“Moving mountains” traditionally has meant doing something considered impossible. But nature has accomplished some considered-impossible things — including having literally moved a mountain 62 miles in a half-hour.

The millennia have seen geology’s immense and turbulent forces do some amazing things — thought-impossible things. Entire contents have moved. Fifty million years ago, an era of serious mountain building gripped the world: bedrock shook and shifted, volcanoes erupted, landslides took place and rivers were carved. Earth’s tectonic plates slid towards and past each other, pushing up mountains.

Yet Heart Mountain, near the present-day border between Montana and Wyoming, has puzzled scientists for years. This scientists do know: at least once in the past, around 50 million years ago, the mountain relocated a significant distance away, a feat that is considered to be the largest known land movement on the face of any continent.

Why this happened and how long it took, however, have remained a mystery.

Rock at the mountain’s summit is 250 million years older than that at its base, suggesting the top — made of ancient Paleozoic limestone — and bottom — a relatively youthful bed of Eocene Willwood soil — have not always been together. The presumption is that Heart Mountain was part of a larger mountain range, until the 62-mile-long ridge somehow became detached from its position and shifted about 62 miles to the southwest. The route was not even much of a downhill slide.

Now an explanation for this particular migrating mountain comes from deep beneath the ground.

Credit: NASA

Dr. Einat Aharonov of the Weizmann Institute’s Environmental Sciences and Energy Research Department, working in collaboration with Dr. Mark Anders of Columbia University in New York, devised a computer model to describe what happened below Heart Mountain 50 million years ago. Their explanation for the phenomenon was published in the March issue of the journal Geology.

A large number of dikes, or vertical cracks, in the rock sets the land’s journey apart from others’. The cracks filled with hot lava, creating a passage for the lava and thus funneling it through the water-saturated layer of limestone, called “the limestone aquifer.” As the dikes directed the lava into the water, the occurrence was similar to that of a pressure cooker: the lava heated both the rock and water to extreme temperatures, causing tremendous fluid pressures. Caught between layers of impermeable slate, the boiling water could not escape.

So, with nowhere to go but up, the tension finally lifted the rock. Thus, the mountain began to glide.

Aharonov and Anders developed a mathematical model, based on the number of dikes in the mountain and their structure, which allowed the two scientists to calculate the temperatures and pressures that would have been created deep within the base of the mountain.

The results showed that the infiltrating hot lava would have turned the water in the aquifer layer into a “giant pressure cooker,” releasing enough force to move Heart Mountain from its original spot in the Absaroka Range to its present-day site near the Montana-Wyoming border.

The entire motion took place in less than 30 minutes, according to the two scientists’ calculation.

You read that correctly: the mountain likely moved about 62 miles in less than a half-hour.

Further, Heart Mountain isn’t the only moveable mountain. Aharonov warns that the Canary Islands, sitting on a volcanic site, could be traveling soon — posing a significant tsunami risk.

Sources

And the Mountain Moved: Scientists Study How Heart Mountain Shifted
Ascribe news release, May 18, 2006

Land Speed Record: Mountain Moves 62 Miles in 30 Minutes
by Corey Binns
LiveScience, May 19, 2006