Alumnus Poses Explanation for Geological Gap

Monday, January 7, 2019

Research from a recent Department of Energy Computational Science Graduate Fellowship (DOE CSGF) alumnus offers a possible explanation for a geological mystery: why a layer of Earth’s crust representing millions of years is missing.

The National Geographic website highlighted research from Brenhin Keller, a 2016 alumnus now a postdoctoral fellow at the Berkeley Geochronology Center. In a paper published in the Proceedings of the National Academy of Sciences, Keller and a team of researchers argue that Snowball Earth, a time beginning about 715 million years ago when much of the planet was believed to be under ice, is responsible for what is called the Great Unconformity.

The researchers, citing evidence locked in ancient minerals, saw a geochemical shift that began at about the time the Snowball Earth period is believed to have begun, covering the planet with glaciers. The team’s evidence suggests the massive glaciers eroded the underlying rock, wiping away millions of years’ worth of sediment and pushing it into the oceans. Subducting tectonic plates then pulled the detritus into the mantle, burying the evidence of about a fifth of the Earth’s geological history, the National Geographic story says.

Keller and the rest of the team acknowledge that their explanation is likely to be controversial and say they’re still seeking answers for a multimillion-year gap between the predicted end of the Snowball Earth period around 600 million years ago and the beginning of the Cambrian period.

Keller was in the DOE CSGF from 2012 to 2016, when he received his doctorate in geosciences from Princeton University.