Robert Norman Clayton (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 The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park neighborhood. The University of Chicago is consistently ranked among the b ...

. Clayton studied

cosmochemistry Cosmochemistry (from Greek κόσμος ''kósmos'', "universe" and χημεία ''khemeía'') or chemical cosmology is the study of the chemical composition of matter in the universe and the processes that led to those compositions. This is done ...

and held a joint appointment in the university's geophysical sciences department. He was a member of the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...

and was named a fellow of several academic societies, including the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

Biography

Born in

Hamilton, Ontario Hamilton is a port city in the Canadian province of Ontario. Hamilton has a population of 569,353, and its census metropolitan area, which includes Burlington and Grimsby, has a population of 785,184. The city is approximately southwest of T ...

, 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 World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

. He said that this created a serious academic environment. 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 The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...

, where he was mentored by geochemist Samuel Epstein. His first academic appointment was at

Penn State University The Pennsylvania State University (Penn State or PSU) is a public state-related land-grant research university with campuses and facilities throughout Pennsylvania. Founded in 1855 as the Farmers' High School of Pennsylvania, Penn State became ...

. In 1958, he joined the chemistry faculty at the University of Chicago, where he took over the laboratory of Nobel Prize winner

Harold Urey Harold Clayton Urey ( ; April 29, 1893 – January 5, 1981) was an American physical chemist whose pioneering work on isotopes earned him the Nobel Prize in Chemistry in 1934 for the discovery of deuterium. He played a significant role in the d ...

. From 1961 to his retirement in 2001, he held joint appointments in the chemistry and geophysical sciences departments. He directed the

Enrico Fermi Institute __NOTOC__ The Institute for Nuclear Studies was founded September 1945 as part of the University of Chicago with Samuel King Allison as director. On November 20, 1955, it was renamed The Enrico Fermi Institute for Nuclear Studies. The name was sh ...

at the university from 1998 to 2001.

Research

Clayton worked in the field of

and is best known for the use of the stable

isotopes of oxygen There are three known stable isotopes of oxygen (8O): , , and . Radioactive isotopes ranging from to have also been characterized, all short-lived. The longest-lived radioisotope is with a half-life of , while the shortest-lived isotope is ...

to classify meteorites. He was aided in his research by

Toshiko Mayeda Toshiko K. Mayeda (née Kuki) (1923–13 February 2004) was a Japanese American chemist who worked at the Enrico Fermi Institute in the University of Chicago. She worked on climate science and meteorites from 1958 to 2004. Early life and educat ...

, who was a specialist technician familiar with the

mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is use ...

equipment required. Their first joint research paper described the use of

bromine pentafluoride Bromine pentafluoride, Br F5, is an interhalogen compound and a fluoride of bromine. It is a strong fluorinating agent. BrF5 finds use in oxygen isotope analysis. Laser ablation of solid silicates in the presence of BrF5 releases O2 for subsequ ...

to extract oxygen from rocks and minerals. They developed several tests that were used across the field of meteorite and lunar sample analysis. Clayton and Mayeda studied variations in the ratio of

oxygen-17 Oxygen-17 (17O) is a low-abundance, natural, stable isotope of oxygen (0.0373% in seawater; approximately twice as abundant as deuterium). As the only stable isotope of oxygen possessing a nuclear spin (+5/2) and a favorable characteristic of fi ...

and

oxygen-18 Oxygen-18 (, Ω) is a natural, stable isotope of oxygen and one of the environmental isotopes. is an important precursor for the production of fluorodeoxyglucose (FDG) used in positron emission tomography (PET). Generally, in the radiopharmaceu ...

to the most abundant isotope

oxygen-16 Oxygen-16 (16O) is a stable isotope of oxygen, having 8 neutrons and 8 protons in its nucleus. It has a mass of . Oxygen-16 is the most abundant isotope of oxygen and accounts for 99.762% of oxygen's natural abundance. The relative and absolute ...

, building on their surprising finding that this ratio for oxygen-17 in particular was different from that found in terrestrial rock samples. They deduced that this difference was caused by the formation temperature of the meteorite and could thus be used as an "oxygen thermometer". They also worked on the mass spectroscopy and chemistry of the

Allende meteorite The Allende meteorite is the largest carbonaceous chondrite ever found on Earth. The fireball was witnessed at 01:05 on February 8, 1969, falling over the Mexican state of Chihuahua. After it broke up in the atmosphere, an extensive search for ...

and studied the Bocaiuva meteorite, finding that the

Eagle Station meteorite The Eagle Station meteorite is a pallasite and type specimen of the Eagle Station group. It was found in 1880 close to Eagle Station, Carroll County, Kentucky (United States). The first description was made by George F. Kunz in 1887. Referen ...

was formed due to impact heating. They also analysed approximately 300 lunar samples that had been collected during

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

s Apollo Program. In 1992, a new type of meteorite, the

Brachinite Brachinites are a group of meteorites that are classified either as primitive achondrites or as asteroidal achondrites. Like all primitive achondrites, they have similarities with chondrites and achondrites. Brachinites contain 74 to 98% (volume) ...

, was identified. Clayton and Mayeda studied the

Achondrite An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystalliz ...

meteorites and showed that variations in the oxygen isotope ratios within a planet are due to inhomogeneities in the

solar nebula The formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud. Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a ...

. They analysed

Shergotty meteorite The Shergotty meteorite (Named after Sherghati) is the first example of the shergottite Martian meteorite family. It was a meteorite which fell to Earth at Sherghati, in the Gaya district, Bihar, India on 25 August 1865, and was retrieved by witne ...

s, proposing that there could have been a water-rich atmosphere in the past on

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

Honours and awards

In 1981, he received the

V. M. Goldschmidt Award The V. M. Goldschmidt Award is an award given by the Geochemical Society at the V. M. Goldschmidt Conference for achievements in the fields of geochemistry and cosmochemistry. The award in honor of Victor Moritz Goldschmidt, a pioneer in both tho ...

from the

Geochemical Society The Geochemical Society is a nonprofit scientific organization founded to encourage the application of chemistry to solve problems involving geology and cosmology. The society promotes understanding of geochemistry through the annual Goldschmidt Co ...

. The next year, the

Meteoritical Society The Meteoritical Society is a non-profit scholarly organization founded in 1933 to promote research and education in planetary science with emphasis on studies of meteorites and other extraterrestrial materials that further our understanding of the ...

awarded him its

Leonard Medal The Leonard Medal honors outstanding contributions to the science of meteoritics and closely allied fields. It is awarded by the Meteoritical Society. It was established in 1962 to honor the first President of the Society, Frederick C. Leonard. ...

. Clayton won the

Elliott Cresson Medal The Elliott Cresson Medal, also known as the Elliott Cresson Gold Medal, was the highest award given by the Franklin Institute. The award was established by Elliott Cresson, life member of the Franklin Institute, with $1,000 granted in 1848. The ...

from the

Franklin Institute The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman Benjamin Franklin. It houses the Benjamin Franklin National Memori ...

in 1985. He was the 1987 recipient of the

William Bowie Medal The William Bowie Medal is awarded annually by the American Geophysical Union for "outstanding contributions to fundamental geophysics and for unselfish cooperation in research". The award is the highest honor given by the AGU and is named in honor ...

from the

American Geophysical Union The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, atmospheric, ocean, hydrologic, space, and planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's act ...

. Clayton became a member of the National Academy of Sciences in 1996 and won the academy's

J. Lawrence Smith Medal J. Lawrence Smith Medal is awarded every three years by the National Academy of Sciences for investigations of meteoric bodies. The medal is in honor of its namesake, the American chemist and meteoriticist, J. Lawrence Smith. Recipients Sour ...

in 2009. Clayton has been named a fellow of the Royal Society of London (1981) and the

Royal Society of Canada The Royal Society of Canada (RSC; french: Société royale du Canada, SRC), also known as the Academies of Arts, Humanities and Sciences of Canada (French: ''Académies des arts, des lettres et des sciences du Canada''), is the senior national, bil ...

. He won the

National Medal of Science The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social scienc ...

in 2004. In 2008, the book ''Oxygen in the Solar System'' was dedicated to Clayton. On December 30, 2017, Clayton died his sleep at his home in Indiana from complications of

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

Biography

Research

Honours and awards

References

Further reading