw great parties. When he got frustrated with haulage costs to the government milling facilities, he built his own mill in Moab right next to the Colorado River. I suppose that it is ironic that the many millions of dollars worth of uranium that the mill produced is kind of balanced against the fact that uranium has been leaching into the Colorado River ever since, and that $300 million is being spent to haul the waste dump to a site near Cisco, one of the places that Charlie had lived in poverty.

Does anyone think that this rock is an alien monument to Jabba the Hut?

In any case, uranium transformed the Canyonlands country. Miners forced access roads into the most inaccessible terrain imaginable in search of riches. The small towns grew rapidly and sometimes painfully. But perhaps the most terrible heritage of the entire episode is that the miners were never told of the horrific dangers of mining uranium from underground mines. Radon gas was a byproduct of the radioactive decay of the uranium, and some of the unventilated mines had gas levels thousands of times the currently accepted safe level. It was hard to accept the danger from an invisible monster that took years to do its work.

Miners worked for a decade or more in the mines, but eventually many of them developed lung cancer and other diseases, and they started dying. Their families suffered too. The dangers came from wives washing coveralls covered with carnotite dust, children playing on mine dumps, and swimming in uranium-saturated waters at the mine sites. The sadness came in the arbitrary nature of the fatalities. Surprisingly healthy miners watched their children die in some instances.

We headed up the road onto the flank of the Lisbon Valley Anticline. We passed a rock that I knew must have had a name, but I had never run across it before (I found out this week that it is called Big Indian Rock).

Without maps or notes, we passed up the Mi Vida (it was tucked away in a side canyon), but saw plenty of evidence of other mining ventures. The anticline was the result of salt bodies rising and piercing the overlying rocks (the salt formed in estuaries and bays that came to be cut off from the western ocean in Pennsylvanian time). Thirty million years ago, the intrusions of the magma that formed the large laccolithic intrusions of the La Sal Mountains and Abajo Mountains provided the hydrothermal fluids that formed ore bodies along fault systems in the anticline folds. The ores included the uranium, but copper was also a major component.

We pulled over at a large open pit operation to have a look. It looked abandoned, but we stayed along the highway just the same. It turned out to be a copper mine, and bits and pieces of azurite and malachite littered the dirt along the road. Of course serendipity cuts both ways. The mine was not abandoned at all, and we were chased off by an irate security guard.

It was a fascinating look at a sad heritage. We made our way back to Highway 191 and soon arrived at Arches National Park, one of the most stunning landscapes on the planet. Our adventures will continue in a future post.

POSTSCRIPT: Check out Andrew Alden's excellent new post on uranium geology for some details on the mineralization process:  http://geology.about.com/od/mineral_resources/a/uraniumnuts.htm