Types of Plate Boundaries

Types of Plate Boundaries Scientists identify the boundaries between two plates by the plate movement. There are three types of plate boundaries: Divergent Convergent Transform

Why do Plates Move? Convection currents in the mantle Cause plates to collide, pull apart or slide Material in mantle is heated floats to surface as it cools it moves back towards the core

Divergent Boundaries A divergent boundary is a boundary where two plates are moving away from each other.

Divergent Boundaries This is an example of a divergent boundary. Bridge across the Alfagaria Rift Valley in southwest Iceland, that is part of the boundary between the Eurasian and North American continental tectonic plates.

Divergent Boundaries A Rift Valley is a deep valley located on divergent boundaries. Remember the mid-ocean ridge? The middle part of the mid-ocean ridge is called a rift valley. Rift = crack Seafloor spreading occurs at divergent boundaries

Divergent Boundaries As divergent boundaries widen rift valleys form and create new crust from magma that makes its way to the surface. As lava builds up it forms underwater mountain ranges . Ex. Mid-Atlantic Ridge

Convergent Boundaries A Convergent Boundary is a boundary between two plates that are moving toward each other.

Types of Convergent Boundaries 1.Continental/Continental- Two plates run into each other and crumble. Folded mountains are created. ex. Himalayas 2.Oceanic/Continental- Crust collide, and trenches are formed in the ocean floor. Melted rock from the subducted plate begins to move upward fueling volcanoes. ex. Andes Mountains 3.Oceanic/Oceanic- Plate is subducted beneath another plate along a trench as a result underwater volcanic mountains erupt. ex. Aleutian Island

Convergent Boundaries One important feature is a deep-sea trench. These form along the subduction zone. Subduction Boundary – When an oceanic plate plunges beneath another plate it is said to be sub-ducting beneath the overriding plate. This boundary between the two plates is a subduction boundary. Ex. Andes Mountains These boundaries can occur between two ocean plates or and ocean and continental plate.

Convergent Boundaries Collision Boundary – The boundary that forms when two continents collide is called a collision boundary. Mountain ranges are usually formed along such boundaries.

The Himalayan Mountains are an example of a collision boundary.

Transform Boundary A Transform Boundary is a boundary between two plates that are sliding past each other. Fault- break in Earth’s crust

Transform Boundaries Movement along transform boundaries is not uniform and can sometimes cause earthquakes. The San Andreas Fault in North America is an example of a Transform Boundary.

Three Types of Boundaries