We have measured 10Be and 230Th depth profiles in Mn-nodules and crusts from the Central North Pacific (2 samples), from the South China Sea (2 samples) and from the South Pacific (1 sample). Comparison of the nuclei's ages derived via 230Th and 10Be datings and other methods (K/Ar and paleontology) shows very good agreement and proofs that distortion of 10Be and 230Th ages due to radionuclide diffusion in Mn-encrustations is negligible (< 20%). In all samples we observe a smooth exponential decrease for larger sections, suggesting constant depositional 10Be fluxes within the time resolution of 0.4 to 0.8 Ma. (resulting from the thickness of the sampled intervals). Growth rates range from 2 mm/Ma to up to 20 mm/Ma. Common to all samples is a remarkable change of growth rate accompanied by a visible change of the mineralogical inner texture, dated at 6.2 Ma. We observe slower growth rates during the last 6.2 Ma than in the previous periods. Provided that the Mn-concentration in deep water has remained constant throughout time (as supported by nearly constant trace metal/manganese ratios of the samples) the data suggest that the bottom water circulation pattern has slowed down since 6.2 Ma BP. Visible changes in the inner texture corresponding to paleooceanographic time marks such as 1.3 Ma (a presumed variation of the ice volume during Middle Pleistocene), 3.3 Ma (Glaciation of the Northern Hemisphere), and 12-14 Ma ago (maximum Glaciation of the Antarctica) strongly suggest that the growth pattern of Mn-encrustations has been influenced by the response of the oceans to the history of climatic changes.