plate tectonics Flashcards
(9 cards)
Name the different layers of the Earth
Crust, Mantle, Outer Core, Inner Core
The Earth’s structure is divided into these four main layers, each with distinct properties.
Identify the scientist who used this evidence to formulate the Theory of Continental Drift
Alfred Wegener
Wegener proposed the theory in 1912 based on geological and fossil evidence.
Outline the Theory of Continental Drift
The continents were once joined together in a single landmass called Pangaea and have since drifted apart
This theory suggests that the continents are not static but move over geological time.
Outline two pieces of evidence that allowed you to match up the model of the continents of Pangaea and explain how they support the Theory of Continental Drift
- Similar fossil records found on different continents
- Geological formations that align across continents
These pieces of evidence suggest that continents were once connected, supporting the idea of continental movement.
Describe why the Theory of Continental Drift was rejected at the time
Lack of a mechanism for how continents could move
Critics argued that without an explanation for the force driving the movement, the theory could not be accepted.
Define the term mid-ocean ridge
An underwater mountain range formed where tectonic plates diverge and new ocean floor is created
Mid-ocean ridges are significant in the study of seafloor spreading.
Outline the trend in seafloor ages away from mid-ocean ridges
Seafloor ages increase with distance from mid-ocean ridges
This trend supports the idea of seafloor spreading, where new crust is formed at the ridges.
Outline Hess’ Theory of Sea Floor Spreading
New oceanic crust is created at mid-ocean ridges and slowly moves away, causing the seafloor to spread
This theory builds on the concept of continental drift by explaining the mechanism of seafloor formation.
Explain how magnetic striping can help support the Theory of Sea Floor Spreading
Magnetic striping shows symmetrical patterns on either side of mid-ocean ridges, indicating new crust formation
The patterns reflect Earth’s magnetic field reversals and support the idea of seafloor spreading.
