Earth and Life Science

Name of Learner:_______________________ Date: ______________

Section:_______________________________ Q1W2

Classification of Rocks and Exogenic Processes

Background Information for Learners

Rocks are naturally occurring materials and aggregate of one of more different minerals.
Rocks are divided into three different classes based on how they are formed. The three
classification of rocks are:
1. Igneous rocks
2. Sedimentary Rocks
3. Metamorphic Rocks
In this activity sheet, you will learn about the different classification of rocks, how rocks are
formed, as well as the different exogenic processes that shape the Earth.

Rock Cycle

Rocks are different from one another and are almost everywhere. They possess different
characteristics that is unique from one type of rock to the other. Rocks can be transformed
from one type to the other according to the process that it went through. The rock cycle is a
series of stages that transforms the different types of rocks and the relationship of each type
to one another

Source: https://upload.wikimedia.org/wikipedia/commons/c/c4/Rockcyc.jpg

Three Classification of Rocks

1. IGNEOUS ROCKS- formed from hardening and crystallization of magma or molten
material that originates deep within the earth.

Two types of igneous rock:

A. Extrusive/Volcanic rock - forms when magma makes its way to Earth’s surface as lava
and then cools. The crystals are very small (fine grained) since the cooling process is fast.
B. Intrusive/Plutonic - It cools slowly beneath the Earth surface and are created by magma.
The intrusive igneous rocks have very large crystals (coarse grained).

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Igneous rocks are classified based on:
1. Composition
FELSIC - light in color; feldspar and silicates
MAFIC - dark in color; made up of magnesium and iron
INTERMEDIATE – between mafic and felsic
ULTRAMAFIC - very dark color
2. Texture - overall appearance of rock
Aphanitic - fine grained
Phaneritic- coarse grained
Porphyritic- large crystals with small crystals
Glassy- non-ordered solid from rapid quenching
Pyroclastic- composite of ejected fragments

Source: Earth and Life Science, Alternative Delivery Mode, Quarter 1 – Module 4: Rocks, First
Edition, 2020

2. SEDIMENTARY ROCK- provide information about surface conditions that existed in

the Earth’s past.
● Particles of sand, shells, pebbles, and other fragments of materials called sediments,
accumulate in layers and over long period of time harden into rocks.
● Compaction-due to increase of pressure of layered sediments it bind together to form the
sedimentary rocks.

Three types of sedimentary rocks

Source: Earth and Life Science, Alternative Delivery Mode, Quarter 1 – Module 4: Rocks, First
Edition, 2020

a. Clastic Sedimentary rock - formed from accumulation of clasts: little pieces of broken
rocks and shells. Examples: conglomerate, breccia, sandstone, shale

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b. Chemical - formed when dissolved minerals precipitate from a solution. Example: Halite -
formed when a body of seawater becomes closed off and evaporates.
c. Organic - rocks formed from the accumulation of animal debris. Example: Coal - composed
of organic matter in the form of plants fragments.

3. METAMORPHIC- These are rocks that form from the transformation of pre-existing
rocks through the process of metamorphism. Metamorphism can involve changes in
the physical and chemical properties of rocks in response to heat, pressure, and
chemically active fluids.

Metamorphism - transformation of one rock type into another.

2 types of metamorphism
1. Regional-due to changes in pressure and temperature over large region of the crust
2. Contact-mainly by heat due to contact with magma

Classification:
a. Texture - refers to the size, shape and arrangement of mineral grains within the rock.
b. Foliation - any planar arrangement of mineral grains or structural features within the rock.
1. Foliated - appeared banded or layered, contains crystals. Example: mica
2. Non-foliated - made up of only few minerals.

Source: Earth and Life Science, Alternative Delivery Mode, Quarter 1 – Module 4: Rocks, First
Edition, 2020

Exogenic Processes on the Surface of the Earth

A. Weathering is the process of breaking down rocks into smaller pieces called
sediments.

Source: https://commons.wikimedia.org/wiki/File:Mechanical_weathering.png

Different Types of Weathering

All rocks undergo weathering, and it takes a long period. There are three different types of
rock weathering: mechanical weathering, chemical weathering, and biological weathering.

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Mechanical weathering is a process wherein rocks are broken down into smaller pieces
without changing its chemical composition due to different temperatures and water.

Source:
https://commons.wikimedia.org/wiki/File:Mechanical_weathering_of_a_cement_bollard_-
_20110501.jpg

Chemical weathering is a process wherein rock materials are changed into other substances
that have different physical and chemical compositions. Some agents of chemical weathering
include water, strong acids, and oxygen. Water hydrates and breaks the minerals in the rocks
through the process of hydrolysis.

Source: https://www.flickr.com/photos/50714845@N08/6433278835

Biological weathering is a process when living things, such as insects and roots of the trees,
contribute to the disintegration of rock materials. For example, mosses and fungi that grow on
rocks produce weak acids that can destroy or dissolve the rocks.

Source: https://commons.wikimedia.org/wiki/File:Bioweathering-salina.JPG

B. Erosion is the transportation of weathered rocks. Agents like running water or rivers,
wind, gravity, groundwater, wave currents, and glaciers contribute to erosion.
Types / Agents of Erosion
1. Water erosion is a type of erosion where the water carries the sediments to different
parts of the bodies of water such as rivers.
2. Wind erosion happens when light materials, such as small rocks and pebbles, are
carried by wind to different places.

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 3. Glacial erosion happens when the ice moves downhill and plucks out chunks of
rocks and causes scraping between the ice and the rock. Plucking and scraping
can lead to the development of other landforms if, for example, the glaciers hit a
mountain and erode it.
4. Soil erosion happens when the topsoil is removed and leaves the soil infertile. This
is caused by wind or flood in an area.

C. Deposition
Deposition is the laying down of sediments to its depositional environment or destination.
The depositional environment can be continental, coastal, or marine.

Continental includes streams, swamps, caves, and deserts.

Coastal includes lagoons, estuaries, and deltas.
Marine includes slopes and bottom of the ocean or abyssal zone.

Source: https://pixabay.com/photos/streams-the-creek-nature-water-4685216/

Source: https://en.wikipedia.org/wiki/Desert

Learning Competency with code

The learners should be able to classify rocks into igneous, sedimentary, and metamorphic
(S11/12ES-Ib-10) and explain how the products of weathering are carried away by erosion
and deposited elsewhere (S11/12ES-Ib-12).

Activity 1 – Identify Me
Direction. Identify the term being asked of in each item. Choose the correct answer from the
given word bank. Write your answer on the space provided.

rock cycle metamorphic

sediments metamorphism
rock mineral
igneous sedimentary

_____1. Aggregates of one or more minerals.

_____2. Any naturally – occurring material that is broken down by weathering or erosion and
deposited through air, water, ice, or gravity.
_____3. A series of changes that transforms or creates rocks from one type to the next.

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_____4. A preexisting rock that is subjected to extreme heat and pressure and transform into
another rock.
_____5. A naturally occurring, inorganic material with definite crystal structure.

Activity 2 – Collect Me

Direction. Collect at least five rock samples in your place and take a photo of the samples. If
you do not have a camera, you can also draw the rock samples that you have collected.
Describe the characteristics of each rock depending on their appearance, texture, color, and
layers (or bands). Answer in a separate sheet of paper.

Activity 3 – Classify Me
Direction. Fill in the table below by providing basic information about the types of rocks. You
may refer to the words in the box below.

Igneous Sedimentary Metamorphic

Types
Examples
Processes

WORD LISTS
Lithification pumice clastic
Metamorphism obsidian intrusive
Cooling Limestone extrusive
Cementation marble non- clastic
Crystallization non - foliated foliated

Activity 4 – Explain Me
Weathering is an important process in the formation of soil. Soil is a mixture of grains, organic
matter, water, and gas.
Erosion is the separation and removal of weathered rocks due to different agents like water,
wind, and glacier that causes transportation of the material to where they are deposited.
Plants, animals, and humans play an important role in the erosional process.

Answer the following questions.

1. How do animals and plants cause weathering and erosion?

2. How do humans affect the rate of erosion?

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 Activity 5 – Create Me
Direction: Complete the concept map using the words below.

Exogenic Processes

Weathering Deposition Erosion

Chemical Mechanical Biological
Water Wind Glacier Gravity

Activity 6 – Watch Me (Optional)

Direction: Watch the link on YouTube: https://www.youtube.com/watch?v=KloyC-vjKwI.

Reflection:

What I have learned:

_________________________________________________________________________
_________________________________________________________________________

What I have enjoyed:

_________________________________________________________________________
_________________________________________________________________________

References:

Dela Cruz, Aileen C., Cristina T. Remotigue, and Ernesto A., Dizon Jr. et. al. 2016. Teaching
Guide for Senior High School Earth and Life Science. Quezon City: Commission on
Higher Education.

Klein, Cornelis, and Robert S. Carmichael. Rock. Encyclopædia Britannica. Encyclopædia

Britannica Inc. March 31, 2020 https://www.britannica.com/science/rock-geology

Jacinto, Josephine P., 2020, Earth and Life Science Quarter 1 – Module 4: Rocks, First
Edition, Cainta, Rizal, Department of Education

Bautista, Rhodora, Jacinto, Josephine P., 2020, Earth and Life Science Quarter 1 – Module
5: Exogenic Processes, Cainta, Rizal, Department of Education

Youtube, “Weathering, Erosion and Deposition”, Accessed August 19, 2020

https://www.youtube.com/watch?v=KloyC-vjKwI

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 Answer Key: 5. Mineral

Activity 1 – Identify Me Activity 2 – Collect Me – answers may

vary

1. Rock Activity 4 – Explain Me – answers may

2. Sediments vary
3. Rock cycle
4. Metamorphic Activity 6 – Watch Me - answers may
vary

Activity 3 – Classify Me

Igneous Sedimentary Metamorphic

Types Intrusive Clastic Foliated
extrusive Non clastic Non foliated
Examples Obsidian limestone marble
pumice
Processes Crystallization Lithification Metamorphism
cooling cementation

Activity 5 – Create Me

Exogenic Processes

Weathering Erosion Deposition

gravity
Mechanical Biological water
Chemical
glacier
wind

Prepared by:

Charmaine C. Llanza
Teacher I