"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 direction and speed of plate movements and the driving forces behind them.
Continental Drift: The hypothesis that suggests that continents have moved and drifted apart over millions of years.
Seafloor Spreading: The process where molten material rises from the mantle and spreads out, creating new oceanic crust at mid-ocean ridges.
Plate boundary types: Divergent, convergent, and transform boundaries.
Hot Spots: Areas where mantle material is molten and rises instead of being forced sideways, creating volcanic activity.
Magnetic Reversals: Occur when Earth's magnetic field flips polarity.
Subduction: When one tectonic plate moves under another plate, due to differences in density.
Mantle Convection: The movement of mantle material due to high temperatures and pressure.
Rift Valleys: Formed when continental crust begins to pull apart and create a gap in the earth's surface.
Plate Boundaries and Geological Hazards: Earthquakes, volcanic eruptions, and tsunamis are often associated with plate boundaries.
Paleoceanography: The study of how ocean conditions have changed throughout geologic time.
Geochronology: The measurement of geological time and the dating of geologic events.
Geodesy: The science of accurately measuring the shape, orientation, and location of Earth's features.
Seismic Waves: Vibrations that travel through Earth caused by earthquakes and other geological events.
GPS and Plate Motion: Measuring the movement of tectonic plates with GPS technology.
Paleomagnetism: The study of Earth's magnetic field in the past, through the examination of magnetic minerals in rocks.
Lithosphere: The rigid outer layer of Earth consisting of the crust and upper mantle.
Asthenosphere: The partially melted layer of Earth's upper mantle beneath the lithosphere.
Plate Kinematics: Describing the movements and relative motions of plates.
The Ring of Fire: An area around the Pacific Ocean where many earthquakes, volcanic eruptions, and tsunamis occur due to tectonic activity.
Continental Accretion: The process of continents gradually growing in size by addition of smaller fragments of land.
Divergent plate boundary: Two plates move apart from each other, creating a gap or rift between them. Magma rises up and fills in the gap, creating new crust. Examples include the Mid-Atlantic Ridge and the East African Rift Zone.
Convergent plate boundary: Two plates move towards each other, causing one to subduct (or dive under) the other. This often results in the formation of a subduction zone, where earthquakes, volcanic activity, and mountain building occur. Examples include the Andean Mountains and the Aleutian Islands.
Transform plate boundary: Two plates slide past each other horizontally, either in opposite directions or in the same direction at different speeds. This can cause friction and pressure, leading to earthquakes. Examples include the San Andreas Fault in California.
Ridge push: This occurs at a divergent boundary, where the elevated ridge pushes the plates apart.
Slab pull: This occurs at a convergent boundary, where the denser plate subducts beneath the less dense plate and drags it down with it due to gravity.
Mantle convection: The movement of hot magma in the mantle creates a circular motion that can cause the lithospheric plates to move.
"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."