Hello, everyone! My name is Ranger Elsie, and I am so
excited to be talking to you all today. I am standing
in front of the gorgeous vista behind me in Shenandoah
National Park, and today we're going to be learning a
little bit more about the world around us.
Or, I guess, more like the world underneath us.
Today, we're going to be talking about the geology of Shenandoah
National Park. Geology is everywhere: the rocks, the landforms we
see, the very earth that we're standing on is
geology. Some of you may have heard of the rock
cycle before. The rock cycle is the changing of one
type of a rock into another type of rock, and it's
continuous. It never ends. Now, there are three types of rock. Now
keep in mind, remember this process has been going
on since the beginning of earth and will continue to happen
throughout the rest of the history of earth--throughout the end of time.
Now, the three main types of rock are igneous rock--so think fire, think
volcanoes. This rock is formed when the molten lava
material cools, and hardens, and becomes solid.
We also have sedimentary rock which is formed from pieces
of other rock that are pushed and smushed together.
And then if you push and smush and add even more heat,
that rock becomes metamorphic rock. Now, you know here in Shenandoah, we
actually have all three types of rock in our park at
one time. Wow! Which is pretty incredible!
Okay, so that's a lot of fancy science words
and to get a better understanding of all of these kinds of rocks and the
processes that happen to them, let's go cook up some
examples in the Shenandoah geology rock kitchen!
Hello everyone! Welcome to our rock kitchen here at
Shenandoah where we use cooking ingredient--food--
to learn all about different kinds of rocks and the geologic processes you can
find right here in Shenandoah. Now, I have my
rock recipe book right here with all of my personal favorite recipes.
And another personal favorite I have with me right here is Ranger Miranda, my
very, very good friend who's going to be helping me
out today. Hello! Now, the best thing about all of these recipes is that you can do
them at home to learn about these rocks, too. Before
you get started though, make sure you grab one of your favorite
adults to help you out and help you keep safe. Now,
we have all of our ingredients right here, but before we got started both
Ranger Miranda and I, we did wash our hands so we don't get any of those gross
germs on anything that we're going to be
eating later. So, with that, let's get started! Let's get
the ingredients!
All right, so now we are going to make a sedimentary
rock. So I have my recipe with me right here
and for ingredients it just says sediment and
glue. So...sediment...hmm... so we're making a sedimentary
rock. But what do you think sediment is? I've heard of it before. I think it's
little pieces of rock, like, that have been broken down?
Yeah, Miranda, you are so exactly right! So sediment is a broken down pieces of rock.
Now this rock could really be anything, right? So,
you can have sand be sediment, mud is sediment,
pebbles--even bits of gravel. Now here in rock kitchen we're not using
real rocks, of course! We are using cereal to represent all of
our different kinds of sediment. So I have
all of my favorite kinds of cereal right here:
We have Cocoa Puffs, we have Lucky Charms, Rice Krispies,
and, of course, delicious Cheerios and Captain Crunch!
So maybe those Rice Krispies are the sand, we have our pebbles,
everything like that. But, so now we have all our sediment.
Does this look like a rock? Not at all. It looks more just like a pile of sand
that you're moving around. Yeah, you're right! So it's not sticking
together. All of these pieces of sediment are still
really separate. But my recipe does say I need glue. Okay.
So we need something to stick to these pieces together,
and today I have some delicious marshmallow fluff.
Now, in the real world there isn't marshmallow fluff just oozing around
everywhere, right?...sticking together our rocks?
So in the natural world, this glue looks like a lot of different
things. but i'm glad that we're using marshmallow fluff
right now. So I'm just gonna pour some of this fluff
out on to my sediment--my cereal. Looks very sticky.
Oh yes. Perfect! That's exactly what I want.
Stick stick stick stick stick!
That still doesn't look like a rock, Ranger Elsie.
Yeah, you're right! So now I have my glue and my sediment, but
it's just kind of sitting there. If i shake it around,
it's still not helping. Maybe I should check my recipe.
Okay, so we added our sediment, we added our glue, now I have to mix my
ingredients together and gently squish them together. So
hopefully that will make my rock look a little bit more
like a rock. All right, here we go. Well we're really being chefs today!
Ooooooo...it is squishing. Oh I'm making a little bit of a mess here.
It's starting to look like bigger pieces of rock, definitely.
So it's sticking together. Some of those sediments are actually kind of squishy
as well.
Hmm... Elsie, is it okay if we just use our hands?
Yeah! I think that maybe we should go for it. I think so too.
All right, so, I am going to make--put the finishing
touches on our sedimentary rock. Can I grab that spoon?
Yeah. Thank you. So we can see exactly what you're doing in there. All
right. So I'm just getting real-- real in here.
I'm gonna gently squish it together. That looks like the tastiest rock I've
ever seen. And here we go!
So you can see that it it is squishing together...
Whoa! And, you can still see the different kinds of sediment that make up this
rock. So when you find a sedimentary rock like sandstone,
if you rub it, if you break it down a little bit, you can see the sediment
that is making it up, just like my cereal sedimentary rock
right here. If I broke it apart you could still see the different things.
So, you can find fossils in sedimentary rock...
So, like I can find the marshmallows in my Lucky Charms.
So this...our sedimentary rocks, they give scientists a great
idea about what the earth looked like at that time that sedimentary rock was
formed, because it's kind of like a snapshot of
the earth and what was on it at that time.
let's go find a sedimentary rock in the park! I'm sitting
in front of a sedimentary rock. So a sedimentary rock is formed by a lot
of different sediments or material or rocks that have
been glued together, bound together in a
process that we call lithification, which is a very fancy
geology word. Now you can tell this is a sedimentary
rock because if you look closely, there are different types of rock that
are stuck inside of it. Now we call these
clasts, which is another fancy geology word that really just means
rock. Now looking at these clasts, we can guess that they were pushed
along the bottom of a river and weathered and eroded
to become these little smaller pieces of rock
that then eventually were glued into this
bigger one. Now we call this kind of sedimentary rock a conglomerate
which is the most fun out of all of the fancy geology words that i just said! Can
you say it with me? Conglomerate. Great job! So
looking at this conglomerate, you can also tell
that it has gone through a little bit of that metamorphic
process. It's not quite exactly just a pure sedimentary rock; it's starting to
be smushed with that added heat and
pressure, but it didn't quite get all the way
there, and so we can still call this a beautiful sedimentary rock.
Ooooooo, yummy chocolate rocks! Delicious! Don't eat them yet, Elsie! We have to make
igneous rock! Man...but they look so tasty, but
I guess you're right. Okay, I'll look at my rock recipe.
So for an igneous rock, it says that we need
rocks: we've got chocolate chips in this case.
Then we need heat, heat, and more heat.
Okay. Holy moly! That's three things of heat!
Whoa! And then just for direction, it says to apply
all heat to rocks to make rock soup. Ooh rock soup! Oh, I know! Sounds tasty,
right? So that seems like a lot of heat, but we
are making an igneous rock. So when I hear the word igneous I think
ignite--like fire, like starting a fire-- and that's because we all need a whole
lot of heat to melt these solid rocks into liquid
to make that rock soup or what we call it magma.
in real life. So underneath the earth's surface,
all of this heat is being applied to these rocks until they actually
melt. Whoa! And after, then we get our magma.
A few things can happen to it, so either, it's kind of like if you had your pot of
soup on the stove and you took it off and then you shoved
it in the freezer. So it can get really, really cold and
then solidify again--kind of turn back from soup into a
solid-- or the other thing that can happen is
that it tries to escape from that pot, so if you've ever seen
something boil over that's kind of what our rock soup can do
or a magma can do. It looks for cracks in the earth's
surface and it can ooze and flow out,
or what is maybe a little bit more fun-- it can explode or erupt! Exactly,
right? So just like a volcano, which is one of the more explosive
things that can happen to our magma, and once our magma touches the air
outside, we start calling it lava instead. That's the difference,
so our igneous rock, it melts and then turns into magma, then
eventually becomes lava. Whoa! Whoa!
So, unlike for our metamorphic rock, I don't think that we can make enough heat with
our hands to be able to turn these chocolate chips into melted
chocolate or a rock soup, so if you are following along with us at
home, this is the time that you grab your adults
because we need some extra help to be able to melt all of these chocolate
rocks. So we're about to go and zap them in the
microwave ,and we'll be right back with you.
Alright, and now we have our beautiful magma.
You can see it's all like nice and rock soupy.
Yeesh! There we go. So
here in Shenandoah, like I said before, we didn't have those explosive volcanoes.
Our volcanoes were oozing like that spaghetti sauce, right, that you
can think of. So slowly through cracks, our
magma was just being oozing kind of down, it was flowing out of the
earth and across the landscape. That's a pretty
slow, it's a very slow ooze. So
we didn't have, like I said, those crazy big volcanoes like Mount St.
Helens', but we did have a lot of volcanic activity and over a long period of time
too. So these this flow--it didn't just happen
one time over and over and over again! These
layers, these lava flows were building up on top
of each other to create the landscape.
Should we do one more lava flow? Yeah!
Whoa! This is a big one! So, eventually all of this lava, it cooled
down into the igneous rock that you can still
find in the park. When that lava after it has flowed out,
it slowly, slowly cools and reforms into the solid rock that we
can walk on today just like here. So you can see when I hit
this, it's no longer that oozy spaghetti sauce
kind of consistency. Instead, this is solid, solid chocolate solid, solid
rock. So, I am sitting on what we call
igneous rock. Now, this is a--called a metabasalt. So, igneous rock--think ignite;
think fire! This rock was formed by
molten lava. So magma underneath the earth
kind of bubbled up--think of a boiling tomato sauce or spaghetti sauce, right?
Sometimes it pops and it splatters everywhere, we had
splatter cones essentially or it kind of oozed out,
and then when that lava, it cooled, it formed this igneous rock. Now
what I''m sitting on is really called columnar jointing,
because when the lava, when it dried, it kind of
cracked and became this amazing rock formation that
we can see here today. So today we are going to be making a
metamorphic rock. Looking at my metamorphic rock
recipe, it says for ingredients I need: rocks
heat, and pressure. So as this is rock kitchen, I didn't want
to use real rocks, so instead I have something a little bit
more tasty. So, I have some different colors of
Airheads right here. Now I thought that
the different colors of Airheads they could represent different rock layers
that have been deposited, or put down, laid down and stacked on top of each
other over time. Okay, but it says to make a metamorphic
rock I also need heat and pressure. And, then all my
directions say is to apply that heat and or pressure. So
Miranda, can you help me? Yeah, sure. What do you think that means? Well it looks
like you have a really good start by laying
down these awesome rock layers. Now we need to metamorphose
them. Metamorphose is another word for change.
So these smell really nice, so we are going to--we have a little way.
What did you say we needed to change them? So
my recipe says that we need heat and pressure. Okay!
So a way to produce heat, a really easy way,
is to get your hands and just rub them together. Rub them really fast,
and you'll start to feel your hands getting hotter and hotter.
Yeah! And when you feel them hot enough, go ahead and grab
your rock layers.
Okay, and you are going to apply pressure with your hands.
Oh, good thing I'm really muscly. Yes, good thing! Use
all your muscles. Now you can reheat up your hands again if you want to get
some more heat. Wow! Look at this. Oh, I can really see all
of these layers I'm smooshing together. Holy moly, yeah
and it's starting to look like a metamorphic rock. A lot of times in
real life when we go out and see them, they are they just look
like they've been just twisted and contorted and that's exactly
what's going on. Now most of the time, almost all of the
time you won't find rocks being metamorphosed at the
surface. They need to be metamorphosed deep down
below where there's enough heat and enough pressure in order to change
them. Keep in mind that is not liquid,
it's not liquid like water, it didn't get enough
heat in order to make it into a rock soup, but it got enough
to really make it look and to really make it look differently.
Wow! So, this is from all of those different layers of rock. I just have
one big rock now. Yeah!
Are you gonna eat that all in one bite? Oh, do you think I can?
I think you probably could, but it might give you a stomachache.
Yeah, maybe I'll just leave our metamorphic rock the way it is now,
but let's go see an example in the park. Good idea!
And this is an example of metamorphic rock that you can find
right here in our park. Do you see this lovely
green rock right here, and there's actually some pink.
This is called unakite, and a fun way to remember that is that it's kind of a
combination between a unicorn and a kite--probably not
something you see every day. Unakite was formed by hydrothermal
activity. Now, hydro means water and thermal means hot.
So, think of the hottest water that you possibly can
seeping through this rock and some of it turned into unakite, and around it
where that hot water didn't quite get to, it's still the granite that you can find
elsewhere in the park. Unakite is one of my favorites because
it is so pretty, right? We see this example of the green; we can
see this pink; it can even be blue. So, this was a lot of heat
that was transforming our rock into a metamorphic rock.
So, now we have those basic building blocks of geology,
let's start using them to create some of the landforms that we see today.
Now, when you're building a Jenga tower, or maybe a delicious
cake, where do you start? Do you start at the top? No! You have to start
at the bottom, right? And then build up the rest of the layers of this cake
or your mountain. Now it's the same thing with geology.
As these rocks are put down or deposited, newer layers are then laid on top of
them to build up the incredible mountains
that we have here today. Now each one of those
layers is kind of like a different flavor made of different materials, so
maybe this layer is...it's purple there, right? So, maybe it's grape?
And then we have blueberry, perhaps lime? So the different geological layers are
very similar, they tell a different story of the earth
at this time.
Even the earth doesn't seem to change very quickly. I haven't gone to sleep one
morning and woken up with a new mountain range in my backyard.
Geology is constantly changing and reshaping the environment everywhere you
go. So today let's explore the basics of
geology and see how they created the Shenandoah
National Park that we see here today.
So to recreate how our mountains here in Shenandoah formed,
we are going to experiment a little bit with those tectonic plates that I
mentioned earlier. So even though I might be very strong, I
can't move entire tectonic plates. I can't move the
entire earth, so instead we're going to be using
graham cracker tectonic plates, and they are floating
on this delicious marshmallow magma. So our mountains formed because of a
convergent plate boundary, so our two plates
pushed together and one
went on top of the other, because one of these plates was heavier
and so it sunk, and you can see here right. All of this
magma, which then we would call lava, rose
up out of the surface and created these mountains.
So right here is a great example of erosion
and actually weathering. So remember, erosion is picking up that material
picking up those rocks that sediment and moving it somewhere else.
So right here is actually an active rock fall which is erosion, right? You can
see all of these big rocks are being pulled
by gravity down the mountain, so eventually they
won't be here anymore. They'll be all the way down at the bottom.
Now when these rocks, they're going to be tumbling down,
they're also going to be weathered by all of that force, right? You can imagine,
remember weathering is that breaking down of the rock into smaller bits of
rock. So I bet that when this rock
rolls down that hill it's going to be slowly broken down into
smaller and smaller pieces of rock. So, right here
all of this sediment is going to be eroded as it tumbles down the mountain
and also weathered along the way all, right my friends?
So do you remember weathering, right, is that breaking
down of that rock into smaller and smaller pieces.
And I am standing next to an excellent example of weathering.
Do you see what is weathering this rock right here?
It's this tree, right? It's incredible! So this tree is actually growing in
between this rock and cracking it apart,
prying it further and further apart until it's becoming
two rocks instead of one. So this is a great example of how living things
can also weather a rock. So weathering can be done by trees; it
can be done by water; it can be done by ice; but this is
just one example that you can see while you're out hiking
of weathering in action. So thank you for joining me on our geologic journey today!
we've learned so much about the awesome rocks of Shenandoah National Park. So,
after learning everything that we have, do you think that Shenandoah is going to
look the same in a million years? In a thousand years? In a
hundred years? What about tomorrow? No, so all of the
processes that we talked about, they might seem like they take a very
very long time, but Shenandoah and the earth is
constantly changing, and so this park that you come
and visit is not going to be the same one that we explore today in this video,
but it is still going to be a Shenandoah that we love very, very dearly,
and need to take care of. So, I hope to see you all in the park very, very soon.
Bye, everyone!