Geochemistry of Rare and Rare-Earth Elements in Manganiferous Sediments of the Polar Urals and Pai-Khoi

Abstract

Data on the concentration of rare and rare-earth elements in the Devonian manganese-rich metasediments of the Polar Urals and Pai-Khoi Ridge are presented. It is shown that Sc, V, Rb, Zr, Nb, Hf, Th, and U represent elements delivered to the metalliferous sediments as a part of the detrital material. Excess (relative to the background detrital material) concentrations are established for Li, Be, Cr, Co, Ni, Zn, Ge, As, Mo, Sb, W, and Pb. They could be delivered from a specific detrital or chemical material (for example, ferruginous), seawaters (hydrogenic sorption of elements), biogenic substance (carbonate, siliceous, phosphate, carbonaceous), diagenetic interstitial pore waters, and hydrothermal solutions. In terms of the concentration of rare-earth elements, the studied rocks are comparable to the present-day diagenetic ferromanganese deposits.