¹⁰Be and ¹⁰Be/⁹Be in manganese nodules

抄録

Depth profiles of ¹⁰Be and ⁹Be concentrations have been measured in five manganese nodules from widely varying locations of the Pacific Ocean. Mean accumulation rate of these manganese nodules ranges from 2.7 to 8.0 mm·m.y.^-1. The variation of ¹⁰Be and ¹⁰Be/⁹Be with depth or time is found to be less than ±30% for periods from 0.4–1.0 m.y. back to 6 m.y. B.P. Surface ¹⁰Be/⁹Be atomic ratio is found to be (9–13) × 10^-8, that shows authigenic nature of manganese nodule acuumulation by comparison with (12–31) × 10^-8 for deep-sea water, (2–7) × 10^-8 for clay sediments and (7–9) × 10^-8 for fossil-rich sediments.