Biographical Memoirs Volume 89 (2007) / Chapter Skim
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HARMON CRAIG
HARMON CRAIG
Pages 44-57
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From page 45... ...
Indeed, John Craig's major activities, after his heroic involvement in World War I, were in running theaters in the northeastern United States. Young Harmon was surrounded by a theatrical crowd during his early childhood.
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From page 46... ...
An undergraduate geology major at the University of Chicago, he was propelled into this world of geochemistry and cosmochemistry without waiting to get his undergraduate degree. The measurement of ancient sea temperature depended on analyzing carbon dioxide released from calcium carbonate fossils and measuring the relative masses of carbon dioxide composed of 18O and 16O.
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From page 47... ...
. Craig's thesis is still today the primary citation for all studies involving variations in 13C/12C in natural materials, Cited in studies ranging from the establishment of food chains to identifying sources of ancient marbles for statues, this remarkable thesis was the harbinger of the impact Craig would have in various areas of geochemistry and cosmochemistry.
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From page 48... ...
These Spoleto papers are the fundamental documents that all atmospheric geochemists as well as hydrologists and oceanographers turn to for guidance in many aspects of light isotope geochemistry. He established the meteoric water line, which defines the unique linear relationship between hydrogen and oxygen isotope ratios in natural terrestrial waters.
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From page 49... ...
It became obvious to all who participated in the summer session that the leaders of what ultimately was to be called the Geochemical Ocean Sections Study (GEOSECS) should be Wallace Broecker of the Lamont-Doherty Earth Observatory, Harmon Craig of Scripps, and Derek Spencer of the Woods Hole Oceanographic Institution.
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From page 50... ...
Craig's interests were not restricted to the oceans and the rocks at their boundaries; he also sought to understand the record of atmospheric changes recorded in cores from the Antarctic and Greenland ice sheets. He was one of the earliest workers to study gases trapped in glacier ice, and he showed that atmospheric methane has roughly doubled due to human activities over the past 300 years.
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From page 51... ...
Craig and his coauthors -- including Somayajulu, who initially made the measurements and was rightly indignant that the quality of his measurements was challenged -- wrote a paper titled "Paradox Lost: 32Si and the Global Ocean Silica Cycle," wherein the role of mixing of two sources of silica trapped by the collecting fibers explained the results and justified the measurements made by Somayajulu. So we see the man who's eye for recognizing quality measurements first showed up in the paper on meteorites was active in deciphering a major marine geochemical problem.
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From page 52... ...
I thank John Craig III and Valerie Craig for insights into Harmon Craig's career throughout his productive life. I have borrowed extensively from an obituary that I wrote for Nature and one that Ray Weiss wrote for the Transactions of the American Geophysical Union (EOS)
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From page 53... ...
The measurement of oxygen isotope paleotemperatures. In Stable Isotopes in Oceanographic Studies and Paleotemperatures.
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From page 54... ...
F Weiss, Dissolved gas saturation anomalies and excess helium in the ocean.
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From page 55... ...
Helium isotopes and mantle volatiles in Loihi Seamount and Hawaiian Island basalts and xenoliths. Earth Planet.
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From page 56... ...
Atmospheric argon contamination of ocean is land basalt olivine phenocrysts. Geochim.
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