Some of the constructive forces that shape and create landforms are crustal deformation, deposition of sediment and volcanic eruptions. The flow of heat through the Earth's crust and the movement of tectonic plates and magma account for some of the more spectacular crustal deformations. The transportation, or deposition, of sedimentary particles by wind, water and glaciers results in the creation of dunes, deltas and other topographical features.
The variety of movements taking place within the outermost portion of the Earth's crust, or lithosphere, are collectively referred to as plate tectonics. These movements represent massive constructive forces that have created major mountain ranges across the world. Depending upon the manner in which they are defined, there are either seven or eight major tectonic plates and several minor plates in the lithosphere. These plates slide over the layer beneath the Earth's crust, which is called the mantle. This movement is driven by convection, which is the process of heat transfer taking place within the Earth.
The manner in which the tectonic plates move in relation to each other determines the type of constructive force exerted on the Earth's crust and its resultant deformation. The three types of plate movement are convergent, divergent and transform. A convergent motion means the plates are moving toward each other, which often results in the formation of mountains. When two plates move away from each other, it represents a divergent motion, while the movement of plates sliding past each other represents a transform motion.