EAS 210 - Lecture Notes

Question 1

Layers of the earth

Answer 1

Inner core (solid iron)
Outer core (liquid iron)
Mantle (silicate mineral with Fe, Mg)
Crust (silicate mineral with Na, Ca, Al)
Lithosphere
Asthenosphere

Question 2

Which layer of the earth is made up of tectonic plates?

Answer 2

Lithosphere

Question 3

Describe Minerals(5)

Answer 3

1. Naturally occurring
2. solid at surface pressure and temperature
3. regular internal structure of atoms (crystalline)
4. narrowly defined chemical composition
5. Usually inorganic

Question 4

Luster

Answer 4

The quality and intensity of light reflected from a mineral

Question 5

Mohs Scale (1-10)

Answer 5

10 - Diamond
9 - Corundum
8 - Topaz
7 - Quartz
6 - Potassium Feldspar
5 - apatite
4 - Fluorite
3 - Calcite
2 - Gypsum
1 - Talc

Question 6

What is fracture? What are the different kinds of fracture?

Answer 6

Fracture refers to the irregular breakage of a mineral
Irregular
Splintery
Conchoidal (curved surface)

Question 7

How are igneous rocks formed?

Answer 7

Molten rock (magma or lava) solidifies

Question 8

Magma vs. Lava

Answer 8

Magma is molten rock beneath the surface of the Earth
Once magma reaches the surface, it is called lava

Question 9

Intrusive vs. Extrusive

Answer 9

Intrusive cools slowly underground
Extrusive reaches the surface and cools quickly

Question 10

Felsic vs. Mafic

Answer 10

Felsic - high silica, lower melting point, high viscosity
Mafic - low silica, higher melting point, low viscosity

Question 11

List the 4 common chemical compositions of igneous rocks. Additionally, list the rock pair and their silica percentages

Answer 11

Felsic: Granite/Rhyolite, more than 65% silica
Intermediate: Diorite/Andesite, 65-53% silica
Mafic: Gabbro/Basalt, 52-45% silica
Ultramafic: Peridotite/Komatiite, <45% silica

Question 12

Magmatic Differentiation

Answer 12

As magma cools, mafic minerals are the first to crystallize (and sink to the bottom). This makes the composition of the remaining liquid more felsic

Question 13

What does Bowen’s reaction series show?

Answer 13

The sequence in which minerals crystallize from magma

Question 14

Viscosity relationships (silica and temperature)

Answer 14

Increasing silica increases viscosity
Increasing temperature decreases viscosity

Question 15

Shield Volcano

Answer 15

Formed by mafic lavas with low viscosity
Very gentle slopes
Common in Hawaii

Question 16

Cinder Cone

Answer 16

A.K.A Scoria Cone
Typically formed by one eruptive episode and considered a monogenetic volcano

Question 17

Composite Volcano

Answer 17

A.K.A Strato-Volcano
Alternating layers of ash and lava
Steeper slopes than shield volcanoes because the lava is more viscous
Generally andesite-rhyolite
Symmetry implies young and active
Very unstable and liable to collapse with major landslides
Usually several millions years for a lifespan

Question 18

Calderas

Answer 18

Form towards the end of the lifecycle of an arc volcano

Question 19

Where are most volcanoes located?

Answer 19

On plate boundaries. Plate tectonics explain volcano types

Question 20

Where are most volcanoes located?

Answer 20

On plate boundaries. Plate tectonics explain volcano types

Question 21

Weathering

Answer 21

The physical and/or chemical breakdown of rock at or near the surface of the Earth to produce sediment

Question 22

Mechanical Weathering and the 3 types

Answer 22

Breaks the rock into smaller pieces. Important because the increase in surface area allows chemical weathering to be more effective
Frost Wedging
Sheeting
Biological Activity

Question 23

Chemical Weathering and the 3 types

Answer 23

Chemical reactions breakdown rock. End result is chemical sediment (Ions dissolved in water). Hot wand wet environments accelerate chemical weathering
Dissolution
Oxidation
Hydrolysis

Question 24

Spheroidal Weathering

Answer 24

The concept that chemical weathering is faster on corners and produces a smooth shape

Question 25

Two types of sediment

Answer 25

Detrital and Chemical

Question 26

Three types of sedimentary environments

Answer 26

1. Continental (Glacial Deposits)
2. Transitional (the transition from continent to ocean)
3. Marine (continental shelf)

Question 27

List and Describe the two main lithification steps

Answer 27

Compaction: Particles pack more closely together
Cementation: Glues the particles together to form rocks

Question 28

Metamorphism

Answer 28

The transformation of rocks as the result of heat, pressure, and/or fluid activity
Occurs below the melting point in the solid state

Question 29

Metamorphic grade

Answer 29

The degree of metamorphic change a rock has undergone