Presentation on theme: "Today, you are going to meet a rock band—but not the kind you may think. These are the rocks that make up the southern Appalachian Mountains, and they."— Presentation transcript:
Today, you are going to meet a rock band—but not the kind you may think. These are the rocks that make up the southern Appalachian Mountains, and they are going to tell you their story. The oldest member of the band is Granny Gneiss.
GRANNY GNEISS: Hello! My real name is Granite Gneiss, but you can call me Granny. And remember, “Gneiss” is not spelled N-I-C-E like it sounds. It’s G-N-E-I-S-S. When you look at me, you can see that I am made of lots of little crystals— mostly black, white, and gray. I am more than a billion years old. That’s older than almost everything you can see around you—a lot older!
When I was formed, all the continents of the world had collided to form one giant continent. During the collision I was pushed and squeezed until my minerals were flattened.
Then I noticed that it was was getting hot underneath me...
...and there were volcanoes erupting all over the place.
FLO: Hello. I came from lava, and you can call me Flo. Some people think that I’m hot stuff, and I was a lot hotter than an oven—about 2000 degrees Fahrenheit. That’s as hot as a melted rock! But I flow slowly—kind of like a thick, hot fudge topping. If you think I was hot stuff, you should meet Tuffy.
TUFFY: Hi! Yes, indeed, I was not only hot, I was explosive! Do you know what will happen if you shake a can of soda for a long time and then open it? Gases in the soda expand and make it explode out of the top.
Well, that’s how I came out of the volcano—like Rocket Rock! Gases in the lava made it explode, and I shot through the air, then fell to the ground and cooled off.
FLO: Do you know in what group of rocks Tuffy and I belong?
We are igneous. That means we were totally melted when we formed!
TUFFY: Those volcanic eruptions were exciting, but when they ended I was out in the open. It rained and snowed on me.
Water froze in cracks and wedged me into pieces, and I started to break up into sand and clay.
SHALE: Hey Tuffy! Do you have a problem with sand and clay? Just remember that we’re the ones who have all the fun! Hi. I’m shale, but my friends call me Shay. I was formed from the clay made when rocks like Tuffy broke up. My sister, Sandy, is made of the sand.
SANDY: Hi! My real name is sandstone, but you can call me Sandy. Have you ever gone river rafting?
Well, that’s what Shay and I did, only we didn’t ride on top of the river, we rode in it, swept downstream by the water.
SHAY: While we were being washed downstream, the continent was pulling pull apart and a deep sea formed.
When we got there, we got into a fast current, and I had the ride of my life. I raced through an underwater canyon at more than a hundred miles an hour. It was so much fun that I rode as long as I could.
SANDY: Fun for Shay, maybe, for me it was more like being spun in a blender! As the water slowed down it dropped me, and I settled down on the sea floor.
SHAY: Sandy couldn’t ride in the water any more because she was too heavy for the slower parts of the current. I am light and flat, so I was able to drift along even in slow- moving water. I was sorry that Sandy missed all the excitement. You won’t believe what I saw!
Way out on the bottom of the sea floor, black steam was coming out of vents into the water. That steam carried tiny bits of valuable metals, and they drifted over me as I lay on the sea floor.
Even now you can see beautiful little golden cubes of pyrite in me in a lot of places. In areas where lots of metal collected, people mined through me to remove the metal. At first people didn’t know that when you cut rocks like me open, rain water can carry acid from my minerals into creeks. This makes them acid like vinegar and is very bad for fish and plants.
SANDY: Yes, everybody has to watch out for that! When Shay was in the sea, it slowly got deeper and deeper because of movement on faults. By the time it stopped sinking, he was covered with miles of sediment.
SHAY: Then the sinking stopped, and the sea dried up. A new sea formed to the west, and it was shallow and warm. A new friend named limestone formed there. We call her Limey, and she is a very nice rock.
LIMEY: Thank you, Shay. Yes, I was born in the sea. Sometimes I’m made of sea shells or corals that turn into fossils. I form in warm water that is not very deep.
Sandy, Shay, and I are all part of the same group of rocks. Can you guess which group?
If you guessed sedimentary, you were right. Sedimentary means “to settle” because we settle out into flat layers.
SHAY: People like Limey because she does a lot to help them.
LIMEY: Yes, I add lime to the soil, which helps plants like peach trees grow better. People also dig me up to make roads and concrete.
In some places I contain zinc, which is a metal that is used to keep the steel in cars from rusting.
In places where water washes parts of my layers away underground, caves form. People like to visit caves because they are so beautiful inside. When I was first formed, there was a much larger and deeper sea to the east. It was like the Atlantic Ocean is today.
FLO: Yes, but it was different, too. When I erupted out of a volcano, I flowed right out under the ocean water onto the sea floor just like lava does today in Hawaii and Iceland.
Plants and animals that had first formed in the sea began to live on land. This was long before the age of dinosaurs, so the plants and animals were a lot different than the ones you see today.
SHAY: The really big change was deep within the earth. The continents started moving closer together. The ocean that was in between them got squeezed smaller and smaller, including the layers of rock like me that were under the water.
Finally, the continents collided. Huge layers of rock slid across each other like they were nothing but a deck of cards. They got shoved higher and higher until they formed mountains.
SANDY: We were buried under tons of rock, and it was hot, too. Shay couldn’t take it. He was softer than me, and when he got squished, all of his little, flat grains lined up and got even flatter.
SHAY: Is there something wrong with flat? Let me tell you something, Sandy. The very best rocks for skipping are flat and break easily into flat pieces just like me.
SANDY: That’s true, but it’s hard to hold on to those smooth, flat surfaces. When you get wet they’re slippery, and rocks on top can slide downhill and become landslides.
GRANNY GNEISS: Are you two at it again? Please excuse them. They argue all the time. Even though they argue, they have been hanging out together for several hundred million years, first in rivers and at the bottom of the ocean and then in the mountains.
SHAY: Yes, with us it’s down and up— first we get washed down into the sea by rivers and streams, then eventually we get shoved up into mountain ranges by continents pushing us around. When we’re high in the mountains, all we need is a hard rain and we’re ready to go again.
While we were up in the mountains, I heard that there was another continental break-up and a new ocean developed. It was called the Atlantic Ocean, and I couldn’t wait to explore it, too.
SANDY: No wonder Shay needs to rest so much. I like riding the rivers, but I’d rather stay in the mountains longer.
SANDY: Shay’s a softy, and he gets washed downstream easily. I like riding rivers, but I stay in the mountains longer because I’m tougher than Shay.
GRANNY GNEISS: When Sandy and Shay are together in the beds of rivers they sometime form beautiful rapids and waterfalls. Sandy is tough, so she makes the ledges. Shay moves out quickly and leaves low areas between ledges.
FLO: Some of us took a lot more heat and pressure than Sandy and Shay during the collision. Just look at what happened to me! I grew long black, needle-like minerals and got new long name, too, but since you are my friend, you can still can me Flo. Some rocks changed so much that you can hardly tell who they used to be—like my friend, Shifty Schist.
SHIFY SCHIST: Hi everybody—it’s about time I got to meet you! I guess they saved the best for last. I used to be volcanic, but I am now a changed rock. Yes, indeed, heat and pressure made a new rock of me. I now have shiny layers that are neatly folded. Do you know what rocks that have been changed by heat and pressure are called?
We’re called metamorphic, which means changed, just like Granny Gneiss.
GRANNY GNEISS: That’s right, Shifty, but some rocks changed even more than we did. They got so hot that they actually melted! At the surface, melted rock comes out of the Earth in volcanoes or lava flows, but some melted rock stays deep underground and cools off very slowly like Baby Gran.
BABY GRAN: Hi! I was afraid you’d all forget me, just because I’m the youngest member of the rock band.
SHIFTY SHIST: Sorry about that, Baby. BABY GRAN: It’s OK Shifty.
BABY GRAN: My real name is granite. I’m not deep in the earth any more. The mountains above me eroded so that I’m at the surface now.
I make rounded, smooth-sided domes like Looking Glass Rock.
TUFFY: I’d never forget you Baby Gran. Although we look very different, we both formed from melted rock deep in the Earth. I’d say we’re almost like cousins!
GRANNY GNEISS: That’s right, Baby Gran, and I was once a granite, just like you before I was metamorphic. Well, now you have met the members of the rock band. We belong to three groups, but we are all related, and the one thing we all do is change. So the next time you see us, I hope you will try to get to know us better. Now, here’s our song!
ALL SING: A Southern Appalachian Rock Band. Double click for sound
There’s Granny and Flo and Baby Gran. There’s Sandy and Shay and Limey, too. And don’t forget Tuffy or Shifty Schist, and the changes that they went through. Double Click here
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