Sea Floor Spreading and Plate Tectonics

Front

Magma, or molten material, __________ and hardens

Back

cools

Front

The oceanic crust is pushed aside on both sides of the 

Back

Mid-ocean ridge

Front

The process by which the ocean floor sinks beneath a deep-ocean trench back into the mantle is known as...

Back

subduction

Front

The land feature that happens when there is subduction is called a...

Back

deep-ocean trench

Front

New crust is always formed at the...

Back

mid-ocean ridge

Front

Older crust is found towards the...

Back

Deep-ocean trench

Front

If there are MORE mid-ocean ridges than subduction zones, what happens to the ocean?

Back

It gets larger

Front

If there are more subduction zones than mid-ocean ridges, what happens to the ocean?

Back

It gets smaller

Front

Which is NOT evidence of sea-floor spreading? Options: Molten magma constantly erupting, Drilling samples of rock, Magnetic stripes, Fossil evidence

Back

Fossil evidence

Front

Sea-floor spreading begins at the 

Back

Mid-ocean ridge