Reading the Rocks

For more than a decade, scientists have dismissed claims that examining carbon-rich rocks could yield clues to the atmospheric and oceanic conditions on Earth hundreds of millions of years ago. Now, however, researchers including members of NAI’s MIT Team are challenging that belief, and suggesting that data gleaned from the rocks sheds light on how changes in the atmosphere and oceans helped set the stage for the emergence of animal life.

In one of the largest studies of its kind, described in the March 14 issue of Nature, a group of researchers led by David Johnston, Assistant Professor of Earth and Planetary Sciences, analyzed hundreds of samples of carbon-rich rock collected from sites in Canada, Mongolia, and Namibia. Their findings show that carbon isotope records from the mid-Neoproterozoic era — between 717 million and 635 million years ago — can be “read” as a faithful snapshot of the surface carbon cycle.