Osamu Ishizuka (Co-chief Scientist, Geological Survey of Japan/AIST, Japan) specializes in geochronology. This very specialized field of study uses mass spectrometers to determine the age of rocks and minerals. Once ages are established, correlations between groups and a sequence of events are proposed. Co-chiefs Osamu and Richard Arculus began their association with a meeting of scientists in Tokyo in 2009. Out of this collaboration bore the premise for Expeditions 350, 351, and 352, all of which are seeking answers to the Izu Bonin Mariana Arc. Osamu will take samples to continue his analysis on shore. (Credit: Bill Crawford, IODP/TAMU) [Photo ID: exp351_036] Back to expedition photos.