Dr. Ursula Alice Marvin

Ursula Marvin was a geologist at the Smithsonian Astrophysical Observatory in Cambridge, Mass., when she and her colleagues were asked to examine an extraterrestrial object: a 10-pound chunk of Sputnik IV, a Soviet satellite that had crashed, superheated at 1,535 degrees Celsius, onto a street in Manitowoc, Wis., before dawn on Sept. 5, 1962.

Investigating a fragment from Sputnik IV — a less heralded part of the space program that had begun with the thunderclap of the first Sputnik’s orbits of Earth in 1957 — proved irresistible to a mineralogical expert.

Clinging to one end of the fragment, Dr. Marvin found, were droplets of minerals, including wustite, an iron oxide.

"Until then, wustite had been viewed as an artificial product too unstable to survive in nature," she said in an oral history interview in 2013 with Derek Sears of NASA’s Ames Research Center. But when she X-rayed samples of several meteorites in the Harvard Museum, she found wustite in all of them, confirming that they were formed through iron oxidation during re-entry into Earth’s atmosphere. "The wustite had always been there," she said, "but nobody had X-rayed meteorite fusion crusts before."

Dr. Marvin — who would later hunt for meteorites in Antarctica and analyze moon rocks from Apollo missions — died on Feb. 12 at a nursing home in Concord, Mass., a niece, Gayl Bailey Heinz said. She was 96.

Ursula Alice Bailey was born in rural Bradford, Vt., on Aug. 20, 1921. Her father, Harold, was a government entomologist (one newspaper called him the state’s "official bug hunter"), and her mother, the former Alice Bartlett, was a schoolteacher.

Young Ursula’s love of the outdoors was sparked while growing up near the White Mountains of New Hampshire, where sunsets "shone with a pink-purple afterglow," she said in a lecture in 1997 to the Harvard-Smithsonian Center for Astrophysics, a joint venture of the Smithsonian observatory and the Harvard College Observatory.

But she did not became interested in geology until she was a student at Tufts University, where she majored in history but was required to study science for two years. Biology bored her; geology transformed her.

"Here was a professor talking about mountains, how they form and change, about rivers, lakes, deserts, beaches, dunes and how the earth itself formed and evolved," she said in the lecture. "I never knew there was such a science."

Inspired, she asked her geology professor if she could change her major.

He rebuffed her, telling her that she should be learning to cook.

Undaunted, she added geology, math and physics courses. The experience of being one of the few female geologists at the time led her, decades later, to advance the cause of female scientists, in part as chairwoman of the women’s program committee at the astrophysics center. After she graduated, she earned a master’s degree in geology from Radcliffe College. Following World War II, she moved to Chicago to be a research associate at the University of Chicago while her husband, Lloyd Chaisson, attended dental school. But their marriage was short-lived, and she returned to Harvard to study for her Ph.D. While there, she met another geology student, Thomas Marvin. They married, and before she had finished her doctorate, Mr. Marvin was hired by a company to prospect for ore deposits in Brazil and Angola. The expeditions, which they undertook together starting in 1953, lasted several years.

Recalling their work in Corumbá, in southwestern Brazil, Dr. Marvin said their job was to search for manganese to use in making steel. "When the water was up, we traveled across country by dugout canoe (sometimes decked out in wild orchids)," she said in the lecture. They returned full time to the United States in 1958. After teaching mineralogy at Tufts for two years, she was offered a job researching meteorites at Harvard before joining the Smithsonian observatory in 1961.

At the time, Dr. Marvin knew nothing about meteorites. But with the space age accelerating, she gladly accepted. She received her doctorate from Harvard in 1969.

As her meteoritic expertise grew exponentially in the late 1970s, Dr. Marvin joined the first of her three expeditions to Antarctica to hunt for meteorites. She was the first woman on the American research teams that traveled there.

"To search for Antarctic meteorites is an exhilarating adventure," she wrote in New Scientist magazine in 1983. She described riding a snowmobile over blue ice and drifting snow: "The glimpse of a dark object starts the heart pounding. Racing toward it, the excitement grows as one sees it is not a shadow, not a glacial cobble, but a meteorite — a piece of rock from another planet."

In 1982, she was part of the team that discovered a lunar meteorite.

"Many miles from camp," she wrote in New Scientist, they found a small specimen with a "frothy, greenish-tan crust" that was unlike anything they had ever seen. When it was later analyzed in Washington, it was found to bear a great similarity to rocks that had been found by astronauts in the lunar highlands.

Following her trips to Antarctica, a small mountain on the ice sheet was named for her (Marvin Nunatak). And her meteorite studies earned her a similar honor in 1991, when the International Astronomical Union named an asteroid for her.

Dr. Marvin’s interest in meteorites knew no geographic boundaries. When a six-pound meteorite ripped through the roof of a house in Wethersfield, Conn., in 1982, she and other scientists arrived to inspect it the next day. It was the second meteorite strike in Wethersfield in 11 years.

"Meteorites are always a dramatic occurrence," Dr. Marvin told The New York Times, "but to have two strike the same town is, well, almost incomprehensible."

She said the second meteorite, which had rolled to a stop under Wanda and Robert Donahue’s dining room table, was probably from an asteroid belt between Mars and Jupiter that she called a "sort of celestial rock garden."

More critically, she was part of a study, funded by the National Aeronautics and Space Administration, that analyzed rocks and soil recovered by Apollo astronauts and Soviet robotic missions.

"We compared rock types from different sites on the moon to work out its geological history," she said in the oral history. Her boss at the astrophysics center, John Wood, "concluded the moon must have had an early magma ocean," she said, adding, "I think that idea still is the best explanation of how the lunar crust was formed."

She described her findings in an article for Science magazine in 1989. In all, she wrote more than 160 research papers and a book, "Continental Drift: The Evolution of a Concept" (1973).

Dr. Wood, a former associate director of the astrophysics center, said in a telephone interview: "We were a small group — just four of us and several technical assistants — that was very passionate about these samples. They were heady times, and Ursula was the mineralogical arm of the team."

She leaves no immediate survivors. Her husband died in 2012.

After the Apollo 17 mission in 1972 — the crew included Harrison Schmitt, a geologist — Dr. Marvin was in Houston when a box of rocks the astronauts had collected was opened. It was the final Apollo mission.

"There was so much of interest to study in the lunar samples," she said in 1997, "that I continued to do it until year before last."