Earth detective

Earth detective

Using the latest techniques to analyze chemical elements, a Queen's University researcher is uncovering some of Nature's deepest secrets
July 1, 2005

Earth scientist Kurt Kyser knows how to read trees. He can get birds to divulge their migratory patterns and moulting cycles. He can even trick mineral deposits into revealing their underground locations.

Just how does this mild-mannered geology professor coax secrets out of inanimate objects and non-verbal living things? Through the science of isotope analysis.

At the Queen’s Facility for Isotope Research, in a high-tech laboratory that rivals anything viewers see on the popular television crime drama CSI, Kyser, his colleagues, and graduate students analyze isotopes from tree cores, bird feathers, rocks, and soil to see what secrets and clues they may hold.

Isotopes are forms of chemical elements that are slightly altered at the atomic level, having a different mass because of different numbers of neutrons but the same number of protons. Researchers like Kyser have developed ways to measure those isotopes, using them as fingerprints that point the way to the object of the search. Unlike the forensic pathologists on CSI, however, Kyser and his team aren’t looking for criminals. They’re seeking answers to fundamental questions about climate change and the environment, and about the evolution and migration in songbirds. And they’re searching for some highly desirable commodities, including uranium, nickel, diamonds, and gold.

“We’re using isotopes as tracers for things moving around in the near surface environment, within 100 metres of the surface that we walk around on,” Kyser says from his office at Queen’s University.

One of the hottest applications for Kyser’s work is mineral exploration. To find ore deposits buried under hundreds of metres of rock and soil, geologists and mining engineers look for elements leaking out from the deposits. Using samples brought to the lab from prospective sites, Kyser and his colleagues use isotopes to fingerprint the origin of the ore or precious metal for which they’re searching. “It’s very tough to do, but with the new infrastructure that we have, we’re developing new technologies to allow that to happen,” Kyser says.

The Queen’s researchers also collect tree cores using a device that drills a tiny hole in a tree, without harming it. By analyzing the elements, metals, and isotopes of metals found in those tree cores, Kyser can trace elevated concentrations of metals nearby. Using older trees, the researchers also uncover a record of what has happened to the environment where the trees have grown. “We’ve now turned this around to look at environmental changes that have occurred in Ontario, or all of southern Canada, for the last 100 to 150 years,” Kyser says. “It leaves a map in the trees.”

Bird feathers also leave a map that Kyser has learned to read, with the help of biologists. How? Radio collars and bands don’t work on songbirds that weigh only eight grams, so the researchers analyze isotopes found in their feathers or tiny drops of blood to learn where the birds spend the winter and where they breed. Through these non-invasive techniques, the team has discovered the migratory and moulting patterns of the American Redstart, a tiny songbird found in Ontario and the Northeastern United States.

“Everything in a bird is basically made of isotopes—carbon, nitrogen, sulphur,” Kyser explains. By comparing the isotopes in the birds’ feathers to the isotopes found in different parts of the world, the researchers have learned that the birds come to Canada to breed before flying to the Caribbean for the winter.

Previous researchers had assumed the birds moult before they fly south. Kyser and his team have discovered that a third or more of the birds fledge late and are raising young late into the season. Then they migrate, and moult along the way. That practice may ultimately weaken generations of the birds. Because the birds are stressed by moulting as they migrate, they arrive late, occupy less desirable habitat, and fledge young that, in their turn, likely become less successful in breeding and producing their own offspring.

Benefits

At the Facility for Isotope Research, Kurt Kyser and his colleagues are developing applications for isotope analysis that serve Canada’s traditional niche in mining and exploration. They’re also enhancing a new area of expertise: environmental remediation.

To find an untapped ore deposit in Canada today, geologists or prospectors have to either stumble upon it, or apply a combination of geophysics, geology, and geochemistry to pinpoint a likely location for nickel, copper, gold, uranium, or diamonds. “We’ve been involved in finding new resources—not just in Canada, but with Canadian companies worldwide,” says Kyser.

Kyser adds that the benefits of isotope analysis for finding precious metals and ores include jobs, income into Canada, revenue from Canadian companies operating overseas, and more resources. “We also play a role in terms of environmental management of the extraction of these resources,” he adds.

For instance, Kyser can use isotopes to document whether metals and chemicals are being released from mine tailings, both old and new. The specific elements and characteristics of those isotopes can identify the source of contamination, which is critical in brown field redevelopment.

The researchers also document the effects of acid rain on vegetation. They demonstrate the presence of sulphur and an elevated metal content in trees. They have been equally successful in showing the recovery of trees and other vegetation from the 1970s onward, when laws requiring pollution controls were first put into effect. “They’re responding very well. We see the metal concentrations drop,” Kyser says.

Kyser’s work on trees also enables the researchers to document changes to the global nitrogen cycle, as reflected by the nitrogen being fixed in trees, and the differences in the concentration in young trees compared to trees that have lived for decades.

The benefits of that research include being able to document and demonstrate changes to our atmosphere and to the earth—evidence that informs and shapes public policy. “Fifty years ago, I don’t think anyone ever thought, that short of world wars, we could ever affect our planet to the degree that we have. As earth scientists, we’re in a better position to appreciate the interconnection of all these systems than a lot of other people.”

Even the isotopes that Kyser and his team analyze from the feathers of the American Redstarts can be used as evidence for policies protecting the birds’ habitat in the Caribbean and Central America. If that habitat is destroyed, it affects the birds’ ability to reproduce, and the timing of when they fledge their young. “If you can figure out what is affecting the reproduction, then you can fix it,” Kyser says.

Partners

At Saskatoon-based Cameco Corporation, Jim Marlatt and his fellow scientists think of themselves as detectives searching for the next big uranium strike.

One of the advantages the Cameco Corporation has over its competitors is geology professor Kyser and his team. Along with Marlatt, Cameco’s Director of Global Exploration, they try to locate uranium deposits at properties Cameco is interested in—in Canada and around the world.

“Exploration is a high-risk, long-term business. It’s based on science,” says Marlatt. “So we are essentially detectives using geo-science, geochemistry, and geology to look for hidden deposits. Kurt and his associates play an important part of that role, by helping us to better understand the science of deposits.”

By analysing the rocks that Cameco brings him, Kyser can date deposits, understand the nature of fluids associated with them, understand the temperature of those fluids, as well as the trace elements that the rocks reveal. “All of these scientific facts go together to create pieces of the puzzle that we try to put together—to point to where these deposits are occurring in the natural environment,” says Marlatt.

Often, the payoff from this research comes years later. But it’s still a critical partnership, Marlatt says. “The research work is just fundamentally important to Cameco and the exploration division in particular. Without it we would not be as effective.”

Chris Oates, the Vice-President of Geochemistry for Anglo American PLC, also works with Kyser to look for nickel, copper, and zinc. “The real reason I selected him is because I wanted someone at the forefront in isotopics research,” says Oates. “He has state-of-the-art equipment that has meant a lot of breakthroughs for us.”

Before isotopic analysis, people “threw dozens of different methods and techniques at oils and sand,” Oates says, “and there was no scientific connection between what was going on above the surface with what was going on below.”

Kyser’s analysis demonstrates connections between the material at the surface and the minerals below. That reduces the cost of exploratory drilling for companies like Cameco and Anglo-American.