A gigantic crack has appeared in the foothills of the Bighorn Mountains in northern Wyoming. This crack isn’t just a few meters wide, mind you: it has opened up a gap 685 meters (2,250 feet) long and 45 meters (150 feet) wide. The locals are somewhat unfortunately nicknaming it the “gash”, as reported by the Huffington Post.
Sudden tectonic movements in Earth’s crust causes earthquakes, which displace large amounts of material in very short periods of time, often producing large fractures at the surface level. Mysteriously, no seismic activity of any kind was reported in the area, meaning that this miniature canyon was formed through other means.
Randy Becker shared a series of images of the chasm on Facebook.
It may have formed in a way similar to how the highly publicized sinkholes around the world are generated. These enormous depressions, which often form extremely rapidly and without any prior warning, appear when the surface layer of soil collapses down into a cavity created by one of several processes.
The dissolving of carbonate rocks by acidic rain or subsurface water is one possible mechanism; variations in the flow of water underground may also serve to undermine the sediments supporting the surface layer. It is possible that this chasm was created in much the same way.
An engineer for the outdoor company SNS Outfitter & Guides thought that it was indeed caused by a similar mechanism: a “wet spring [season] lubricating a cap rock”, as reported by the Huffington Post.
A cap rock is a mechanically strong rock normally resistant to weathering; they do, however, overlie weaker rocks prone to becoming unstable when infiltrated by a significant volume of water. It appears as if a particularly rainy Wyoming springtime is to blame here for causing the cap rock to slip off, exposing the weaker rock to the rain.
SNS captured an image of Wyoming’s mysterious new cavity.
This sudden major fracture would not normally be cause for concern, but this mountain range happens to be located fairly close to the Yellowstone caldera, a dormant supervolcano that has recently shown signs of its magma chamber being recharged. However, rising magma would cause seismic activity as it forces its way up through the crust, something which as mentioned was undetected at the time of the formation of the crevasse.
Nevertheless, social media will no doubt make the unfounded connection anyway.