Honors Earth Science
Notes Packet #11
Chapter 3: Rocks
3.1: The Rock Cycle
 Why do we study rocks?

They are clues to the ______________________________ in which they were formed.

All of Earth’s ______________________________ include rocks and minerals.

Examples: Erosion, Mountain Building, Earthquakes
 _______: Any solid mass of mineral or mineral-like matter that occurs naturally as part of
our planet.

Most rocks are a mixture of ______________________________.

Classified into 3 groups:

_____________________________________________

_____________________________________________

_____________________________________________
 ______________________________________: All of the continuous processes that cause rocks to
_______________.

______________________________: Water, air, land, and living things.

Most changes take place over long periods of time.
 Processes of the rock cycle:

______________________________: Molten rock beneath Earth’s crust cools and hardens


Igneous rocks form.
Rocks on the surface undergo ______________________________: Process where rocks are
physically and chemically broken down by water, air, and living things.

Weathered pieces are called ______________________________.

Sediments can be moved by water, gravity, glaciers, and wind.

Eventually, sediments are ___________________________________________ to form
Sedimentary rocks.

If rocks get buried deep within the Earth they are subject to
____________________________________.

Under these extreme conditions rocks change to
__________________________________ rocks.

If ______________________________ raises higher, rock may melt and form magma which
can start the cycle all over again!
 Where does the ______________________________ come from for the rock cycle?

______________________________ from the Earth’s interior forms igneous and
metamorphic rocks.

Weathering and movement of weathered material are external processes powered
by energy from the _______________.
3.2: Igneous Rock
 Igneous: From the Latin word ‘ignis,’ meaning ‘_________________________.’
 Formation of igneous rocks:

______________________: Magma hardens _____________ Earth’s
surface.

We would never see these rocks if it wasn’t for
______________________________ and
_____________________________.

Magma consists of mainly Si and O (along with some
other elements).

When magma cools (______________), it allows minerals to grow in size
forming crystals.


Example: Granite, a very common intrusive rock.
_________________: When lava hardens ___________ the Earth’s
surface.

It cools quickly, so minerals do not have time to
______________________________.

Example: Rhyolite
 There are two ways to classify igneous rocks:
1. Based on ______________________: Describes the appearance of an igneous rock based
on its size, shape, and the arrangement of its interlocking ____________.


________________ Texture: Magma cools _______________.

Centers of crystal growth develop.

Slow cooling=large crystals.
_____________________ Texture: _______________ cooling.

Results in rocks with small, interconnected
mineral grains.

_______________ Texture: If lava spews onto Earth’s ____________.

No time for ions to arrange themselves into crystals.

Example: Obsidian

________________ Texture: Large amounts of magma
underground may take 10’s of thousands of years to
_____________________.

Rocks will have a variety of mineral sizes due to the
different rates of cooling.

Example: Andesite
2. Based on ______________________________: Proportions of light and dark minerals in the
rock.

______________________________ Composition: Made up almost entirely of the light
colored silicate minerals ______________________________ and
______________________________.

Contain about 10% dark silicate minerals (biotite mica and
amphibole).


These are the major rocks of the ______________________________ crust.

Example: Rhyolite is an extrusive granitic rock.
______________________________ Composition: Rocks made up of dark
______________________________ minerals and
_____________________________________________.

Rich in the elements ______________________________ and _______________.

Because they contain iron, they are darker and denser than granitic
rock.


This is the main type of rock of ______________________________ crust.

Examples: Basalt and Gabbro
________________ Composition: Rocks with a composition between granitic and
basaltic.

Named after the common volcanic rock ______________________________.

Contains 25% dark silicate minerals.
 i.e. amphibole, pyroxene, and biotite mica

Another dominant mineral in andesitic rocks in plagioclase feldspar.
3.3: Sedimentary Rock
 Sedimentary: From the Latin word ‘sedimentum,’ meaning ‘______________________________.’
 Sedimentary rocks form when solids settle out of a ______________________________ such as
water or air.
 The sediments eventually become ______________________________ and form rocks.
 Processes involved in the formation of sedimentary rocks:
1. ______________________________: Any process that __________________________ rocks into
sediments.
•
Often the _______________ step in sedimentary rock formation.
•
_____________ weathering happens when minerals in rocks change into
something new.
•
____________________ weathering breaks the pieces into smaller parts.
2. ______________________________: The physical ______________________________ of rock
sediments.
•
___________________ of erosion: _______________, _______________, ___________, and
_______________.
•
When energy is lost, sediments fall. This is called ______________________________.
•
Sediments are deposited according to ____________. The ____________________ fall
out first.
3. ______________________________: A process that _____________________________ or compacts
sediments.
•
Caused by the _________________________ of sediments.
•
Much of the _________________________ in the sediments is driven out.
4. ______________________________: Takes place when dissolved minerals are deposited in
the tiny spaces among the sediments.
•
Sediments are ‘_________________________’ together.
 Classification of Sedimentary Rocks: According to how they were formed.

___________________________ Sedimentary Rocks: Made of weathered bits of rocks and
minerals.

Many different minerals are found in clastic rocks.

__________________ and _________________________ are the most common.

Clay is the most abundant product of chemical weathering.

Quartz is very common and resist to weathering.

Clastic rocks are grouped according to the size of the sediments:
 ______________________________: Rounded, gravel-size or larger particles.
 ______________________________: Particles are angular.
 ______________________________: Particles are sand-sized grains.
 __________________________: Very fine-grained (most common
sedimentary rock).
 ______________________________: Another fine-grained rock.

______________________________ Sedimentary Rocks: Form when dissolved minerals
precipitate from water solutions.

This happens when water __________________________ or boils off, leaving a solid
product.

Examples: Limestone, rock salt, chert, flint, and rock gypsum, and chalk.

About 90% of ________________________ are formed from biochemical sediments,
such as the _______________ and ____________________ remains of organisms that
settle in the ocean.
 Features of Some Sedimentary Rocks: Clues to how, when, and
where they were formed.

_____________________________: Each layer records a period of
sediment deposition.


Oldest at the bottom, youngest at the top.
______________________________: May indicate that the rock
formed along a beach or stream.

_____________________________: Formed when wet mud or clay dried
and shrank, leaving indicators of dry weather.

________________________: Traces or remains of ancient
life.

Unique to sedimentary rock.

Indicate climates and environments at the time.

Also indicate dates, matching up rocks from different places.
 Remember Wegener???
3.4: Metamorphic Rock
 _____________________________________________ means ‘to change form.’
 Formed when _______________ and _________________________ is applied to existing rock.
 Often look much different than the original rock.
 Formation of metamorphic rock: Most metamorphic changes occur at very elevated
______________________________ and ______________________________.
 Conditions found a few kilometers below the Earth’s surface and extending into the
upper mantle.
 Occurs in one of two settings:
 ______________________________ metamorphism: When magma forces its way into
rock.
 Changes here are _________________________.
 Example: Marble, which forms when magma intrudes a limestone
body.
 ______________________________ metamorphism: During mountain building large
areas are subjected to extreme pressures and temperatures.
 Changes produced are considered _______________________________
metamorphism.
 Agents of Metamorphism: Heat, pressure, and hydrothermal solutions.
 During metamorphism, rocks are usually subjected to all three of these agents at
the same time.
1. ______________________________: The most important agent.
•
Provides the heat to drive chemical ______________________________.
•
The heat comes from magma contact and change in temperature with depth
(____________________________________________________________).
•
When heated, minerals become unstable and
_____________________________________________ to form new minerals that are stable
at these temperatures.
2. _____________________________________________: Also increases with depth.
•
Pressure within Earth is applied in all ______________________________.
•
Pressure causes the spaces between mineral grains to close.
•
This results in a more compact, dense rock.
•
Pressure may also cause minerals to ______________________________ into new
minerals.
•
Increased temperature and pressure cause rocks to _______________ instead of
fracture.
•
This causes mineral grains to flatten and elongate.
•
During mountain building, this produces intricately folded rocks.
3. ____________________________________________________________: Hot, water-based solution
that escapes from a mass of magma during crystallization.
•
Solutions aid recrystallization by making it easier for _______________ to move.
•
An increase in ______________________________ will increase the rate of
metamorphism.
•
May result in a rock’s overall ______________________________ change.
 Classification of Metamorphic Rocks: Classified by ______________________ and
___________________________.

____________________________________ metamorphic rock: When the rock has a
______________________________ or ______________________________ appearance.

When rocks undergo ______________________________ metamorphism, they
become compact and dense.

When shale is subjected to high temperatures and pressures, _______________
is formed.

The pressure on the shale causes the clay minerals to align in a similar
direction.

Some minerals recrystallize with preferred orientation at right angles to the
force. This give rocks a banded appearance, called
______________________________.


Examples: Gneiss and schist.
Schist 
______________________________ metamorphic rock: A
metamorphic rock that is not banded.

Most contain only one ___________________________.

Example: Limestone (calcite crystals)
undergoes metamorphism to form
______________________________.

Examples: Quartzite and anthracite.