Unit 7 Bell Work Day 3

Front

Who proposed the Theory of Continental Drift?

Back

Alfred Wegener

Front

What is sea-floor spreading?

Back

The process by which new oceanic crust is formed at mid-ocean ridges and older crust moves away from the ridge.

Front

When did Pangaea begin to break up?

Back

About 250 million years ago.

Front

What does the theory of continental drift state?

Back

The continents were once joined in a super-continent and have moved over time.

Front

Why was Wegener's theory of continental drift initially rejected?

Back

He could not identify the cause behind continental drift.

Front

What evidence supports the theory of continental drift?

Back

Matching fossils, land formations, and climate evidence across continents.

Front

What are lithospheric plates?

Back

Rigid segments of the Earth's crust that move and interact at their boundaries.

Front

What is the significance of mid-ocean ridges?

Back

They are underwater mountain ranges where sea-floor spreading occurs.

Front

What is the role of convection currents in plate tectonics?

Back

They drive the movement of lithospheric plates in the Earth's mantle.

Front

What is the difference between continental drift and plate tectonics?

Back

Continental drift refers specifically to the movement of continents, while plate tectonics encompasses the movement of all lithospheric plates.