From the Gangplank to the Big Hole: Deep History in the High Plains

If you drive west along Interstate 80 from Cheyenne, Wyoming, you'll soon begin to cross the Rocky Mountains. But the strange thing is, you might not realize it. In this part of Wyoming, the high plains are really, really high. They form a great ramp that goes up to 7,000 feet--almost to the top of this section of the Laramie Range, which is low by Rocky Mountain standards. When you get to the place where the plains touch the granite of the mountains, you're higher than any point in the eastern United States, but it's mostly a big flat place. The only clue at first that you're crossing a mountain range are a few low granite hills that poke up through the plains.

This highest section of the high plains is called the Gangplank, and it played a key role in American history. When the Union Pacific railroad was looking for a way across the Rockies, they weren't interested in the soaring, craggy peaks to the north and south. That's much grander scenery, but you don't want to build a railroad through it. What they needed was a smooth climb to a gentle mountain pass, and this is where they found it. The trains still go this way today, sharing the Gangplank with Interstate 80.

The Gangplank isn't the most scenic entrance to the Rockies, but it's an fascinating place--once you know what what you're looking at. This is a landscape with a story to tell, and that story is much, much older than the Transcontinental Railroad. If you could go back in time about 30 million years, most of the Rocky Mountain region looked a lot like this stretch of I-80 today. The mountains were already millions of years old, and they had eroded until they were almost buried in their own debris, which formed sloping plains like the Gangplank. Only the tops of the mountains protruded, as the granite hills still do here. The Gangplank region is a fossil landscape; a window into a mostly-vanished world.

This world began to change a few million years ago, when rivers began to eat away at the plains and uncover the mountains. Geologists aren't sure if this happened because the whole region was lifted, making the rivers steeper, or because the climate grew wetter, making the rivers more powerful. Perhaps it was a bit of both. In any case, the mountains were uncovered, in an event known as the Exhumation of the Rockies. Because the Gangplank is between two rivers, it was left behind as one of the only places where the plains still rise to the mountaintops. The rocks here preserve an unusually complete record of the rise, burial, and resurrection of the Rocky Mountains.

It's an epic tale, and to understand it, a good place to start is to leave the interstate at Exit 345, and pull into a parking lot full of big rigs. At the east end of the lot is a sign about the Gangplank and its geologic history, with a nice (though slightly outdated) diagram, shown to the right.

As the image shows, three very different geologic structures come together here. The "You are here" marker is at the edge of the Gangplank, which is made of almost-horizontal layers of rock. At 5 to 37 million years old, these rocks are youngsters. But just a couple miles west, you enter a far more ancient landscape. Here the granite and metamorphic rocks are between 1.4 and 1.7 billion years old. Hard, ancient rocks like this are called basement rocks, because they form the foundation for most of North America (though they're often deeply buried below younger layers of sedimentary rock).

Now, if you look north or south, you may see layers of red and tan rock that poke up through the plains at a steep angle. These range from about 300 million to 65 million years old. They're mostly buried here, but in other parts of the Rockies they're exposed and and breathtaking. At places like Red Rocks near Denver, or the Flatirons near Boulder, you can see that they lean against the ancient basement rocks like a stack of plywood against a wall.

But they weren't always tilted like this. Before the Rockies began to rise around 70 million years ago, they were flat. Then the basement rocks rose from deep underground and tilted them upward; pushing them aside like a man coming up through a trap door. But what about the near-horizontal rocks of the Gangplank? Why weren't they shoved sideways? Because they weren't there yet. They formed as the mountains began to wear down, and that's why they're still relatively flat.

That's the basic story you get as you stand on the high, flat expanse of the Gangplank and read the sign above. But standing by the interstate looking at a sign isn't that satisfying. What we need is a place where we can descend down into the the rocks sketched on the sign, and see them in real life. Luckily, there's just such a place a few miles to the south, just across the Colorado border.

To get there, take the I-80 service road a couple miles west and head south on Harriman Road. It's a dirt road, but a relatively civilized one. To your left, you'll soon get a good look at the tilted sedimentary rocks that lean against the ancient granite. After driving among stubby granite hills for a few miles, you'll emerge into a sweeping landscape of red mesas and the high, snow-capped peaks of the Colorado Front Range. It's big, beautiful country.

Our destination is Red Mountain Open Space, a public park managed by the city of Fort Collins, Colorado. The park is in a valley the ranchers here call the Big Hole. As holes go, it is quite large, especially if you look into it from the edge of the Gangplank. To get a basic sense of the geology of the Big Hole, take a look back at the sign from I-80. South of the Gangplank is an eroded region of older, tilted sedimentary rocks. That's the landscape we're in now, but with one wrinkle.

No, seriously--there's an actual wrinkle in the rocks here, and it's a big one, called the Sand Creek Anticline. To see it, head east from the open space parking lot on Bent Rock trail, following Sand Creek. Soon you'll enter a canyon that cuts straight through a hill of red and salmon-colored rock. We'll call this Red Mountain. The rocks here rise and then fall again in a big arch, or anticline. The picture above shows the curve in the rocks inside the canyon. When you leave the canyon and look back to the south at Red Mountain, as in the picture below, you get an even better view of the anticline. The yellow lines show how the rock layers bend inside the canyon, while the steep layers in the foreground have eroded into formations called flatirons. This anticline is an asymmetrical one--the layers on one side are much steeper than the other. There's a reason for that, as we'll see.

If you turn around here and look north, you'll see that the Sand Creek Anticline runs for several miles through the Big Hole. The hill in the next picture doesn't have a name that I can find, so I'll call it Swoop Mountain, because the rocks here take a big swooping path across it. On the left side of Swoop Mountain, you can see the same red rocks that form Red Mountain, but there are several younger layers lying on top (these layers once covered Red Mountain, too, but have eroded away.) As the yellow lines show, all the layers across Swoop Mountain drop down from the west (slanting down off the Rocky Mountain front) and suddenly rise again steeply, like the rocks in Red Mountain (visible on the far right). Then they slope gradually to the east. Some of the yellow lines go through empty space, because some of the rocks have eroded away. The lines show how the rocks would bend if they were all still there. Swoop Mountain shows that surface landforms don't necessarily mirror the shape of the rocks below. Here the rocks bend downward right where the surface bends upward as a hill.

From down here in the Big Hole, we see that the sign on I-80 is basically correct, but simplified. The layers here do slope down to the east, but they have a sharp bend in the middle that doesn't appear on the sign. The reason for the bend, most likely, is that the basement rocks below the surface have a fault in them--they've broken into two blocks here. The block on the east side of the valley has lifted and rotated, leaving the sedimentary rocks draped over the fault like carpet over a cracked concrete floor.

But what about the Gangplank? How does it fit into all this? You can see it on the horizon in the picture above, but to get a better look, we need to hike to the other side of Swoop Mountain. From there, you see the view below. The cliffs on the right are the Chalk Bluffs; the escarpment formed by the southern edge of the Gangplank. The picture shows that these rock layers are basically flat. They weren't tilted and warped by the rising Rockies, because they formed afterward--from the eroding Rockies. The red layers on the left are tilted, though you can't see it very well in the picture.

The contact between these two rock layers is an example of an angular unconformity--a place where rocks of different ages and angles meet. There's no physical gap between the two layers, but over 150 million years is missing from the rock record. The deep red rocks are about 245 to 285 million years--older than the dinosaurs. The white rocks sitting on top of them here--more visible in the picture below--are called the White River Formation. They formed in a time when the dinosaurs were long extinct and strange prehistoric mammals roamed the West. But 150 million years is is just a minor gap. Further east, the White River Formation lies directly on top of basement rocks that are at least 1,400 million years old. That's a lot of missing history. Luckily, much of it can be found in other places.

I should mention one more feature, because if you take this hike, you'll notice it. Walking back toward the parking lot, on the east side of Swoop and Red Mountains, you'll see the weird crest of white rocks in the image below. Those are layers of gypsum from the Permian Period, when this part of the country was a shallow, salty lagoon near a hot desert--similar to the salt flats of today's Persian Gulf. Water evaporated rapidly in these conditions, leaving behind deposits of gypsum (or alabaster, if you want it to sound fancy). These layers erode and dissolve faster than most other rocks, often leaving cavities that can cave in as sinkholes. Rattlesnakes like to gather in one of the sinkholes near here to spend the winter in cozy heaps, so watch your step in these parts.

We've covered a lot of ground here, and an enormous amount of time, so maybe it would be good to step back and look at the big picture. That would be the image below. This is an aerial view of the whole region, copied from Google Earth and labeled by me. Now, I'm librarian, not a geologist, so take it with a grain of salt--the lines and boundaries are far from exact, and will likely make real geologists cringe.

Satellite Image from Google Maps. Amateur annotations by the author.

Here we see the Big Hole in the right foreground, the basement rocks of the Laramie Range to the left, and the Gangplank to the northeast. Interstate 80 is a few miles past the top of the image. In the Big Hole, you can see how the sedimentary rocks tilt to the east, pop up again at the Sand Creek Anticline, and then tilt eastward again. To the northeast, the Gangplank is much less tilted, but it also slopes gradually eastward to form the the western Nebraska plains. The caprock of the gangplank is a coarse sandstone called the Ogallala Formation. It's very porous, and it gets waterlogged below the ground to the east, where it forms the famous Ogalalla Aquifer.

This is vast, impressive country, spanning big distances and stupendous amounts of time. It's a whole series of ancient worlds, stacked one on top of the other. That's true in many places, of course, but here you can descend into the remnants of those former worlds, and think about how they rose and fell. It's a wondrous landscape that can tell many stories, and the more stories you learn, the more wondrous it becomes.

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To Explore Further:

Geology Underfoot Along the Front Range. Lon Abbot and Terri Cook

Roadside Geology of Wyoming. David Lageson and Darwin Spearing

Roadside Geology of Colorado. Felicie Williams and Halka Chronic

Geologic map of the Table Mountain quadrangle and adjacent parts of the Round Butte and Buckeye quadrangles, Larimer County, Colorado, and Laramie County, Wyoming. Courtright, T.R., and Braddock, W.A.

Geologic map of the Laramie 30' x 60' quadrangle, Albany and Laramie Counties, Wyoming: Wyoming. Ver Ploeg, A.J., and Boyd, C.S.

Stratigraphic Chart of Colorado.

Hopes and Dreamers: DACA and the Purpose of Morality

With the fates of 800,000 DACA applicants on the line, I wonder if it’s a good time for Americans to reflect on the moral issues at stake in this situation. These days people on either side of the political spectrum tend think the other side is simply amoral. But that’s usually not true (even if a few on both sides really are amoral). Most people on different sides of the political spectrum actually think morals (or ethics, I’ll use the words interchangeably) are crucially important, but they think of morality in fundamentally different terms. The words “morality” and “ethics” mean something very different to conservatives than to liberals. This isn’t just my opinion--there’s a lot of psychological research to back this up.

The DACA issue highlights these different ways of thinking about ethics or morality. For example, you’ll hear many liberals (including me) and moderate conservatives saying that Dreamers did nothing wrong. They were brought here by their parents, they had no choice in the matter, and often barely remember the country they came from. But you’ll hear other conservatives saying, “The law is the law. They’re here illegally.” For them, that’s the critical moral fact. These folks may actually believe that morality requires that Dreamers be deported. They’re not trying to be evil (how many people really try to be evil?) As hard as it is for liberals like me to imagine, most are actually trying to do the right thing, within their moral framework.

But a lot of pain in this world has been inflicted by people trying to do the right thing--that’s why it’s so important to consider carefully what the right thing actually is. So let’s do that. If different sides are framing morality in such different terms, then maybe it would be helpful to lay these different approaches on the table and compare them. To put it another way, maybe this is a good time for Americans to think about what morality is fundamentally about. What’s the stuff actually for? What’s the point of being moral or ethical in the first place?

I once spent a couple of years reading everything I could about ethical theories, but I finally realized that for me, ethics boils down to something very close to the Golden Rule: treat others as I would want them to treat me. When in doubt about the right thing to do (and there’s often doubt) err on the side of compassion. As I see it, the fundamental fact that even makes ethics necessary is that other people have feelings. They have pleasures and pains, and hopes and dreams, just like I do, and theirs are just as intense as mine. I can’t prove that, but I think it’s an extremely safe assumption. (I should also say I’m not that good at following the Golden Rule, but I should be, and this is why I think so.)

Anyway, if ethics is fundamentally about the fact that other people have hopes and feelings, the next question is: who should I treat ethically? My answer is: anyone capable of pleasure and pain, and hopes and dreams. In other words, any human being (and many animals, too, but that’s another topic). That means how I treat someone shouldn’t depend on what language they speak, or what God they do or don’t pray to, or what country they were born in, or live in now. Those things don’t matter. What matters is that they are human, and have feelings and hopes just as intense as mine.

Some people will be reading all this and shaking their heads, because again, many Americans fundamentally disagree with my view of what morality is about. For them, morality is about other things: maybe it’s about following rules or laws scrupulously, or purity in sex or language. Maybe it’s about doing what they believe God wants, or making sure people get the rewards or punishments they deserve (an eye for an eye, etc.). For many people, a crucial component of morality is in-group loyalty: watching out for “your” people, and being suspicious of others. They actually see that as the right thing to do. Again, that's hard for liberals to remember, so we risk falling into the intellectually-lazy habit of thinking they are simply amoral.

Of course, not all conservatives think in these “if you’re not one of my people, you matter less” terms, but many on the far right do, and it’s not hard to find examples. Not long ago a guy told me he would rather see a million foreigners die than one American. A million! I’ve heard similar sentiments all my life. They’re not uncommon. And for some people with that outlook, it’s a pretty narrow group that counts as an American. You can see this if you drive down the interstate and see those motel billboards that have the little Christian fish on them, or say “American-owned”. That’s to tell travelers that the motel isn’t owned by immigrants with non-English accents and “foreign” religions. It doesn’t matter that those immigrants are most likely naturalized citizens who therefore ARE Americans, every bit as much as I am. They don’t match some people’s image of what an American is, and very often that means they don’t get the same moral consideration. They’re seen as “other”, and you better believe that makes a difference in how some people treat them.

But the fact is, most people have trouble empathizing with people who are different from them (I’ve already noted how hard it is for liberals like me to remember most conservatives believe they are doing the right thing.) Maybe it just requires more imagination to put ourselves in such different shoes, or maybe it’s human nature. Everyone does it, to some extent. But for some on the right (notice I didn’t say “all”) that basic human tendency is something to be embraced. They think it’s just self-evident that “our people” deserve more moral consideration than “others”. They also tend to think rules or laws should be followed scrupulously even if they cause human suffering.

I think both of these assumptions need to be seriously questioned, because they’ve both caused an enormous amount of pain in this world. That’s why I think people need to stop and ask themselves something they may never have asked before: what is morality really about? Why be moral at all? What if the reason rules and laws exist in the first place isn’t for their own sake, but for the sake of making the world a nicer place to live in; to make societies more conducive to life, liberty, and the pursuit of happiness? And what if all people are, in fact, created equal? What if whether you should treat someone decently doesn’t depend on whether they are “your people”, but whether they’re human beings with hopes, dreams, and feelings? Because that’s exactly what they are, and the hopes and dreams of 800,000 human beings are riding on how people answer these important moral questions.

Thoughts on Ideological Purity

A couple of times recently I've heard the phrase "ideological purity", and thought, "That's really what some people want, isn't it?" Part of the reason our country is so polarized, I think, is that there are vocal minorities on both sides of the political spectrum who insist on ideological purity. They have an orthodoxy, and they try to enforce it. They view moderate and independent members of their own party as heretics (or at least dangerously lapsed), and they view the other party as infidels and villains so irredeemable that it's a waste of time to engage with them.

On the far right is a vocal minority that refuses to compromise on anything, and attacks more moderate conservatives, calling them "Republicans in Name Only" or even "cuckservatives". Or they accuse them of being slaves to political correctness. 

Which brings us to the far left. While some conservatives have distorted the meaning of political correctness beyond recognition, and claim they're "not bowing to political correctness" when they're really just being rude or hateful, some on the left really do insist on a rigid form of political correctness. It is an orthodoxy, and they do try to enforce it. After all, the literal meaning of the words "politically correct" implies that there's a political viewpoint--and manner of speaking--which is indisputably the "correct" one. We've all seen the conservative speakers shouted down on liberal campuses, and even "ideologically impure" liberal professors have been targeted for their heresies. And have you noticed there's a whole genre of articles circulating on social media entitled "Why You Need to Stop Saying ________."?

Some on the far left really do try to tell others, across the political spectrum, exactly how they should be thinking and speaking. It may be worse on the left than the right, and I say that as a moderate liberal. Even as I write this, I'm wondering who will be offended by it, and whether they will write me off as a heretic. Do moderate conservatives have similar fears?

In any case, I think there are many problems with these attempts to enforce orthodoxy. One is that more moderate and independent types on both sides (who are actually the majority) are afraid to speak their minds, not for fear of being attacked by the other side, but for fear of being attacked by the orthodox wing of their own side. So there's fragmentation and bad blood within as well as between political parties, and the country grows more fragmented and dysfunctional. 

But there's another problem with ideological orthodoxy that I want to focus on here, and it is this: Once you declare that one particular stance on an issue cannot be wrong, and should not be questioned, you have stopped reasoning about that issue. And once you declare that others can't question an ideology, you've said that they must stop reasoning, too. People with rigid ideologies may still be "thinking", in the sense of spending mental energy defending or elaborating that ideology, but if there is no possibility of changing their ideology, they aren't really reasoning. Because the whole point of reasoning is to discover truths you didn't already know. Isn't it?

And chances are, there's a lot we don't already know. What are the chances that either extreme on the political spectrum (which is an artificial construct anyway) in this particular country, at this particular time in history, has finally got it figured out? Not very high, if you ask me. The universe is far bigger and more complex than our little primate brains can easily grasp. I have undergraduate and graduate degrees in psychology, and if there's one clear lesson to be learned from psychology it's that the human mind is easily fooled. Our senses are woefully limited, and we fall prey to dozens of different perceptual illusions, cognitive biases, and logical fallacies. As a species, our ability to see the world clearly is so pitiful that for most of human history we didn't know the shape of the planet we spent every day of our lives on. We were so sure it was flat that we attacked the people who said it wasn't. We probably burned a few at the stake for it.

We know more now, of course (and we're slightly more tolerant of opposing views). There are things we can be confident of, but they're mostly things which can be empirically verified. We're confident enough now that the world is round, for example, that we can call it a fact. But most ideologies aren't entirely, or even mostly, factual. They're full of opinions about complex systems like economies and social dynamics that can't easily be pinned down empirically, as well as value judgments and ethical stances that may never be empirically testable. But you wouldn't know this when talking to the ideologically orthodox on both sides of the the political spectrum. They sound for all the world like they're talking about established facts, when they're usually just expressing opinions and forgetting the difference. (I've been guilty of this myself, of course).

And perhaps we can be confident of some things we can't really call facts. As I stop and think this over (that's the main reason I write these--to clarify my thoughts), I suppose there are some moral opinions that we can be pretty confident in, too. We can be confident that murder, rape, and slavery are wrong, for example--confident enough to enforce legal penalties against them. But these are clear cases that most people agree on, whereas many of the opinions people express as though they were facts really are just opinions, and not ones that most people can agree on. 

So here's the question I want to ask people at both far ends of the political spectrum: Are you really that sure that your opinions are right? So sure that you can stop reasoning about them? So sure that you can tell others to stop questioning and reasoning as well? Should anybody be THAT confident in their opinions?