The Theory of Plate Tectonics
The theory of plate tectonics explains how Earth’s outer shell is divided into large, moving pieces called lithospheric plates. These rigid plates float on the partially molten mantle beneath them, constantly moving at rates of 2-15 cm per year. The theory, developed in the 1960s by McKenzie, Parker, and Morgan, describes how new oceanic crust forms at mid-ocean ridges while old crust is destroyed at subduction zones, creating earthquakes, volcanoes, and mountain ranges.









