Tag Archives: Colorado Plateau

Western Colorado Road Trip

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Recently I had a meeting in Gunnison, so I made a short trip of it.  From Denver I went up to Buena Vista and over Monarch Pass, but this time I went over the old Monarch Pass road, abandoned when the highway on upper reaches of the Pass was widened and straightened.  Modern mountain highways are expensive, moving mountainsides and filling low spots.  The older roads tended to follow the lay of the land more closely.  They were cheaper to build but slower and more dangerous.

I like the old roads, even more if they aren’t paved.  Old Monarch Pass follows the recipe.  It’s narrow, winds around and goes up and down.  It had about three inches of partially melted snow, making for some slick spots and lots of mud, but not the mud that likes to trap unsuspecting cars.  I was going slow, so I got to enjoy the scenery and a pretty day.  I rolled the windows down, opening up my steel cocoon a bit.  Good thing.

I stayed in Gunnison, and next morning I drove up to Crested Butte, one of my favorite ski towns, with some of the flavor of an old mining town remaining, in contrast to the modern European Chalet style of Vail.  No  McDonald’s, no chain restaurants, and lots of local businesses.  I had coffee in a place without WiFi.

Kebler Pass during the Aspen Color

Next was Kebler Pass, one of the best drives in the state.  It goes from Crested Butte to east of Paonia, and is mixed gravel and pavement.  If you want the best fall aspen viewing in Colorado, Kebler Pass is the place.  Huge stands of quakies with good mountain backdrops.  The leaves were gone on this trip, but the beauty remains.  To the south are the West Elk mountains and and a large, mostly untraveled wilderness area.  The Elk Mountains are North and east, some of the wildest peaks in the state.

I was in big, beautiful, rugged country mostly empty of human development.  Emptiness and solitude, part of why I love Western Colorado.  The road comes out outside of Somerset, a coal mining town between Paonia and McClure Pass above Carbondale.  Big coal mines there, mostly shut down.  That’s mining in Colorado.  Dig lots of stuff, then go broke and leave a big mess behind.

I like Paonia, fruit trees below mountains, no McDonalds, no Walmart, as it should be.  There is lots of pretty farm country from Paonia to the turnoff to Grand Mesa outside Delta.  The Grand Mesa road climbs to the top of the 10000 foot tall flat topped Mesa.  It’s wet country, catching the storms coming across the desert country to the west.  My main memories are going fishing there with my father.  Lots of lakes, mosquitoes, gnats, and

View From Lands End. Impossible to Photograph the Panorama

cold nights.  I did not become a fisherman.  The Land’s End road runs west from the highway to the rim of the Mesa.  The view is unsurpassed.  The San Juan’s to the south, the Uncompahgre Plateau across the Gunnison River valley to the west, and the Grand Valley of the Colorado under the Bookcliffs and the Roan Plateau.  You can see into Utah.  The road winds off the Mesa to Whitewater.  Steep and twisty gravel.  I’m saving that part for next time.

I went on over the mesa to Collbran, where I continued my search for the big landslide off the mesa that killed three men running a mile off the mountain.  I didn’t find it, but ran round some nice farm and ranch country while looking.  When I got home I printed out a map.  Duh.

Colorado River Below Kremmling

That night I stayed in Parachute off I-70 in oilfield country.  Enough about that.  Next day I followed the Colorado River from Dotsero to Highway 40 at Kremmling.   Again, I crossed a lot of wild country with a bit of development in spots.  The river runs in a succession of canyons and narrow valleys.  No spectacular mountains, just lots of good rugged country.

After Kremmling, Highway 40, Granby, Winter Park, and Berthoud Pass to eastern Colorado, and home.

Posted in Colorado River, Kebler Pass, Lands End, Old Monarch Pass, Road Trips, Stories, Western Colorado

Draining the Colorado Plateau

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Grand Canyon

About 600 Million years old, the Colorado Plateau has been relatively stable throughout it’s history.  It has uplifts, interesting laccolithic mountains, lava flows, and In the last six million years or so, produced some of the most spectacular scenery on the earth.  Canyons.  Many canyons carved into many layers of rock, much of it red.  The canyons grew upstream from the Grand Canyon, the most spectacular of the canyons.

Some of the Colorado Plateau, Bryce Canyon

The Plateau is big, about 130,000 square miles.  It could swallow some of those little Eastern states with hardly a belch.  Utah east of the Wasatch mountains just east of Salt Lake.  Colorado west of the Rocky Mountains, south of the Uintah mountains and north of that rough country in northern New Mexico and Arizona.

For much of its history the Colorado Plateau was drained interiorly, no outlet to the oceans and surrounded by highlands.  The rivers then flowed north from now gone highlands in Arizona into a succession of mostly fresh water lakes.  The lakes left signatures such as the Green River Formation with its oil shale and landslides.  The Piceance and Uinta basins are examples. I grew up on a margin of the Piceance Basin.

Colorado River

Around six million years ago, the Colorado River flowed south, found its way onto the Basin and Range Province and eventually to the Gulf of California.  It is ironic such a powerful river responsible for carving all those canyons seldom reaches the sea, diverted onto land by recent despoilers, us.  The shift from internal drainage to the Colorado River with all the canyons carved by the river and tributaries is something of a mystery.

The answer is elevation change.  The Colorado Plateau ended up higher than the Basin and Range province to the west.  Was the Plateau uplifted or did the Basin and Range subside?  The change in elevation is relatively recent and gave the Colorado River the opportunity to begin draining the Plateau.

The Basin and Range With Stretch Marks

The Basin and Range is known as an extensional region.  As the Pacific Tectonic Plate slides northward along the North American Plate, it is stretching and pulling the Basin and Range to the west.  As it pulls apart, some big blocks stay at about the same altitude while adjacent blocks drop down to fill the void.  Thus we have basins and ranges.  There are theories that the entire province subsided as well.

This is probably not the case, as the crust under the region is thinner, a function of stretching, not uplift.  With uplift, we would expect the crust to be thicker.  The crust is thicker under the Colorado Plateau, suggesting uplift created by the remnant of the Farallon Plate subsiding and allowing lighter rock to rise and allow uplift.

I won’t go into detail about the various layers in the crust responsible for all this.  It is complex and all the stuff is way down there. Some are thicker, some thinner, as some rise their chemistry and density changes, and my eyes start glazing over.  Take it this way, that big thick and somewhat dense Plateau has stayed in one place and has had several periods of uplift.

The most recent uplift left the Plateau higher than the Basin and Range.  A stream on the western margin cut its way into the highland to the east and the Plateau started draining through the new canyon.  What a canyon it is, 6000 feet deep.  As the river cut its way down, all the tributary streams followed suit by making their own canyons.  The region is arid and has lots of cliff forming rocks, so deep, narrow canyons formed, some so narrow you can stand on the bottom and touch each wall.

I wanted the Basin and Range to sink, but is too thin and lightweight so it stretches.  The Colorado Plateau is also being pulled by that Pacific Plate, but instead of stretching, that big thick slab is rotating clockwise.  I am going to dig around and try to figure out why the Plateau stays in-one piece with all the activities going on all sides, but it is for later.  My working hypothesis is since the Colorado Plateau houses the center of the universe, it has stayed intact out of respect.

Posted in Basin and Range, Colorado Plateau, Colorado River, Grand Canyon, Plate Tectonics, Stories

The Enigma of the Colorado Plateau

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Although I have lived somewhere along Front Range Colorado most of my life, I still think of the Colorado Plateau as home.  I am dedicated to the region because of its Geology.  All that rock is just sitting there looking at you.  There aren’t too many plants to get in the way.  I grew up looking at the red rock of the Colorado National Monument just across the river from home.

Thing is, the red rock is mostly from the Mesozoic.  There is a lot of boring buff colored rock from the Cenozoic, notably the Green River Formation.  The Green River Isn’t much to look at, but it has a huge present day impact.  Look at my piece on the Formation in Categories.

I am currently interested in the time after the Green River Formation was deposited.  The literature on this time on the Plateau is relatively sparse, mostly because it was more a time of erosion, not deposition.  A large part of the deposition was in fresh water lakes with only remnants of the sediments today.  Those red rocks forming canyons and arches get all the press.

For most of its existence, the Colorado Plateau had no outlet to the sea.  Then, a bit less than six million years ago. The Colorado River decided to head for  Baja California.  There have been lots of explanations for this happening, but they boil down to elevation change.  The Plateau ended up higher than the Basin and Range province to the west.  That area was once a highland, but big tectonic forces changed everything. Then, a stream eroding east carved enough of a canyon to capture the Colorado Plateau drainage which became the Colorado River.

As you are aware, the Pacific Plate is colliding with the North American plate.  The collision is not at right angles, the Pacific Plate is headed northeast.  As it slides along, it pulls on the North American plate, somewhat pulling it apart.  The area east of the Sierras known as the Basin and Range is being stretched.  As it stretches, big blocks called grabens drop down, leaving mountain ranges between them.  The area ended up lower than the Colorado Plateau.

The Basin and Range Stretched

It’s not entirely clear if The Plateau was uplifted during this time by remnants of the same forces responsible for creating the Rocky Mountains.  It seems to me the uplift was earlier, but my reading on the issue is not conclusive. The fact is the Plateau ended up higher than the Basin and Range.  Erosion then began digging away in the area west of Grand Canyon, hooking up with the internal drainage of the Plateau.  Canyon cutting began.

All those spectacular canyons are younger than six million years.  An interesting sidelight is that the stretching of the Basin and Range continues, and the Colorado Plateau is slowly rotating clockwise.  The question for me is why is the Plateau still in one piece?  Compression, stretching, rising magma, new mountains, collapsing Nevada, huge volcanic fields, Arizona mountains wearing away, all this stuff going on all over the neighborhood, but this one slab mostly stays in one piece. Why?

My personal hypothesis is, as the Plateau houses the Center of  the Universe, it necessarily stays in one piece.  I haven’t found anything in the literature to support this, so we will look at some other explanations.  By the way, the Center of the Universe is within a 100 mile radius from the confluence of the Green and the Colorado.  Let me know if you find it.

In the meantime we will see what the geologists have to say.  Usually they reach some consensus, except here.

If you want to explore all this on your own: Carving Grand Canyon, by Wayne Ranney and Geological Evolution of the Colorado Plateau of Western Colorado and Eastern Utah… by Robert Fillmore.

Posted in Basin and Range, Canyonlands, Colorado Plateau, Colorado River, Geology, Grand Canyon, Green River Formation, Plate Tectonics, Stories

Kodel’s Canyon

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Geologic Time Scale

Growing up in Fruita, Colorado on Colorado’s Western Slope I had rich opportunities for exploration.  The area is amazingly diverse, offering the 10,000 foot elevation Grand Mesa to the east, the stark Bookcliffs to the north, and the spectacular red rock canyons of the Colorado National Monument just south of town.  All this surrounds the Grand Valley where I grew up. These areas and others were within short driving distance, with the Monument in bicycle range just across the Colorado River.

My friends and I used to take our .22s across the river and assault hundreds of rocks.  Our wandering took us across the National Monument boundary into Kodel’s Canyon.  Nobody went there in those days so we didn’t worry about having illegal guns in the park.  The canyon was smaller than the others, but we had the place to ourselves.  The approach is a deeply eroded plain of Dakota Sandstone from the river to the canyon.  The Cretaceous Dakota grades off to the Mancos Shale of the Grand Valley floor.

Kodel’s Canyon

That Mancos Shale is usually called Stinking Desert by many.  It is somewhat infertile unless well drained, and results in mostly barren gray flats.  Lots of barren gray flats from central Utah to Delta, Colorado.  With water and good drainage to carry the salt away, it can be farmland.  We would leave home on the valley floor and climb into the red rock Kodel’s Canyon.  At the mouth of the Canyon is the Kodel’s Canyon fault, where the Uncompahgre Uplift shoved all those Older Jurassic red rocks above the Cretaceous Valley.

Looking at the Grand Valley from Colorado National Monument

The bottom of the canyon is smooth rounded granite and schist geologists call basement rocks.  They are seldom found exposed on the Colorado Plateau, covered by thousands of feet of sedimentary rocks.  The time gap between those old basement rocks and the sedimentary rocks sitting on them is over a billion years.  It’s called the Great Unconformity, where all the rocks deposited during that billion years were eroded away.  This gap is found in many places worldwide, but there are also many places where the rocks missing in our canyon were deposited and remain to be seen and enjoy.  Think the Flatirons, Red Rocks, and the Garden of the Gods, all Cambrian.  Those rocks sit on Precambrian Gneiss and Schist 1.7 billion years old.

Those old rounded black rocks are great for climbing and we did it.  Today it’s called bouldering.  We didn’t have climbing ropes, so we used our .22s as climbing aids.  Dangerous?  Yes. Fun? You bet.

Among the guys I grew up with, only one had any injury running around across the river.  Jerry had a seriously sprained ankle.  The two guys with him helped him down to the road and help.  He exploited the ankle to excess.  At Boy Scouts we always played Capture the Flag after the meeting.  Jerry would hobble down to get the flag defying anyone to stop him.  I walked over and pushed him down.  I don’t think he ever forgave me.

Posted in Colorado National Monument, Fruita, Geologic Time, Geology, Gold Mining, Great Unconformity, Guns, Hiking, Kodel's Canyon, Memoirs, My Story, Rock Climbing, Stories, Uncompahgre Uplift

rat in cage two bottles

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The World Famous Green River Formation, for oil shale, not beauty

The World Famous Green River Formation, for oil shale, not beauty

About fifty million years ago the Grand Canyon and the Colorado River did not exist.  The area was surrounded by the Wind River Mountains, the Uintah Mountains, the San Juans, the Uncompahgre Plateau, and the newly formed Rocky Mountains.  This huge area had no outlet to the sea.  The climate was similar to our current Gulf Coast, warm and moist.  During the six million years we are exploring, things changed.  Lakes formed and receded, land rose and subsided, and through all this the surrounding highlands were sending their sediment into the lakes.   

The Green River Formation is the result of all the sedimentation.  It is up to ten kilometers in depth, thinner at the margins.  At first the lakes were fresh water, but later became saline, leaving large deposits of carbonate rocks.  The trona deposits at Green River, Wyoming are some of the richest in the world.  The margins are sandstone and conglomerate interlaced with the fine silt that filled most of the basin.  The formation is rich in the fossils of the abundant life in the lakes.  They are world famous for their variety and abundance.   

There was an anoxic layer at the bottom that preserved the organisms settling there.  The lakes were abundant in blue-green algae.  The remains of the algae are the source of the oil shale deposits the region is known for.  The oil shale is there in millions of barrels, but it is expensive to extract the petroleum from the rock.  It may never be commercially viable, but the formation has been extensively studied as a result.  

Green River Formation Map

Green River Formation Map

Standing in my home town of Fruita looking north, the white cliffs behind the Book Cliffs are the Green River Formation.  The Roan Plateau is huge, but does not attract visitors like the red rock country to the south.  A huge exposure is the highlands west of I-70 from Rifle to DeBeque Canyon. 

My interest is from visiting ranchers and hunting in the Douglas Pass area in my youth.  Most of our visits were to ranches in the Green River Formation.  The elevations varied greatly.  The ranches were along West Salt Creek, but there were back country roads that went from sagebrush desert to piñon-juniper to oak brush shaly hillsides with sandstone rims to high country timber with world class mud.  In fact, the mud is world class everywhere in the region. 

Back before four wheel drive became common, there was a pile of rocks at the bottom of every big hill.  Load them in the back of your pickup, go where you planned, and unload them on the way home.  There is a network of canyons with side canyons branching off.  All of it is fine deer habitat.  My favorite places were at the head of a canyon with the wind in my face and a view of the LaSal Mountains and the Uncompahgre Plateau in the distance.  Flat, wooded country gives me the creeps. 

Access to a lot of the country is difficult.  Most of the land is BLM land, but the early ranchers homesteaded the choice land that had water.  The private land meant locked gates.  We knew some of the ranchers, family friends.  Hunting season was a big deal.  There were maybe a dozen or more people, hunting during the day and drinking and playing poker at night.  The big ranch house had a big kitchen with a wood burning stove along with the stove in the big main room.  There was a light plant in the shed next to the house.  It looked like no generator you see these days.  There were also lots of Coleman lanterns when the light plant failed.  Good times and lots of venison.  The unheated bunkhouse was upstairs. 

Douglas pass was up the main road, gravel in those days.  It isn’t that high by Colorado standards, but made up for it with the switchbacks up the head of the canyon to the summit up through that shale.  When the shale is wet, it moves.  The road trapped the runoff, wetting the soft shale, and most every spring one or more places slid.  The mountainside now is braided with old road cuts.  It wasn’t much of a main road in the 1950’s, but now there is so much oil and gas development that the road is a paved state highway that the highway department spends money on. 

The road crosses the desert above the Highline irrigation canal before it goes into the canyon.  It is on the Mancos shale, responsible for all that flat desert in Colorado and Utah that turns to grease when it is wet.  There was one hill the road went over then descended into the wash on the north side.  That meant the road was on a north facing slope for a distance.  That hill was named Coyote, because it could bite and gnaw on you if it was wet.  A bit farther north was a ten or twelve foot high rock on the side of the road, all by itself.  

The county employee maintaining the road in those days had his grader blade scrape on that rock every time he bladed the road.  It would leave a bump, so he would have to drag dirt over to level things out.  One day he got fed up and dug that rock up and moved it off the road.  It was probably a two day project, but he never had to fight that damn rock again. 

After I could drive, I ran around that desert quite a bit.  I learned how to drive a two wheel drive pickup in that greasy stuff from my father.  He was the telephone man in Fruita, responsible for maintaining the toll line as far as Cisco, Utah.  That meant navigating two ruts through the cheat grass and sagebrush.  He could put a two wheel drive pickup into places that were a challenge for a Jeep.  Rocks in the back, chains if needed, put it in second gear and putt along.  He seldom used the granny gear or used the gas pedal.  Those old Chevy sixes would just lug their way along.   

I am as guilty as any back country explorer for spending most of my time in the Rocky Mountains or the Utah red rock country, but the Mancos Shale and the Green River formation are calling me.  I just need to see if my tire chains are in good shape.  I think I will go over Douglas Pass, loop around and look the Piceance Basin over. From Rifle I will go down to Plateau Creek (my father and grandfather said platoo crick) and up to Collbran to look at the big slide.

Posted in Colorado Mountains, Colorado Plateau, Colorado River, Federal Land, Geology, Green River, Green River Formation, Landslides, Oil Shale, Pipelines, Stories, Uncompahgre Uplift, Utah, Western Colorado

The Colorado Plateau Part Two

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Colorado Plateau Country

Colorado Plateau Country

There is a lot of beautiful country on the Colorado Plateau, but there is the other side.  The term many use is the stinking desert.  My home town has an annual rainfall of about eight inches.  Before the Utes were run out and ditches were dug, the Grand Valley was a sparse desert.  The irrigation projects made much of the valley green, but north of the Highline Canal is the desert.  It is a fairly barren desert, not like the Sonoran Desert with its green saguaro cactus.

Mancos Shale Soil

Mancos Shale Soil

The soil, if you can call it that, is fairly infertile, high in salts, and high in toxic selenium.  It’s called the Mancos Shale.  The Mancos Shale, called the Pierre Shale east of the Rockies, runs from South Dakota to central Utah.  It is an ancient sea floor, Cretaceous in age, of the inland sea covering much of North America.  Shale is mud rock, laid down as the sea advanced and retreated over millions of years.

The lower part of the Bookcliffs and the valley floors are Mancos Shale.  In its natural state it is a scrub grassland, supporting small populations of deer, antelope, prairie dogs, sage grouse, cottontails, and some Bison.  When the Northern European Americans arrived, they saw grazing land.  The sheep and cattle came.  The ranchers did well for a few years, but their expectations were unrealistic for such a dry area.  Soon, most of the good grass was gone, replaced by cheat grass and sagebrush.

The area between Delta and Grand Junction is a prime example.  My father, born in 1903, lived in Grand Junction after 1918.  He told me that at that time, there were extensive stands of tall bunch grasses.  They are gone.  That desert is one of the most barren stretches I am aware of.  It is hilly, so irrigation water went to flatter areas.  It is close to towns, so lots of ranchers grazed their stock on the land.

Much of the Mancos shale country is BLM land today.  In the old days, the Land Office and the Grazing Service leased land to ranchers.  There were allocations on the number of head allowed on each segment, but there was little enforcement.  The grass mostly disappeared.  Thus, the stinking desert.

I-70 from Palisade to the west of Green River, Utah is on the Mancos.  Highway Six from where I-70 veers south almost all the way to Price is on the Mancos.  Travelers on those highways have the bare Bookcliffs and the bare desert floor to look at for over 200 miles.  Their impression was what tended to keep the canyon country to the south relatively isolated.  Locals had all that magnificent country mostly to themselves.

Art in Salt Creek Canyon

Art in Salt Creek Canyon

The a uranium and oil and gas booms of the 1950s built a large network of roads and opened the canyon country up for tourism.  Those flat deserts remain empty, along with the mostly shale country of the Bookcliffs and the Tavaputs Plateau to the North.

When I went to Arches in the 1950s, we drove down two tracks winding through the sand.  This year during the height of the season, cars were lined up literally for miles.  Canyonlands National Park is also crowded, people lined up.  I remember going there and often seeing no one.

From Green River to Hanksville is mostly flat, dry desert, with 70 miles from the highway turnoff to the Maze District Ranger Station in Canyonlands.  The greater part of Navajo country in southern Utah, New Mexico, and Arizona is fairly flat desert.  Monument Valley is flat desert that happens to have some rocks sticking up.  Have you ever driven from Albuquerque to Flagstaff on I-40?  Flat desert.

Henry Mountains

Henry Mountains

The Colorado Plateau does have some other features.  Mountains, tall, green, and wet, supplying water to the desert.  Three ranges of mountains, the La Sals near Moab, the Abajos, known to locals as the Blues, and the Henry Mountains, near to nowhere.  The La Sals are the tallest, over 12,000 feet.  The Abajos and the Henrys stretch to 11,000 feet.  They stand in contrast to the red rock country surrounding them, and provide a welcome relief.  People go there in summer to cool off and enjoy the wildlife.

Geologically, the mountains are Laccoliths, formed by a neck of molten magma rising to a weaker junction between two layers of sandstone.  At that junction the magma moves laterally, forming a mushroom shaped dome of igneous rock in the domain of sandstone.  The overlying strata usually erode away, leaving the igneous core.  The Henrys are the type location for Laccoliths, being the subjects of the earliest study, and displaying the domed shape.

Salt Creek Canyon

Salt Creek Canyon

The three ranges are important to ranching, providing water, hay farming, and a summer range, with the stock wintering on the desert.  Salt Creek, draining north from the Blues, has a canyon with year-round water, arches, and Ancestral Puebloan ruins and rock art. The canyon also provides access to a park in the midst of the Needles District of Canyonlands.  I like that park because it was never grazed.  It provides a look at the land before cattle came, trampling or eating everything, mangling stream banks, and bringing alien species like cheat grass.  No I won’t tell you where it is.  Go look for yourself.

 

Posted in Arches, Bookcliffs, Canyonlands National Park, Colorado Plateau, Colorado River, Environment, Geology, Green River, History, Memoirs, My Story, Southwestern Archaeology, Southwestern History, Stories, Utah, Western Colorado

The Colorado Plateau Part One

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Colorado Plateau Scenery

Colorado Plateau Scenery

I am a child of the Colorado Plateau.  I was born and grew up in Fruita, Colorado, and still think of Fruita as home, although I have lived along the Front Range of Colorado most of my life.  The Grand Valley of the Colorado River is near the Grand Hogback, the eastern extent of the plateau in that area.  The Grand Valley is green due to irrigation, but the annual precipitation averages around eight inches a La year, fairly typical of the Plateau.

I am sure that the center of the universe (well, my universe) is somewhere within 100 miles from the confluence of the Green and Colorado rivers.  It is fitting, therefore that the Plateau is somewhat unique geologically.  All those striking layers of varicolored rock formed into spectacular scenery by the work of the Colorado River and its tributaries are relatively undisturbed compared to the Plateau’s neighbors, the Rocky Mountains,  the Basin and Range, the Wasatch and Uintah mountains and the  Mogollan Rim in Arizona.   Pretty neat neighbors, eh?

Those places have been folded, faulted, stretched lifted, collapsed, and otherwise deformed.  The Plateau, on the other hand has remained relatively stable through much of geologic time.  It is this big slab, poked, lifted, twisted, drowned, buried, and eroded several times but still mostly intact.  There were just enough deformation and intrusion to make things interesting.

The reasons for this stability are still somewhat controversial, bit have to do with the Pacific Plate coming our way and north at about the rate your fingernails grow, and the North American Plate headed west at about the same speed.  At different times they have behaved in different ways that, coupled with the somewhat thicker crust under the Plateau, have resulted in this unique region.  I don’t have the space or understanding to explain all those processes, but we can see the result.

An interesting fact is that the entire plateau seems to be rotating clockwise as the Pacific Plate grinds along northward.  That movement is also what is pulling the Basin and Range province apart.  Don’t look for any big changes next week.  This process is really slow.  While all this plate movement is going on, our friends the Green and Colorado rivers just keep digging.  On rare occasions you can see the digging, when there are exceptionally big thunderstorms during the summer monsoon.  A lot of stuff goes into the rivers then.  Today, Lake Powell is catching it, and will become one huge mud flat until the dam eventually fails.

Looking at all these processes requires a different sense of time than how we live from day to day.  In geologic terms, sixty million years (60ma) is relatively brief.  We think of our world as stable (unless you live in the Bay Area) but in truth, everything is on the move, it is just a bit slow.

Upheaval Dome

Upheaval Dome

The Colorado River will eventually bring the entire plateau down to sea level.  Look at Grand Canyon or any of the tributary canyons to see how it works.  My favorite is the San Juan.  Some fine canyons and not as cluttered up with people.  Another place to see the processes of change is Upheaval Dome in Canyonlands National park.  A great big rock came along and smashed down, forming a huge crater and shaking everything up for a long way around.  You can see rocks turned to waves from that hit all the way to Dewey Bridge.

That big crater tried to form a lake, but it is dry there.  The water did make its way to the river, cutting as it went, and now the crater has an outlet.  The crater will get bigger as the cliffs erode back until it is just a depression, then, gone.

There is a plug of gypsum in the crater.  When all that rock was blown out by the impact, the pressure on the stuff under the crater was lowered.  Some of that stuff down there is salt, known as the Paradox Formation, which can flow.  The salt goes into the river, but gypsum isn’t quite as soluble and there it is.  The salt is from an ancient sea that alternated between filling and drying up as sea level rose and fell.  That left a lot of salt which was then buried under a lot of rock.

The Dolores River Leaving the Paradox Valley

The Dolores River Leaving the Paradox Valley

That salt moving around and being dissolved is responsible for much of the scenery in the Moab and surrounding areas.  As it dissolves, some of the overlying rock drops down, creating some fairly large valleys.  Paradox Valley, Sinbad Valley, Lisbon Valley (uranium, oil, and gas), Spanish Valley (Moab), Castle Valley, Fisher Valley, are all big grabens.  They are big blocks that dropped down as the salt leached away. Paradox Valley and Spanish Valley have rivers coming out of a canyon on one side, and going across the valley into a canyon on the other side.  Moab has the Colorado, Paradox has the Dolores.  That makes for some fine scenery.

Paradox Salt Disrupting Things

Paradox Salt Disrupting Things

The fins and arches in Arches and Canyonlands come from the same process on a smaller scale.  All that magnificent scenery is a result of that ancient sea floor full of salt being buried by a colorful succession of rocks that the rivers and the wind could work on.

An exception to the salt influencing the process resulting in fins and arches is Rattlesnake Canyon in Colorado near Fruita.  The river is solely responsible for the work.  The arches are just as cool, and not all full of people.

Next time, some of the other interesting things about the Colorado Plateau, one of the most interesting places on the planet.

Posted in Arches, Colorado Plateau, Colorado River, Geology, Green River, Rattlesnake Canyon, Stories, Uncompahgre Uplift, Utah, Western Colorado

The Bookcliffs and the River

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Bookcliffs

Bookcliffs

The Book Cliffs are the neglected stepchildren of Western Colorado and Eastern Utah. That is somewhat ironic, because they stretch from Palisade and Mt. Garfield about 200 miles to Price, Utah. Rising about 1000 feet from the valley floor, they are the longest escarpment in the world. Above the Book Cliffs is a bench With the Roan Cliffs forming another escarpment  Behind the cliffs is the Roan Plateau, rising to about 8000 feet in elevation. With the wide change in elevation and precipitation from eight inches annually to around thirty, there is wide diversity in plant and animal life. There are energy resources as well. Natural gas, tar sands, oil, coal, and that huge deposit of oil shale.   The region is known as the Tavaputs Plateau.

The plateau is home to the Desolation Canyon Wilderness and due to the wide range in elevation and precipitation, a diverse range of plant and animal life. There are three reasons why the area is not very popular with visitors.

First, look south. Colorado National Monument, Arches, Canyonlands, Capitol Reef, Bryce Canyon, Zion, and Grand Canyon National Parks. There are the three mountain ranges and all that wondrous red rock carved into some of the best scenery on earth.

Next, accessibility. Douglas Pass is the only paved road in the vast area. The many dirt roads are accessible only as long as they are dry. Traditionally, the only people there were stockmen and the Utes on their reservation. In recent times there has been much energy-related activity that comes and goes.

The third reason? Shale. It is not only shale, there are layers of sandstone, even limestone. It’s all gray or shades of tan. Driving on the drab Mancos shale landscape of I-70, looking north you see drab cliffs. More of the same gray rock, just standing up. Roads built on that shale changes into some of the most slippery substances known after a rain or snow.. People are just not inspired to go there.

Growing up in Fruita, Colorado, I spent quite a bit of time in areas on either side of the Douglas Pass road, which was gravel and dust at the time. We had rancher friends, and deer season was a big social scene. It is wild, mostly empty country, home to lots of cattle, some sheep, a few ranchers, and a lot of wildlife. It is also famous for some of the most treacherous mud in the world. There are some sandstone lenses (we called them rims), but it is mostly shale, a former lake bottom that now sits thousands of feet above the Grand Valley, where the people live.

Colorado National Monument. Bookcliffs on the horizon

Colorado National Monument. Bookcliffs on the horizon

I used to look at the Colorado National Monument with its red rocks to the south. To the north were the relatively drab Bookcliffs with the whitish Roan Plateau above them. Why the difference? The Monument is famous, with lots of information about the Uncompaghre Uplift lifting the Uncompahgre Plateau thousands of feet compared to the Grand Valley. As the plateau, erosion took the more recent rocks off, leaving the more resistant sandstone.

I thought some sort of uplift must have formed the Bookcliffs. Well, partly. When the entire Colorado Plateau was uplifted at the same time as the Rockies, The Colorado River just dug away, carrying the eroded rock to the sea. It is still digging, and is eroding those Bookcliffs to the north. Under the Bookcliffs are the rocks of the Monument. Someday the land will be fairly flat between Grand Junction and Craig. We won’t be around, however. These things take time.

So, the Colorado Plateau was uplifted and after that the Uncompahgre Plateau went up some more and wore down. The rocks exposed at the Monument are, a few miles north, well below the rocks of the Bookcliffs who are headed north as the river gnaws away. The Colorado River rules, it is just a bit slow.

Posted in Bookcliffs, Colorado Plateau, Environment, Geology, Stories, Uncompahgre Uplift, Western Colorado