Heart Mountain Slide Levitated on Gas
The world’s largest landslide moved a mountain range 31 miles on a cushion of carbon dioxide, geologists say.
How to move a mountain: float it on a frictionless cushion of gas. That’s what happened in Wyoming, geologists think. At the speed of an Indy 500 sprint car, the “World’s Biggest Landslide Floated Like a Hovercraft” for 31 miles, Becky Oskin writes for Live Science. Here are the mind-boggling stats:
The Heart Mountain landslide is the largest landslide ever found on Earth’s surface (larger landslides exist in the ocean). Many scientists think the slide was triggered by a violent volcanic eruption in Wyoming’s Absaroka volcanic field 48.8 million years ago. The blast launched a 31-mile-long ridge of Madison Limestone toward the Southeast. The slab broke up as it traveled; now, more than 100 huge limestone blocks are scattered across some 1,310 square miles (3,400 square kilometers) of younger rocks in northwestern Wyoming and southeastern Montana.
The mechanism for this long-runout landslide has been debated for a century. The slope in some places is only 2 degrees. What could move so much mass across such a long, nearly-level distance without crumbling it to pieces? Oskin says that another debate concerns the speed: some say the blocks raced at 1/3 the speed of sound, covering the distance in just 3 minutes. Others think it took over a million years.
Now, laboratory experiments on limestone and dolostone rocks from the landslide seem to support the idea that the landslide slid catastrophically fast. In the tests, conducted at INGV Rome’s specialized laboratory, Mitchell and his colleagues ground together limestone and dolostone at high pressures and speeds to mimic the landslide. Almost as soon as the experimental landslide started, the rocks started to break down and release carbon dioxide gas.
That gas, they postulate, could have created a frictionless cushion, letting the mountain blocks float over the landscape. With that kind of frictionless surface, the size of the mountain doesn’t matter, the geologists say. It works in theory and with small-scale models, but a UK hasn’t yet found any signal in the rocks of the effects of carbon dioxide flotation.
“Even I have a hard time visualizing a mountain moving 50 kilometers [31 miles], but you can move it if the friction is low enough,” said lead study author Tom Mitchell, a geophysicist at University College London in the United Kingdom.
Satellite pictures in the article show the vast extent of this record landslide.
One item not mentioned in Live Science’s article is that many of the blocks of “old” rocks sit conformably on “young” rocks on a flat surface contact. Since The Genesis Flood (Morris & Whitcomb, 1961), creation geologists have been fascinated with this formation, and have proposed alternative theories. Readers may wish to evaluate articles and papers on ICR, CMI, and other creation resources.
It should be noted that the “scientific method” (there is no one method) cannot be applied to one-time historical events. You can’t replay the tape. The best a geologist can do is examine all the current evidence, then propose a model or mechanism that explains the most data with the least ad hoc conditions. A good analyst takes note of all proposed theories fairly. The take-home lesson for most of us is that major geological changes can occur quickly—even moving a mountain range in minutes.