MAGMATISM, PARTIAL MELTING, AND TECTONIC SETTING.pptx

Magma
I kept myself
I hid to deep
Burned myself, with my own heat
I must go out, must go with the flow
My red tears shouted pain, as it glows
So as I am, later on it would be tough
I freed my burning self and I'll go reach the top
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OBJECTIVES
 Describe the characteristics of magma.
 Identify the substances/elements
present in magma;
 Explain the processes involved in the
formation of magma.

What is magma?
▪ is defined as molten rock found below
the earth's surface. It's a Greek word
which means 'thick ointment.’
▪ Magma is found in the magma
chamber of the volcano.
▪ This molten state, when solidified,
creates igneous rocks found on the
surface of the Earth.
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Magma
Chamber
Crater
Conduit

Composition of Magma
▪ Magma is mainly
composed of oxygen
(46.6%) and silicon
(27.7%).
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What is magmatism?
▪ is a process under the
earth’s crust where
formation and movement
of magma occur. These
happen in the lower part
of the Earth’s crust and in
the upper portion of the
mantle, known as
asthenosphere. 9

What is magmatism?
▪ is a process under the
earth’s crust where
formation and movement
of magma occur. These
happen in the lower part
of the Earth’s crust and in
the upper portion of the
mantle, known as
asthenosphere. 10

How is magma formed?
▪ The magma present in the lower crust
and upper mantle of the Earth is formed
or generated through the process of
partial melting. In this process, different
minerals in rock melt at different
temperature and pressure.
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The solid rock
contains the
minerals quartz,
feldspar, biotite,
and hornblende.
The first minerals
that melt are quartz
and some types of
feldspar. The
background
represents magma.
Minerals such as
biotite and hornblende
generally melt last,
which changes the
composition of
magma.

Melting in the Mantle
▪ 1. AN INCREASE IN TEMPERATURE:
Conduction in mantle happens when
heat is transferred from hotter molten
rocks to the Earth’s cold crust. As
magma rises, it is often hot enough to
melt the rock it touches. This is called
heat transfer melting. It happens at
convergent boundaries, where
tectonic plates are crashing together. 13

▪ Rocks are composed of minerals. These
rocks start to melt once the temperature
in the lower crust and upper mantle
increases or exceeds the melting point
of minerals. The temperature of mantle
is around 1200 degrees Celsius. Rock
minerals such as quartz and feldspar
begin to partially melt at around 650-850
degrees Celsius. 14

▪ Rocks are composed of minerals. These
rocks start to melt once the temperature
in the lower crust and upper mantle
increases or exceeds the melting point
of minerals. The temperature of mantle
is around 1200 degrees Celsius. Rock
minerals such as quartz and feldspar
begin to partially melt at around 650-850
degrees Celsius. 15

▪ 2. A DECREASE OF PRESSURE:
Mantle rocks remain solid when exposed
to high pressure. However, during
convection, these rocks tend to go
upward (shallower level) and the pressure
is reduced. This triggers the melting of
magma. This is known as
decompression melting. This process
occurs at the Mid-Ocean Ridge, an 16

▪ 2. A DECREASE OF PRESSURE:
Mantle rocks remain solid when exposed
to high pressure. However, during
convection, these rocks tend to go
upward (shallower level) and the pressure
is reduced. This triggers the melting of
magma. This is known as
decompression melting. This process
occurs at the Mid-Ocean Ridge, an
underwater mountain system. 17

▪ 3. ADDITION OF VOLATILES:
▪ When water or carbon dioxide is added to
hot rocks, flux melting occurs. The
melting points of minerals within the rocks
decrease. If a rock is already close to its
melting point, the effect of adding these
volatiles can be enough to trigger partial
melting. It occurs around subduction
zones. 18

▪ 3. ADDITION OF VOLATILES:
▪ When water or carbon dioxide is added to
hot rocks, flux melting occurs. The
melting points of minerals within the rocks
decrease. If a rock is already close to its
melting point, the effect of adding these
volatiles can be enough to trigger partial
melting. It occurs around subduction
zones. 19

An area
where two
plates meet
where there
is often
earthquake
Subduction Zone

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CONCEPT MAP
Directions: Complete the concept
map about Magmatism. Choose your
answers from the word pool.

36
QUIZ
Directions:
Choose the letter of the best answer.
Write the chosen letter on your paper.

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1. What term should be used to describe a semi-
liquid hot molten rocks located beneath the
Earth?
A. lava C. rocks
B. sand D. magma
2. In what part of the earth does magmatism
happen?
A. Asthenosphere C. Earth’s core
B. Earth’s crust D. Lithosphere

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3. Which of the following is NOT a factor of
partial melting?
A. addition of volatiles C. increase in pressure
B. decrease in pressure D. increase in temperature
4. What is the most abundant element in
magma?
A. Oxygen C. Aluminum
B. Silicon D. Iron

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5. What happens to the temperature of rocks
during partial melting?
A. It decreases.
B. It increases
C. It remains the same
D. All of the above

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ASSIGNMENT
Use the word
MAGMATISM as an
acronym. Use each letter
to describe your most
favorite person.
M –
A –
G –
M –
A –
T –
I –
S –
M –

QUOTATION
“Look for the heat in your
life. And always be
inspired by that heat to
move forward.”
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MAGMATISM, PARTIAL MELTING, AND TECTONIC SETTING.pptx

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