Plate Tectonics (Wegener to Vine-Matthews, 1912–1966)

Alfred Wegener proposed continental drift in 1912 after noticing that Africa and South America fit together like puzzle pieces and shared identical fossil species — but he was ridiculed for lacking a mechanism. The vindication came in the 1950s–60s through seafloor spreading evidence and the Vine-Matthews hypothesis of 1963, which confirmed that Earth's crust is divided into tectonic plates moving on a fluid mantle. Plate tectonics explained earthquakes, volcanoes, mountain formation, ocean basins, and the distribution of every mineral deposit on Earth. It is to geology what evolution is to biology: the single unifying theory that makes everything else make sense.