University of Saskatchewan

September 23, 2014   

How I Spent My Summer Vacation

Patricio Desjardins hiking at Lake Louise in Banff National Park (Photo courtesy of Fallon Clarke)
October 16, 2007

U of S student studies 500-million year-old rocks to understand North America's geological evolution

October 15, 2007
Fifteenth in Series
For The StarPhoenix
By Wendy Gillis

When Patricio Desjardins hikes through the Canadian Rocky mountains, it’s with a backpack full of rocks.

This summer, the geology PhD student and a team of fellow geologists and assistants spent four weeks exploring the trails of Lake Louise in Banff National Park, sometimes slogging for days through rain, hail, and snow and hiking more than 150 kilometers just to find the perfect rock.

They hope to learn what the area was like more than 500 million years ago when it was the floor of an ocean – not the middle of a continent.

“In geology, our perspective of time is completely different because we don’t think in seconds or minutes or hours,” says Desjardins. “When we look at rocks, we are thinking in millions of years.”

By studying the ancient ocean, Desjardins hopes to understand its impact on the evolution of the North American continent.

To learn about the ocean, Desjardins and his team searched for sedimentary rocks – rocks made up of sand, gravel, and clay – that act as natural recording devices, telling stories about an ocean that existed millions of years ago.

“In the structure of the rocks, you can see how the sediment is piled together – you can see waves, currents, tides, and all the processes involved,” he says. “I study the different layers because each layer represents a time and at one point it was actually the floor of an ocean.”

He also uses the rocks to learn about organisms that lived in the ocean. One of his specialties is in the field of ichnology, the study of the interaction of living organisms with ocean sediments. In the same way that sedimentary rocks capture the movement of ocean water, the movement of ocean organisms is also recorded in the rocks. But finding the rocks, and then using the information they present, is where the real work comes in.

“With geology, you have to look at it like you have a puzzle. Most of the pieces are missing, and the ones you do have are broken in half,” jokes Desjardins.

He and the team spent a lot of their time looking for specific types of rock, sometimes slogging for days through bad weather to locate just one of these “puzzle pieces.” He says they once spent 10, rain-soaked days on a certain trail, and only found the rock they were looking for in the last hour of the last day.

Now that his field work is complete, Desjardins says he must use creative analysis, as well as scientific knowledge, to find the answers to life as it was millions of years ago. “The most fantastic part is that geology can be very much like an art,” says Desjardins. “You have this data, and from that you have to make your interpretation – I have to use my imagination to reconstruct this 500-million-year-old ocean. It’s not easy so you need a passion for it.”

Desjardins’ research has potential implications for industry. Sedimentary rocks often contain oil and gas, so a better understanding of the environments where rocks were formed will lead to more accuracy in predicting oil locations. One of his research assistants this summer was funded by Shell Canada.

Desjardins will submit his research to several international peer-reviewed journals upon completion of his PhD within the next two years.


Wendy Gillis is a student intern with the U of S Research Communications office.

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