Geomagnetic reversals
Inversiones del campo magnético terrestre
- Date
- 1906 / 1929 / 1963 · confidence high
- Place
- Massif Central, France (Brunhes)
- Credited to
- Bernard Brunhes (1906), Motonori Matuyama (1929), Allan Cox, Richard Doell and Brent Dalrymple (time scale, 1963-66)
- People
- 👤 Allan Cox1873–1896👤 Bernard Brunhes1867–1910👤 Motonori Matuyama1884–1958👤 Richard Doell1893–1950
- Field
- Cosmos & Earth
What was discovered
Brunhes found lavas magnetised in reverse; Matuyama arranged them chronologically; Cox and colleagues built a potassium-argon-dated scale of reversals. Earth's polarity flips irregularly every few hundred thousand years.
Coordinates of Pontfarein (Cantal), where Brunhes took his lava samples.
What it led to
- Key proof of seafloor spreading (Vine-Matthews magnetic stripes)
- Magnetostratigraphy
- Understanding of the core dynamo
Built on
- Earth as a magnet: geomagnetic field1600
- Potassium-argon dating (Aldrich and Nier)1948-1957
- Earth's magnetic field (Gilbert)
- Néel's palaeomagnetism
Made possible
- Apparent polar wander curves (Runcorn)1956
- Alternating magnetic stripes of the Pacific seafloor (Mason and Raff)1955-1961
- Seafloor spreading1960-1963
- Applied potassium-argon dating
- Towed magnetometers