EXAMINATION OF HYDROTHERMAL INFLUENCES ON OCEANIC BERYLLIUM USING FLUIDS, PLUME PARTICLES AND SEDIMENTS FROM THE TAG HYDROTHERMAL FIELD

We have carried out a comprehensive study of the distributions of Be-9 and the cosmogenic radionuclide Be-10 in fluids, nearfield sediments, and neutrally buoyant plume particles associated with the TAG hydroth ermal field. These results, coupled with previously published uranium decay series radionuclide distributions [1,2], suggest that the level of MnO2 in iron oxide rich sediments and particles may play a role in Be scavenging. In addition, the data are used to quantify the net effe cts of nearfield coprecipitation with FeS and of scavenging by iron ox yhydroxide plume particles on the oceanic balance of the Be isotopes. These calculations suggest that hydrothermal input of Be-9 is nearly b alanced by nearfield and plume removal processes, and that hydrotherma lly induced scavenging has a negligible effect on the oceanic Be-10 bu dget.