Cosmic clues to Earth's past

John Gosse

It sounds like science fiction: Can cosmic rays predict earthquakes and volcanoes? CRC Chair John Gosse wants to find out.

John Gosse isn«t having flashbacks to the 1960s when he talks about "cosmic rays." This Canada Research Chair in Earth System Evolution studies some of the biggest changes to happen in Earth«s history. And he does it by analyzing the imprint of cosmic rays "invisible, high-speed particles from space" on rocks.

As trippy as it may sound, cosmic rays bombard the Earth and everything on it constantly. When these rays hit rocks exposed to Earth«s surface, a change in the rock«s atoms can occur, producing isotopes, or atoms with different physical properties. Measuring these isotopes can determine how long the rock has been exposed, providing vital clues as to how the Earth has changed in the past, and how it may change in the future. "It«s sort of like looking at the redness of a sunburn to figure out how long you«ve been in the sun," he explains.

In Gosse«s Cosmogenic Nuclide Exposure Dating Facility, rock samples are broken down to allow for the detection of isotopes. Once the ratio of isotopes is analyzed, Gosse is able to figure out when the last glaciers scraped their way across Nova Scotia, or the last time an earthquake shook the Andes. Since its inception, the lab has processed about 1000 rock samples, amounting to over $1 million worth of work.

Much more than just telling us of events in the past, analyzing these isotopes can also provide information to help predict when a region might be hit by an earthquake, or whether climate change and melting glaciers will threaten coastal cities. "The million dollar question is when the next earthquake will be, or the next volcano eruption. By looking at past events, this research can be used to predict when these kinds of events are likely to happen again,« he says. "Cosmogenic isotope work has also shown us that there has been rapid climate change in Earth«s past. This data can be used to test different models of current climate change, and help us make better predictions about climate change in the future."

Coming from the University of Kansas, where he still maintains a lab, two things influenced Gosse«s decision to conduct research at Dalhousie. "For my family, Halifax is a great place to be," he says. "But Dalhousie also has a number of unique geochronology strengths, so setting up a research group here allows you to attract some of the best students and post-doctoral fellows in the world." Along with a talented lab technician, his seven-member research group includes students from the United States, Ireland, Chile and Argentina.

Gosse is a geomorphologist and Associate Professor with the Dalhousie Department of Earth Sciences, Adjunct Professor (Earth and Environmental Sciences) at Lehigh University, Bethlehem PA, and Adjunct Professor (Department of Geology) at the University of Kansas, Lawrence KS. He directs the Cosmogenic Nuclide Exposure Dating Facility at Dalhousie, and a sister lab at the University of Kansas. In 2004, he was awarded the Killam prize, and the Petro Canada award for young innovators.