Seafloor Spreading and Plate Tectonics Review

Plate Tectonics Review Lesson

Friday November 6th

Alfred Wegner

• Theory of Continental Drift

• 5 Pieces of Evidence

• Glaciers

• Fossils

• Mountains

• Puzzle like fit

• Coal Deposits

Multiple Select

Check all of the pieces of evidence that Wegner cited to back his theory of Continental Drift

• Fossils

• Human Remains

• Mountains

• Coal

Harry Hess

• Wegner couldn’t prove How or Why

• Harry Hess Came along in 1953

• Using Sonar found evidence of mid ocean ridge

• Led to phenomenon of Seafloor Spreading

• CONVECTION CURRENTS MOVE PLATES

• Now Wegner’s theory had how and why

Multiple Choice

What process in the mantle underground moves the continents and cycles hot lava up from the core?

• Seafloor Spreading

• Convection Currents

• Subduction

• Volcanoes 🌋

Plate Tectonics

• With Alfred Wegners theory of Continental Drift+Harry Hess discovery of seafloor spreading=PLATE TECTONICS

• The Earth is not a smooth ball like a marble but stitched together like a baseball

• The plates that make up the earth move at different boundaries

• We call these meeting points or Cracks, Plate Boundary/Faults

Multiple Choice

What do we call the cracks in between tectonic plates?

• Subduction

• Convection

• Caverns

• Faults/Plate Boundaries

Type of Plate Boundaries

• Divergent (Divides)

• Transform (Slides)

• Convergent, Continental-Continental

• Convergent, Oceanic-Oceanic

• Convergent, Continental-Oceanic

• Convergent Collides

Multiple Choice

Convergent boundaries

• Collide

• Divide

• Slide

• Subduction

Convergent Boundaries

• 2 Continental plates collide and then fold upwards (folded mountains)

• Continental and oceanic plates collide and then one will sink under another in a process called subduction

• Trenches and Volcanic Mountains form from this

• When 2 Oceanic plates collide subduction also occurs and the crust will melt back into magma creating Volcanic Islands

Multiple Choice

At a convergent boundary when one plate sinks under another it is called what?

• Seafloor spreading

• Convections

• Subduction

• Collision

Transform Boundary

• Two plates slide and scrape up against one another in opposite directions

• The lithosphere is neither created or destroyed in this process

• This boundary can cause faults and earthquakes

• An example of this would be in California at the San Andreas Fault

Multiple Select

Mark all that are true about transform boundaries

• Creates Earthquakes

• Subduction Occurs

• Creates Fault Lines

• Found where two plates slide past each other in opposite directions

Divergent Boundary

• Two Oceanic or continental plates divide or move away from one another

• When oceanic plates divide as in seafloor spreading underwater volcanoes are created

• Magma rises up creating new crust on the ocean floor and mid ocean ridges

• When continental plates divide rift valleys are formed

Multiple Choice

Divergent boundaries are the reason Harry Hess found...

• The ocean

• Continental Drift

• Convection

• Seafloor Spreading

Multiple Choice

What type of Boundary would lead to that landform

• Convergent

• Divergent

• Transform

Multiple Choice

What type of boundary would cause what you saw in the last picture

• Convergent Oceanic Oceanic

• Convergent Continental Oceanic

• Convergent Continental Continental

• Transform

Multiple Choice

What type of Boundary would cause the landform in the last picture

• Convergent

• Transform

• Divergent

Multiple Choice

What type of boundary would be in the last picture

• Convergent

• Divergent

• Transform

Multiple Choice

What type of boundary would be created at the picture in the last slide

• Divergent

• Convergent

• Transform

Poll

Do you feel ready to move on?

• Yes

• No