Tectonic Plates and Continental Drift

This page introduces the concept of tectonic plates and their role in shaping Earth's surface. It covers the formation of Pangea, the characteristics of continental and oceanic crust, and the three main types of plate boundaries.

Definition: Pangea was the supercontinent that existed approximately 300 million years ago, where all continents fit together like a puzzle.

The page explains the differences between continental and oceanic crust, highlighting that continental crust is thicker and less dense, while oceanic crust is thinner and more dense. It then introduces the three types of plate boundaries:

1. Transform plate boundary: Where plates slide past one another.
2. Divergent plate boundaries: Where plates move away from each other.
3. Convergent plate boundary: Where plates collide.

Highlight: As the distance from the mid-ocean ridge increases, the age of the rock also increases. This is crucial evidence for seafloor spreading.

The page also touches on the concept of magnetic patterns on either side of mid-ocean ridges, which mirror each other and provide further evidence for plate tectonics.

Lastly, it introduces different types of seismic waves:

Vocabulary:

• P-waves: Travel through all materials
• S-waves: Travel through solids only
• Surface waves: Travel only on the surface

The page concludes by mentioning that three seismograph stations are needed to determine the location of an earthquake epicenter and introduces the concept of convection currents in the mantle.