About the Authors

Barbara P. Nash


Affiliation Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, United States of America

Michael E. Perkins

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: BN. Performed the experiments: BN. Analyzed the data: BN MP. Contributed reagents/materials/analysis tools: BN MP. Wrote the paper: BN.