Geochemical studies of long-lived Th isotopes by mass spectrometry will be continued on previously collected water column and pore water samples. The effects of bacteria and colloids on chemical scavenging will be explored to increase our understanding of the aqueous geochemistry of Th. This should lead to more effective usages of Th isotopes as tracers and chronometers of chemical scavenging, sedimentation, and paleoceanographic processes. Sensitivity of the mass spectrometric method for the determination of Th in seawater has been improved substantially. With this tool, some important marine geochemical issues which have up until now been impossible or otherwise too difficult to do will be undertaken. The technical advancement has also prompted modification of the analytical scheme to include the analysis of Pa-231 by mass spectrometry. The new technique will open up avenues for important marine geochemical and geochronological studies in the years to come.
