Magma Formation

Question 1

Process in magma differentiation where it combines and mixes magma.

Answer 1

Magma Mixing

Question 2

Partial Melting

Answer 2

• It refers to a process that creates a magmatic melt from a portion of a solid rock less than the whole.
• refer to the geothermal graph

Question 3

A chemical process by which the composition of a liquid, such as magma, changes due to crystallization.

Answer 3

Crystal Fractionation

Question 4

Denser minerals crystallize first and settle down while the lighter minerals crystallize at the latter stages.

Answer 4

Crystal Settling

Question 5

It is a complex process whereby a single melt can produce a wide variety of different igneous rocks.

Answer 5

Magmatic Differentiation

Question 6

It results from the transfer of heat and decompression.

Answer 6

Magma Generation

Question 7

The heat generated by long-term radioactive decay.

Answer 7

Radioactive Heat

Question 8

The heat generated during the Earth’s formation.

Answer 8

Primordial Heat

Question 9

A discontinuity between lower mantle and outer core.

Answer 9

Guttenberg Discontinuity

Question 10

Explain Geothermal Gradient

Answer 10

• The temperature increase with depth into Earth.
• Pressure also plays a part when melting rocks. • Higher pressure means higher melting point.
• Thus, the gradient is not a straight line, but a curved one.

Question 11

What is Magma?

Answer 11

Magma is defined as molten rock found below the earth’s surface. It’s a Greek word meaning ‘thick ointment.’

Question 12

What are the composition of magma?

Answer 12

It is composed of whatever elements made up the minerals in the source rocks, since it is a variety of rocks that are melted therefore the composition is unclear.

Question 13

Explain Decompression Melting

Answer 13

• Going back to the Geothermal Gradient graph, the rocks goes up decreasing its depth and pressure, but not the temperature.
• This allows the rock to melt at that temperature because of the lowered pressure.
• This usually happens in divergent boundaries. This creates new magma!

Question 14

Explain Flux Melting

Answer 14

• Convergent Boundaries
• When the H2O from the descending plate (the denser plate) are compressed into the hotter mantle rocks above.
• Helps break the chemical bonds decreasing the melting point of the rock.
• This completely disorganizes the geothermal graph, pushing the partial melting and the liquid melting stage to the left, thus allowing melting.

Question 15

Explain Heat Transfer Melting

Answer 15

• Due to the Flux Melting, some magma are stuck beneath the continental lithosphere above, the stuck magma melts the surrounding rocks.

Question 16

What “melting” produces a lot of magma?

Answer 16

Decompression Melting

Question 17

Where can magma form?

Answer 17

• Mid-oceanic ridges
• Mantle plumes (hot spots)
• Subduction Zones

Question 18

Why and how magma rises?

Answer 18

Since magma is less dense than the surrounding country rock, it rises faster when the difference in density between the magma and the surrounding rock is greater.

Question 19

MAGMA FACTORS to VISCOSITY

• Higher Temperature means?
• Higher Silica Content means?
• Higher content of H2O means?

Answer 19

• Lower Viscosity
• Higher Viscosity
• Lower Viscosity

Question 20

Explain Bowen’s Reaction Series

Answer 20

Minerals that Crystallizes First (In Order):
• Olivine
• Plagioclase Feldspar
• Amphibole and Biotite
• Muscovite Mica and Potassium Feldspar
• Quartz