Nature · Earth Science
The drifting jigsaw that shapes the world
Earth’s rigid outer shell is broken into a dozen or so vast plates that drift slowly over the hot, flowing mantle beneath. Their grinding, colliding and pulling apart builds mountains, opens oceans, triggers earthquakes and fuels volcanoes — the master process behind the map of the world.
Heat from deep within drives slow convection in the mantle, dragging the plates above it at the speed fingernails grow. Over hundreds of millions of years this motion tears continents apart, rafts them across the globe and slams them back together — reshaping oceans and mountain ranges alike.
Plates pull apart, collide and slide past one another — building ridges, trenches, mountains and faults.
Where plates pull apart
Where plates separate, magma wells up to create fresh crust, building undersea mountain chains and tearing continents open into rift valleys and new seas.
Where plates collide
When plates converge, one may plunge beneath the other into the mantle, or they may buckle upward into towering ranges. These zones host Earth’s deepest trenches and mightiest quakes.
Where plates grind past
At transform boundaries, plates scrape past one another. Stress builds as they lock, then releases in sudden jolts — the earthquakes of great faults like the San Andreas.
Continents on the move
Plate motion carries the continents on a slow dance across the planet, gathering them into supercontinents like Pangaea and then splitting them apart — explaining why coastlines and fossils match across oceans.