By GAIL GALLESSICH

NANOSIZE DIAMONDS HAVE been discovered in the Greenland ice sheet, according to a study reported by scientists in a recent online publication of the Journal Glaciology. The finding adds credence to the controversial hypothesis that fragments of a comet struck North America and Europe approximately 12,900 years ago.

“There is a layer in the ice with a great abundance of diamonds,” said co-author James Kennett, professor emeritus in the Department of Earth Sciences. “Most exciting to us is that this is the first such discrete layer of diamonds ever found in glacial ice anywhere on Earth, including the huge polar ice sheets and the alpine glaciers. The diamonds are so tiny that they can only be observed with special, highly magnifying microscopes. They number in the trillions.”

This discovery supports earlier published evidence for a cosmic impact event about 12,900 years ago, Kennett explained. He said that the available evidence in the Greenland ice is consistent with this layer being at or close to this age, although further study is needed.

Co-authors on the study, in addition to Kennett and a team of researchers from the University of Maine, include scientists from many universities and research entities. James Kennett’s son, Douglas J. Kennett, of the University of Oregon, is one of the 21 scientists who contributed to the report.