Arches of stone seem to defy explanation, but a new study may have solved the mystery of how these and other strange natural stone wonders form.
The bewildering shapes apparently owe their origin in large part to how rock can strengthen when squashed from above, scientists explained.
Mysterious rock formations such as arches, bridges, pillars and mushroom-shaped pedestal rocks occur all over the world. Geologists mostly think these form due to erosion from wind and water, as well as from the weathering effects of salt and frost.
However, lead author of the new study Jiří Bruthans, a geologist at Charles University in Prague, and his colleagues did not think erosion and weathering alone could explain how many of these natural sculptures arose. They also noted that prior research did not explain how the upper parts of arches remain stable.
Now, the researchers said they can help explain how these rock formations develop by accounting for the way rock can strengthen when compacted by weight from above.
"The results were shocking for me when I started to realize how simply nature carves all these shapes," Bruthans said.