The formation of fresh areas of oceanic crust which occurs through the upwelling of magma at mid-ocean ridges and its subsequent outward movement on either side.
〔地质〕海底扩展（说）
Example sentencesExamples
After much thought, he proposed in 1960 that the movement of the continents was a result of sea-floor spreading.
The main figure demonstrates how sea-floor anomalies, also known as magnetic stripes, develop during sea-floor spreading.
Reversals of the Earth's magnetic field, allied to sea-floor spreading, have left their imprint in the form of a magnetic tape recorder on the sea-floor.