Cobalt-nickel-bearing sulfides in phosphorite of Jurassic sediments of Ybskoye occurrence (Sysola depression)

The results of study micromineral segregations of Co-Ni-bearing iron disulfides (pyrite structure) and mineral phases with stoichiometry of thiospinels, corresponding to siegenite and Cu-bearing greigite-linnaeite-polydymite composition, are represented. These sulfides were found in phosphorite of Jurassic sediments of Ybskoye occurrence (Sysola depression, northeast of the Eastern European Platform). It is suggested that these sulfide micro-minerals are late-diagenetic forms (due to authigenic remobilization) of concentrating of trace (disseminated) elements (copper, cobalt, nickel), which initially were absorbed by clay substance of coprolite pellets contained in the phosphorite.