Lesson 2b: Plate Tectonics Part 2

Question 1

What are the 3 major plate boundaries?

Answer 1

1. Divergent
2. Convergent
3. Transform

Question 2

What types of forces are associated with divergent plate boundaries?

Answer 2

two plates move apart, resulting in the upwelling of hot material from the mantle to create a new sea floor.

Question 3

What types of forces are associated with convergent plate boundaries?

Answer 3

Two plates move together, resulting in either:
- oceanic lithosphere descending beneath an overriding plate that is eventually reabsorbed into the mantle.
- a collision of two continental blocks to create a mountain belt.

Question 4

What types of forces are associated with transform plate boundaries?

Answer 4

Two plates grind past each other without the production or destruction of the lithosphere.

Question 5

What are the different types of divergent plate boundaries?

Answer 5

1. Oceanic - Oceanic
2. Continental Rift (Continent - Continent)

Question 6

What are the different types of convergent plate boundaries?

Answer 6

1. Ocean - Continental
2. Ocean - Ocean
3. Continental - Continental

Question 7

What are the different types of transform plate boundaries?

Answer 7

1. Ocean - Ocean
2. Ocean - Continental
3. Continental - Continetal

Question 8

What are the geologic features associated with divergent boundaries?

Answer 8

Oceanic-oceanic: Midocean ridge, shallow focus earthquakes, rift valley, volcanoes
Continental rifts: Lithosphere is stretched and thinned, volcanoes,

Question 9

What are the geologic features associated with convergent boundaries?

Answer 9

Oceanic-Oceanic: Subduction zones, earthquakes and volcanoes that can cause tsunamis, volcanic island arc, and ocean trenches
Oceanic-Continental: subduction zones, earthquakes and volcanoes that can cause tsunamis, continental volcanic arc, deep-ocean trench
Continent-Continent: Earthquakes, mountain belts (no volcanoes), suture/fold-and-thrust belt.

Question 10

What are the geologic features associated with transform boundaries?

Answer 10

Earthquakes but no volcanoes, found mostly on the ocean floor

Question 11

Give some examples of divergent boundaries.

Answer 11

Oceanic-Oceanic: Silfra fissure, Iceland
Continental Rifts: East African Rift Valley, Mount Kilimanjaro, Tanzania, Red Sea Rift

Question 12

Give some examples of convergent boundaries.

Answer 12

Oceanic-Oceanic: The Aleutian Islands, Alaska, Mariana trench, Central America trench, Philippine trench, Japan trench, Tonga trench, Kermadec trench, Java trench
Oceanic-Continental: Coastal Range Batholith, Western US
Continent-Continent: Himalayas, Mount Everest, the Appalachians

Question 13

Give some examples of transform boundaries.

Answer 13

Continent-Continent: San Andreas fault zone
Oceanic - Continent: Alpine Fault Zone

Question 14

Basaltic rocks contain ______ (Fe3O4), an iron-rich mineral influenced by Earth’s magnetic field.

Answer 14

Magnetite

Question 15

Does the Earth’s magnetic field occasionally reverse its polarity?

Answer 15

Yes

Question 16

Rocks having the same magnetism as the present magnetic field exhibit ______.

Answer 16

Normal polarity

Question 17

Ocean floor sediments become ____ and ___ as you move further away from a mid-ocean ridge.

Answer 17

Older and thicker

Question 18

The Hawaiian Islands are thought to have been formed at a ____.

Answer 18

Mantle plume/hot spot

Question 19

A divergent boundary is a boundary between two plates that _____.

Answer 19

Move away from each other

Question 20

Divergent boundaries are places where:

Answer 20

1. Basaltic lava erupts from volcanoes.
2. Shallow focus occur
3. New ocean lithosphere is created

Question 21

Seafloor spreading occurs along mid-ocean ridges and is associated with ___________ plate boundaries.

Answer 21

Divergent

Question 22

The Red Sea is an example of ______.

Answer 22

Initial rifting of a continent