Characteristics of the Seafloor

Which statement describes the relationship between seafloor spreading and continental drift?

As the seafloor spreading occurs, the continents move.

Which statement explains what happens to older crust during seafloor spreading?

It moves away from a mid-ocean ridge

What is the orientation of the magnetic stripes of iron contained in rocks that support the idea of seafloor spreading?

North and south

Which statement accurately describes one aspect of plate tectonics that involves subduction and seafloor spreading?

Older crust is melted at subduction zones.

Why do rocks on the ocean floor form a pattern of magnetized stripes?

The rocks contain iron that points in different directions depending on Earth's polarity

How do magnetic stripes of iron in ocean rock provide evidence of seafloor spreading?

They reveal a matching pattern on either side of the ridge.

What is the first step of seafloor spreading?

a crack forms in the oceanic crust

Which is the first step in the seafloor spreading process?

a crack forms in the oceanic crust

How does oceanic crust move along mid-ocean ridges?

away from the ridge

describes one event that happens at deep-ocean trenches?

denser plates slide under lighter plates

what is one piece of evidence of seafloor spreading?

drilled core samples

Which type of material becomes molten rock at subduction zones?

heavy plates

Which event causes the formation of trenches in Earth's crust?

lithosphere colliding

From which location does seafloor spreading originate?

mid-ocean ridges

Which concept is described in the theory proposed by Hess?

mid-ocean ridges are sites of seafloor spreading

Which material rises from cracks in oceanic crust?

molten rock

By which mechanism does older oceanic rock move at a ridge?

new molten material rises and moves the rock

feature of Earth is created at mid-ocean ridges?

new ocean floor

The rocks contain iron that points in different directions depending on Earth's polarity.

new oceanic crust is created

Which discovery did scientists make at mid-ocean ridges that caused them to conclude that new rock was being formed by molten material?

pillow shaped rocks

describes all new rocks that form near an oceanic ridge?

provide evidence to seafloor spreading

When scientists analyzed drilling samples from the Glomar Challenger study, which discovery did they make about rocks in relation to a mid-ocean ridge?

rocks closer to the ridge are newer

According to the theory proposed by Harry Hess, what causes continents to move?

seafloor spreading

Which type of zone is located at a deep-ocean trench?

subduction

1. Which information did the Glomar Challenger study in 1968?

the age of rocks in various places in the ocean

Which evidence originally supported Hess's idea of seafloor spreading in 1968?

younger rocks are closer to mid-ocean ridges