What’s Old, Rare, and the Size of a Refrigerator?

NIKI WILSON – On Science, Jasper Fitzhugh
July 28, 2011
Scientist from Alberta Geological Survey makes new discoveries in Jasper 

As we sit here chilled by the perpetual rain of this Jasper summer, it is difficult to imagine the intense heat produced by liquid rock boiling over 3,000 kilometres below the surface. For most of us, this will remain an obscure concept, something that loosely informs childhood conversations about digging a hole to China.

But not for Dr. Dinu Pana of the Alberta Geological Survey, who this summer laid his hands on a rock outcropping formed from molten rock that found its way to the surface millions of years ago. “There are very few in the Rocky Mountains,” says Pana, who found this one along the Miette River west of Jasper. “Finding rare rocks are certainly moments of major excitement.”

According to Pana, this outcropping of “magmatic rock” is the only one discovered so far in Jasper National Park, and considering it’s only the size of a refrigerator, finding it in a park 10,000 km2 is a needle in a haystack endeavor.

Dr. Dinu Pana samples rock for the Alberta Geological Survey. Photo credit: Dr. Dinu Pana.

Magmatic rocks are formed by the crystallization of magma deep in the earth’s crust. Over time, they find their way up through cracks in the Earth’s crust, or through the process of being thrust toward the surface by the movement of the earth’s plates and subsequently exposed by erosion. Analysis and dating of these rocks helps scientists understand the original geological setting before the mountain building process began.

Pana’s geological investigations in the Rockies are part of a larger project launched three years ago by the Alberta Geological Survey. The objective of the project is to create a comprehensive, seamless map of the Rocky Mountains and Foothills area. The map will compile all geological maps in the Alberta portion of the Rocky Mountains and Foothills and deliver an updated map of the Alberta mountains at a scale of 1:500,000, an adequate geological base for informed economic, environmental, and regulatory decisions. Eventually it will be accessible on the Alberta Geological Survey website.

“We are the custodians of Alberta geology and want to have all the geological information captured in digital format, and offer it to all stakeholders,” says Pana.

The Rocky Mountains and Foothills are part of a geological belt called the North American Cordillera, which extends from Alaska to Mexico for 5,000 km. They have been geologically mapped at different scales, by different generations of workers over more than one century. Therefore, the geological information included on existing geological maps for different areas varies widely. The Alberta Geological Society is hoping to fill in knowledge gaps using cutting edge laboratory techniques.

Pana says another major component of the project is to identify the age of the thrust faults that led to the formation of these mountains. “The mountains are a combination of folds and thrust faults. Because these structural features led to the rising of the mountains, we are interested in better understanding the mountain building processes, which has many other implications. We will put an age, in millions of years, on the timing of these thrust faults.”

Until recently, it was difficult to pin down the exact time slices of rock were thrust up and pushed over the rocks beneath, creating a fault in the process. To overcome this hurdle, Pana and research associates used a new scientific technique to date clay minerals found in the fault rock along the thrust lines. These clay minerals were formed in the thrusting process, transformed by the strain and shearing of the rocks as they ground together. There are a number of thrust faults throughout the Rocky Mountains, including the Nikanassin thrust just southwest of Cadomin.

Thrust Southwest of Cadomin. Image Credit: Dinu Pana, Alberta Geological Survey.

The results of the clay dating have led Pana and his team to understand exactly what rock moved where, and when.

“The rocks you have in Jasper come from around Valemount and the Rocky Mountain Trench. They were pushed from their original location in B.C. towards the plains starting about 160 million years ago.”

Pana says it didn’t happen all at once, but occurred in pulses over more than 100 million years. “The rocks near Hinton and Cadomin arrived more recently: between 54 to 52 million years ago.” The movement towards the plains by Rocky Mountain and Foothills rock finished at about 52 million years old.

Pana says understanding these dates is important, “because it helps us understand how and when the mountains have been formed, and how the formation of the mountains has influenced the deposition of sediments and the formation, migration and trapping of hydrocarbons in rock formations of the Alberta Basin and Foothills (which is highly important for the [oil and gas] industry). In order to understand the basin, we need timelines.” A better picture of how the sedimentary basin of Alberta formed is not only beneficial to the oil and gas industry, but also to the development of government regulations for exploration.

The new geological map and timelines will also be useful in other aspects of land management. Those involved in planning and improving highways will understand the geological structure of each slope, and in some cases be able to use the map to predict where instability may occur during big weather events. Pana says, “it also has some meaning for people dealing with environmental issues and vegetation. It is important to know the bedrock substratum so that you know what [will grow there].”

It’s an exciting time to be doing this kind of work. “We are now at a different stage of work and understanding due to new analytical techniques. We can now do much more refined analysis, and improve on our understanding,” Pana says.

Some of the best labs in the world are involved in this work, making the projects attractive to those in the field. “How can this work not be exciting when you can improve on existing knowledge, bring up new concepts and prove or disprove existing theories?”

Add to that the excitement of rare finds like the refrigerator-sized magmatic rock, and there is definitely no shortage of inspiration to get Pana out in the field.

“It keeps me motivated, and it is so far from routine – always something new. It is the excitement of the scientist pushing the limits.”