Yes. The sulfur isotope signature appears not only to be one of the strongest arguments for a change in atmospheric oxygen content and chemistry 2.45 billion years ago, but it is also a tracer that can be used to study other geologic processes.

The paper describes and interprets the significance of the signature of atmospheric sulfur chemistry that was trapped by the ancient rock record. The atmospheric signature is preserved as a small deviation in the ratios of the four isotopes of sulfur that was produced in the atmosphere, transferred to Earth's oceans and continents, and then trapped in the rock record. The sulfur isotope ratios of rocks older than 2450 million years carry this record of atmospheric chemistry and by 2000 million years ago the signature disappeared.

  How did you become involved in this research?

By accident. We were in the process of undertaking analyses of sulfur from rocks to check for the signature of ancient microbes that metabolize sulfate, and instead, we found that the sulfur isotopes told a story about the ancient atmosphere.