Week 4 Pt. 2

Question 1

Magma

Answer 1

A body of molten rock found at depth, including any dissolved gasses or crystals

Question 2

Lava

Answer 2

Magma that reaches the earths surface

Question 3

Volatile

Answer 3

Gasses, gaseous components of magma dissolved in the melt. Volatiles will readily vaporize(form a gas) at surface pressures

Question 4

Granitic (felsic) composition

Answer 4

A compositional group of igneous rocks indicating that the rock is composed of almost entirely light colored silicas

Question 5

Basaltic (mafic) composition

Answer 5

A compositional group of igneous rock indicating that the rock contains substantial dark silicate materials and calcium rich plagioclase feldspar

Question 6

Andesitic (intermediate) composition

Answer 6

A compositional group of igneous rocks that contains at least 25% dark silicate materials. The other dominant material is plagioclase feldspar

Question 7

Ultra mafic

Answer 7

J

Question 8

Difference between lava and magma

Answer 8

Magma is molten rock below the surface of the earth, it is called lava when it reaches the surface and can come from volcanoes as lava

Question 9

3 main components of magma

Answer 9

Liquid: melt
Solid: crystals of silicate materials
Gaseous: volatiles

Question 10

Describe the crystallization process

Answer 10

As the temperature of the liquid drops, ions pack more closely together as their rate of movement slows. When they are cooled they confine to ions in an orderly crystalline arrangement. (Opposite of melting)

Question 11

Compare and contrast extrusive and intrusive igneous rocks

Answer 11

Intrusive: magma, forms deep in earth, loses heat slowly, coarse grained(visible) crystals (phanaritic)

Extrusive: lava, on earths surface, loses heat fast, fine crystals(microscopic)

Question 12

Igneous rocks are composed of mainly what mineral group

Answer 12

Silicate minerals

Question 13

How do light colored igneous rocks differ from dark colored ones

Answer 13

Dark igneous rocks have dark minerals. They are mafic/ basaltic, more iron and mg more dense

Light= opposite, granitic

Question 14

4 basic compositional groups of igneous rocks in order from highest Si content to least.

Answer 14

Granitic
Andesitic
Intermediate
Basaltic

????

Question 15

Define igneous texture

Answer 15

3 factors

1. Rate at which molten rock cools( dominant)
2. Amount of silica present in the magma
3. amount of dissolved gasses in the magma

Question 16

How does cooling rates influence crystal size

Answer 16

Bigger crystals can form when there is more time to cool.

Question 17

6 major igneous textures

Answer 17

Glassy
Porphyritic
Phaneritic
Vesicular
Pyroclastic
Aphanitic

Question 18

How are granite and rhyolite different/ the same

Answer 18

Both fine grained/ might colored silicates.

Rhyolite is fine grained and contains glass fragments and voids from cooling rapidly at the surface, granite is intrusive.

Question 19

Intrusive igneous rocks are also called _____

Answer 19

Plutonic

Question 20

Extrusive igneous rocks are also called

Answer 20

Volcanic rocks

Question 21

Glassy texture

Answer 21

Composed of unordered atoms

Question 22

Porphyritic texture

Answer 22

2 distinctly different crystal sizes

Question 23

Phaneritic

Answer 23

Mineral grains Large enough to see with a naked eye

Question 24

Vesicular texture

Answer 24

Extrusive rock that contains holes from gas bubbles

Question 25

Pyroclastic texture

Answer 25

Produced by the consolidation of fragments that may include ash, blobs, blocks from a volcanic explosion

Question 26

Aphanitic

Answer 26

Fine grained, Crystals too small to see with a naked eye

Question 27

How does magma rise

Answer 27

Density contrast

Overlying pressure