Radioisotopes of beryllium (10Be and 7Be) and aluminum (26Al) are produced by the interaction of cosmic rays with atoms in the atmosphere and on the Earth's surface. They enter the ocean via wet/dry fallout, and in the case of 26Al, via aeolian transport to a certain extent as well. They have different half-lives. They and their stable counterparts, 9Be and 27Al, have varied geochemical source functions, behavior, and pathways, yet are linked in some way through isotopic kinships. Together, they can be used as powerful time an process tracers for a number of oceanographic and geophysical problems such as marine geochronology, ocean mixing, past and present intensity of dust transport and ocean margin productivity, and aerosol behavior. The improvement of measurement techniques of these isotopes in recent years allows the potential of their tracer utility to be explored. The basic distributional features and geochemical behavior of 10Be and 9Be in the ocean-atmosphere system has been studied. This past effort is now extended to the study of 26Al, as data base on this isotope in the ocean borders on virtual non- existence. Measurements will be made of 26Al/10Be and 7Be/10Be in seawater, and 26Al/10Be,10Be/9Be and 26Al/27Al in authigenic phases of deep-sea sediments and ferromanganese deposits. From the measurement will come: (1) better understanding of the comparative marine geochemistry of 26Al and 10Be, (2) refinement of the geochronology with 10Be/9Be, (3) evaluation of the absolute dating method of 26Al/10Be, (4) estimation of the input of the land- originated 26Al to the ocean, and (5) exploration of the possibility of using the isotope systems to trace past variations in ocean circulation and atmospheric dust transport.
