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LESSON TITLE: THE IGNEOUS, SEDIMENTARY AND
METAMORPHIC ROCK
_______________________________________________________
Name of Teacher –Writer: JUDY D. DUMAWA
School: SANTIAGO NATIONAL HIGH SCHOOL
Republic of the Philippines
DEPARTMENT OF EDUCATION
Region I
Division of Ilocos Sur
EARTH & LIFE SCIENCE 11/12
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Specific Objectives:
Learning Competency
Classify rocks into igneous, sedimentary, and metamorphic
(S11/12ES -Ib-10)
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You have learned from the previous lesson about minerals composing rocks and
their different characteristics.
For today’s lesson you shall be taking a look at rocks’ three major classification, the
igneous, sedimentary and metamorphic.
Here is a checklist of what you are going to need to do in this self-learning kit.
□ Read and understand the objectives of your self-learning kit.
□ Perform the short pre-assessment activity.
□ Proceed to the discussion / learning proper.
□ Pay attention to the generalization part of your self-learning kit.
□ Perform the post–assessment activity.
- Goodluck!
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Write what you think are the activities that occur in each
of the different stage of life. Goodluck!
(Write your answers on your notebook)
4. 4
What changes have you observed from the activities of
each stages of life?
As can be observed in the story, it followed a timeline and
each stages of life comes with corresponding changes in the
appearance and activities. The toddler became a kid, grew up a
teen, had a job, until he found partner and started a family. Similar
to the development of your story, Earth’s many processes follow a
timeline and changes. In the process of rock cycle, the timeline
could be in eons or a very long time. An average lifespan of
Filipinos is 62 for the males, and 73 for females with a combined
average of just 69 years; whereas there are some rocks that are
about 3 billion years old.
The difference in the timeline of rocks and human life is
staggering, so much that rocks are seen as unchanging objects as
implied by the quote ‘Diamonds are forever’ and another Ilocano
quote ‘Awan ti tao nga bumato’.
Do rocks change? They do! But they change oh so slowly
(think in millions of years), that we humans having very short
lifespan compared to rocks, may not easily observe.
In today’s lesson, you will be discovering about the three
kinds of rocks, and how they are formed. Goodluck!
The Earth is a terrestrial and dynamic planet evidenced by the fact volcanoes
are erupting and earthquakes are occurring every day. All this because of the
movements of the tectonic plates. Tectonic plates are the many separate plates that
compose the earth’s crust that are slowly moving and pushing against each other.
As the plates move and push against each other, earthquakes and volcanic eruptions
occur.
However, these seemingly destructive forces of earthquake and volcanic
eruptions create mountains, ridges, canyons and rifts. And, as rocks are exposed to
these new environments, rocks undergo changes, hence, rock cycle occur.
Geologic time is a scale that exceeds human experience. While natural
phenomena like earthquakes and volcanic eruption may speed up rock cycle. Most
of geologic processes occur very slowly, like the formation of mountains, or the
lithification of sediments on a lake may take hundreds or even millions of years.
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What are rocks made of?
Rocks can be made of one or more minerals. Organic matter may also
become a composite of rock. The composition of minerals in a rock is dependent
on the manner and environment where it was formed.
What is weathering and erosion?
Weathering is the process where rocks and soil are dissolved away and worn
into smaller pieces due to environmental factor. There are three types of
weathering namely physical or mechanical, biological and chemical weathering.
Let’s check them out!
1. Physical Weathering
When rocks disintegrate into smaller pieces, like when water enters
the pores of rocks and then freezes cracking the rocks.
2. Biological Weathering
When rocks disintegrate by the action of living organisms, like when
a tree or other plants creep into rocks as they grow cracking rocks open.
Moss, algae and lichens grow over rocks and produce chemicals the further
break down the surface of the rocks.
3. Chemical Weathering
When rocks are broken down by chemicals. The process takes time,
like when acid rain hits rocks and dissolve rock grain
Erosion is when the broken-up pieces of rocks are transported to a new location.
There are various types of erosion namely physical, water erosion, glacial erosion
and wind erosion.
1. Physical Erosion
When land gets eroded by various factors without the chemical
composition being changed. Rocks become smaller and then get eroded
through physical erosion and then form clastic sedimentary rocks.
2. Erosion by Water
When moving water caused by floods, rain, rivers, lakes and oceans
wash away sediments. Coastal erosion greatly affects communities living
along the seashore.
3. Wind Erosion
Wind continuously transports sand, sediments and ash dust from one
place to another.
4. Erosion by Ice
As the glaciers move downward they carry soil with them. The eroded
sediment is called moraine.
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The diagram shows an igneous rock could become a metamorphic or a
sedimentary rock, depending the type of condition it is exposed to.
When an igneous rock is exposed to extreme temperature and heat, it
becomes a metamorphic rock. On the other hand, if it is exposed to erosion,
deposition and diagenesis, it becomes a sedimentary rock.
A metamorphic rock when melted could become an igneous rock upon
crystallization. Or a metamorphic rock could become a sedimentary rock when
exposed to erosion, deposition and diagenesis.
A sedimentary rock could become an igneous rock upon melting and
crystallization.
As can be inferred, rock cycle does not follow one direction, depending on the
environmental condition a rock is exposed to, an igneous rock could become
sedimentary, or metamorphic or another igneous rock,
Figure 1. The rocky cycle
Rock Cycle
It is the slow transformation of rocks, in geologic time. The three types of
rocks, sedimentary, metamorphic and igneous rocks are changed when exposed
to new conditions in the environment. Let us study the image below to further
understand what rock cycle is.
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1. Sedimentary Rocks
Sedimentary rocks are formed from the sediments (small particles) of other
rocks. There are three kinds of sedimentary rocks, clastic, organic (biological) and
chemical sedimentary rock.
The Three Types of Rocks
1.1 Clastic Sedimentary Rocks are
composed of fragments or clasts of pre-
existing minerals and rocks. Clastic
sedimentary rocks are formed by weathering
process which break down rocks into pebble,
sand or clay particles by exposure to wind,
ice and water. Clastic and nonclastic
sedimentary rocks are the only members of
the rock family that contain fossils as well as
indicators of the climate that was present
when it was formed.
1.2 Organic (Biological)
Sedimentary Rocks like coal, formed from
hard biological materials like plants, shells,
and bones that are compressed into rock
forms.
Organic sedimentary rocks formed
from the accumulation and lithification of
organic debris, such as leaves, roots, and
other plant or animal material.
1.3 Chemical Sedimentary Rocks
like limestones, halite, and flint form from
chemical precipitation. A chemical
precipitate is a chemical compound—for
instance, calcium carbonate, salt and silica—
that forms when the solution it is dissolved in,
usually water, evaporates and leaves
compound behind.
Figure 2.1 Sandstone, a clastic
sedimentary rock
Figure 2.2 Coal, an organic
sedimentary rock
Figure 2.3 Gypsum, a chemical
sedimentary rock
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2.1 Foliated Metamorphic Rocks are
rocks with flat or elongated minerals which
was put into immense pressure, the minerals
line up in layers, creating foliation. Foliation is
the aligning of elongated or platy minerals,
like hornblende or mica, perpendicular to the
direction of pressure that is applied.
2.2 Nonfoliated Metamorphic Rocks
are formed the same way but they do not
contain the same minerals that tend to line up
under pressure and thus do not have the
layered appearance of foliated rocks.
Nonfoliated rocks can also form by
metamorphism which occurs when magma
comes in contact with the surrounding rock.
Figure 3.1 Phyllite, a foliated
metamorphic rock
Figure 3.2 Quartzite, a nonfoliated
metamorphic rock
Types of Metamorphism
1. Contact Metamorphism
It is a type of metamorphism in which a body of rock is changed due to exposure
to pressure and very high temperature due to a body of intruding magma.
2. Regional Metamorphism
It is a type of metamorphism in which rocks are changed over a wide area by
deep burial and heating due to large scale forces of plate tectonics.
Figure 3.3 Contact and Regional Metamorphism
2. Metamorphic Rocks
These are rocks that have been changed from their original form by
immense heat or pressure. Metamorphic rocks have two classes namely, foliated
and nonfoliated.
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3.1 Intrusive Igneous Rocks Granite and
diorite are examples of common intrusive rocks.
They have a coarse texture with large mineral
grains, indicating that they spent thousands or
millions of years cooling down inside the earth.
3.1 Extrusive Igneous Rocks Rocks like
basalt and obsidian have very small grains and a
relatively fine texture. This happens when a
magma erupts into lava, it cools more quickly that it
would if stayed inside the earth, giving crystals less
time to form. Obsidian cools into volcanic glass so
quickly when ejected that the grains are impossible
to see with the naked eye.
Extrusive igneous rocks can also have a
vesicular, or “holey” texture. This happens when
the ejected magma still has gases inside of it so
when it cools, the gas bubbles are trapped and end
u giving the rock a bubbly texture. An example of
this is pumice.
Figure 4.2 Obsidian, an
extrusive igneous rock
Figure 4.1 Diorite, an
intrusive igneous rocks
Trivia Time!
A massive sculpture carved into
the granite face of Mount Rushmore in
the Black Hills in Keystone, South
Dakota. Gutzon Borglum created the
sculpture's design and and managed
the project's execution from 1927 to
1941 with the help of Lincoln Borglum,
his son.
3. Igneous Rocks (derived from the Latin word for fire) are formed when
molted hot material cools and solidifies. Igneous rocks can also be made a couple
of different ways. When they are formed inside of the earth they are called 1)
Intrusive or plutonic igneous rocks. If they are formed outside or on top of Earth’s
crust, they are called extrusive or volcanic igneous rocks.
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IGNEOUS ROCK
Pressure
Temperature
METAMORPHIC ROCK
IGNEOUS ROCK
SEDIMENTARY ROCK
Temperature
IGNEOUS
ROCK
IGNEOUS
ROCK
METAMORPHIC
ROCK
EROSION
SEDIMENTARY
ROCK
Activity #1 Rock Transformation
Direction: Fill in the diagram with the missing process or type of
rock. Goodluck! (Write your answers on your notebook)
Refer to the rock cycle diagram on page 6.
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1. Metamorphic rock is buried deep becoming magma.
2. Magma is erupted as lava, cools down and becomes igneous rock
again.
3. Igneous rock is weathered from wind and rain transforming it to bits
and pieces.
4. After deposition, small pieces of rocks compacts and consolidates
into sedimentary rocks.
5. Pressure and heat from within Earth change the composition of the
rock turning it into metamorphic rock.
6. The small pieces of rocks are carried away by wind and water via
erosion and then deposited.
3 4 5 1 2
Activity #2 Sequencing the Rock Cycle
Direction: Create a properly sequenced rock cycle by writing the number of each
sequence on the boxes provided below the randomly sequenced events.
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The are three kinds of rocks:
1. Igneous rock
2. Sedimentary rock
3. Metamorphic rock.
Sedimentary rocks are classified into, clastic, organic and
chemical sedimentary rocks.
Metamorphic rocks are classified into foliated and
nonfoliated metamorphic rocks.
Igneous rocks are classified into intrusive and extrusive
igneous rocks.
Magma solidifies upon cooling into an igneous rock.
Weathering disintegrates rocks into smaller pieces, in situ.
Erosion carries smaller pieces of bits of rocks away.
One kind of rock could be transformed to any kind of rock,
depending on the environment that one particular of
rock was exposed to.
Make a list of at least 5 rocks and their usage, that you
utilize in your day to day activities. Write them on your
notebook.
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Multiple Choice: Write the letter of the correct answer on your notebook.
1. A kind of rock formed by the fragments of pre-existing minerals and rocks.
a. Clastic Sedimentary Rock b. Intrusive Igneous rock
c. Foliated Metamorphic Rock d. Organic Sedimentary Rock
2. Rocks are flat or elongated minerals and are lined up in layers.
a. Clastic Sedimentary Rock b. Intrusive Igneous rock
c. Foliated Metamorphic Rock d. Organic Sedimentary Rock
3. Granite and diorite belong to this classification of rock.
a. Clastic Sedimentary Rock b. Intrusive Igneous rock
c. Foliated Metamorphic Rock d. Organic Sedimentary Rock
4. What kind of rock is formed when materials like plants, shells and bones are
compressed to form rocks?
a. Clastic Sedimentary Rock b. Intrusive Igneous rock
c. Foliated Metamorphic Rock d. Organic Sedimentary Rock
5. What process occurs when melted magma solidifies?
a. Melting b. Deposition c. Crystallization d. Erosion
6. A kind of metamorphism that occurs over a large area exposed to pressure.
a. Regional b. Contact c. Foliated d. Nonfoliated
7. The following can cause erosion EXCEPT:
a. Wind b. Water c. Glacial d. Sun
8. A type of weathering that occurs when acid rain drops on the rocks.
a. Biological b. Chemical c. Physical d. Organic
9. The process of being deposited as a sediment.
a. Erosion b. Weathering c. Sedimentation d. Compaction
10. Choose which statements about rock cycle are true.
I. Lava hardens becoming an igneous rock.
II. Small bits of rocks are carried away by erosion
III. Weathering is when rocks are transported.
IV. An igneous rock could become another igneous rock.
a. I only b. I and II only c. I, II and IV d. I, II, III and IV
