Le Pichon, Xavier (1937– )

French geophysicist who worked out the motions of the earth's six major lithospheric plates. His work was instrumental in the development of plate tectonics.

In 1968 he published Sea-floor Spreading and Continental Drift in which he depicted the earth's lithosphere divided into six major plates. The boundaries between the plates were shown to have high seismic activity and occurred along mid-ocean ridges, island arcs, active orogenic (mountain-building) belts and the transform faults revealed earlier by J Tuzo Wilson.

Le Pichon was born in Vietnam. He became a research assistant at Columbia University's Lamont–Doherty Geological Observatory, New York, in 1963. He received many awards, including the Maurice Ewing Medal of the American Geophysical Union (1984) and the Wollaston Medal of the Geological Society of London (1991). He is currently a professor in the Department de Geologie at the Ecole Normale Superieure in Paris, France.