Plate Boundaries

Tectonic Plates

• The large pieces the Earth’s crust is divided into

• These plates float on the semi-fluid mantle below them

Plate Boundaries

____ ____ are on the ocean floor around the edges of continents or even within continents

1. Divergent Plate

2. Convergent Plate

3. Transform Plate

Types of Plate Boundaries

Divergent Boundaries

• Plates move away from each other

• This movement results in the creation of new crust such as magma rises from the mantle, solidifies, and forms new oceanic crust

• Responsible for the continuous reshaping and formation of Earth’s crust

• Forms Rift Valleys, Mid-Ocean Ridges and Volcanoes

Convergent Boundaries

• Places where tectonic plates collide or come together

• Contribute to the formation of mountains, volcanic activity, and earthquakes

Continent-Continent Collisions

• When two plates of continental lithospheres collide, they buckle and thicken

• Causes mountains to form

Continent-Ocean Collisions

• When an oceanic lithosphere collides with a plate of continental lithosphere, the oceanic lithosphere subducts because it is denser

• Causes trenches and island arcs to form

Ocean-Ocean Collisions

• When two plates of oceanic lithospheres collide, the old denser plate plunges downward under the other plate

• Causes trenches and mountains to form

Transform Boundaries

• When two plates slide past each other horizontally

• The movement along these boundaries can cause earthquakes, as the plates grind against each other

• Unlike convergent or divergent boundaries, there is no creation or destruction of crust

• Forms Fault Lines and Earthquakes