Description, Beryllium characteristics and chemical composition of manganese nodules from the Pacific Ocean

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.. 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) x 10**-8, that shows authigenic nature of manganese nodule acuumulation by comparison with (12-31) x 10-8 for deep-sea water, (2-7) x 10**-8 for clay sediments and (7-9) x 10**-8 for fossil-rich sediments.