Accumation rates of manganese in a pelagic sediment core using 231Pa activity

For a pelagic sediment core taken in the Atlantic Ocean, The decrease of unsupported 231Pa was used for the determination of the accretion rate. 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.