9.1 - Moving Continents Flashcards
What is continental drift?
A revolutionary new theory proposed by Alfred Wegener, who claimed the continents were once connected to each other in a landmass called Pangea and concluded that the continents must have somehow separated and drifted across the oceans.
What was the Continental Drift Theory based on?
1) The continents seemed to fit like a jigsaw puzzle
2) Fossils of the same prehistoric species were found in continents far away
What is seafloor spreading?
A theory proposed by Hess that a new rocky crust was being formed at the ocean ridges and spreading outwards.
How are ocean trenches formed?
When the crust sinks down into Earth.
What is Subduction?
The process of a one tectonic plate sinking down underneath another tectonic plate
Support For Seafloor Spreading Theory?
1) Magnetic Striping
2) Age of the Seafloor
3) Sediment Thickness
What is magnetic stripping?
Patterns of alternating magnetism.
