Harmon Craig

During World War I, John Craig (1868-1931) and his wife, actress Mary Young, led the first professional American stock theater company to travel to France and entertain troops at the front.

He was named after his uncle, Harmon Bushnell Craig (1895-1917), but does not use his middle name.

Harmon Craig's grandparents on his father's side were actors, directors and producers.

While they entertained the troops, their sons Harmon Bushnell Craig (1895-1917) and John Richard Craig, Jr. (1896-1945) served in the war effort.

John Craig, Jr. received a French Croix de Guerre for his efforts as a second lieutenant of artillery, working with French 75s.

Harmon Bushnell Craig died serving with an ambulatory corps run by the American Field Service, and was posthumously awarded the French Croix de Guerre.

In November 1924, John Craig, Jr. married Virginia Stanley of Wichita, Kansas.

They had three children: Harmon (named after his uncle), John Richard III (named after his father and grandfather), and Stanley Craig.

Harmon Craig's mother, Virginia Stanley, was descended from Quakers who helped found schools for freed slaves.

His mother's involvement with the Quakers was a strong influence on Harmon Craig.

Harmon Craig studied geology and chemistry at the University of Chicago.

Harmon Craig (March 15, 1926 – March 14, 2003) was an American geochemist who worked briefly for the University of Chicago (1951-1955) before spending the majority of his career at Scripps Institution of Oceanography (1955-2003).

Craig was involved in numerous research expeditions, which visited the Great Rift Valley of East Africa, the crater of Loihi (now known as Kamaʻehuakanaloa), the Afar Depression of Ethiopia, Greenland's ice cores, and Yellowstone's geysers, among many others.

This led to him being described as "the Indiana Jones of the Earth sciences", someone "whose overriding impulse was to get out and see the world they were studying".

Craig made many significant discoveries in geochemistry.

He is credited with establishing the field of carbon isotope geochemistry by characterizing carbon's stable isotopic signatures in various natural materials.

This had immediate applications in radiocarbon dating.

By studying stable and radioactive carbon isotopes in the biosphere and air-sea system, he derived the atmospheric residence time of carbon dioxide with respect to oceanic uptake.

His work laid the foundation for isotopic studies of the carbon cycle, and was fundamental to understanding carbon sequestering in the oceanic and the terrestrial biosphere and the modulation of global warming.

Harmon Craig was born March 15, 1926 in Manhattan, in New York City, to John Richard Craig, Jr. (1896-1945) and his wife Virginia (Stanley) Craig.

In 1944, he joined the U.S. Navy, serving as a communications and radar officer during World War II.

After the war, he continued his education at University of Chicago, working with Nobel Laureate Harold Urey.

Craig credits Urey with giving him valuable advice on how to choose scientific problems: "If you go into a project, it's got to be a scientific problem that has rooms that continue into other rooms."

Craig earned his Ph.D. in 1951, with The geochemistry of the stable carbon isotopes, a thesis on carbon isotope geochemistry.

Craig created his thesis to find the measurement of ancient sea temperature.

Craig used the carbon dioxide released from calcium carbonate fossils as a basis for future researches involving the carbon system.

The masses of carbon dioxide that are produced by 18O and 16O were used to calculate respective masses.

Craig's study of the carbon isotope produced corrections that deal with mass fractionation and radiocarbon ages.

Craig's thesis work is considered a foundational accomplishment for its studies of 13 C and 12 C in a wide range of natural materials, including everything from ocean water to the atmosphere; volcanic gases; plants, coal, diamonds, and petroleum; sediments, igneous rocks and meteorites.

His theory has been applied to applications as varied as determining food chains and the identifying the sources of stone for ancient statues.

Karl Turekian has stated that "Craig's 35-year-old dissertation is still the measure of all subsequent work in the field."

Craig joined the Enrico Fermi Institute at the University of Chicago as a research associate in 1951.

In 1953, Urey and Craig published results showing that chondrites, meteors from the Solar System, did not have a single fixed composition, as had been assumed.

After carrying out analyses of the chemical composition of hundreds of different meteorites, they reported that chondrites fell into two distinguishable groups, high iron (H) and low iron (L) chondrites.

Their work "underscored the value of reliable chemical data" and led to significant improvements in data analysis in the field.

It led to a better understanding of the materials and processes involved in forming planets.

In 1955 Harmon Craig was recruited to Scripps Institution of Oceanography by Roger Revelle.

His laboratory at Scripps eventually contained five mass spectrometers, one of them a portable unit.

As a professor of geochemistry and oceanography at Scripps, Craig developed new methods in radiocarbon dating and applied radioisotope and isotope distribution to various topics in marine-, geo-, and cosmochemistry.

In addition, from 1969 to 1989, Harmon Craig served as an editor for Earth and Planetary Science Letters.