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October 11, 2001 Yves Gélinas: Pinning down the origins of petroleum



Yves Gélinas

Yves Gélinas researches marine organic chemistry

Photo by Andrew Dobrowolskyj

by Janice Hamilton

To his undergraduate students in chemistry, Assistant Professor Yves Gélinas is probably just another new young face in the Department of Chemistry and Biochemistry. What they don’t know is that Gélinas is starting his academic career with a bang: an article in the Oct. 5 issue of the prestigious journal Science.

Gélinas, whose main interest is in marine organic geochemistry (MOG), modestly suggested that Science publishes papers about topics that are “newsy,” and that his research fits the bill because it is related to a current hot topic, the global carbon cycle. Nevertheless, he added, it settles a 20-year-old debate among petroleum scientists.

Transformation of organic matter

Gélinas, who just arrived at Concordia, wrote this article as a postdoctoral fellow at the University of Washington in Seattle. There, his advisor was John I. Hedges, a man Gélinas considers a genius. In his research, Hedges uses various techniques to study marine organic matter.

Collaborating also with Jeffrey A. Baldock, a Canadian scientist living in Adelaide, Australia, Gélinas looked at factors affecting the transformation of organic matter to petroleum in ocean sediments.

He explained that some of the organic matter produced at the ocean surface eventually settles on the bottom. Most of it decomposes, giving off carbon dioxide in the process, but a small amount is preserved in sediments.

Over thousands of years, as more and more sediment builds up, the organic matter reaches a depth where high temperature and pressure transform it into petroleum. Gélinas was interested in the decomposition of freshly deposited organic matter, and in the effect oxygen has on this process. Some organic matter is only degraded when oxygen is present, and it is this type of organic matter that is the precursor of petroleum.

“In 1980, a model was introduced that tried to explain the conditions that were necessary for petroleum to form in sediments at the bottom of the ocean,” he explained. “That model stated that you had to have conditions with no oxygen for the formation of petroleum.

“Someone else challenged that model in the mid-80s with a different idea. Since then, people have assumed that the first model was right, but there was no demonstration to prove it,” Gélinas said.

“We think we have a good answer confirming the first hypothesis that will settle this debate once and for all.”

The study looked at core samples of sediments Hedges had collected from oceans around the world. Gélinas also spent a month off the coast of Mexico, collecting additional samples. “During my years in Seattle, I developed a method to remove the minerals from these sediments so you can concentrate the organic matter. We then tested these samples with NMR spectroscopy, a tool used to probe their molecular structure.”

What is most important to him about this line of research is the wealth of information contained in marine sediments.

“When you take a core sample of sediment from the bottom of the ocean, you have an exquisitely detailed record of the history of life on Earth.”

A Quebecer, Gélinas did his undergraduate and graduate work at UQAM, followed by a year at University of Massachusetts in Amherst, and three and a half years in Seattle.

Now he is happy to be back in Montreal, and excited about the prospect of continuing his research interests in marine organic geochemistry with colleagues at Concordia, McGill and UQAM. In a few years, he will also teach a graduate-level course in aquatic chemistry at Concordia.