Dec 1, 2010 14:04 GMT  ·  By
Model showing that water infiltrates rocks in an uneven manner, preferring certain channels over the others
   Model showing that water infiltrates rocks in an uneven manner, preferring certain channels over the others

While caves are the stuff of wonder for speleologists and of adventure for spelunkers, they also represent a mystery for physicists, who have been trying to figure out how the structures form for years. Now, a new mathematical model was developed to explain the mystery.

One of the most important puzzles related to cave formation has until now determining how minute droplets of liquid can make their way through solid rock, eventually forming massive conduits that later become underground siphons, galleries, corridors and halls.

The “active” ingredient in cave formation is a liquid made up of water and carbonic acid, the same chemical that forms as carbon dioxide is attracted from the air, and trapped in the world's oceans.

According to the new model, it would appear that the fluid is capable of focusing its flow at very high speeds, but inly in certain channels. This results in some channels becoming larger and more complex than others, which do not allow the acid to penetrate very deeply.

The new investigation could have a large array of practical applications, considering that its findings are applied to everything having to do with fluid flow. Dam restoration and protection, sewage treatment facility insulation and gray water containment are the first to come to mind.

“Most of the models in cave formation today don’t have this mechanism at all,” explains University of Warsaw physicist Piotr Szymczak, who conducted the work with University of Florida in Gainesville (UFG) chemical engineer Anthony Ladd.

The equations the team developed to explain cave formation will be detailed in an upcoming issue of the esteemed scientific journal Earth and Planetary Science Letters, Wired reports.

Investigators say that the basic of how caves develop have been known for more than a century. When minute cracks develop in limestones, they channel water and carbonic acid through.

This weak acid starts eating away at the limestone, and eventually creates larger cracks and channels. But the researchers were now interested in learning how this process can result in cave systems that are hundreds of kilometers in length.

The Kentucky, US-based Mammoth Cave features 580 kilometers of corridors and halls, and to assume that it was formed through this process would be nonsensical.

In the new model, the experts propose that, as water finds fractures in rocks, it focuses its action alongside tiny ripples in the material, preferring them in the detriment of others.

“This mechanism of channeling speeds your dissolution time quite a lot. That’s what allows it to penetrate so deep,” Szymczak explains.

These conclusions could allow hydrological engineers make sense of why, sometimes, caves form under dams very quickly, and not over eons as it happens in nature.