Intro to Geology: Crash Course Geology #1

0:00 Hi, I'm Sage and this is Earth.

0:03 Explosive volcanoes oozing red hot lava,

0:06 gargantuan gorges carved millions of years ago by rushing rivers,

0:10 and earthquakes that trigger 100-foot waves.

0:13 Our planet is massive, but it's also tiny.

0:17 It's a [music] sparkling gemstone that can fit in your hand.

0:21 Grains of sand that travel across the wind.

0:24 The scale is truly mind-blowing.

0:27 So, don't let anyone tell you geology is just a bunch of rocks, okay?

0:31 This is Dwayne, the pet rock, and this is Crash Course Geology.

0:37 [music] Rocks rock.

0:42 I hate puns.

0:43 So, what is geology, exactly?

0:47 Broadly, it's the study of the Earth.

0:50 But, that can mean a lot of different things, and it has.

0:53 Let's go back in time for a sec.

0:55 Long before geology became its own field of study,

0:58 indigenous peoples gathered a wealth of knowledge about the Earth.

1:02 Havasupai oral tradition describes a river

1:05 carving the Grand Canyon, which it did.

1:08 And there's a site in Arizona with fossilized

1:10 Dilophosaurus tracks that the Diné, or Navajo,

1:13 traditionally called a place with bird tracks way

1:16 before we knew birds were descended from dinos.

1:18 For many native cultures, then and now,

1:21 the Earth and its elements are part of an interconnected

1:23 system that we humans are a part of.

1:26 Check out Crash Course Native American History to learn more.

1:29 Across the world, early scientists and scholars

1:31 wanted to understand the world around them.

1:33 Persian scientist Ibn Sina noticed that layers of rock

1:36 build up with the youngest rocks on top,

1:38 an essential observation for dating specific rocks.

1:41 In the same century, Chinese thinker Shen Kuo figured out

1:44 that moving water shapes the land through erosion,

1:47 and inferred from fossils that Earth's climate has changed over time.

1:51 Take another trip across the globe,

1:52 and you'll find the folks who usually get all

1:54 the credit for developing geology as a science, Europeans.

1:57 There was a 16th century German scientist Georgius Agricola,

2:01 so-called the father of mineralogy,

2:03 who observed that rocks appear in layers and that earthquakes

2:06 and volcanoes might have something to do with Earth's molten guts,

2:10 like kimchi has everything to do with mine.

2:12 And then there were the 18th

2:13 century naturalists James Hutton and Georges Cuvier,

2:16 who had opposing theories about geological activity.

2:18 James was like, "Earth's geological processes work the same

2:21 today as they have forever." And George was like,

2:25 "There is geological processes are caused by major

2:27 catastrophes." They were both kind of right,

2:29 but we'll get to the dirt on that drama in a later episode.

2:33 Wait, I thought we weren't doing any more puns.

2:36 Unfortunately, a lot of the geologic knowledge acquired in this era was

2:39 a result of combing stolen land

2:41 for resources that could be exploited for profit.

2:43 And indigenous and enslaved peoples' perspective and contributions

2:46 to European colonizers' research went largely unacknowledged.

2:49 Rather than recognize the interconnectedness of different aspects of geology,

2:53 early Western geologists largely explored questions about

2:55 the Earth without considering the relationships between those phenomena.

2:59 But in the 1960s, a different theory

3:01 became widely accepted that really shook things up.

3:03 I'm talking about the theory of plate tectonics,

3:06 the idea that massive plates make up the Earth's

3:09 outer layer and slip and slide and smash together,

3:12 building mountains and making and breaking continents.

3:15 Because of these plates, Earth's got a surface that flexes.

3:18 Hit with the flex, Dwayne.

3:21 And Earth's the only planet we know with active tectonic plates,

3:24 a quality some geologists think is essential for life.

3:27 With the discovery of plate tectonics,

3:28 geologists finally recognized the Earth as one big interconnected system.

3:32 Kind of like the indigenous people were saying all along.

3:37 So, the definition of geology has changed over time.

3:39 And humans have been interested in it since we could pick up rocks and be like,

3:43 "Hey, cool rock." But why?

3:47 What's geology got to do with us?

3:50 Well, if we operate under the assumption

3:51 that Earth is one big interconnected system, then we are a part of it.

3:56 Not just in jewelry stores or museum gift shops,

3:59 talking about the minerals in your toothpaste,

4:01 the smartphone in your pocket, and the building you live in.

4:04 All products of geology, and that's just on a small scale.

4:08 Geology also shapes the places you live,

4:10 like through people's settlement patterns,

4:11 or the places they formed and maintained communities.

4:14 Let's dig a little deeper.

4:15 Behold the East Coast of the United States.

4:17 We've got plains here and rocky terrain here.

4:20 And this guy in the middle, that's called the fall line.

4:22 Connects a string of major cities like a big connect the dot.

4:25 Millions of years ago, this was the Atlantic coastline.

4:28 But over time, the Appalachian Mountains eroded,

4:30 and all that worn-away rock or sediment was carried out by rivers out here,

4:34 forming [music] the coastal plain.

4:36 If you were on a boat traveling upstream

4:37 from the Atlantic just a few hundred years ago,

4:40 you'd get [music] stuck at this fall line.

4:42 You'd hit fast-moving rapids, waterfalls,

4:44 you know, things you shouldn't go chasing.

4:47 [music] If you wanted to trade stuff, you'd have to dock your boat and haul

4:49 your wares on land until the water was calm again.

4:52 [music] Indigenous people knew this, but European colonists just

4:54 had to figure it out the hard way for themselves.

4:56 As they struggled to get further inland, [music] a place to set up camp.

4:59 So, at the fall line,

5:00 that point where they couldn't travel any further [music] upstream,

5:03 settlers built pitstops.

5:05 And those pitstops became towns,

5:06 which eventually grew into cities like Philadelphia,

5:10 Baltimore, Washington D.C., later home to a variety of avian mascots.

5:14 [music] I still don't know what Gritty is, though.

5:16 And today, if you ever drive down I-95, you'll be right on that fall line,

5:20 traveling the boundary no boat could ever cross.

5:23 These kinds of geological considerations have

5:25 affected where people live throughout history.

5:27 Like, humans have always loved building

5:29 civilizations on river plains with nutrient-rich soil.

5:32 I see you, Mesopotamia, with the good dirt.

5:34 Geology not only affects where you live,

5:36 but also what it's like to live there, including the weather.

5:40 Like, the Andes Mountains of South America are so tall,

5:43 they create the world's driest desert on one side,

5:46 and keep the Amazon rainforest lush on the other.

5:50 Geological features even influence the hazards

5:52 of living in a certain area like flooding,

5:55 landslides, earthquakes, and tsunamis.

5:57 So, yeah.

5:58 Geology is way more than rocks.

6:01 And we need folks to study all of this like geochemists who

6:05 examine the chemicals that the Earth cycles between the land, water, and sky.

6:09 Oceanographers who study geological processes under the sea.

6:13 Paleontologists who dig up old dead stuff.

6:16 And planetary scientists who explore the geology of other worlds.

6:19 Although, sometimes geology is all about rocks.

6:22 Don't worry, we didn't forget about you sedimentologists.

6:24 You won't find geologists in just one place, either.

6:26 They're all over the planet at universities, research labs,

6:29 government agencies, and companies focused on energy,

6:32 mining, and the environment.

6:33 Somewhere out there,

6:34 there's a geologist who identified the minerals in the laptop you use.

6:37 A geologist who monitors your water making sure it's safe to drink.

6:41 There's even a geologist protecting you from Earth's powerful blasts and shakes.

6:45 And despite geology's complicated history,

6:47 today's indigenous geologists are making waves in the field.

6:50 They're combining traditional knowledge with western

6:52 science to bring new insights and better shape our policies for doing geological

6:56 work on tribal lands like Shalianne Chavarría,

6:59 a member of the Pueblo of Santa Clara, who works to incorporate Pueblo teachings

7:03 and culture into the US Geological Survey.

7:05 Geologists often work like detectives to piece together the truth

7:08 about Earth's past and present using clues in today's rocks.

7:14 Hey, Roll man.

7:15 My office polished to a luster [music] with a stone

7:17 called Swagger of a boulder 12 times his size.

7:21 Somehow, I knew he had a story to tell.

7:25 Where were you 50,000 years ago?

7:29 But he just wasn't talking.

7:31 Geologists can help us answer big questions like how did life form?

7:36 Can we reduce the risks of earthquakes and volcanic eruptions?

7:39 What will happen to the Earth as its climate

7:41 warms and how can we manage its natural resources sustainably?

7:44 It might even help us figure out how the Grand Canyon got here,

7:47 cuz we don't totally know.

7:50 Wait.

7:51 I could just ask you.

7:53 What's that?

7:54 We know a Can tell them?

7:56 Us against rock on our code.

7:58 No, I understand.

7:59 As far as we know, Earth is a one-of-a-kind,

8:02 and we humans get to experience it all.

8:04 It's mountains, volcanoes, glaciers, and hoodoos,

8:06 which they seem like they shouldn't exist, but absolutely do.

8:09 Look at that thing.

8:10 Geology, and Earth itself, is too big to just be one thing.

8:15 It involves fossils, water, oil, and weather.

8:18 It reveals processes that have been chugging along for billions of years,

8:22 dramatically transforming our planet over time,

8:25 all while we bop around playing video

8:27 games and doing our nightly skin care routines.

8:29 Geology touches your everyday life, and if you let it,

8:32 it'll give you a brand new perspective on the world.

8:35 There's so much more to learn.

8:36 I can't wait to hit rock bottom together.

8:40 Oh, that one didn't even make sense.

8:41 Next time, we'll look back at Earth's past and discover

8:44 what it was really like in its toddler years.

8:47 See you then.

8:48 Thanks for watching this episode of Crash Course Geology,

8:50 which we filmed at our studio in Indianapolis,

8:52 Indiana, which was made with the help of all these dope people.

8:55 If you want to help keep Crash Course free for everyone,

8:57 forever, you can join our community on Patreon.