Runcorn, Stanley Keith

▪ 1996

      British geophysicist (b. Nov. 19, 1922, Southport, Lancashire, England—d. Dec. 5, 1995, San Diego, Calif.), was the first to discover evidence of the periodic polar reversals of the Earth's magnetic field. In the 1950s he was a pioneer in the fledgling discipline of paleomagnetism, or remanent magnetism, the study of the residual magnetism in rocks. Magnetic minerals within rocks generally align their magnetic domains permanently to the Earth's field at the time of the rock's formation and deposition, which thereby provides a lasting chronology of geomagnetism. Through this line of study he helped to establish the theories of polar wandering, the migration of the Earth's magnetic poles over time; continental drift, the slow horizontal shifting of continents in relation to one another and to the ocean basins; and plate tectonics, the independent movement of the Earth's outer shell relative to its underlying mantle. In the 1960s he suggested that the Moon, generally thought to be an inactive celestial object, had once possessed a magnetic field. Runcorn was educated at the University of Cambridge (B.A., 1944; M.A., 1948) and the University of Manchester (Ph.D., 1949), where he studied under the Nobel Prize-winning physicist Patrick M.S. Blackett. During 1950-56 Runcorn conducted research at Cambridge that paralleled Blackett's work at Manchester. From 1956 to 1988 he was director of the physics department at King's College, a part of the University of Durham that was reorganized as the University of Newcastle upon Tyne in 1963. At the end of his career, he held a chair (1989-95) at the University of Alaska.

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▪ British geophysicist

born Nov. 19, 1922, Southport, Lancashire, Eng.

died Dec. 5, 1995, San Diego, Calif., U.S.

      British geophysicist whose pioneering studies of paleomagnetism provided early evidence in support of the theory of continental drift.

      Runcorn was educated at the University of Cambridge (B.A., 1944; M.A., 1948) and the University of Manchester (Ph.D., 1949). He was assistant director of geophysics research at Cambridge from 1950 to 1955, and from 1956 to 1988 he was professor of physics and head of the physics department at King's College, which was part of the University of Durham and became the University of Newcastle upon Tyne in 1963.

      In the late 1940s and '50s Runcorn helped establish the field of paleomagnetism (remanent magnetism)—i.e., the study of the residual magnetization that is evident in ancient rocks. Such rocks preserve fossilized traces of the direction of the Earth's magnetic field that prevailed at the time the rocks were formed. Runcorn's analyses of rocks in Europe provided evidence of periodic reversals of the Earth's field (geomagnetic polar reversals (geomagnetic reversal)) over geologic time. Moreover, his data suggested that the Earth's north magnetic pole had moved, or wandered, widely over hundreds of millions of years. Runcorn's first explanation was that the geographic pole of the Earth had itself migrated, but this was contradicted by evidence that the drift of the magnetic pole as shown by American rocks was different from that shown by European ones. The magnetic curves of the European and American rocks could be aligned, or reconciled, however, on the assumption that those two continents had formerly been joined and had subsequently drifted apart into their present-day positions. Impressed by this result, Runcorn became an early proponent of the theory of continental drift, and the paleomagnetic data obtained by him and other researchers eventually provided some of the strongest evidence in support of the theory.

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