"Plate tectonics is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates which have been slowly moving since about 3.4 billion years ago."
The theory that Earth's crust is divided into large plates that move and interact with each other.
Introduction to Plate Tectonics: A brief history of the scientific discovery of plate tectonics and the basic concepts behind the theory.
Types of Plate Boundaries: The three main types of plate boundaries (divergent, convergent, transform) and their characteristics.
Plate Motions: The direction and speed of plate movements and the driving forces behind them.
Lithosphere and Asthenosphere: The structure and composition of Earth's outer layers and their relationship to plate tectonics.
Volcanoes and Earthquakes: The relationship between plate tectonics, volcanoes, and earthquakes and their distribution around the world.
Subduction Zones: The process of oceanic crust sinking beneath a continental plate and creating volcanic arcs.
Mid-Ocean Ridges: The seafloor spreading centers where new oceanic crust is formed.
Hot Spots: Volcanic activity that is unrelated to plate boundaries, often associated with mantle plumes.
Plate Tectonics and Mountains: The relationship between plate tectonics and the formation of mountain ranges such as the Himalayas and the Rockies.
Plate Tectonics and Climate Change: The interplay between plate tectonics, ocean currents, and atmospheric circulation that can affect global climate over geologic time frames.
Divergent Plate Boundaries: Where two plates move away from each other, creating a gap between them which is often filled with molten magma from the mantle. This results in the creation of new crustal material and is responsible for many of the world's oceanic ridges.
Convergent Plate Boundaries: When two plates move towards each other, and the denser plate is slowly forced beneath the lighter, overriding plate. This can cause volcanic activity, earthquakes, and mountain formation.
Transform Plate Boundaries: The boundary where two plates slide past each other horizontally. This results in a lot of seismic activity and can cause earthquakes.
Subduction Zones: The area where one tectonic plate is forced beneath another into the mantle by gravity. This process results in the formation of deep ocean trenches and volcanism.
Continental Rifts: Locations where continental plates are moving apart causing a split or rift in the continent. This can lead to volcanic activity and the formation of new ocean basins.
Collision Zones: Places where two continental plates collide, forming mountains such as the Himalayas.
Hot Spot Volcanism: Occurs when a tectonic plate moves over a fixed hot spot of magma, creating a chain of volcanoes like the Hawaiian Islands.
"The model builds on the concept of continental drift, an idea developed during the first decades of the 20th century."
"Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s."
"Earth's lithosphere is broken into seven or eight major plates."
"Where the plates meet, their relative motion determines the type of plate boundary: convergent, divergent, or transform."
"Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries."
"The relative movement of the plates typically ranges from zero to 10 cm annually."
"Tectonic plates are composed of the oceanic lithosphere and the thicker continental lithosphere, each topped by its own kind of crust."
"Along convergent plate boundaries, the process of subduction, or of one plate moving under another, carries the edge of one plate down under the other plate and into the mantle."
"The lost surface is balanced by the formation of new oceanic crust along divergent margins by seafloor spreading."
"This process of plate tectonics is also referred to as the conveyor belt principle."
"Tectonic plates are able to move because Earth's lithosphere has greater mechanical strength than the underlying asthenosphere."
"Plate movement is driven by a combination of the motion of the seafloor away from spreading ridges due to variations in topography and density changes in the crust."
"At subduction zones, the relatively cold, dense oceanic crust sinks down into the mantle forming the downward convecting limb of a mantle cell. This is the strongest driver of the plates."
"The relative importance of other proposed factors such as active convection, upwelling and flow inside the mantle, and tidal drag of the moon, and their relationship to each other is still the subject of debate."