Plate Techtonics 2

Question 1

What are the three types of plate boundaries?

Answer 1

• The three types of plate boundaries include:

1. Divergent boundary
2. Convergent boundaries
3. Transform boundary

Question 2

What is a divergent boundary?

Answer 2

• Divergent boundary: when two plates separate
- Creates new oceanic crust
- Sea floor spreading
- Can occur in the middle of continents: Continental
rift.

Question 3

What is a convergent boundary?

Answer 3

• Convergent boundaries: when two plates collide

• Denser crust goes beneath the less-dense crust
  
  • -> This process is called subduction
• Causes deep sea trenches, volcanoes, and mountains.

Question 4

What is a transform boundary?

Answer 4

• Transform boundary: when two plates slide past each
other
- No crust is created or destroyed
- Results in earthquakes and fault

Question 5

What are the two types of tectonic plates?

Answer 5

• Two types of tectonic plates
  1. Oceanic crust
     - Denser
  2. Continental plate
      - Less dense
• Most plates are made up of both oceanic crust, and 
  continental crust

Question 6

What is the term used to describe when two plates meet?

Answer 6

• Where two plates meet = a fault

Question 7

What is a mantle convection current?

Answer 7

• Mantle convection current = a current in the mantle
where cooler, denser material sinks and warmer less
dense materials rises.

Question 8

What is a mid-ocean-ridge?

Answer 8

• Mid-ocean-ridge: mountains along the ocean floor

Question 9

Between ocean rocks and land rocks, which are younger?

Answer 9

• In general, ocean rocks are much younger than land
rocks
- Rocks near mid-ocean-ridges are younger than ocean
floor farther away from the ridge

Question 10

What is sea floor spreading?

Answer 10

• Sea floor spreading: the process of magma rising to the

surface at mid-ocean ridges to form new crust

Question 11

What is the continental drift theory?

Answer 11

• Continental drift theory:
- 250 million years ago, all of the continents were
combined into one super continent called Pangea.
- Proposed by Alfred Wegener

Question 12

What evidence is there about the continental drift theory?

Answer 12

• There were same rock structures across oceans
• There are tropical plants remains found in Antarctica
- Evidence that Antarctica was much warmer

Question 13

How do volcanoes form?

Answer 13

• Volcanoes can form on convergent boundaries:
- Oceanic crust –> oceanic crust
- Continental crust -> oceanic crust
• When the denser crust reaches deep enough to melt
into magma and that magma rises to form a volcano

Question 14

How do mountains form?

Answer 14

• Mountains can form on convergent boundaries:

- continental crust –> continental crust

Question 15

How many plate exist on earth?

Answer 15

• The number of plates: 12