Class lectures part 3

Question 1

What is subsidence

Answer 1

Sinking of the earth’s lithosphere

Question 2

What is the Mid Continental rift

Answer 2

Largest failed rift on earth

Question 3

Failed rifts can happen how? (3 ways)

Answer 3

1. Not enough tensional force pulling apart
2. Plate reconfigures change forces at edge of plates
3. Extension starts occurring in a weaker zone somewhere else

Question 4

What is Transgression

Answer 4

Shorelines move inland due to sea level rise

Question 5

What is regression?

Answer 5

Sea level fall, coastal sediments exposed

Question 6

How does Metamorphism happen?

Answer 6

Due to changes in Temperature, Pressure, Tectonic Stress, Fluids

Question 7

What is the role of heat in Metamorphism?

Answer 7

Atomic structure changes and heat weakens atomic bonds allowing atoms to rearrange

Question 8

What are sources of heat energy

Answer 8

1. Geothermal gradient
2. Magmatic intrusions
3. Compression

Question 9

What are the Metamorphic processes?

Answer 9

1. Recrystallization
2. Phase Change
3. Neo crystallization
4. Plastic Deformation
5. Pressure solution

Question 10

What is Recrystallization

Answer 10

Minerals change size and shape but not identity

Question 11

What’s Phase change

Answer 11

Mineral transforms into a new crystal structure

Question 12

What is Neo Crystallization?

Answer 12

New minerals form old protolith with different chemical makeup

Question 13

What’s Plastic deformation

Answer 13

Mineral grains soften and deform

Question 14

Differential Stress

Answer 14

Stress greater in one direction than another

Question 15

What is Normal Stress

Answer 15

Stress is perpendicular to the surface

Question 16

What’s Shear Stress

Answer 16

Stress is parallel to the surface

Question 17

What is foiliation

Answer 17

Planar fabric that cuts through the rock

Question 18

Pressure solution

Answer 18

Occurs in ‘Wet’ rocks at low temp

Question 19

What is Plastic deformation

Answer 19

Occurs at higher temperature

Question 20

What does Foliated mean

Answer 20

Through going planar fabric (differential Stress)

Question 21

What does Non Foliated mean

Answer 21

No planar fabric present

Question 22

What is shearing

Answer 22

Extreme shear causes original contrasting rocks to smear in parallel bonds

Question 23

What is Metamorphic differntiation

Answer 23

Chemical reactions cause felsic and mafic materials to grow in distinct layers

Question 24

What is Prograde metamorphism

Answer 24

Occurs when a rock is buried deeply during mountain building

Question 25

Retrograde metamorphism

Answer 25

Occurs as deep seated rocks are brought back to the surface decreasing temperature and pressure

Question 26

Metamorphic facies

Answer 26

Set of mineral assemblages that indicate a certain range of pressure and time conditions

Question 27

Types of metamorphism

Answer 27

Thermal Burial Dynamic Regional Hydrothermal Subduction Shock

Question 28

What is Contact (or Metamorphic) aureole

Answer 28

Due to heat from a body of magma invading a host rock, alteration bands are created

Question 29

What is Regional Metamorphism

Answer 29

Tectonic collisions from huge mobile belts

Question 30

Dynamic Metamorphism

Answer 30

Breakage of rock by shearing at a fault zone

Question 31

Hydrothermal Metamorphism

Answer 31

Alteration by hot, mineral rich water

Question 32

Subduction metamorphism

Answer 32

Subduction creates the unique Blueschist (and ecolgite) facies

Question 33

Shock metamorphism

Answer 33

Impacts generate a compressional shock wave which then generate high pressure minerals

Question 34

Metamorphic "shields"

Answer 34

Large regions of ancient high grade rocks exposed in continental interiors

Question 35

Types of lava flows

Answer 35

Basaltic, Andesitic, Rhyolitic

Question 36

Volcanic deposits may include what?

Answer 36

Pyroclastic debris Preexisting rock Landslide debris Lahars

Question 37

What are Andesitic or Rhyolitic eruptions

Answer 37

More Si, More viscous, More gas, More explosive, more debris

Question 38

What is Pumice

Answer 38

Frothy Volcanic glass

Question 39

What is Ash

Answer 39

Fragments <2 mm in diameter

Question 40

What is Lapilli

Answer 40

Larger clumps of ash stuck together by water in the air

Question 41

What are the parts of a volcano

Answer 41

Magma chamber, Fissures, Vents, Conduits, Craters, Calderas

Question 42

What is a crater

Answer 42

Bowl shaped end of a conduit atop a volcano

Question 43

Fissures

Answer 43

Linear tear that produces a curtain of fire

Question 44

Caldera

Answer 44

Gigantic volcanic depression, bigger than a crater

Question 45

What is Volcanic architecture

Answer 45

Volcanoes come in many shapes and sizes

Question 46

Categories of Volcanic Architecture

Answer 46

Shield volcanoes-largest Stratovolcanoes (composite)-Intermediate size Cinder cones-Smallest

Question 47

What is a shield volcano

Answer 47

Looks like a shield laying on the ground

Question 48

What are cinder cones

Answer 48

Smallest volcanos

Question 49

What are Stratovolcanoes

Answer 49

Large cone shaped volcanoes with steeper slopes

Question 50

What are Effusive eruptions

Answer 50

Lava outpouring

Question 51

What are Explosive eruptions

Answer 51

Release pressure catastrophically

Question 52

What are Strombolian eruptions

Answer 52

Regular "burps" of magma

Question 53

What are vulcanian eruptions

Answer 53

Moderately sized and explosive

Question 54

What are plinian eruptions

Answer 54

Huge explosive eruptions

Question 55

What are Surtseyan eruptions

Answer 55

Vent erupts in shallow seawater

Question 56

What are convergent boundaries

Answer 56

Most volcanoes form there

Question 57

What is Flux melting

Answer 57

Subducting oceanic lithosphere adds volatiles

Question 58

What is an Oceanic Hotspot

Answer 58

Mantle plume under an oceanic plate

Question 59

What is a continental hot spot

Answer 59

Through a continental plate

Question 60

What are flood basalts

Answer 60

Voluminous lava eruption above a plume

Question 61

What is Liquefication

Answer 61

Water saturated soils can lead to liquefication

Question 62

What is a pyroclastic flow

Answer 62

Superheated ash clouds

Question 63

What is Ashfall

Answer 63

Buries landscapes killing plants and crops

Question 64

What can Gas and Aerosols do?

Answer 64

Aerosols can cause respiratory problems in people and volcanic gases can be poisonous

Question 65

What are Tsunamis

Answer 65

Explosive eruptions at island arcs

Question 66

What is the Recurrence Interval

Answer 66

Average time between eruptions

Question 67

How does an Earthquake occur?

Answer 67

Builds up and releases elastic energy along a fault

Question 68

What is a fault?

Answer 68

A fracture in the crust on which sliding occurs

Question 69

What is a fault scarp

Answer 69

Displacement at the land surface creates a fault scarp

Question 70

What is a fault trace

Answer 70

Shows the fault intersecting above the ground

Question 71

What is a reverse fault

Answer 71

Hanging wall moves up relative to the footwall

Question 72

What is a Thrust Fault

Answer 72

Special kind of reverse fault

Question 73

What is a strike slip fault

Answer 73

One block slides literally past the other block

Question 74

What is displacement

Answer 74

Offset or amount of movement across fault