Waterfalls are graceful monuments to nature's power. In each gentle curve and thrilling plunge, these watery edifices record the dynamic forces thought to be key players in their formation, allowing scientists to tease through the history of the surrounding landscape.

But now, a study published in Nature suggests a new mechanism for creating a waterfall that throws a wet blanket on some of geologists' long-held assumptions.

Until now, scientists largely reckoned that waterfall formation needed some type of external trigger acting on a river. Some waterfall-forming processes could be fast, like an earthquake shifting blocks of land to create a step over which water can fall. Others could be glacially slow, like sea-level changes or even different types of rock eroding