Wash. U. postdoc shoots precision into evidence of snowball earth

| Contributing Reporter

Professor David Fike from the Department of Earth & Planetary Sciences presents an ancient fossil-rich sedimentary rock at the isotope geochemistry laboratory. His postdoctoral research associate, Dr. David Jones, has recently published an article in the journal “Science” about his work on global glaciation, which was funded by the National Science Foundation.

David Jones, one of Washington University’s Earth and Planetary Sciences postdoctoral research associates, was recently published in the journal “Science” for research done during his graduate studies at Harvard University.

The article discusses evidence found by geologists of global glaciation, a phenomenon that caused sea ice to extend to the equator 716.5 million years ago, bringing new precision to a “Snowball Earth” event long suspected to have taken place around that time.

Jones, working as part of team led by Francis A. Macdonald, analyzed and collected the rocks that went into making one of the figures, entitled “Victoria Island,” in the article.

“My work entailed three weeks of field work on Victoria Island in the Canadian Arctic Archipelago followed by work in a geochemistry laboratory to prepare the rock samples and measure their carbon isotope ratios,” Jones said. “I also collected the rocks that were used to paleomagnetically determine that Victoria Island was located very close to the equator at the time that glacial rocks were deposited in other parts of Canada and Alaska.”

His work contributed to the article in “Science” that was released this past week, which was funded by the National Science Foundation and led by scientists at Harvard.

Jones’ work for this article was done when he was a graduate student at Harvard and continues to influence his work at Wash. U. today.

Carrie Kincaid, a sophmore majoring in Environmental Studies, stressed the importance of Jones’ work in relation to her studies.

“This discovery is really, really important for this field of work,” she said. “It was previously thought that glaciers existed only through some of North America; no one knew they existed so far south on the planet. It’s amazing to now know that glaciers would have covered the entire earth at one point. This contributes to the climactic history of the earth.”

Currently, Jones’s work “focuses on understanding how the global carbon and sulfur cycles behaved at the time of the first mass extinction in the history of life on Earth, an event that happened roughly 440 million years ago, at the end of the Ordovician Period,” he explained.

Jones and his colleagues tackled these questions by collecting sets of sedimentary rocks that were deposited in the oceans at the time of the event, but are now exposed on land. He then analyzed the chemistry of the rocks to document changes in their carbon and sulfur isotope ratios through time.

Sophomore Kyle Vickstrom, another Environmental Studies major, echoed the importance of the research.

“This research is so important because of the current state of global climate change,” he said. “It could give us some clues as to what kind of danger we’re in by comparing our current sulfur and carbon levels to that of the levels 440 million years ago.”

Today, Jones is a postdoctoral research associate in the laboratory of Professor David Fike in the Department of Earth & Planetary Sciences at Wash. U.

For more general information about David Jones and his lab group, go to: biogeochem.wustl.edu.

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