Title: Today, you are going meet a rock band to help explain about the changing earthbut not the kind of ro
1When you look at the land around youthe rocks,
mountains, streams, and other features, you may
think they have always been the way they look
now. But the entire Earth is changing all the
time in ways that might surprise you.
Today, you are going meet a rock band to help
explain about the changing earthbut not the kind
of rock band you might expect. These are the
rocks that make up the Central Appalachian
Mountains, and they are going to tell you their
story. The oldest member of the band is Granny
Gneiss.
2GRANNY GNEISS Hello! My real name is
Granite Gneiss, but you can call me Granny. My
name is not spelled N-I-C-E like it sounds. Its
G-N-E-I-S-S. I have seen a lot of changes
since I was formed over a billion years ago.
Continents have moved around and have collided
with each other. Mountains have grown, then
eroded or worn down into tiny pieces of sand,
then formed again. Ive seen dinosaurs come and
go, and volcanoes erupt. Ive seen it all, I
tell you. In fact, Im one of the oldest things
on Earth. Nothing you can see around you is
nearly as old!
3When I was born, all the continents of the world
had collided to form one giant continent. During
the collision I was pushed and squeezed until my
minerals flattened and some look like eyes.
4Then, I noticed that it was getting awfully hot
underneath me, and suddenly
5there were volcanoes erupting all over the place.
6FLO Hello. I came from one of those volcanoes,
and you can call me Flo. A lot of people think
that I am hot stuff. Maybe thats because when I
formed, my temperature was about 2000 degrees
Fahrenheit. Thats a lot hotter than an oven.
Its hot enough to melt rock! But I flow
slowlykind of like a thick, hot fudge topping.
When I cooled off, I became a black rock with
crystals too tiny to see with your eye. But if
you think I was hot stuff, you should meet Tuffy.
7TUFFY 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 make it explode out
of the top.
8Well, thats how I came out of the volcanogases
in the lava carried me out of the top and I
exploded. I thought I was Rocket Rock! It was
really exciting when I shot through the air.
Then I fell to the ground and cooled off.
9FLO Do you know what group of rocks Tuffy and I
belong to?
10We are igneous. That means we were totally melted
when we formed!
11TUFFY The eruptions were exciting, but when they
ended, I was out in the open.
12It rained and snowed on me. Water froze in cracks
and wedged me into pieces, and bit by bit I
started to break up into tiny pieces of sand and
clay.
13SANDY Hey Tuffy! Do you have a problem with sand
and clay? Just remember that were the ones who
have all the fun! Hi. My name is sandstone, but
my friends call me Sandy. When Tuffy broke up or
eroded into sand and clay, I was formed. Im
made of sand, and my brother, Shay, is made of
clay.
14Have you ever gone river rafting? Well, thats
what we did, only we didnt ride on top of the
river, we rode in it washed downstream by the
water!
15After we rode in the river for a long time we got
to the seashore. My pieces of sand were heavier
than Shays tiny pieces of clay. When the river
finally carried me to the ocean I was too heavy
to be moved by the water any more. I stayed where
I fell along the seashore and formed a beach. My
brother Shay was lighter and floated out to sea
before settling to the bottom.
16SHAY Hi. Im shale, but you can call me Shay. I
form in deep water where its quiet and calm.
There is another rock that forms as far out in
the ocean as I do.
17SHAY Her name is Limey and she is very useful to
people. After all of the continents were
together, they drifted apart, and for a long time
most of what is now the United States was covered
by a huge, shallow sea. Thats where I met
Limey.
18LIMEY Thank you, Shay. Yes, I was born in the
sea. Sometimes Im made of seashells or corals
that turn into fossils. I like warm, shallow
water.
19SANDY Limey, Shay, and I are all part of the
same group of rocks. Can you guess which group?
20LIMEYIf you guessed sedimentary, you were right.
The word sediment means to settle because we
settle out into flat layers, usually underwater.
21SHAY People like Limey because she does a lot to
help them.
22Yes, lime in soil helps plants like apple trees
grow.
23LIMEY People also dig me up to make roads and
concrete.
24When I change to marble it is easy to cut big
strong blocks for making buildings. Did you know
that the Washington Monument is made of marble
that used to be limestone? I also help teach
your class at school. The chalk your teacher uses
is made of a very pure form of limestone.
25Sometimes, when water dissolves me underground, I
make caves. People like to visit caves because
many are so beautiful inside. Caves also provide
homes for bats, which eat lots of mosquitoes and
flies every day.
26When I was forming, there was a much larger and
deeper ocean to the east. The ocean was a lot
like the Atlantic Ocean of today, but it was
different, too.
27FLO Yes, there were islands and volcanoes in the
ocean. 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. Talk about cold water! I turned rock
hard in seconds.
28Since Granny first formed life had been slowly
developing on Earth. By this time, about 400
million years ago, plants and animals had come
out of the oceans and were adapted to life on
land. This was a long, long time ago, even before
age of dinosaurs, and the plants and animals
looked a lot different than the ones you see
today.
29SHAY The really big change was deep within the
earth. The continents started moving closer
together again. The ocean that was between them
got squeezed smaller and smaller, including the
layers of rock that were under the ocean. Then
some of the volcanic islands ran right over the
top of me. Now thats a lot of pressure!
30Finally, the continents collided. It was like a
big truck running into a giant snow bank. Huge
layers of rock slid across each other like they
were nothing but a deck of cards.
31SANDY We were buried under tons of rock, and it
was hot, too.
32SHAY Yes, but the collision pushed us right
back up into the mountains, so we could ride
rivers again. With the first hard rain, Im ready
to travel back to the ocean again.
33SANDY Im harder than Shay, and I like being up
high on the ridges and cliffs. But Ive been here
for a few million years and I am ready to go for
a ride. Lets go!
34GLOMMY Hey! Wait for me! I want to go, too!
35SANDY Look out! Here comes Glommy!
36SHAY Glommy is made of pebbles that are so big
it takes a flood to get her moving.
37SHAY When water slows down, the pebbles fall
straight to the bottom, because they are so
heavy. When pebbles get cemented together they
make a rock called conglomerate. Thats Glommy!
38SANDY After Glommy settled down, I enjoyed the
ride. The lake we were washing into formed when
the continent started to pull apart again, and
water filled low areas. One of those areas was
in what is now northern Virginia between Reston
and Leesburg.
39There was lots of oxygen in the air and bits of
iron in me rusted or turned red, and soon I had a
new red outfit.
40 But then melted rock came up along cracks, and I
got roasted. When the melted rock cooled, it got
solid and hard and its used on a lot of roads
now.
41SHAY Roasted feet wasnt the only thing that
happened to Sandy thoughno indeed! One day the
water in the lake was so low that she was at the
surface. She was just lying there in the sun
minding her own business when she felt something
very heavy walking on her.
42Heres a closer look at the lake and there it is.
43A dinosaur walked right across Sandys new red
outfit.
44SANDY That dinosaurs big old feet sank right in
and made footprints all over me. Then, about 200
million years later, people found the dinosaurs
footprints in a quarry. They got excited and
called in scientists from the USGS. They all
made a big exciting fuss about it.
45They cut out a big block of me to display the
footprints. I loved being noticed by all those
people. If you visit the USGS and see the
dinosaur footprints, I hope you will notice me,
too.
46SHAY With the water drying up and land rising,
it was time to move on. The new Atlantic Ocean
was right nearby and since it was downhill from
us, off we went on another river ride.
47FLO Well, Tuffy and I are still in the
mountains, but we cooled off a long time ago. We
changed even more when the continents collided.
I used to be jet black, but Im dark green now.
Some rocks changed so much that you can hardly
tell what used to belike my friend, Shifty
Schist.
48SHIFTY SCHIST Hi everybody! Its about time I
got to meet you! I guess they saved the best
for last. I used to be a volcanic rock, but I am
completely changed. Yes, indeed, heat and
pressure made a new rock of me. High
temperatures and pressures deep in the earth let
new minerals grow and pushed them into shiny
layers that are neatly folded. Do you know what
kind of rock I am?
49I am metamorphic (that means changed), and like
all rocks, I just keep on changing. As a matter
of fact, just like all my rock band friends in
the hills and mountains around here, Im about
to go on another river ride.
50GRANNY GNEISS Hey Shifty, that sounds like fun.
Id like to go, too.
51GLOMMY Hey! Wait for me! I want to go!
52SHIFTY Look out! Here comes Glommy! OK,
Glommy, hurry up!
53GRANNY GNEISS Now you have met the members of
the rock band. We belong to three groups, but we
are all related, and one thing that we all do
is change. So the next time you see us, stop
and look closely to get to know us better. So
all togetherWhat is your favorite rock?
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