The Abandoned Lands...A Journey Through the Colorado Plateau: A day in the canyonlands, part 4

The nice thing about blogging is that one gets to set one's own rules and deadlines. I'm easily distracted and can drift from one project to another, and then drift back. So it is with this project on the Abandoned Lands. Off and on for the last five months we have been examining our summer journey through the Colorado Plateau, and we've reached the 12th day of a 16 day trip. But what a day this was! It started with a fiery sunrise, included a hike to see the largest arch in the world, and added a tour of an Indiana Jones movie set ("that cross belongs in a museum!"), and it was barely past noon...

And now we were headed into the canyon lands, preserved as Canyonlands National Park and Dead Horse Point State Park. This province of the Colorado Plateau has been deeply incised by the Green and Colorado Rivers, enough to expose upper Paleozoic sedimentary rocks. We hadn't seen rocks that old since we left the Grand Canyon ten days earlier. The late Paleozoic rocks at Grand Canyon had been a mixture of marine and terrestrial rocks, but in Canyonlands, the bright red colors told us the rocks were almost exclusively terrestrial.

Except for one thin bit of beach sand ...a layer called the White Rim Sandstone (below). From our perch at Grandview Point, we were looking at the last advance of a seashore in Permian time, some 270 million years ago. It would be tens of millions of years before seas would once again cover the region.

This is a vast empty quarter; it's hard to imagine making any kind of living here, but people migrated into the region, and most abandoned it soon after. The Native Americans made the maybe the most successful effort, with evidence of Archaic peoples arriving thousands of years ago. The Ancestral Pueblo people occupied the region from 200 BCE, and another group, the Fremont, arrived around 800 CE. Both groups abandoned these lands before 1300. It was several hundred years before others reoccupied the land, with the arrival of the Utes, the Paiutes, and the Navajo. The Spaniards largely ignored the region, but outlaws in the late 1800s utilized the intricate canyons as hideouts.

One after another, others moved through this landscape: ranchers, uranium miners, trappers, gold miners, oil drillers. And then they moved on. In the early 1960s, riches of a different kind were recognized: the scenic nature of the canyons. In 1964, Canyonlands became a national park.

In contrast to the vast expanse of Canyonlands, Dead Horse Point is a miniscule property of just over 5,000 acres (8 square miles). But what a spot! It is perched on the edge of a 2,000 feet cliff overlooking the Colorado River and the eastern side of Canyonlands National Park.

There was an interesting spider in the picnic area, too! Anyone know what kind it is?

The shadows were finally starting to lengthen, but our day wasn't yet done. Most of the students made the 1.5 mile hike to Delicate Arch to watch the sunset. I headed up to camp for a different walk...

More next time!

The Colorado Plateau Story: the real Jurassic Parks

Today we make a return to our series on the geologic story of the Colorado Plateau. The Mesozoic Era left a stunning variety of rocks across the region. The Triassic story, with the Moenkopi and Chinle formations has been told, but today we explore a few of the real Jurassic Parks, the ones in which the scenery is formed by rocks laid down during the Jurassic Period. The scenery makers today are the Wingate Sandstone and the Kayenta Formation, which can be seen especially well in three parks: Capitol Reef National Park, Colorado National Monument, and Vermilion Cliffs National Monument. The Wingate appears in a prior post involving Canyonlands National Park. I notice that Geology Happens is a fan of the Wingate as well.



The Wingate Sandstone formed in early Jurassic time as sand dunes migrated across the increasingly arid region. The layer tends to be bright orange-red, and has the crossbedded structure typical of rocks formed from dunes. Dune environments are not generally conducive to the preservation of fossil material, but reptile trackways are occasionally discovered.

The Kayenta Formation lies above the Wingate and is most often exposed as a series of colorful ledges and slopes. It formed as a series of rivers flowed across the dune fields from the Wingate deserts. It contains numerous trackways of dinosaurs and other reptiles. Fairly easy to erode, it is not well-known as a scenery-former but it plays a critical part in the dramatic scenery at Zion National Park (to be covered in a near-future post).

Colorado National Monument lies just south of Grand Junction and Fruita, Colorado (the top picture, and this one from a previous post). It is one of our lesser-known parks, but is well worth a visit if you travel through the region. The park preserves a spectacular eroded monocline, which is a folded sequence of rocks where the layers are horizontal at either side of the flexure, much like a rug thrown over a stairstep. A marvelous paved road snakes in and out of canyons, mostly within the Kayenta Formation just above the Wingate cliffs. And the Wingate cliffs are incredible, a sheer drop just a few steps beyond the edge of the road. Although such roads are not being built in national parks today as a matter of preservation policy, I have to appreciate the effort that went into the construction of this one. There are many, many wonderful overlooks, a modest campground, and a decent visitor center. Lots of services are available in the nearby towns. Some very important dinosaur discoveries were made just outside the park (in younger formations), and signs point to the quarry sites.



Capitol Reef National Park is illustrated in the second picture above, and in the uranium post a few days ago. The park lies in the practically unhabited region of south-central Utah (Torrey and Hanksville are the main urban centers with a combined population of about 500). The park preserves another spectacular monocline, the Waterpocket Fold, that runs nearly 100 miles in a north-south direction. The "reef"of the park name refers to the difficulty settlers had in crossing the rugged eroded rocks of the monocline. Even today, a single paved highway crosses the structure, and a few unpaved gravel roads. A Mormon settlement (Fruita) was established here in the 1800's, and the fruit orchards are still maintained by the park service and volunteers. A favorite park activity is picking cherries and other fruits in season. The region was utilized in earlier times by the Fremont people, a lesser known culture than the Ancestral Puebloans of Mesa Verde and other areas to the south.


Vermilion Cliffs National Monument is at the same time one of the more familiar and least-visited monuments in the United States. The interior of the park is rarely visited, and there are few facilities of any sort for tourists; a true wilderness park. On the other hand, hundreds of thousands, maybe millions of people drive past the park on Highway 89 from Jacob Lake to Lees Ferry and Navajo Bridge, where the Vermilion Cliffs cannot be missed or ignored. The sheer cliffs rise 3,000 feet above the highway, and are just beautiful. California Condors have been re-introduced into the region, and the lucky traveler might just catch a glimpse.


Even with my more or less yearly visits to the region, I have never been in the monument, with one huge exception. Most of the park is a vast high plateau, but the northeast portion of the monument is dissected by an incredible gorge carved by the Paria River. The headwaters of the Paria lie to the north at Bryce Canyon National Park. Where the river reaches the Navajo Sandstone, it has cut an extremely deep canyon, the Narrows, with a major tributary, Buckskin Gulch, which is one of the longest deepest slot canyons in all of the Colorado Plateau.


I was in the Boy Scouts, and one of the last trips I took as a scout was a six-day backpack down the Paria River to Lees Ferry. It was one of the greatest adventures of my life, and probably had a lot to do with my eventual choice to become a geologist. Just the same, I knew little of geology at the time, and I would dearly love to repeat the adventure one day. I will search for my pictures of the event, but I had a camera I had no idea how to use, so the pictures that came out at all were over- and under-exposed. Plus, I dropped the camera in quicksand, and it was never the same after that (i.e. it never worked again at all).


Have you ever been in real quicksand? It's not very much like Hollywood quicksand, but it was an invigorating experience sinking to my knees most unexpectedly. I had walked across about 50 feet of it before actually breaking through, and it was lots of fun getting back out!

Time Beyond Imagining - A Brief History of the Colorado Plateau: The Real Jurassic Parks

As we move forward in time, we reach the geologic period called the Jurassic, one of the few units of the geologic time scale that is familiar to many laypeople. We have Steven Speilberg and Michael Crichton to thank for that, and yes, dinosaurs rose to prominence in the terrestrial landscape, but lots more was going on as well, including a lot of interesting non-dinosaurs, including our own small furry predecessors creeping about in the underbrush (the mammals first appeared in the late Triassic, about the same time as the first dinosaurs).

So what are the real Jurassic Parks? In the movies, the park was an island populated by reconstituted dinosaurs that ate people and each other. The Jurassic Parks of the Colorado Plateau are the ones in which the most dramatic scenery is provided by Jurassic-aged rocks, which include the Wingate, Kayenta, Navajo, Carmel, Entrada, Summerville, and Morrison formations. The parks include the familiar Zion, Arches, Capitol Reef, and Canyonlands national parks, and the less familiar Grand Staircase-Escalante, Navajo, Rainbow Bridge, Vermilion Cliffs, and Colorado national monuments. Notable state parks include Kodachrome, Goblin Valley and Dead Horse Point, all in Utah. Many of the dramatic cliffs included within the Glen Canyon National Recreation Area are also made of Jurassic rocks. And let us not forget the actual Dinosaur National Monument, the one that actually has dinosaurs (although at last report, they did not eat park visitors).

Today's photos include a parting shot of the Chinle Formation at Petrified Forest National Park, simply because I came across it in a lost file and liked it, and a picture from near the head of the Schafer Trail in Canyonlands National Park, which is cutting across ledges of the Kayenta Formation as it prepares to plunge down the Wingate cliffs to the White Rim, discussed in a previous post.

The Schafer Trail leads to the White Rim Trail, which winds for a hundred miles or so through the heart of Canyonlands National Park. It is one of the life-list goals that I haven't accomplished yet. It pretty much requires at least two days to travel, and three or four days by bike. The Schafer Trail was originally carved by cattlemen and improved by uranium miners (they worked pretty hard...).

So, why the dramatic colorful cliffs? Something important had changed, causing the Triassic floodplains to disappear. The silts and clays and river channels were replaced by desert dune sands, which quite often form prominent cliffs when hardened into solid rock. The deserts formed because Pangea had begun to break apart, and North America was now moving northwest, into the subtropics where the prevailing air circulation results in dry conditions. We see a similar situation in the Middle East and Sahara Deserts today.

Time Beyond Imagining - A Brief History of the Colorado Plateau: A Final Transgression

With today's post we reach the rim of the Grand Canyon, and the end of the Paleozoic rocks of the Colorado Plateau. But these pictures are not of the Grand Canyon, although some similarities exist. Both canyons were carved by the Colorado River, for instance. We are in southeastern Utah at Canyonlands National Park. Our vantage point is the Island in the Sky plateau that overlooks the confluence of the Green and Colorado Rivers. Unlike the Grand Canyon, the oldest rocks visible are Permian in age, and the upper canyon walls are in Mesozoic rocks (the age of the dinosaurs, basically).

Hikers in the Grand Canyon who have a geological background don't measure their progress in miles and feet the way normal people do. We note our location by the strata through which we are strolling. The base of the Supai Group means a long slog through red dirt. The base of the Redwall almost always means a tough climb is ahead. The greatest relief to geological hikers is to arrive at the top of the Coconino Sandstone, where we realize that only two more formations lie between us and a cold beer or iced tea: the Toroweap Formation and the Kaibab Formation. Both are easily visible in yesterday's post, the Toroweap as the forested slope above the sheer Coconino cliff, and the Kaibab as the ledgy cream-colored cliff forming the rim of the canyon. Like the Coconino, both formations are Permian in age, the very latest part of the Paleozoic Era.

The Toroweap Formation is rather variable in composition, ranging from dune sands, evaporites (forming in drying bodies of water), and limestone. It formed in a time of changing sea level, where the shoreline transgressed and regressed repeatedly, forming dune fields, tidal flats and sabkhas (coastal salt flats). Fossils are generally rare, given the harsh conditions in which the rocks formed.

The Kaibab Formation is more marine in origin, being composed of limestone, dolomite, and sand. In many places chert nodules can be found. The chert is a form of altered quartz that can develop long after deposition. The layer is rich with fossils: crinoids, brachiopods, sponges, bryozoans, shark teeth, nautiloids, fish, and some of the last trilobites to inhabit the earth (the Kaibab Formation on the North Rim of the Grand Canyon was the site of my first childhood fossil discoveries). Many of these species were doomed: the end of the Permian was marked by the worst mass extinction event ever recorded. Something like 95% of all the species on the planet disappeared, for reasons that have not yet been determined, although many hypotheses are proposed.

So why the pictures of Canyonlands National Park? Note the white rock layer sandwiched between thick layers of red rock. This layer is appropriately called the White Rim Sandstone (the White Rim is a very prominent terrace in Canyonlands), and being Permian in age, is related to the Coconino, Toroweap and Kaibab formations. The sea that formed the Kaibab and other late Permian marine layers transgressed from the west onto the continent. This is indicated in part by greater thicknesses to the west. On the other hand, the farther east and north that one travels, these layers become thinner. And thinner. By the time we reach Canyonlands National Park, the marine sands are only a few feet thick and then pinch out. We are looking in these photographs at the last beach of the last Paleozoic sea.

We have reached the rim of the Grand Canyon, and the end of the Paleozoic story. The reconstruction of the supercontinent Pangea was complete. World ecosystems had been devastated by extinctions almost beyond imagining. The world had changed completely, and the Mesozoic age had begun. Dramatic changes are coming! In another post, though....

Time Beyond Imagining - A Brief History of the Colorado Plateau: Old Salt

So, what do the Arches at Arches National Park, the Potash Mine just outside Canyonlands National Park, the tragic 2008 earthquake in the Sichuan Province of China, and the Southern Appalachians have in common?

Well, ok, not much, but bear with me. In the last post on the geology of the Colorado Plateau, we were exploring the formation of a rather extensive mountain range in southwest Colorado, where the Rocky Mountains are today (but these mountains, the Ancestral Rockies, were eroded away in the late Paleozoic era). We were left wondering why mountains could be rising in the interior of the continent, when most mountain ranges seem to develop along continental margins.

The breakup of the supercontinent Rodinia in late Proterozoic and Early Paleozoic time had a huge impact on the patterns of sedimentation in the Colorado Plateau, with a series of transgressions and regressions that gave rise to the formations of most of the recent posts. The continents remained as separate entities through much of Paleozoic time, but landmasses began to converge upon one another, and a series of collisions produced Himalayan-sized mountain ranges (which is coincidently the reason the Himalayas happened: Asia and India are colliding). A collision between a portion of Europe and the eastern part of North America raised the northern Appalachian Mountains. Asia and Europe connected to form the Ural Mountains, and in Pennsylvanian time, Africa crashed into the southeastern United States to raise the southern Appalachian Mountains. The supercontinent of Pangea was being constructed, bit by bit.

(As a side note, I should point out that when geologists speak of colliding and crashing continents, we are living in a totally different time reality. The colliding continents are moving no faster than 5 or 6 inches a year. Yes, India is crashing into Asia, but it has been happening now for 40 million years)

The collision of Africa and the SE United States explains the Appalachians, but what about the tragic earthquake in the Sichuan Province? The Ancestral Rockies formed at about the same time as the Appalachians, but the two ranges are separated by a thousand miles or so. In the same way, the mountains of central China are far from the Himalayas, but their origin is related to the buckling of the crust related to this continental collision. The process of buckling produces earthquakes, and in highly populated regions this produces tragedy. Peripheral buckling of the crust along ancient fault lines related to the collision with Africa is at least one explanation for the origin of the Ancestral Rockies.

The Potash Mine? Just south of the town of Moab, and on the edge of Canyonlands National Park, there is an exceedingly odd sight: the evaporation ponds of a potash mine. The turquoise blue, seen here from Dead Horse Point, clashes with the red beds of Permian formations. At the mine, holes are drilled into salt layers, and water is injected to dissolve the salts and bring them to the surface. The brine is evaporated, and the salts are harvested and transported away.

The salt is also related to the formation of the Ancestral Rockies. When the crust is buckled and mountains rise, in other places the crust is pushed downwards. A feature called the Paradox Basin developed southwest of the Ancestral Rockies. It flooded with seawater, but for some reason the connection to the ocean was cut off, and the water evaporated, leaving behind thick deposits of salt and other evaporite minerals. Water flooded in again, and the cycle was repeated, at least two dozen times. Eventually the salt layers were thousands of feet thick.

What is the connection to Arches National Park? Well, this post has become long, and I will discuss that issue next time!