Plate tectonics (from the Late Latin tectonicus, from the "pertaining to building") is a scientific theory that describes the large-scale motion of Earth's lithosphere. This theoretical model ...

The various color lines represent different types of boundaries between tectonic plates: Blue-purple lines depict divergent boundaries, where plates split apart; red triangles indicate convergent ...

At divergent boundaries in the oceans, magma from deep in the Earth's mantle rises toward the surface and pushes apart two or more plates. Mountains and volcanoes rise along the seam.