Named for Kunihiko Nishiizumi, nuclear chemist at the University of California at Berkeley. Nishiizumi is renowned for his work on cosmogenic nuclides in meteorites, particularly meteorites from the moon, and the determination of the terrestrial ages of meteorites. He also led the determination of surface exposure ages and erosion rates of terrestrial rocks, from 10Be and 26Al produced by cosmic rays in quartz, and used this technique to determine ages of ancient surfaces in Antarctica and Australia and of meteorite craters. (M 24917) _ _.