A host of components, exemplars within this paradigm:
Basic definition for plate tectonics: the outer shell of the earth (the lithosphere) consists of distinct curved plates that behave relatively rigidly and move large horizontal distances with respect to each other at average rates of centimeters per year. Oceanic crust is formed at seafloor spreading centers and recycled into the mantle at subduction zones. Plate interiors are relatively unaffected, but plate margins are areas of concentrated geologic activity.
Wegener and continental drift in the 1920s; a failed revolution:
Seafloor spreading and the revolution succeeds in the 1960s.
Why were many detailed studies of rock magnetism being done in the 1950s?
A chain of thought: natural remnant magnetization (NRM) -> polarity reversals and magnetostratigraphy -> striped magnetic anomalies on the sea floor -> basic idea of seafloor spreading.
Summary: the linear magnetic anomalies are acquired as oceanic crust forms at the spreading ridges through histories of magnetic field reversals and then moves away.
Transform ridge geometry.
Model for oceanic crust: captured in diagram above.
In place oceanic crust is all younger than some 200 Ma.
On to other types of plate boundaries.
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