Igneous Petrology (Part 1 - Magmatic Processes, Magma Series, Types of Magma)

Question 1

The sub-branch of Petrology that primarily focuses on processes and rocks that are formed from magma and lava.

Answer 1

Igneous Petrology

Question 2

Molten rock material generated by partial melting of Earth’s mantle and crust.

Answer 2

Magma

Question 3

Magma that rises and erupts onto the surface of Earth.

Answer 3

Lava

Question 4

The liquid portion of the magma.

Answer 4

Melt

Question 5

The gaseous portion of the magma

Answer 5

Volatiles

Question 6

The solid portion of the magma

Answer 6

Crystals

Question 7

Magma will move towards areas with what pressures

Answer 7

Less pressure

Question 8

What does more undissolved gases mean in magma?

Answer 8

Greater volume = More explosive

Question 9

More fluid magma tends to contain what content?

Answer 9

less SiO2 content

Question 10

What does greater SiO2 concentration mean?

Answer 10

More viscous = More explosive

Question 11

The processes were the magma or lava looses its heat and crystallizes

Answer 11

Crystallization

Question 12

Rocks that formed as a result of crystallization of magma or lava.

Answer 12

Igneous Rocks

Question 13

Igneous rocks that formed beneath the surface as a result of loosing mobility.

Answer 13

Plutonic Rocks

Question 14

Will tend to have larger crystal sizes as they have time to grow.

Answer 14

Intrusive Igneous Rock

Question 15

Igneous rocks that solidified at the surface as a result of extrusion.

Answer 15

Volcanic Rocks

Question 16

Will tend to have smaller crystal sizes as they rapidly cool and crystallize from the cooler environment.

Answer 16

Extrusive Igneous Rock

Question 17

The process where your pre-existing rock is heated to the point of partially melting.

Answer 17

Partial Melting

Question 18

The partial melting within the Earth’s crust.

Answer 18

Anatexis

Question 19

What are the factors that determine the types of magma?

Answer 19

1. Composition, temperature and depth of the source rock.
2. Percent partial melting of the source.
3. Source rock’s previous melting history.
4. Diversification processes

Question 20

Origins of Magma

Answer 20

Temperature increase
Decompression melting
Addition of volatiles

Question 21

Increase of temperature with depth

Answer 21

Geothermal gradient

Question 22

Occurs as a result of decrease in pressure in the system. (Also known as adiabatic melting)

Answer 22

Decompression melting

Question 23

Agents that reduces melting temperature of a substance.

Answer 23

Flux

Question 24

Occurs when crystallization along the walls of the magma chamber in which crystals preferentially form and adhere to the edges.

Answer 24

Marginal Accretion

Question 25

Includes fractionation processes that occur when crystals develop with significantly different densities than the surrounding magma.

Answer 25

Gravitational separation

Question 26

A process during fractional crystallization where the first dense minerals that mineralize sink and accumulate at the bottom of the magma body.

Answer 26

Crystal Setting

Question 27

A process during fractional crystallization where the first lighter minerals that mineralize float and accumulate at the top of the magma body.

Answer 27

Crystal Flotation

Question 28

A process during magma cooling that occurs when the magma bod is subjected to stress.

Answer 28

Filter pressing

Question 29

Occurs whereby liquids and crystal are segregated due to factors such as velocity, density or temperature.

Answer 29

Convective Flow Segregation

Question 30

Two or more dissimilar magmas coexist but retaining their distinctive characteristics.

Answer 30

Magma Mingling

Question 31

Thorough mixing of two or more magmas, with the individual characteristics no longer recognizable.

Answer 31

Magma Mixing

Question 32

Development of more than one type of igneous rock in situ from a common magma.

Answer 32

Magmatic Differentiation

Question 33

The incorporation and digestion of solid or fluid foreign materials, such as the wall rock

Answer 33

Magmatic Assimilation

Question 34

Inclusions in magmatic bodies.

Answer 34

Xenolith

Question 35

One parent magma fractionates to produce two or more distinctly different daughter magmas with different compositions

Answer 35

Liquid Fractionation

Question 36

Involves the selective diffusion of ions in the magma due to compositional, thermal or density gradients.

Answer 36

Differential Diffusion

Question 37

Also called liquid-liquid fractionation, the separation of magma into two or more distinct immiscible liquid phases.

Answer 37

Liquid Immiscibility

Question 38

Consists of genetically-related magmas with a composition that evolved from a common, original, parental magma.

Answer 38

Magma Series

Question 39

Record a progressive decrease in iron and magnesium with increasing SiO2 and alkali concentrations.

Answer 39

Calc-alkaline magmas

Question 40

What rocks produce in calc-alkaline

Answer 40

Andesites, Dacites, Rhyolites, Basalts

Question 41

Experience enrichment in iron at low to moderate SiO2 concentrations with increasing fractionation due to depleted MgO and CaO from early crystallization of forsterite olivine and Ca-plagioclase.

Answer 41

Tholeiitic magmas

Question 42

What rocks produce in tholeiitic magmas

Answer 42

Large volumes of basalt

Question 43

Magmas that are less common than calc-alkaline or tholeiitic magmas, highly enriched in Na2O and/or K2O

Answer 43

Alkaline magmas

Question 44

Characterized by high concentrations of silicic and basic rocks, with little intermediate rocks

Answer 44

Bimodal magma suites

Question 45

A graphical method used to discriminate samples through their chemical content into correctly identifying an igneous rock.

Answer 45

Variation Diagrams

Question 46

Bivariate diagrams showing the relative content relationship of oxide compounds with SiO2 as the magma evolves.

Answer 46

Harker Diagrams

Question 47

With increasing silica, what trends follow

Answer 47

1. Decrease in TiO2, FeO, MgO, CaO and P2O5 2. Increase in K2O and Na2O 3. No strong variation in Al2O3.

Question 48

8 most abundant elements in the continental crust

Answer 48

Oxygen Silicon Aluminum Iron Calcium Sodium Potassium Magnesium

Question 49

Explain the types of Magma from Ultramafic to Felsic

Answer 49

yes

Question 50

Explain Bowen's Reaction Series

Answer 50

letsgo kaya mo yan

Question 51

Igneous rocks that are dominantly composed of dark-colored silicates but can commonly appear green, enriched in olivine, pyroxene and plagioclase.

Answer 51

Ultramafic

Question 52

What rocks form in Ultramafic

Answer 52

Peridotite and Komatiite

Question 53

Why is komatiite extinct again?

Answer 53

aba malay ko (joke) ano raw temp pressure NOT FAVORABLE!!!! Ultramatic but volcanic (no ultramafic lava exist) tsaka ano kasi hindi na favorable ang setting sa earth ngaun frfr

Question 54

Igneous rocks that are dominantly composed of dark-colored silicates such as pyroxenes, plagioclase and amphiboles.

Answer 54

Mafic

Question 55

Mafic is also called?

Answer 55

Basaltic

Question 56

mafic magma may form what rocks depending on its texture.

Answer 56

Gabbro or Basalt

Question 57

Igneous rocks that are gray-colored to salt-and-pepper, depending on the size of the mineral grains.

Answer 57

Intermediate

Question 58

Intermediate is also called?

Answer 58

Andesitic

Question 59

What rocks would form depending on its texture in Intermediate?

Answer 59

Diorite or Andesite

Question 60

Igneous rocks that are dominantly composed of light-colored silicates such as quartz and feldspars.

Answer 60

Felsic

Question 61

Felsic is also called?

Answer 61

Granitic

Question 62

What rocks would form in felsic, depending on its texture?

Answer 62

Granite or Rhyolite