Three years ago, Hazel Barton, a biologist from Northern Kentucky University, traveled to southern Venezuela to star in an Animal Planet documentary entitled "The Real Lost World." While there, she visited Mount Roraima, the largest of the flat-topped South American tepuis. Tucked into the summit is a 10.4-km long, crystal cavern of pink and amber quartzite.
"Roraima Sur Cave is the longest quartzite cave in the world," says Barton. Most caves form in limestone, which dissolves easily in the slightly acidic ground water that leaches from microbe-rich soils. But that process doesn't explain how Roraima Sur was carved out of quartzite, which is highly resistant to chemical deterioration. The walls of the cave crumbled in her hands, and chambers were loaded with opal "soda straws," a geological novelty found nowhere else in the world. "I went in there and was like, 'Holy crap, look at all these microbes!'" says Barton. ...
