University of Alberta Edmonton, Canada May 30, 1997

How old is that rock?

Most advanced thermal ionization mass spectrometer in the country will soon reside at U of A

By Michael Robb

Where's it from? And how old is it?

Those are two big questions earth scientists love to answer definitely-give or take a few million years. But those two seemingly simple questions aren't always easy to answer.

Earth scientists at the University of Alberta, however, are about to receive a new piece of equipment that will allow them to answer those two big questions in an increasingly accurate manner. Earth and Atmospheric Sciences professor Dr. Robert Creaser is flying to Europe this spring to choose a thermal ionization mass spectrometer, a new machine worth about one million dollars that, once installed, will be the most advanced in Canada.

The machine will enable researchers to gather precise and accurate isotopic measurements on geologic materials. "The technique has been around for a very long time, but the new machine is much more sensitive," says Creaser, who along with Drs. Heaman, Luth, Chacko, Nesbitt, Erdmer, Jones, Machel, Sharp and Muehlenbachs, successfully applied for a major installation grant from the Natural Sciences and Engineering Research Council to pay for the machine. "We'll be able to analyze much smaller samples, single crystals, with much higher precision."

The new machine will be capable of negative ion mass spectrometry for osmium isotope studies, a widely used technique developed by Creaser. It will also allow researchers to date very young rocks; the existing mass spectrometers on campus are not able to do that with the degree of accuracy necessary. Dr. Brian Jones, for example, will be able to determine the age of limestones in the Cayman Islands. That will allow researchers to reconstruct global sea level changes. Dr. Larry Heaman will use the new machine to date intrusions of igneous rock in the earth's crust, to learn more about how the continents have been assembling and disassembling over time. A number of other geologists, petrologists and geochemists, students and staff, will use the machine. In addition to University support, the researchers also had support for the NSERC application from the private sector in the province. Mining companies, for example, will pay for the use of the machine. Samples will be analyzed to determine the formation of ore deposits. "We hope to expand industrial use of the facilities," says Creaser, and to think of new ways of using the machine.

The University is also planning to construct a new lab in the Earth Sciences Building to house the new and existing mass spectrometers, a move researchers have welcomed.

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