(Table 1) Platinoids in Fe-Mn crusts and nodules from the Pacific Ocean

Platinoid element contents were determined in 16 samples of Fe-Mn crusts and nodules collected during dredging deep-sea mound slopes of the Pacific Ocean from the equator to 27°N. The method of neutron activation analysis with pre-concentration of the platinoids was used for these determinations. There is no relationship between platinoid contents in deep-sea (>3000 m) Fe-Mn nodules with depth of sampling, as well as with age of nodule layers. It is concludet that ultramafic rocks are the primary source of platinoids in Fe-Mn nodules.

Major element and cadmium contents in phosphorites from Pacific seamounts

Cadmium contents in studied rocks from Pacific seamounts usually lower than both in biogenic-diagenetic shelf phosphorites and in pelagic sedimentatary-diagenetic Fe-Mn nodules. In general, the behavior of Cd in phosphorites, phosphatized rocks and iron-manganese-phosphate crusts from the seamounts shows that phosphorus, iron, and manganese are apparently of normal sedimentary origin.