Glaciovolcanism, or sub-glacial volcanic activity, may sound like an obscure topic of research, but to University of British Columbia PhD candidate Alex Wilson, it’s a geological world of wonders that reveals clues about climatic conditions on Earth millions of years ago.
Wilson’s research focus is southwest British Columbia, a rugged region known as the Garibaldi Volcanic Belt that has been shaped over the past four million years by the advance and retreat of the Cordilleran Ice Sheet. At its maximum extent, this ice sheet covered a vast area of western North America, including all of British Columbia, parts of Alaska and the Yukon, northern Washington state and northwestern Montana.
The region has also been peppered with glaciovolcanism. There have been at least one hundred eruptions over the past two million years across the entire Garibaldi Volcanic Belt, many of which occurred beneath ice due to the intermittent coverage of continental ice sheets. This is where things get interesting for Wilson.
When a volcano erupts beneath ice, the lava cools rapidly, resulting in highly unique geologic features that are indicative of the presence of ice. Although most remnants of the Cordilleran Ice Sheet in B.C. have melted away, due to the unique nature of some of the volcanoes in the Garibaldi Belt, Wilson has been able to reconstruct the progress of the ancient ice sheets.
“So far, we’ve used volcanoes to reconstruct several important climatic transitions in the past. We’ve even provided evidence for at least three ancient glaciations that we had no idea about previously,” says Wilson, who plans to defend his doctoral thesis before the end of 2019.
Through a combination of radiometric dating and studying volcanic rocks, scientists like Wilson can determine with reasonable accuracy whether or not an eruption occurred beneath ice, and therefore the climate that existed at the time of the eruption. Wilson’s ultimate goal is to reconstruct the climate and environment of southwest B.C. over the last few million years.
“Most current paleo-climate methods, such as ice core samples, are only good back to roughly 400,000 years,” he says. “I am trying to develop the techniques and establish the ‘rules’ so that others can do this in other places around the globe, like the Andes, Iceland, and Antarctica.”