Continental drift

Continents Drift Theory

A theory proposed by Alfred Wegener stating that continents have moved horizontally to their current locations.

Evidence for Continental Drift

Includes similarities in continent shapes, fossil evidence like Mesosaurus, marks from ice sheets, location of coal beds, and rock type and structural similarities.

Convection

The process where hot magma rises up and then sinks down, dragging the lithosphere plates with it.

Driving Forces of Plate Boundaries

Convection, gravity-driven ridge push, and gravity-driven slab pull.

Convergent Boundaries

Boundaries where plates move together, creating volcanic mountain ranges and folded mountains.

Subduction of Oceanic Plates

When oceanic plates collide with continental plates, the thinner and denser oceanic plate subducts.

Subduction of Oceanic Plates (Oceanic-Oceanic)

When two oceanic plates collide, the older, cooler, and denser plate subducts.

Continental Collision

When two continental plates collide, the crust is folded and faulted.

Transform Boundary

A type of boundary where plates slide past each other.

Age of Ocean Rocks

Rocks on ocean plates are older as you move away from the ocean ridge, indicating that ridges are where ocean floors form.

Heat Flow Measurement

Heat flow along the ridge indicates new crust formation, with decreasing temperature as distance from the ridge increases.

Magnetic Polarity of Ocean Floor

Study of the ocean floor's magnetic polarity shows the movement of plates as the magnetic field aligns itself.