Chemical composition of manganese micronodules at various depths in core 710KH from campaign SO11 of R/V Sonne

Inside core 710KH, manganese micronodules are much more abundant in the coarse fraction (> 40 μm) of the dark brown clay horizon than in the upper sedimentary unit and are characterized by higher ratios and higher Ni and Cu contents than those from the upper-sediment horizon. This reflects the fact that these "overconsolidated" sediments are well oxidized and that element remobilization from the micronodules has not taken place within this sediment type. In the upper sedimentary unit there is a sharp drop in the ratio and Ni and Cu contents of the micronodules immediately beneath the sediment surface, reflecting the selective migration of Mn and other transition elements such as Ni and Cu from the micronodules.