In the America's with David Yetman

(David) For bold, naked and spectacular geology in North America.

The place to visit is the Colorado Plateau.

It's a kaleidoscope of visual wonders like none other in the world.

(Announcer) Funding for in the Americas with David Yetman was provided by Robert and Carol Dorsey.

Additional funding for In the Americas with David Yetman was provided by Laura and Arch Brown and by the Guilford Fund.

(David)The Colorado Plateau is a large area where four states Arizona, New Mexico, Utah and Colorado meet.

It has a lot of natural wonders, included are nine national parks Some of the most famous throughout the world.

You go around a corner and you find a new formation unlike anything you've seen.

It's a place to be cherished, to visit, to wander around, to study, and then go ask a geologist what's going on.

The Colorado Plateau Slick Rock Country.

(Richard) These are the beginning of hoodoos or these hoodoos about to die.

(David) I am fortunate to be closely related to a trained geologist.

He is my brother, Richard Yetman.

(Richard) This is younger than the andrada sandstone into which it has been formed.

(David) Much of the Colorado Plateau and Arizona and New Mexico is part of the Navajo Indian Reservation north of the Navajo town of Kayenta, the landscape suddenly changes as dark shapes rise from the plains.

(Richard) Oh, you mean Agathla.

(David) Probably the most prominent landmark in all of northeastern Arizona.

It's a volcanic plug.

The name apparently means some wall in the Navajo language, and it's a very important monument for the Navajos themselves.

(Richard) Remember that when these were made or formed, they were five to ten thousand feet underground.

So this is not something that was above the ground.

This is very deep.

(David) But this particular example of crazy volcanic activity took place about 25 million years ago.

Since that time, wind and some rain and maybe even a little bit of snow have eroded the landscape, about at least 3000 feet down.

So that where the top of that volcano is, we would have been looking down at it from above.

Agathla is a very special place.

The Navajos consider it extremely important.

So do I. I wish I could climb to the top of Agathla because I suspect that, via binoculars, I could see Mexican hat.

I know.

It's on the other side of the San Juan, but then I once was with someone who referred to it as Mexican Tack, because it looked more like a thumbtack than a hat.

(Richard) Or the Pierre Hat.

(David) Many of the Colorado Plateaus most spectacular landforms lie in southern Utah near Mexican hat the geology becomes weird and, well, breathtaking.

If you ask a geologist how are these monuments possible here?

They'll say something like differential erosion, which doesn't tell you much unless you think that the top of these wonderful monuments are almost 300 million years old.

At one point, the land was equal or above where they are now.

And wind and rain have taken away everything but the hardest part of the rock and left behind these formations.

Somewhere at the top there, probably 275 million years old.

And the farther down we go, the older it gets.

And it's taken that long.

Plus the forces of plate tectonics that raise the land up to produce the sculptures, the monuments, the magnificent palaces that we see in Monument Valley.

(Richard) We're in the desert and there's a river right over the hill there.

(David) Yeah, the San Juan And its not just a little trickle.

(Richard) How do you know?

(David) Ah, listen, I know these things, but I have to tell you, I've floated down it a couple of times.

And one thing that is baffling to me is it cuts right through that huge ridge up there, the Rapley Anticline and that took some doing because I've tried to cut through rock like that and I can't do it but a river can.

(Richard) So the cap is made of Cedar Mesa sandstone.

It's kind of odd that there's this little remnant I left here.

I don't think there's any other left around.

Maybe there's some up there, but very peculiar that it would end up being... (David) Somehow the pedestal its on then is a more durable rock.

(Richard) More durable or less durable?

Yeah, that remains to be seen.

(David) This is the San Juan basin.

The San Juan River is just over here a little way.

This is strange.

(Richard) It's a strange place.

And don't you love the way that this anticline comes down from there?

You can see.

You can actually see it diving into the earth up here.

(David) Somehow, that was formed by compression forces pushing the earth together, so it goes up like this, and the top of it just erodes away.

The river cut its way through this huge geological thing over here.

They call it the Rapley Anticline.

(Richard) Near Mexican hat, we see these great chevrons of purple and gray, which really look like a Navajo rug.

And the locals refer to it as the Rapley rug because of the contrast and the colors there.

Theyre so representative of what local people make.

(David) We're coming up to Comb Ridge.

(Richard) The sandstone was lifted up like this and eventually went like that.

But all that stuff down there is gone now.

So what we're seeing are these limbs that are stuck up in the air like that.

And up in here it appears these plates are sticking up almost like stegosaurus fins.

(David) Because the Colorado Plateau is stable 40 or 50 million years ago when a plate, a tectonic plate, burrowed in from the west as it moved east, it caused things to rise as the compression of the earth took place.

We think of the analogy of a chisel moving in a piece of wood, fairly soft as it moves across, it kicks up a piece of wood before it drives it up into the air.

And that's sort of what the plates did a few miles beneath the surface as they gradually moved, forcing what was ever in front of them up into the air and creating these mounds where ultimately erosion took away the top and left the bottom.

Next, its Valley of the Gods.

And this is hard to beat in this drive dirt road and it's, it's sort of a semicircle.

It's not going straight to anything.

(Richard) And I think it's actually better than Monument Valley, quite honestly.

(David) Oh, I do, too.

I do too.

(Richard) Theres so much more variation here.

(David) You know, that land ownership and it's like our country is basically the federal government and Indian reservations.

(Richard) Directly behind us.

(David) The Navajo Tribal Park of Monument Valley.

(Richard) So when we travel throughout the Colorado Plateau, we're going to see probably just about every textbook example of sedimentary rock exposures or types of erosion that occur to it.

And we're going to see things that aren't even mentioned in the books.

(David) From the end of the Valley of the God's Road is only a few miles straight miles, and there on the edge of Cedar Mesa is the Moki Dugway.

(Richard) Many people have turned back on this road.

(David) They have and I'm wondering how many have fallen off because they didn't turn back.

(Richard) Whats great is the contact between the Cutler Formation and the Cedar Mesa Sandstone.

(David) I mean, there's this sandstone straight up and down, and then all of a sudden this other formation that they call the Cutler goes off at a kind of a an angle.

It is part of Natural Bridges National Monument and Canyon Country.

(Richard) We're walking on Cedar Mesa Sandstone, a wind derived sandstone, as opposed to weather-deposited, aeolian.

And the big question is where did the sand come from?

(David) And these are all these are frozen dunes then?

(Richard) These are essentially frozen dunes.

This canyon has an amazing an amazing, sinulosity about it.

(David) I like the word.

(Richard) Things seldom go straight here.

(David) So it's constantly the water is constantly trying to find weak places and it goes around a bend.

And then naturally that forces water to the other side, which creates another bend.

And so you have this unending bendy river.

(Richard) Well, so here's continued examples of frozen dunes.

(David) Yeah, you can see two different angles then coming in.

(Richard) The one below, it's pushed back like that.

You come around the corner here, we can probably see another facet of it.

Yeah, So this one comes back like that and then up against this big bluff up here with relatively flat dunes.

You wonder how many eons the wind blew in one direction for these to become an established dune and then move on to the next layer.

(David) And how much weight had to be put on top of them to force them to become rock?

(Richard) Don't you love these water stains on here?

Now, truthfully, wouldn't this make a wonderful wall in a house?

(David) Its artistic.

I think one of the most fascinating things about the whole Colorado Plateau is how many places people lived.

Wherever there was water, youll find a site.

(Richard) Where there was water, people lived.

These are places where the ancient ones would sharpen sticks for example.

They would take a stick That they wanted to get turned sharp.

And I think they use sticks a lot.

They probably would do this like that.

Marks left behind after the sandstone was used as a tool to improve other tools.

(David) This is a protected site.

It would be warm here in the winter and cool here in the summer.

It's safe from the rain, whatever rain there was.

And the view they had of the natural bridge is just hard to believe.

Yeah, you could look right out into White Canyon.

(Richard) Well, there's that bridge right there, isn't it?

You can actually see on the inside cut there where it turned and went all the way around like that.

(David) Tell you what.

The river must have been really happy the day it made that first little hole, it started as a trickle and then... (Richard) Once it blew through..

Probably so.

(David) Probably so.

The water would pond up there and there would be a current that would be acting like sandpaper at the bottom winding that sand around, hitting it.

Yeah.

And all it takes is time.

A million years or so.

(Richard) And from here, that's got to be 300 feet down, don't you think?

And then as you look at this creek bottom down below here and it heads into this gorge.

(David) This white canyon empties directly into the Colorado River.

And once we get down there, we can make it to Hanksville on the way to Hanksville is the Henry Mountains.

(Richard) Looming ahead of us.

(David) The Henry Mountains are what geologists call a Lacolith, which is a kind of a fun word, but it is as though they were a huge amoeba type blob of magma, enormous pushing up from deep in the earth, forcing the surface up just like an abscess or a boil, but never bursting through the top.

But everything above that gets pushed up into the air and over the millions of years, then erosion gradually takes its toll and shows what has happened.

(Richard) Why do I get the feeling these rocks are going straight up and down?

[David laughs] (David) Now my understanding is that in the Colorado Plateau, the rocks are horizontal.

These are not.

(Richard) These are age defiers, rule defiers.

(David) Boulders are different colors, which means different rock origin.

Wow.

Oh, my God.

[Richard laughs] We got white and red and brown and gray and then purple.

(Richard) This whole area was covered with the same kind of sandstone we've seen for the last several days, thousands of feet thick, tens of thousands of feet thick.

(David) Basically, flat, laid down flat.

(Richard) At some point in the last 25 million years, the magma underneath the earth started pushing up and it got to these layers, these rocks are alternating with sandstone.

This is called diorite.

This rock were in now.

And then sandstone again.

And then Diorite.

And then ultimately there's another major push and the whole mountain starts to raise up like this.

So it comes up and Fast like this.

And now keep in mind, this is still two miles below land surface.

(David) What we had was then these layers of sandstone, which we've seen everywhere in the four corners, and then that those sills, those layers of the volcanic stuff.

(Richard) Pancake pancake material.

Yeah.

(David) Pushed up.

And what we're seeing here is these layers made vertical.

And we look here, here's a sandstone, there's the diorite.

(Richard) So these are upturned sills.

(David) No wonder they couldnt figure it out.

And everywhere there's little remnants of the sandstone forced up into the sky.

And then if it was two miles up, everything's been eroded for the last 25 million years, wound up in the Colorado River Basin somewhere.

If we look way up here, you see a little piece of color that's got sort of reddish purplish and grayish in there.

That's actually a piece of the original ground of at least the original sedimentary rock that was glommed onto by this volcanic matter, the diorite and held onto while everything else was being pushed up into the air.

And there it is, waiting for gravity some day to pull it down.

(Richard) This is a classic talus slope, and the higher you get, the looser it gets.

And eventually you don't want to get any higher.

Because why would I go any higher?

There's a piece of that purple sandstone slash silt stone.

So here's a chunk of it from ancient times eroded to come down this canyon.

This is just one example of the rocks that have been eroded away from the top of this mountain.

There's very little of this left.

And probably the only remaining pieces that piece up there that was not assimilated by recent erosion.

Theres a lot of other reddish rocks here.

But I don't see any others of this color.

This is the great example of the diorite sill that was injected horizontally between the limbs of the sandstone two miles deep in the earth.

And now, oh, my gosh, look at it.

It is almost vertical.

(David) Almost straight on, straight up.

It was horizontal.

Now is vertical.

(Richard) Oh, my gosh.

And on this side, look at its absolutely flat.

It went in between the sandstone, opened it up and created what's called a sill.

And this could have been miles wide.

And then ultimately, when the mountain came to its final formation, it pushed everything up, opened it up.

And now we're looking at what was a sill, looks like a dike.

The water pocket fold extends from northern Arizona all the way up to almost central Utah.

And the best exposure of it is in Capitol Reef National Park.

(David) One of the crazy things about a monocline like this is you see the red part here and you know this, but if you start climbing up there, there's a white above it.

You climb across the red part up the hill.

You're actually getting into older rock, the higher you climb, confusing if you're trying to figure out what stratum or what in the Colorado Plateau.

(Richard) And they are the textbook example of a Chevron.

(David) Exactly.

(Richard) Up and down, up and down.

And since we have all this red defining here at the bottom, it really gives definition to that part of it that spurs that have come off of that massive reef.

Can you imagine being a traveler 100 years ago and trying to figure out a way to get over?

(David) Oh, we found a great valley here.

Let's cross.

And its, what, 100 miles long?

(Richard) Yeah, 100 miles long.

30 million years ago, we would probably be 3000 feet higher or more, and there would have been a fold here, but it would been much more gentle than it is now.

We would not have had the erosion of the top of the fold as much so we could have walked conceivably up to the top of it over the top and back down to level ground again.

As it is now we get to the top of this fold as you're going to be a large truncated section that has been removed by erosion just because of the stress put on the sandstone when it bends like that.

The plasticity isn't followed through to the areas that are exposed.

The plasticity stays in the areas that are secure, particularly areas underground.

These are things that take place over a long period of time.

It could be hundreds of thousands to millions of years for something to actually end up folding to the point where it is now.

(David) Up, up, up, up, up the road is going to go from, I don't know, from about 4000 feet up to 9000 on that place they call Hell's Backbone.

A lot of visitors to the Four Corners Slick Rock country region don't realize if you get high up in the mountains there are forests and big time forests and pine and fir and spruce.

Like right here in the upper Escalante region.

(Richard) This area down below us is referred to as Box Death Hollow.

Now, I don't know why it's called that, but it kind of an ominous name.

(David) Yeah, doesn't sound great.

(Richard) But it's quite a declevity from here.

It's probably close to a thousand foot drop down to the bottom of that valley.

(David) From a distance you would not realize how convoluted that is and how far down that is.

And I don't want to try to drop down there right now with the wind.

I'm not sure I want to do it when there isn't any wind.

(Richard) Where do you want to go?

Then?

(David) I think Ill just stay right here and hold onto my hat.

But at the the difference in the air from down where you were earlier on the Colorado and the remnants of Lake Powell.

And up here at 8000 feet, we're in two different continents, almost.

Hell's backbone is high in the mountains.

20 miles south by a dirt road, we find geology that's, well, bizarre.

When I see something like this, you call it the jewel.

Good idea.

I keep thinking everything is laid down flat.

Why isn't it stay flat and, cause I know sedimentary rock, which is flat, flat, flat.

This is not.

This is straight up.

(Richard) Just about straight up.

(David) Yeah, well.

Sort of in its own way.

Now, tell me, how does it get from this to this?

(Richard) So we are in right in the middle of the fold of a monocline, which means it went like this and it went down and like that.

And we are at this apex which is eaten away.

And now we're down here looking up and we're seeing all these pieces that are left from that fold, sticking up.

We're seeing the innards, we're seeing the guts of the sedimentary layer that was here.

(David) This is a jewel.

(Richard) This this is a crowning jewel.

(David) The colors are from the original horizontal strata and the chemical composition is different.

And a lot of them, there's iron in them brought down from up above.

Some are more clay and some more mud.

(Richard) A lot of the colors now are accentuated because of the fracturing thats taken place.

They're compressed, the colors are now compressed.

And instead of being lightly red, they're deep red and they go white instead of white is chalky white.

(David) It is chalky white.

(Richard) So because this is in the middle of this fold, these rocks here have been so compromised it instead of being hard sandstone and hard silt stone, they've turned almost to mud.

But the advantage to that to us is look at what it did to the color.

But you still you can see the verticality of it.

You see how the whole thing was almost straight up and down here.

(David) It's just like really something out of Tolkein, you know, out of Lord of the Rings.

(Richard) Maybe this is where he wrote the book.

(David) I wonder if he came here and wrote for a few weeks.

From what I can see here, it's utterly sensational.

It's earth shaking in its beauty and it's kind of boring compared to what we saw back there.

(Richard) Well, let's just put it this way The best is behind us.

(David) So far.

The Colorado Plateau portion of northern Arizona and southeastern Utah is best known for its monuments, its hillsides of sedimentary rock and its deep canyons.

But every once in a while, magma explodes to the surface, creating a convoluted landscape unlike any other on the face of the earth.

Join us next time In the Americas with me, David Yetman.

The Colorado Plateau is internationally famous for its geological wonders, but for thousands of years, myriad native peoples have also called it home.

Well, the story is that I believe it was National Geographic Society sent some people out to explore in this area and found this.

And the reds were so sharp that they were reminded of this wonderful new film called Kodachrome, named it Kodachrome and the state took it over State Park.

(Richard) What if it was 20 years or 30 years later?

Would they have called it ektachrome because of the blue sky?

(David) No.

But now they would have called it Digital State Park.

(Announcer) Funding for In the Americas with David Yetman was provided by Robert and Carol Dorsey.

Additional funding for In the Americas with David Yetman was provided by Laura and Arch Brown and by the Guilford Fund.