Across
- 4. core Dense ball of solid material at the center of the Earth
- 6. The name of the single landmass that broke apart about 225 million years ago
- 8. core A layer of molten iron and nickel that surrounds the inner core of the Earth Convergent boundary A plate boundary where two plates move toward each other
Down
- 1. spreading The process by which molten material adds new oceanic crust to the ocean floor
- 2. Drift Alfred Wegener's hypothesis that the continents were once one huge land mass but have since then drifted apart
- 3. ridge The undersea mountain mountain chain where new ocean floor is produced; a divergent plate boundary
- 5. Thickest layer of the Earth; it consists of two layers - the lithosphere and the asthenosphere
- 7. currents Cause the plates to move; between the lithosphere and the asthenosphere
- 9. of Plate Tectonics Theory that pieces of the Earth's lithosphere are in motion,driven by convection currents in the mantle