Download Section 2: Rocks and Minerals

The Earth’s Crust
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Earth’s Crust Unit.
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Vocabulary
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The Earth’s Crust
1. ________________- a sudden, violent shaking of the Earth
2. ________________- a scientist who studies rocks to learn about the history and
structure of the Earth
3. ________________- the scientific theory that the Earth’s crust is made up of
plates that slowly shift position
4. ________________- a deep, long valley in the ocean floor.
5. ________________- melted rock formed in the Earth’s mantle
6. ________________- an opening in the Earth’s surface that releases magma from
the mantle
7. ________________- magma that has reached the Earth’s surface
8. ________________- a type of rock formed from magma
9. ________________- a type of rock formed by the pressing together of smaller
particles of rock or the remains of living things
10. ________________- a type of rock formed when igneous or sedimentary rock
changes under very high temperatures or pressure
11. ________________- a process that breaks down rocks and minerals
12. ________________- rocks on the Earth’s surface broken down by weathering
to very tiny pieces that mix with the nutrients from living and once-living things
13. ________________- the wearing away of rock and soil
14. ________________- a large, slow-moving field of ice
Section 1: Plate Tectonics
Drifting Continents
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The Earth’s Crust
The Earth’s crust __________________. Most of the time we don’t even feel the
movements.
An __________________is a sudden violent shaking of the Earth.
In California, there is at least one earthquake every __________________.
Earthquakes are caused by a shifting of pieces of the Earth’s
__________________.
Most earthquakes are so _____________ that only scientists notice them.
However, every 50 to 100 years a big one comes along and does a lot of
__________________.
A __________________ is a scientist who studies rocks to learn about the history
and structure of the Earth. They also study the __________________of the Earth’s
crust and what causes them.
Most geologists think that all the continents were once part of one big
supercontinent called __________________.
About 200 million years ago, pieces of land began __________________ free from
Pangaea.
These landmasses came together and separated many __________________.
Eventually they __________________ to the positions they are in today.
_______________ ______________ is the scientific theory that states that the
Earth’s crust is made up of plates that slowly shift position.
A plate is a large piece of the Earth’s __________________.
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The Earth’s Crust
The movement of these plates causes __________________.
Some of these __________________ are very big, but there are smaller plates, too.
A plate can include a landmass, such as a __________________, as well as a
section of the __________________ floor.
The plates are __________________ all the time. However, they move very
slowly.
Most of the United States is on the North American plate, which is drifting
__________________.
__________________ drift is the theory that the Earth’s large landmasses are
carried along, or drift, because of the movement of the plates.
The Earth’s crust is moving because the crust __________________ on the hot,
softer rock of the mantle.
Trenches and Mountains
The __________________of the Earth’s crust may bump into each other, or
__________________.
As they collide, one plate may be forced __________________ the other.
This plate gets pushed down into the hot __________________, where the crust
__________________.
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The Earth’s Crust
When one plate gets pushed down under another beneath the sea, a
__________________ forms between them.
A trench is a deep, long __________________ in the ocean floor.
Sometimes two __________________ plates pile up against each other on land.
This is how __________________ range are formed.
Mountains build up very __________________!
Over __________________ of years, the plates push against each other.
As they push, the land gets shoved __________________ making mountains.
This is how the __________________ in South America and the Himalayas in
Asia were formed
Mount __________________ in the Himalayas in Asia is 29,028 feet above sea
level. It is the highest point on Earth.
Earthquakes
Sometime instead of two plates pushing into each other, they
__________________ past each other.
This is true of the Pacific and North American plates. They meet along the
__________________ coast of North America (California).
The __________________ plate moves about 2 inches each year in the northwest
direction.
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The Earth’s Crust
Many __________________ occur along the coast.
Each time there is a sudden __________________ between the plates, an
earthquake occurs.
Two huge pieces of the Earth’s __________________ may rub against each other.
The plates do not slip by each other __________________.
__________________ holds the upper layers of the crust together. However, the
plates continue to move __________________ down.
__________________ builds up on the surface. Finally, when the
__________________ becomes too great, the plates slip.
The sudden movement sends __________________ waves through the Earth. An
__________________ is the result.
Volcanoes
Sometimes, when plates move, __________________ form in the crust.
Melted rock, called __________________, squeezes up from the Earth’s mantle.
An opening in the Earth’s surface that releases magma from the mantle is called a
__________________.
The word volcano is also used to describe the __________________ that builds up
around the opening.
Volcanoes can form on dry land or on the __________________ floor.
The magma comes up through openings called __________________.
Magma that has reached the Earth’s surface is called __________________.
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The Earth’s Crust
As the lava cools, it hardens into __________________. Over time, the lava builds
up and creates a mountain.
When volcanoes occur in the ocean floor, they can create __________________.
The __________________ Islands were formed this way.
Some volcanoes erupts __________________. Lava, ash, and hot gas explode high
into the air.
Other volcanoes erupt more __________________. The lava flows quietly onto the
surface.
Section 1 Review
True or False- Most geologists think that all the continents were once attached.
True or False- When two plates collide, they can form trenches or mountains.
True or False- The Earth’s plates float on the crust.
Section 2: Rocks and Minerals
The Earth’s crust is made up of __________________.
There are many different kinds of rocks. Some of the __________________
properties of rocks are color, shape, hardness, and __________________.
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The Earth’s Crust
There are __________________ basic kinds of rock: igneous, sedimentary, and
metamorphic rock.
 __________________ Rock
– It is formed from __________________ (forced up from the mantle or
lower crust).
– When it reaches the surface, the magma hardens into
__________________.
– Kinds of igneous rock are obsidian, basalt, and granite.
– Igneous rocks make up ________ of the Earth’s crust.
 __________________ Rock
– They are formed by the __________________ together of smaller
particles of rock or the remains of living things.
– They take a __________________time to form.
– Beds of clay, sand, or gravel may harden to make sedimentary rock.
– Types include: shale, sandstone, coal, and limestone.
– Sedimentary Rocks are the most __________________rocks on the
Earth’s surface.
 __________________ Rock
– They are formed from sedimentary or igneous rock that changes under
high __________________ or pressure.
– When igneous or sedimentary rocks become extremely hot, they
change __________________.
– They metamorphize.
– Two kinds of metamorphic rock are marble and slate.
Building Rocks from Minerals
All rocks are made up of __________________.
There are at least __________________ different kinds of minerals.
Each mineral has a unique __________________ makeup.
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The Earth’s Crust
Many minerals are pure elements. However, most are __________________ of
elements.
Some examples are talc, __________________, quartz, and bauxite.
Weathering
__________________ is a process that breaks down rocks and minerals.
__________________ water, ice, rain, plants, animals, and chemicals all help to
weather rocks and minerals.
For example, as a river flows, it washes away little bits of rock from the riverbed.
These bits of rock are swept __________________. As they move, they bump into
other rocks and tumble along the bottom. Slowly, they break into
__________________ and smaller pieces.
_____________ also causes rocks to weather. Rocks have many cracks. Water fills
the cracks in the rocks. When the water freezes, it __________________. The
freezing water, or ice, acts like a wedge to break the rock into smaller pieces.
__________________ causes weathering, too. Raindrops beat on rocks like
millions of little __________________. Eventually the rocks wear down. Rain also
causes the weathering by mixing with gases in the air to make a weak acid. This
acid __________________ certain minerals in rocks. Over time, the rocks
crumble.
Even __________________ help weather rocks. Some plants start growing in the
cracks of rocks. As the roots grown, they __________________ on the rocks and
help break them apart.
__________________ is an important product of weathering.
Soil is made up of __________________ on the Earth’s surface broken down by
weathering to very tiny pieces that mix with the nutrients from living and once
living things.
A layer of soil takes __________________ of years to form.
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The Earth’s Crust
Erosion
Erosion is the wearing away of __________________ and __________________.
Like weathering, a __________________ can cause erosion.
Very slowly, a river valley can be carved out of rock by __________________
water.
Valleys that are cut by rivers are V-shaped.
__________________ can also erode soil by blowing the rich top layer away.
A __________________ is a large, slow moving field of ice.
Glaciers cause erosion, too. As they move, they __________________ out
everything in their paths.
Valleys cut by glaciers are U-shaped.
Section 2 Review
What are four physical properties of rocks?
What are three things that cause weathering?
How do glaciers cause erosion?
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