Thomas Edvard Krogh

Thomas Edvard Krogh , called Tom Krogh , (born 1936 in Peterborough , Ontario ; † April 29, 2008 ) was a Canadian geologist , specialist in geochronology and curator at the Royal Ontario Museum .

Life

Krogh studied from 1955 mining engineering and geology at Queen's University (Kingston) with a master's degree in 1960 and received his doctorate in 1964 at the Massachusetts Institute of Technology , where he specialized in geochronology. He then worked at the Carnegie Institution in Washington DC (first as a post-doctoral student, then as a permanent member), where he dealt with rubidium-strontium dating . From 1970 he turned to uranium-lead dating, for example, of zircons and from 1975 he was back in Canada as the founder and head of the geochronology laboratory at the Royal Ontario Museum (Jack Satterly Geochronology Laboratory). In 1976 he also became a professor at the University of Toronto . In 1979 he became a curator at the Royal Ontario Museum, which he remained until his retirement in 2001.

He improved the accuracy of uranium-lead dating, which is particularly used in dating very ancient rocks from the Precambrian. His methods became the standard worldwide. With them, sources of error from lead pollution caused by the environment could be reduced and increasingly smaller samples could be examined. The processes revolutionized the understanding of the first billion years of earth's history and put the understanding of tectonic processes in the Archean and Proterozoic on a solid basis. He himself especially studied the Precambrian in Ontario (Grenville County, Lake Superior). His investigation of zircons in the Sudbury Basin confirmed the old age and the formation as a meteorite impact crater. By examining the age of the zircons in the worldwide precipitation as a result of the impact of the Chicxulub meteorite on the Cretaceous-Tertiary border , he and colleagues were able to localize the location of the impact.

In 1999 he became a Fellow of the Royal Society of Canada , in 1991 the J. Tuzo Wilson Medal of the Canadian Geophysical Union and in 1989 he received the Logan Medal . In 1991 he received an honorary doctorate from Queen's University in Kingston. In 1994 he became a member of the Norwegian Academy of Sciences and was a Fellow of the American Geophysical Union . He received the President's Medal of the Mineralogical Association of Canada . He was involved in the Canadian Lithoprobe program to study the structure of the lithosphere .

Fonts

• with DW Davis, IS Williams: Historical development of zircon geochronology, in: JM Hanchar, PWO Hoskin (Ed.) Reviews in Mineralogy and Geochemistry, Volume 53, 2003, pp. 145-181
• mit SL Kamo, B. Bohor: Shock metamorphosed zircons with correlated U-Pb discordance and melt rocks with concordant protolith ages indicate an impact origin for the Sudbury Structure, in: A. Basu, S. Hart (Ed.), Earth Processes: reading the isotopic code, Geophysical Monograph 95, Washington, DC: American Geophysical Union, 1996, pp. 343-353.
• with SL Kamo, V. Sharpton, L. Marin, AR Hildebrand: U-Pb ages of single shocked zircons linking distal K / T ejecta to the Chicxulub crater, Nature, Volume 366, 1993, pp. 731-734.
• Improved accuracy of U-Pb zircon ages by the creation of more concordant systems using an air abrasion technique, Geochimica et Cosmochimica Acta, Volume 46, 1982 pp. 637-649.

Web links

• Biography of Sandra Kamo, Jack Satterly Geochronology Laboratory, 2008