Volcanic mountains

Visit volcanic deposits, landslide rubble and more in southern Alberta

With scorching temperatures expected this weekend, what could be better than getting into an air-conditioned vehicle and going on a road trip through Alberta?

Calgary geologist Dale Leckie, author of The Scenic Geology of Alberta: A Roadside Hiking and Tourism Guide has suggestions on what to visit.

He joined The stretch Thursday to share some of these landscapes and explain how they came to be.

Crowsnest Volcanoes

Volcanoes are very rare in Alberta’s history, but west of Coleman at Crowsnest Pass you can see deposits from an ancient volcanic explosion, Leckie said.

Over 100 million years ago, a volcano exploded where now Cranbrook, British Columbia is located.

“The best way to describe it is that it takes its toll on the landscape,” Leckie said.

Superheated gases – estimated at 1,000 ° C – flowed down the slope of the volcano, instantly charring the trees. The eruption’s deposits covered 1,800 square kilometers and were buried kilometers deep.

As the mountains formed, these deposits were pushed 90 miles to where they are now exposed at Crowsnest Pass, at a place called Iron Ridge.

Frank Slide

In the middle of the night of April 29, 1903, Crowsnest Pass shook.

Turtle Mountain, long called “the mountain that moves” by the Blackfoot, broke loose with the largest landslide in Canada.

“It only took 100 seconds for all of these rocks to collapse, and that left a layer of rocks almost 45 meters thick,” Leckie said.

“The debris went down into the valley and across the slope, which is pretty amazing.”

The rubble, much of it still today, destroyed half of the mining town of Frank and killed more than 90 people. He created a lake in the valley and covered the road and the railroad.

The Canadian Pacific Railway brought in 1,100 men to clear the tracks in 17 days, but it took three years to rebuild the road, Leckie said.

The landslide was caused by geological processes.

“Those rocks over there were bent, bent, pushed, pushed over each other,” Leckie said. “And when that happens, they fracture, they break, they weaken.”

The Alberta climate’s freeze-thaw cycles also helped loosen the rocks.

Legend of the lost lemon gold mine

In the mid-1800s, two trappers named Blackjack and Lemon discovered a rich deposit of gold. Some say it was east of the Continental Divide, others say it was west, BC

But after finding him, Lemon killed Blackjack with an ax and became unstable. He went to Montana and told his story, but everyone who searched for the mine – Lafayette French, King Bearspaw, John McDougall, the Blackfoot Cloudwalker woman – searched in vain.

“There is also a supposedly curse on those who seek gold,” Leckie said, with people experiencing sudden death, firestorms and illness.

Geologically, Leckie said, up and down the Rocky Mountains, from Bragg Creek in Montana, there is a series of cliffs made up of unusual conglomerate or cemented gravel.

It contains distinctive rock types from east-central British Columbia, with pebbles from ancient volcanoes and granites. It is important to note that it also contains gold, although the location of the legendary mine is still unknown.

With files from The Homestretch.