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Hence, it was critically important to evaluate the result obtained by Yu et al., to see whether the conclusions were robust, or whether factors other than ocean currents could have produced similar patterns at the present day and during the last glacial maximum. 12.16b), which were related to the presence of biogenic opal. suggested that biogenic opal was much more effective at scavenging Pa than clay minerals. calculated average burial fluxes for each climatic stage, based on initial radionuclide abundances, dry bulk density, and sedimentation rate. High radionuclide fluxes during interglacial periods were attributed to focussing of marine snow (radionuclide-bearing diatoms) by strong bottom currents.
These fluxes were positively correlated with sedimentation rate (Fig. Low radionuclide fluxes during glaciations were attributed to bulldozing of sediments by grounded ice shelves, which replaced young (Pb also makes it ideally suited to the dating of historical-age sediments.
This result cast doubt on the widely favoured model in which the conveyer belt was thought to have partially or completely ceased during the last glacial maximum (section 14.1.7).As noted above, all nuclide quantities in this chapter will be presented in terms of activities (unless stated otherwise).