Unit 2: Lesson 2 Developing a Theory Review

Front

What is seafloor spreading?

Back

The process by which new oceanic crust is formed from magma rising through cracks in the ocean floor, causing the seafloor to expand.

Front

What is the lithosphere?

Back

The rigid outer layer of the Earth, consisting of the crust and the uppermost part of the mantle.

Front

What is the asthenosphere?

Back

The layer directly below the lithosphere that behaves like a plastic material, allowing tectonic plates to move.

Front

What are tectonic plates?

Back

Large sections of the Earth's lithosphere that move and interact at their boundaries, causing geological activity.

Front

How do scientists determine the age of the seafloor?

Back

By analyzing rock samples from the ocean floor and using radiometric dating techniques.

Front

What are isochron maps?

Back

Maps that show the age of the ocean floor, displaying stripes of different ages parallel to mid-ocean ridges.

Front

What is a mid-ocean ridge?

Back

An underwater mountain range formed by plate tectonics, where seafloor spreading occurs.

Front

How do continents move according to seafloor spreading?

Back

Continents move in tandem with the spreading seafloor along mid-ocean ridges.

Front

What is the role of magma in seafloor spreading?

Back

Magma rises through cracks in the ocean floor, solidifying to form new oceanic crust.

Front

What evidence supports the theory of seafloor spreading?

Back

Evidence includes the age of rocks, magnetic patterns on the seafloor, and the distribution of fossils.