John Reynolds (physicist)

John Hamilton Reynolds ( born April 3, 1923 in Cambridge (Massachusetts ), † November 4, 2000 in Berkeley ) was an American geophysicist.

Life and work

Reynolds studied at Harvard University ( summa cum laude Bachelor 1943) and interrupted by military service in World War II with the U.S. Navy in the South Pacific at the University of Chicago, where he received his doctorate at Mark Inghram. He dealt there with mass spectrometers, where he was influenced by the Chicago physicists Harold C. Urey and Enrico Fermi. He turned the mass spectrometry on geological and cosmic dating problems, for example on meteorites.

In 1950 he was Assistant Professor at the University of California, Berkeley, where he worked with the geological research group of John Verhoogen and his students. He developed there, the first static (not pumped operated ) glass mass spectrometer for noble gases. He improved the potassium - argon dating in geology. Reynolds discovered isotopic anomalies in meteorites, which pointed to elements derived from the period before the formation of the solar system. For example, in 1960 he found a xenon -129 anomaly which he to the decay of iodine 129 led back (half-life 16 million years ), with possible origin from a supernova before formation of the solar system.

He spent a sabbatical year at the University of São Paulo, where he helped build a geochronologisches laboratory.

He was a member of the National Academy of Sciences (1968) and the American Academy of Arts and Sciences (1980 ). In 1965 he received the Wetherill Medal of the Franklin Institute, 1967, the J. Lawrence Smith Medal of the National Academy of Sciences, 1973 NASA Exceptional Achievement Award and the Leonard Medal of the Meteoritical Society, and in 1988 the Berkeley Citation. In 1987 he became an honorary doctorate from the University of Coimbra in Portugal.

His research also provided the basis for the paleomagnetic dating of Allan Cox, Richard Doell, Brent Dalrymple, who all came from Berkeley. Also played in the dating of early human remains found in the Olduvai Gorge his method an important role.