5.2 a&b Plate Boundaries Review

5.2 a&b Plate Boundaries Review

Reviewing how plates move and the features they produce

5.2.a Learning Target

🏹 5.2.a - I can identify, compare, and contrast different plate boundaries.

Plate Boundaries

• Divergent = Plates separate, moving away from each other due to tension

• Convergent = Plates move towards each other due to compression

• Transform = Plates slide past each other in opposite directions due to shearing

Multiple Choice

What kind of plate boundary has plates sliding past each other due to shearing forces?

• Convergent

• Divergent

• Transform

Multiple Choice

What kind of plate boundary consists of plates pushed together by compression?

• Convergent

• Divergent

• Transform

Multiple Choice

What kind of plate boundary is made of plates being pulled apart by tension?

• Convergent

• Divergent

• Transform

Subduction

• Wherever an oceanic plate is converging, subduction occurs.

• This occurs at continental-oceanic or oceanic-oceanic boundaries.

• Oceanic crust is denser so it slides under the less dense continental crust.

• Older, colder (denser) oceanic crust slides under younger, less dense oceanic crust.

Multiple Select

Which of the following is true about subduction? Select ALL that apply.

• The denser continental plate moves under the oceanic plate.

• The denser oceanic plate moves under the continental plate.

• The denser older oceanic plate moves under the younger oceanic plate.

• The denser younger oceanic plate moves under the older oceanic plate.

5.2.b Learning Target

🏹 5.2.b - I can identify geologic features produced at different plate boundaries.

Transform Boundary

• Earthquakes and fault systems occur along transform boundaries

• Roads, crop rows, and other features can be off-set (displaced) due to plate motion

• Ex: San Andreas Fault in California

Multiple Select

Which of the follow are true about transform boundaries. Select ALL that apply.

• Plates move slide horizontally past each other at transform boundaries.

• Earthquakes occur along transform bounaries.

• Mountains and volcanoes form here.

• The Mid-Atlantic Ridge is on a transform boundary.

• The San Andreas fault (CA) is on a transform boundary.

Divergent Bondary

As continental plates separate, the following occurs:

Magma rises, thinning the crust.

Blocks of rock fall, forming rift valleys and fault block mountains.

Long ridge mountains form on each side of the rift valley.

Magma erupts in the rift, creating denser crust that becomes seafloor.

Divergent (cont'd)

• Over time, the new crust is covered by water.

• As it widens, it becomes a long lake, then a long sea, and eventually a new ocean.

• The oceanic divergent boundary then consists of a mid-ocean ridge with a rift valley.

Divergent examples

• The Mid-Atlantic Ridge is an example of an oceanic divergent boundary.

• The East African Rift Valley is an example of a continental divergent boundary

Multiple Select

Which of the following can occur along a divergent boundary? Select ALL that apply.

• Deep-sea trenches

• Ridge mountains

• Fault block mountains

• Rift valleys

• Hot spot volcanism

Multiple Select

Which of the following are examples of divergent boundaries? Select ALL that apply.

• San Andreas fault

• Marianas trench

• East African Rift Valley

• Ring of Fire

• Mid-Atlantic Ridge

Convergent Boundaries

• There are 3 types of convergent boundaries: oceanic-continental subduction, oceanic-oceanic subduction, and continental-continental collision.

Oceanic-Continental Convergence

• The denser oceanic crust subducts under the continental crust.

• Where the plates meet, a sea trench forms.

• As the ocean plate subducts, it melts. This magma rises and erupts through the overlying continent, creating a volcanic mountain arc along the coast.

Oceanic-Continental Convergence Example

Mt. St. Helens and the other volcanic mountains of the Cascade Range in the western USA

Oceanic-Oceanic Convergence

• The older, colder ocean plate is denser and subducts under the younger ocean plate.

• Where the plates meet a deep-sea trench forms.

• As the plate subucts, it melts. The magma rises and erupts through the overlying ocean plate, creating a volcanic island arc.

Oceanic-Oceanic Convergence Example

The Mariana Trench (lowest point in ocean) and the island nation of Japan.

Continental-Continental Convergence

• As 2 continents converge, they collide into each other because they are the same density.

• As they crash, the rocks are folded and cracked (faulted) and thrust upwards.

• This forms folded mountains.

• There is NO VOLCANISM.

Continental- Continental Convergence Example

The Himalayas are a modern collision between the Indian plate and the Eurasian plate.

The Appalachian Mountains were made by an ancient collision in the formation of Pangaea.

Multiple Select

Which of the following can be found where two ocean plates move towards each other? Select ALL that apply.

• Convergent Boundary

• Subduction

• Trench

• Volcanic Mountain Arc

• Volcanic Island Arc

Multiple Select

Which of the following can be found where 2 continental plates move towards each other? Select ALL that apply.

• Convergent Boundary

• Subduction

• Folded Mountains

• Volcanic Island Arcs

Multiple Select

Which of the following can be found where a continental plate and an ocean plate move towards each other? Select ALL that apply.

• Convergent Boundary

• Subduction

• Trench

• Volcanic Mountain Arc

• Folded Mountains

Multiple Choice

Which of the following is an example of a place where 2 continental plates have collided into each other?

• Japan

• Mt. St. Helens

• Appalachian Mountains

• San Andreas Fault

Multiple Choice

Which of the following is an example of a place with an oceanic-continental convergent boundary?

• Himalaya Mountains

• Mariana Trench

• Mt. St. Helens

• San Andreas Fault

Multiple Choice

Which of the following is an example of a place where 2 oceanic plates move towards each other?

• Appalachian Mountains

• Mariana Trench

• Mt. St. Helens

• San Andreas Fault