Accumation rates of manganese in pelagic sediments using 130Th activity

For 7 pelagic sediment cores, the decrease in unsupported 130Th activity with depth in the core was used to establish the mean accumulation rate over the last 300 000 years. Because CaCO3 is a Mn-free diluent, the Mn concentration results and the sediment accumulation rate results are given on a carbonate-free basis. CaCO3 content ofcores raised from below the carbonate compensation level is taken as zero. The in situ density of water-free deep-sea cores was assumed to be 0.7 g/cm³ , this could lead in some cases to an error.