Ch.4 Igneous Rocks and Intrusive Igneous Activity

Question 0

Magma that reaches the surface

Answer 0

Lava

Question 1

Molten rock material below the surface.

Answer 1

Magma

Question 2

Material from the forceful eruption of magma into the atmosphere.

Answer 2

Pyroclastic Material

Question 3

extrusive rocks cool and crystallize very quickly.

Answer 3

Volcanic

Question 4

(intrusive) rocks cool and crystallize very slowly.

Answer 4

Plutonic

Question 5

Silica rich; gooey and thick

>65% silica; abundant Na, K, Al.

Answer 5

Felsic

Question 6

Silica poor; thin and runny

(52% - 45%) silica; abundant Ca, Fe, Mg.

Answer 6

Mafic

Question 7

Compositions between felsic and mafic

(53% - 65%) Silica content

Answer 7

Intermediate

Question 8

<45% Silica content

Answer 8

Ultra Mafic

Question 9

A substance’s resistance to flow.
Temperature is a factor, but composition is a more important factor.
In lava and magmas the formation of silica tetrahedral networks controls this.

Answer 9

Viscosity

Question 10

Extrusive; fine grained (small crystals), rapid cooling.

Answer 10

Aphanitic

Question 11

Intrusive; coarse grained (large crystals), slow cooling.

Answer 11

Phaneritic

Question 12

phenocrysts and groundmass, two stage cooling history.

Answer 12

Porphyritic

Question 13

Fragment generated by explosive volcanism.

Answer 13

Pyroclastic

Question 14

No crystal structure

Answer 14

Glassy

Question 15

Gas cavities

Answer 15

Vesicular

Question 16

Composed of volcanic ash

Answer 16

Tuff

Question 17

Composed of volcanic glass.

Answer 17

Obsidian

Question 18

Composed of volcanic glass, vesicular, ______ floats on water.

Answer 18

Scoria and Pumice

Question 19

describes the sequence of mineral crystallization in a cooling magma.
Shows how mafic, intermediate and felsic magmas could derive from a single original parent mafic magma

Answer 19

Bowen’s Reaction Series

Question 20

Contains only ferromagnesian silicates.

Answer 20

Discontinuous Branch

Question 21

Contains only non ferromagnesian silicates.

Answer 21

Continuous Branch

Question 22

country rock is consumed by magma

Answer 22

Assimilation

Question 23

Crystals form and sink to the bottom

Answer 23

Crystal settling

Question 24

When a mafic and felsic magma chamber mix to form an intermediate magma.

Answer 24

Magma Mixing

Question 25

Cracks on the ocean floor where magma reaches the ocean waters.

Answer 25

Spreading Ridges

Question 26

Melting of ocean sediments and Si rich continental crust.

Answer 26

Subduction Zones

Question 27

A tabular or sheet like pluton that is concordant (parallel) with the rock layers.

Answer 27

Sill

Question 28

A tabular or sheet like pluton that is discordant with the rock layers

Answer 28

Dike

Question 29

A pluton with a mushroom like shape

Answer 29

Laccolith

Question 30

The largest of the plutonic bodies (at least 100 km2)

Answer 30

Batholith

Question 31

Smaller than batholith (less that 100 km2)

Answer 31

Stock