The initial exploration for²⁶Al chronology in deep-sea ferromanganese crust

BackgroundThe deep-sea ferromanganese crust (DSFC) is a natural archive for recording the history of the Earth’s evolution, as one of the most common authigenic assemblages in marine sediments. Although the depositional age dating using meteoric ¹⁰Be has been successfully used in the study on the chronology of DSFC, the research on ²⁶Al has not seen relevant reports in this aspect due to the influence of factors such as measurement sensitivity and ²⁶Al in situ production. MethodThe first exploration for ²⁶Al chronology in DSFC was carried out by using accelerator mass spectrometry (AMS) measurements of ¹⁰Be and ²⁶Al, and the comparison of relationship between isotopic ratios and concentrations of Al and Be. ResultsThe growth rates of G.R = (1.44 ± 0.09) mm/Ma, (3.58 ± 0.29) mm/Ma, (1.52 ± 0.10) mm/Ma and (2.93 ± 0.14) mm/Ma are derived using ¹⁰Be/ ⁹Be, ²⁶Al/ ²⁷Al ratios, ¹⁰Be and ²⁶Al concentrations, respectively. ConclusionThe ²⁶Al chronological methods have been explored based on a DSFC sample and encouraging results were obtained. The results are preliminary and insufficient; some information is still needed to explain the difference between ²⁶Al and ¹⁰Be chronology.