Geology of the National Parks

Deep Time GeoClips (optional)

During three weeks in May 2004, two hardy Penn State geoscientists traveled through 12 stunning National Parks of the southwestern United States with 13 lucky students. The trip was sponsored by CAUSE (Collaborative Active Undergraduate Student Experience), an annual course offered by the College of Earth and Mineral Sciences. Richard Alley, Evan Pugh professor of geosciences, led the expedition. CAUSE 2004 was an extension of his course, "Geology of National Parks," and allowed students to interact with and learn from the rocks and landscapes of Arizona, Utah, and Colorado. In the following videos, Alley explains the concept of deep time, how it tells the history of our planet, and how it affects our lives.

Richard Alley, Ph.D., is Evan Pugh professor of geosciences in the College of Earth and Mineral Sciences,

—Emily Rowlands

What is Deep Time?

Click here for a transcript of the What is Deep Time? video.

What is deep time? Deep time, something very much older than us. Very much older than written history. Something that's old enough to encompass the glorious things that we see as geologists, 4.6 billion years of this planet.

If you go to the Grand Canyon and you look at this great trench holding a river at the bottom of it, and you think that the world is as old as written history, you're very confused. Because how can that river be down there when we can see what the river is doing? We know how rapidly the river is changing the world. People have been coming there for a couple of centuries and writing down what they know about it. And native peoples have been there for a few thousand years. And we know that its changed a little bit in that much time.

And so what's it doing there? Why is it there? If you open the door to deep time, you say OK, a sheet of paper a year, that much erosion, taking a sheet of paper off the rock every year, and you have way more time than is needed to carve that canyon. A sheet of paper a year in a million years, and you have the canyon.

And then you can start to see these greater stories. Because that's the time to cut the canyon. But how long did it take to make the rocks first? And so you see these tremendous stories that are sitting there. And you go out and look at the canyon. If you live in a shallow time, you look at the canyon and you say, isn't that great? It would make a nice picture. It would make a nice post card. And then you go to the visitor center.

And if you live in deep time, there's all these stories. And you can sit there and play in your mind's eye, the beauty of the seas coming and the seas going. And you can imagine what was that lizard that ran up the back of that sand dune, that's fossilized, and that big cliff, the first big cliff down from the rim of the canyon? There were lizards running across sand dunes when that was there. Why were there sand dunes there?

There's these amazing stories. And you stand there for an hour, and you're still thinking about them. And then you got to go walk down in and look at them closer. And rather than running to the gift shop and taking off to Las Vegas to waste your money gambling somewhere, you're lost in deep time. And it's just beautiful.

Deep Time and Beliefs

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I do think it's difficult for people to conceive of the age that we have here for a number of reasons. One is that, if you are a literal believer in certain sacred books, you believe that the earth is no older than written history. Now, as a geologist, my predecessors, back mostly in the 1700's, faced this. These were people who really believed in the sacred books and who, at the same time, had to look at the rocks and make sense of them. And some of them ended up, no, I don't believe the rocks.

Some of them ended up actually renouncing their religious beliefs. Many of them said, no, I can be a religious person and I can believe the rocks. But we're going to have to let a day be a little longer than 24 hours in the very beginning. They had to find some compromise between the two. People who absolutely believe, word for word, literal interpretation of certain particular sacred books simply cannot believe the age of the canyon.

I'm a religious person. I won't subject you to my beliefs. I am a religious person. And I belong to a very large religion that has several million members. And we have no problem with the age of the canyon.

Deep Time and Climate Change

Click here for a transcript of the Deep Time and Climate Change video.

If you want to ask, is nature going to undo what we humans are doing to the world-- we're burning fossil fuels. We're taking the carbon out of that and putting that carbon into the atmosphere-- and that's changing things. It's changing how easily plants breathe. It's changing how well shells in the ocean can be made by clams and corals. It's changing the climate. It's changing all sorts of things.

Nature will undo that. How rapidly? And so for that, we have to go back and look at how rapidly has nature done things over deep time.

And we do know. Nature has changed carbon dioxide in the atmosphere a whole lot. The dinosaurs lived in a world that had a lot more carbon dioxide in the atmosphere than we do, and they were fairly happy in that world.

It was a warm world. There were no ice sheets at the poles. It was warm all the way to the poles. There were crocodiles almost to the North Pole, and palm trees in Wyoming, and all sorts of things.

But the change between a low carbon dioxide world and a high carbon dioxide world that nature did is 100 million years, and we're doing it in 100 years. And so, is it likely that nature is going to undo what we're doing rapidly at a time that we would notice it? No. And so one needs to understand how rapidly does the world work by itself, and how rapidly do we change things. And so knowledge of deep time comes into questions like this.

Deep Time and You, Part 1

Click here for a transcript of the Deep Time and You, Part 1video.

There really are things that matter to you that come out of deep time. That's one reason we have a geosciences department at Penn State. If you've got a job-- you're a geoscientist. You took an undergraduate degree here, you get a job with an oil company, and you're supposed to tell them, should I drill an oil well here or not? We know that oil is made by cooking dead organic material, dead algae for the most part. You know that if you've had oil in your engine and your engine gets too hot, the oil will burn up. Oil is flammable. If rocks have been too hot back in the past, you won't get oil out of them.

And so you need to know, has it been hot enough to cook those rocks? Has it not been too hot to break them down? What happened to them. And so to figure that out, you need to know something about how deeply they've been buried, how long they were down there, how long it took them to come back up, what is their path through time, temperature, space. And that requires knowledge of deep time. Some rocks are not going to give you oil, because it burned up. There's a little bit of carbon, a little bit of graphite, stuck in there, and you're not going to find oil out of that. And so you need to know something about that.

Deep Time and You, Part 2

Click here for a transcript of the Deep Time and You, Part 2 video.

Knowledge of evolution. AIDS was going to happen, something like that. Antibiotic-resistant bacteria are going to happen. Things that are alive are survivors. And things that are alive have ways to adapt if their environment changes. We have to beat that by being smart, because evolution is very slow process. It takes hundreds, thousands of generations. Modern humans have not been around long enough that evolution acts on us very much.

I have bad eyes. This is true. I've probably given my children bad eyes. But physical evolution doesn't matter to that any more. We solve it by being smart. I don't get eaten by a sabertooth tiger, A, because there aren't many sabertooth tigers running around out there, and B, because I have glasses so I can see. And so we outsmart these things, because we don't change fast enough by biological evolution that it matters, but bacteria that reproduce any 20 minutes-- they do.

And so we should know that evolution will happen, that we see the record of it in deep time, and that it matters to us. Because if you don't a really good expert in what bacteria are doing, what viruses are doing, what the flu is doing, how we can beat that when they change-- because they will change-- you're likely to die in the next pandemic. And if you do have really bright people across the street over here who are figuring out the new antibiotics and figuring out the new vaccines and figuring out what we can do about it when that happens, then we can go on being happy and healthy and terrific.

And so these knowledge of deep time things, whether it be oil, whether it be environmental issues, whether it be evolution bringing new diseases that we have to deal with, deep time matters.