Sea Floor Spreading and Plate Tectonics

Where does a Deep-Ocean Trench occur?

A convergent plate boundary where one continental plate and one oceanic plate collide.

What happens at a Deep-Ocean Trench?

Old Ocean Floor sinks toward the mantle

Where does a Mid-Ocean Ridge occur?

A divergent plate boundary; 2 oceanic plates move away from each other

What happens at a Mid-Ocean Ridge?

Sea-Floor Spreading occurs

What contributions did Alfred Wegner have on earth's geology?

He started the theory of sea-floor spreading

What contributions did Harry Hess have on earth's geology?

He discovered mid-ocean ridges and deep-ocean trenches

What 3 types of evidence did Harry Hess have to support Sea-Floor Spreading?

Molten Material, Magnetic Stripes, Drilling Samples

Example of molten material that Harry Hess had...

Pillow shaped rock, magma when it cools quickly

Example of Drilling Samples that Harry Hess had...

Closer to mid-ocean ridge is newer, farther from mid-ocean ridge is older

Type of plate movement at divergent plate boundaries.

away from each other

Type of plate movement at convergent plate boundaries.

toward each other, with oceanic - continental oceanic sinks below continental

Type of plate movement at transform plate boundaries.

slide past each other in opposite directions

Landforms along divergent plate boundaries (continental-continental)

Mid-Ocean Ridges, Rift Valley

Landforms along divergent plate boundaries (oceanic- oceanic)

Mid-Ocean Ridges

Landforms along convergent boundaries (continental-continental)

Mountain ranges, volcanoes

Landforms along convergent boundaries (continental-oceanic)

deep-ocean trenches

Landforms along transform boundaries

earthquakes, faults

How do volcanoes form?

When there is a weak spot in the earth's crust and magma rises to the surface

Difference between magma and lava

lava is magma that rises to the surface of the earth

What is the Ring of Fire?

a major belt of volcanoes that surrounds the pacific ocean

Where is the Ring of Fire, locate it?

around the pacific ocean

How is a hot spot volcano formed?

When magma erupts through the crust and reaches the surface