Robert Norman ClaytonFRS (March 20, 1930 – December 30, 2017) was a Canadian-American chemist and academic. He was the Enrico Fermi Distinguished Service Professor Emeritus of Chemistry at the University of Chicago. Clayton studied cosmochemistry and held a joint appointment in the university's geophysical sciences department. He was a member of the National Academy of Sciences and was named a fellow of several academic societies, including the Royal Society.
Born in Hamilton, Ontario, Clayton grew up in a working-class family that supported (but could not pay for) his pursuit of higher education. None of Clayton's close family members had ever attended college. His high school teachers encouraged him to apply to Queen's University, and he received enough scholarship funding to attend the school. Clayton said that around half of his classmates were a decade older and had served in World War II. He said that this created a serious academic environment.[1]
After graduating from Queen's University with undergraduate and master's degrees, Clayton completed a Ph.D. in 1955 at the California Institute of Technology, where he was mentored by geochemist Samuel Epstein. His first academic appointment was at Penn State University. In 1958, he joined the chemistry faculty at the University of Chicago, where he took over the laboratory of Nobel Prize winner Harold Urey. From 1961 to his retirement in 2001, he held joint appointments in the chemistry and geophysical sciences departments. He directed the Enrico Fermi Institute at the university from 1998 to 2001.[2]
Clayton worked in the field of cosmochemistry and is best known for the use of the stable isotopes of oxygen to classify meteorites.[1] He was aided in his research by Toshiko Mayeda, who was a specialist technician familiar with the mass spectrometry equipment required. Their first joint research paper described the use of bromine pentafluoride to extract oxygen from rocks and minerals.[3] They developed several tests that were used across the field of meteorite and lunar sample analysis.[4][5][6]
Clayton and Mayeda studied variations in the ratio of oxygen-17 and oxygen-18 to the most abundant isotope oxygen-16, building on their surprising finding that this ratio for oxygen-17 in particular was different from that found in terrestrial rock samples.[7] They deduced that this difference was caused by the formation temperature of the meteorite and could thus be used as an "oxygen thermometer".[8] They also worked on the mass spectroscopy and chemistry of the Allende meteorite[1][9] and studied the Bocaiuva meteorite, finding that the Eagle Station meteorite was formed due to impact heating.[10]
They also analysed approximately 300 lunar samples that had been collected during NASAsApollo Program.[11] In 1992, a new type of meteorite, the Brachinite, was identified.[12] Clayton and Mayeda studied the Achondrite meteorites and showed that variations in the oxygen isotope ratios within a planet are due to inhomogeneities in the solar nebula.[13] They analysed Shergotty meteorites, proposing that there could have been a water-rich atmosphere in the past on Mars.[14]
^Clayton, Robert N.; Mayeda, Toshiko K. (1963-01-01). "The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis". Geochimica et Cosmochimica Acta. 27 (1): 43–52. Bibcode:1963GeCoA..27...43C. doi:10.1016/0016-7037(63)90071-1. ISSN0016-7037.
^Clayton, R. N.; Onuma, N.; Grossman, L.; Mayeda, T. K. (1977-03-01). "Distribution of the pre-solar component in Allende and other carbonaceous chondrites". Earth and Planetary Science Letters. 34 (2): 209–224. Bibcode:1977E&PSL..34..209C. doi:10.1016/0012-821X(77)90005-X. ISSN0012-821X.
^Malvin, Daniel J.; Wasson, John T.; Clayton, Robert N.; Mayeda, Toshiko K.; Curvello, Walter Silva (1985). "Bocaiuva-A Silicate-Inclusion Bearing Iron Meteorite Related to the Eagle-Station Pallasites". Meteoritics. 20 (2): 259–273. Bibcode:1985Metic..20..259M. doi:10.1111/j.1945-5100.1985.tb00864.x. ISSN0026-1114.
^E., Nehru, C.; M., Prinz; K., Weisberg, M.; M., Ebihara; N., Clayton, R.; K., Mayeda, T. (July 1992). "Brachinites: A New Primitive Achondrite Group". Meteoritics. 27 (3): 267. Bibcode:1992Metic..27R.267N. ISSN0026-1114.{{cite journal}}: CS1 maint: multiple names: authors list (link)
