Jon Pelletier (image) University of Arizona Caption Jon D. Pelletier is an associate professor of geosciences at the University of Arizona in Tucson. Credit Maria Schuchardt, UA Lunar and Planetary Laboratory. Usage Restrictions This photo may only be used in conjunction with an article about the research described in this release. Photo credit must be given as stated. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.