The six tectonic regimes explain the plates and their relationships: cratons, hot spots, divergent borders, ocean basins, convergent boundaries, and transform boundaries (see diagram below).
Cratons are large stable bodies that consist of mostly rock that formed as a result of the accumulation of minerals through time. They can be found at the center of many continents and help to bind them together. The term "craton" comes from the Greek word kratos meaning "strength" or "power".
Hot spots are areas where crustal plates collide and melt, causing volcanoes to erupt material into the atmosphere or oceans. These collisions often cause earthquakes too. Europe is an example of a hot spot continent. It's made up of several pieces of crust that sit on top of vast reservoirs of molten rock called intrusions. As these pieces of crust move over the reservoir they heat up and become more buoyant, eventually rising out of the liquid rock and forming new continental crust.
Divergent borders are those that separate two cratons that aren't connected by any sort of plate. An example of this is between Africa and South America. Their borders converge at a point near the South Atlantic Ocean but don't connect anywhere else.
The movement of the plates causes three types of tectonic borders: convergent boundaries, where plates move into one another, divergent boundaries, where plates move apart, and transformational boundaries, where plates shift sideways in regard to one another. These movements cause faulting and folding of the rock within or near the boundary zone.
Convergent boundaries occur when two plates approach one another head-on and collide. The impact creates a deep trench between them called a subduction zone. At this point, the rocks on either side of the trench are forced beneath the water surface. This is bad news for anyone living on the ocean floor because it means they are now at risk from being dragged into the trench and destroyed. The only way to escape this fate is if you find yourself lifted up out of the trench onto land again. The Rockies and Himalayas are good examples of what happens when two plates converge.
Divergent boundaries occur when two plates move away from one another and leave a space between them called an accretionary wedge. New rock is created as the opposing plates grind against each other, causing mountains to be formed. One example of a divergent boundary is found where the Pacific Plate meets the North American Plate near Washington State.
Transform faults occur when one plate slides with respect to another.
Divergent, convergent, and transform plate borders are the three types of plate tectonic boundaries. The three basic types of plate borders are seen in this image: divergent, convergent, and transform. Divergent borders separate large plates that are moving apart from one another. Convergent borders occur where two smaller plates collide and merge into a single larger one. Transform borders change the shape of the underlying rock beneath them; they can be smooth or jagged.
Divergent plate boundaries include oceanic trenches, volcanic arcs, and continental shelves. Trenches form when plates move away from each other at the margins of continents. The mid-oceanic ridge is an example of a divergent plate boundary. It forms where two large plates (one moving northward, one moving southward) slide past one another. As they do so, they grow older and deeper as new ocean floor is created by the ridge.
Continental shelves are divergent plate boundaries located near continents. They form where large plates push up against continents. As they do so, deep valleys are carved out underneath the plates, creating more land than before the collision. Continents also move toward one another over time, bringing their edges closer together. This is called indeterminate growth. As they do so, they often collide and merge with other continents, forming big mountains like Mount Everest or Rodondo Hill.
Divergent and convergent borders, transform fault boundaries, and plate boundary zones are the four types of tectonic plate boundaries established by plate movement. These surface features define the limits of major geological plates that cover most of the Earth's surface.
Divergent borders occur where two plates move away from each other. The mid-oceanic ridge systems are a good example of this type of border. Here, pieces of crust rise up from the mantle and drift apart to form new oceanic plates. This process removes material from the edge of the crust and causes the crust to get thinner over time.
Convergent borders occur where two plates move together. Large areas of continental crust can be formed in this way; for example, parts of Europe and North America were once made up of several small fragments of crust that collided with one another and now form a single continent.
Transform faults occur where one plate moves under another. These fractures release energy as heat and increase the rate of global warming. One example is the San Andreas Fault in California; it is responsible for causing many large earthquakes as it breaks down its rock layer.
Plate boundaries occur where two plates meet.