Radionuclide Ratios as Proxies of Particle Flux

The P.I. proposes to initiate a systematic study of chemical scavenging processes, with a focus on the relationship between 231Pa/230Th and 10Be/230Th ratios found in sediments and the composition and flux of particles settling through the overlying water column. They will take advantage of the sampling opportunity provided by the US.JGOFS Equatorial Pacific process study to derive empirical relationships between the nuclide ratios and the flux and composition of particulate matter. These relationships will then be applied to nuclide ratios measured in the sediments deposited at these sites from the present through the last glacial maximum, and possibly earlier. The objective is to evaluate changes in particle flux (and thus, indirectly, primary production) that have accompanied, or responded to, past changes in climate.