Over the summer, Rahul Chawlani (left) turned up the heat to study the composition of rock samples from the Great Oxygenation Event, a time more than 2 billion years ago when Earth's atmospheric oxygen spiked. In collaboration with Claire Bucholz, assistant professor of geology, he warmed the samples in an oven that reached more than 1,000 degrees Celsius to remove trapped water so that he could obtain a pure sample of the rock.
Credit: Lance Hayadisha/Caltech