Plate Boundaries

Front

The gradual movement of the continents across the earth. In 1912, Alfred Wegener introduced this theory but he did not fully understand what caused the plates to move.

Back

Continental Drift Theory

Front

New ocean crust is formed at ocean ridges and destroyed at deep-sea trenches.

Back

Sea Floor Spreading

Front

Plates converging (coming) together.

Back

Convergent boundaries

Front

The point where one plate dives beneath another plate. Destroys crust.

Back

Subduction Zone

Front

Where two plates are sliding horizontally past one another. No destruction or construction - Crust is deformed or fractured (earthquakes). Example - San Andreas fault

Back

Transform Boundary

Front

A zone of frequent earthquakes and volcanic eruptions that encircle the basin of the Pacific Ocean.

Back

Ring of Fire

Front

Made mostly of basalt - Thinner and More Dense.

Back

oceanic crust

Front

Made mostly of granite - Thicker and Less Dense.

Back

continental crust

Front

The rising of regions of the crust to higher elevations

Back

uplift