Chemical composition of ocean manganese nodules from the Pacific Ocean using different techniques

The pressure effect upon the thermodynamics or kinetics of mineral formation is suggested as the governing agent in the depth dependence of the mineralogy.

The minor elements, Pb and Co, appear concentrated in the dMnO2 phase, whereas Cu and Ni are more or less excluded from this phase. In the manganites, Pb and Co are relatively low in concentration, whereas Cu and Ni are spread over a wide range of values. The oxidation of Pb and Co from divalent forms in sea water to higher states can explain their concentration in the dMnO2 phase.