Mayeda, expert in isotopic measurements, dies at 81

Toshiko K. Mayeda, who conducted research on climate, meteorites and lunar rocks in a research career that spanned more than 50 years, died Friday, Feb. 13, at the University’s Bernard Mitchell Hospital following a bout with cancer. She was 81.

Mayeda, a Senior Research Associate in the Enrico Fermi Institute, received her B.S. in Chemistry from the University in 1950. She then became a laboratory technician for Nobel laureate Harold Urey. One of her first papers, co-written with Sam Epstein, a research associate in Urey’s laboratory, remains an influential work today.

“This was the beginning of the use of stable isotope measurements of rain and snow in climate studies, especially important today for global warming studies,” said Robert Clayton, the Enrico Fermi Distinguished Service Professor in Chemistry and Geophysical Sciences and the College. Isotopes, which are varieties of a common element that differ only in their atomic weight and mass, can be used to reconstruct a variety of physical phenomena, including the temperatures at which the rocks containing them were formed.

Another important paper, co-authored with Urey in 1959, became a seminal study in the constituents of primitive meteorites, which are the most pristine materials left over from the formation of the solar system.

A third paper, which Mayeda co-authored with another Urey associate, Cesare Emiliani, in 1961, helped establish firm dates for the ice age using isotopic measurements. And in 1983, she co-authored a paper with Clayton that established the relationship between various types of Martian meteorites.

Since 1958, Mayeda had worked with Clayton full time until she became ill in early January. Her services were much in demand from scientists around the world who needed oxygen isotopic measurements in order to properly classify their meteorite specimens. “She’s been the one who did all the work,” Clayton said.

Mayeda’s daughter, Sibyl Yau, Clinical Director of the Gastrointestinal Procedure Unit at the University Hospitals, said her mother’s passions were her scientific work and her long-time collaboration with Clayton. “Very far down in the deepest part of her, that’s who she was,” Yau said.

Mayeda was the recipient of the Society Merit Prize from the Geochemical Society of Japan in 2002. That year, an asteroid also was named in her honor.

She mentored many Chicago graduate students who went on to start their own laboratories in the United States and abroad. Many of them came to know her as “mom.”

Mayeda loved to travel with her husband, daughter and son-in-law, Yau said. She had visited nearly every state in the country, took annual trips to Florida and often returned to Japan.

Born to Matsusaburo and Haruko (Okada) Kuki in Tacoma, Wash., on Feb. 7, 1923, Mayeda spent most of her childhood in Japan, living first in Yokkaichi, where her mother died, and then in Osaka. She returned to Tacoma after graduating from high school. She and her father were sent to the Tule Lake Internment Camp in California after the United States entered World War II.

The residents of the camp lived in corrugated tin barracks with tarpaper floors, but they brightened their lives by organizing dances and practicing ikebana, the Japanese art of flower arranging. “They tried to have a quasi-normal life,” Yau said.

At Tule Lake, Mayeda met her husband, Harry, whom she married on Feb. 10, 1952. Harry Mayeda died last year.

Mayeda is survived by her daughter, Sibyl Yau of Skokie, Ill.; her son-in-law, Jack Yau; three sisters-in-law, Yoko Kuki, Pearl Zarilla and Helen Saiki; and many nieces and nephews.