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Montana geologist and ecologist lead tour through the Beartooth Mountains

Posted at 8:31 PM, Jul 08, 2020
and last updated 2020-07-09 15:47:59-04

A drive up the Beartooth Pass south of Red Lodge can offer awe-inspiring views, but it's difficult to fathom the natural forces that brought the fauna and the landscape to the beauty seen today.

Two men who've made careers out of studying the Beartooth Mountain's geology and ecology gave a special tour on Wednesday, helping to bring some perspective to the natural beauty.

Ecologist Phil Robertson and geologist Ennis Geraghty regularly lead tour groups up the Beartooth Highway, making several stops to talk about the landscape and the plants there.

Robertson taught field ecology courses in the Beartooths for 36 years before his retirement. One topic on this trip: the forest and how its trees are dependent on wildfire to reproduce.

“These are fire-dependent forests. The species that we have here have evolved characteristics that both promote and resist fire," Robertson said.

Robertson said there are about 12 types of cone-bearing, or coniferous, trees found in the Beartooths. Some like the lodge pole pine, need fire to reproduce, he said.

Fire is a natural part of life in the forest. The seeds of a lodge pole pine are found in its cones and only released when the cone is burned. The fire also clears the forest floor of any duff or undergrowth, leaving rich soil and plenty of sun for the forest to grow anew.

“When that cone crop is heated, they open up and they disperse all their seeds at one time. What happens after a fire (burns) through a lodge pole pine stand is you get regrowth all of the same age. When you look up on these hills, you’ll see these carpets of lodge pole trees that all came up after the fires in the late 1800s in this part of the Beartooths,” Robertson said.

The cones of a Lodge Pole pine tree near Red Lodge.

From its start in Red Lodge, the tour winded its way up the Beartooth Pass to the overlook at Vista Point. From there, it was easy to see how the soil left from geologic events affects where the forest will grow.

Geraghty spoke of a massive glacier that cut out the valley of Rock Creek around 12,000 years ago.

“The Beartooths were covered under thousands of feet of ice that melted and eroded off and carved out those beautiful lakes, headwalls, cirques and just beautiful alpine topography," Geraghty said.

In their wake, the glaciers left different types of soil. From Vista Point, you can see the valley mostly blanketed with trees. Some areas near the bottom of the valley, however, are bare. Robertson said the glacier left soil in those areas that wasn't conducive to growth.

The gaps in tree growth represent where the glacier left soil that trees find tough to grow in.

Geraghty has worked as a mining geologist with the Stillwater Mine since 1988, helping track down the location of platinum and palladium mixed in these massive landscapes. He spoke of another mine across the valley from Vista Point that has been abandoned since 1943.

Up Forest Service Road 421, you'll find access to the Hellroaring Plateau, the location of the abandoned mine. Geraghty said shipping closures from South Africa during the tail end of World War II forced U.S. manufacturers to seek domestic ore to make weapons.

A look from Vista Point at Forrest Service Road 421. At it's end, a mine pulled chromium to use as an ingredent in the steel that made WWII planes and tanks.

Miners found chromium on the Hellroaring Plateau, a major ingredient in the steel that made America's tanks and planes for the war.

“If you could imagine mining up on top of the Hellroaring Plateau, not sure if they did in the winter, but I know they sure did in the summer. And they trucked the ore down to Red Lodge where it was concentrated. There’s several deposits over there with five or six mines. There was only one on this side of the valley," Geraghty said.

The mines only operated from around 1941 to 1943, Geraghty said.

Billions of years of geologic history can be found in the Beartooths. The mountains were formed about 65 million years ago thanks to plate tectonics, Geraghty said. The North American plate collided with the Pacific plate, jutting some of the peaks to 10,000 feet or higher.

“These rocks are so old. South of Livingston, there’s the oldest date in the Beartooths at 3.5 billion years old. So you have a tremendous amount of geology to work with. South of Red Lodge is 3.4 billion years old. The Stillwater Complex, with the platinum and palladium, came in seven billion years ago," Geraghty said.

To put those billion-year dates in perspective, recorded human history only goes back about 5,000 years.

So the next time you snap a photo on your drive up the Beartooth Pass, take a moment to ponder where the mountains were three billion years ago.

A view of the valley in the Beartooth Mountains carved out 12,000 years ago by an advancing glacier