EGU22-1260, updated on 27 Mar 2022
https://doi.org/10.5194/egusphere-egu22-1260
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Manifestation of various stages PGE mineralization in the different locations Ospa-Kitoy ophiolite massif (East Sayan, Russia).

Olga Kiseleva, Evgeniya Ayriants, Dmitriy Belyanin, and Sergey Zhmodik
Olga Kiseleva et al.
  • Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russian Federation (kiseleva_on76@mail.ru)

A study of chrome-spinels and PGE mineralization (PGM) from the podiform chromitites has been carried out on the area of four locations of the Ospa-Kitoy ophiolite massif (northern and southern branches East Sayan ophiolite). It has been established that different PGM assemblages formed at different stages of formation of the Ospa-Kitoy ophiolite massif, at various temperature and fluid regimes, are present at four sites. The chromite pods show both disseminated and massive structures. There are veins of massive chromitites, 0.01-0.5 m thick and 1-10 m long, rarely disseminated, schlieren, and rhythmically banded ores, which are discordant to the host ultramafic rocks. (Os-Ir-Ru) alloys occur as inclusions in the Cr-spinel or intergrowth with them (fig 3a). In addition, FePt3 alloys are found in the PGM assemblage. In such grains, decomposition structures of solid solutions represented by osmium lamellas can be observed. Polyphase PGM assemblage: (Os, Ir, Ru), (Ni, Fe, Ir),  (Ir, Ru, Pt)AsS, CuIr2S4, (Os, Ru)As2, Rh-Sb,  PtCu, and Pd5Sb2 are localized in serpentine, in close association with sulfides, sulfoarsenides, arsenides of nickel.