Harmon Craig

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Harmon Craig (born March 15, 1926 in New York City , † March 14, 2003 in La Jolla ) was an American geochemist and oceanographer. He applied isotopic chemistry to many geological, oceanographic, and cosmochemical problems.

life and work

Craig studied geology and chemistry at the University of Chicago (interrupted his service as an officer in the US Navy during World War II), where he received his doctorate in 1951 with a thesis on the geochemistry of carbon isotopes under Harold C. Urey . The dissertation made contributions to radiocarbon dating , in particular by studying the variation of carbon 13 to 12. He was then at the Enrico Fermi Institute at the University of Chicago, until 1955 at the invitation of Roger Revelle to the Scripps Institution of Oceanography , where he was until End of his career stayed. There he was professor of geochemistry and oceanography.

He made early theoretical contributions to the isotope balance of the oceans and the carbon dioxide balance of the oceans and the atmosphere. He was one of the first to investigate the gas content in ice cores and investigated the increase in methane and nitrogen oxides in the atmosphere due to human exposure.

From 1970 he was on the part of the Scripss Institution co-head of the Geosecs (Geochemical ocean sections study) program of the Scripps Institution, the Woods Hole Oceanographic Institution ( Derek Spencer ) and the Lamont-Doherty Earth Observatory ( Wallace Broecker ), with which the chemistry and isotopes of the world's oceans have been studied and the largest amount of data on ocean chemistry has been collected to date.

He discovered hydrothermal sources in geologically active zones on the sea floor through isotope measurements on the surface (helium 3, radon) and through a total of 17 diving trips with Alvin (DSV-2) , including in the Mariana Trench . He led a total of 28 oceanographic expedition trips, but also studied geologically active zones on land, for example in the East African Rift, the Dead Sea, in Tibet, China and the volcanic islands and volcanic areas in the Pacific and the Indian Ocean. From the higher proportion of helium 3 compared to helium 4, he identified sixteen hot spots worldwide .

In Chicago, he and Urey investigated the isotopic chemical composition of chondrites and found that they fell into two groups.

Honors and memberships

In 1987 he received the Vetlesen Prize and in the same year the Arthur L. Day Prize and in 1983 the Arthur L. Day Medal . He was a member of the National Academy of Sciences (1979) and the American Academy of Arts and Sciences (1976). In 1998 he received the Balzan Prize , in 1979 the VM Goldschmidt Medal of the Geochemical Society and in 1982 the Special Creativity Award for oceanography from the National Science Foundation. He was an honorary doctor from the University of Paris and the University of Chicago.

literature

  • Alexander E. Gates: Earth Scientists from A to Z, Facts on File, 2003

Web links

Individual evidence

  1. ↑ Craig: The geochemistry of the stable carbon isotopes. In: Geochim. Cosmochim. Acta. Volume 3, 1953, pp. 53-92.
  2. ↑ Craig: The natural distribution of radiocarbon and the exchange time of carbon dioxide between atmosphere and sea. In: Tellus. Volume 9, 1957, pp. 1-7.
  3. ↑ Craig, Chou: Methane: The record in polar ice cores. In: Geophys. Res. Letters. Volume 99, 1982, pp. 1221-1224.
  4. ↑ For example, Craig, WB Clarke, MA Beg: Excess 3 He in the Sea: evidence for terrestrial primoridal helium. In: Earth Planetary Science Letters. Volume 6, 1969, pp. 213-220.
  5. ↑ Urey, Craig: The composition of stone meteorites and the origin of meteorites. In: Geochim. Cosmochim. Acta. Volume 4, 1953, pp. 36-82.
personal data
SURNAME Craig, Harmon
ALTERNATIVE NAMES Craig, Harmon Bushnell (full name)
BRIEF DESCRIPTION American geochemist
DATE OF BIRTH March 15, 1926
PLACE OF BIRTH New York City
DATE OF DEATH March 14, 2003
Place of death La Jolla