Use of cosmogenic 10Be AND 26Al in phillipsite for the dating of marine sediments in the south pacific ocean

摘要: We report the first measurements of cosmogenic 10Be and 26Al in authigenic marine phillipsite a core from South Pacific Ocean (14°S, 161°W). The measurement these two isotopes is now feasible by accelerator mass spectrometry milligram quantities samples. concentrations decrease with depth 3.3·109 to 0.23·109 7.8·107 <0.97·106 atoms g−1, respectively. Assuming that all was formed at sediment-water interface, calculated sedimentation rates 10Be,26Al 26Al/10Be profiles are approximate agreement each other indicate low rate 0.12–0.38 mm ka−1 (on CaCO3-free basis) has prevailed this location throughout past 10 Ma. These previously reported 230Th (and 131Pa) rates, but disagreement those some publications on cores Pacific. The extrapolated-to-surface ratio about ten times greater than atmospheric production 4·10−3, whereas ferromanganese nodules, it appears be five smaller. It seems preferentially accumulates respect 10Be, nodules accumulate 10Be. between obtained indicates relative uptake remained constant past.