In 1987, Mrs. Clarke retired after 20 years as a family planning special-projects coordinator and medical counselor in the obstetrics and gynecology department at the Hospital of the University of Pennsylvania. Two years later, she took a three-week cruise and got to see the continent her father described as "incredible, unbelievable and fantastic."
After her return she gave lectures about the continent to community groups. "I always thought of Antarctica as being black and white," she told an audience in Wallingford in 1991. Instead, she found that though there was a lot of white, "there were also beautiful blues and greens shining through." She remembered standing on an island, watching and being watched by 40,000 penguins, and sailing close to a nine-mile-long iceberg.
Her quest was over, she said. She had finally found out what appealed so much to her father.
Mrs. Clarke grew up in Boston. During World War II she volunteered for the war effort, tending livestock and milking cows on a farm in Maine.
In 1947, she married William A. Clarke Jr., whom she had met while attending Swarthmore College. They raised four children in Swarthmore, where she was a Girl Scout leader for many years. She and her husband divorced in 1969.
Mrs. Clarke also was involved with several social activism organizations, including the Women's International League for Peace and Freedom and Pendle Hill, a Quaker study center in Wallingford.
She is survived by daughters Eleanor, Evelyn and Marie; son Richard; and eight grandchildren.
A memorial service will be held at 2 p.m. Dec. 1 at Kendall Crosslands Retirement Community, 1660 E. Street Rd., Kennett Square. Mrs. Clarke donated her body to science.
Donations may be made to the World Wildlife Fund, Box 97180, Washington, D.C. 20090.
Contact staff writer Sally A. Downey at 215-854-2913 or email@example.com.