Analysis of Manganese deposits from the Atlantic and Indian oceans

Accumulation rates of 1-2 mm/million years are reported for manganese crusts on deep-sea rocks. These rates are the same as most reported accretion rates for manganese nodules suggesting a similar mechanism for this formation. Manganese crusts on large deep-sea rocks provide convincing evidence that net sediment accumulation in these areas has been zero for many millions of years.