The article presents new data about mineralogy of manganesesilicate rocks, contact-metamorphosed analogues of siliceous-rhodochrosite rocks. Of particular interest to these rocks is the presence of Au–Ag–Pd–Pt mineralization. The purpose of the research was to obtain new data on the mineralogy and origin of the little-studied manganesesilicate rocks of the Mokrushinskaya area of the Olginsky district. As a result, new information was obtained for spessartine, pyrophanite, cobaltine, and costibite from manganesesilicate rocks, and a group of minerals and mineral varieties were identified and studied that are rare in nature and previously unknown in Sikhote-Alin (pyroximangite, manganocummingtonite, manganogrunerite, nickeline, zigenite, cobalipentlandite, rich in Co pentlandite, parkerite, compound PbBi(TeS), native silver and other minerals). It is shown that the parageneses of manganesesilicate rocks of the Sikhote-Alin and their constituent rock-forming minerals differ in composition depending on the area of their distribution. These features reflect differences in the chemical composition of protoliths of manganese silicate rocks, which indicates significant regional variations in the facies conditions of accumulation of Mn-rich metalliferous sediments. It has been established that manganesesilicate rocks are composed of various associations. The earliest ones were formed at the temperature ~500–550 °C as a result of contact metamorphism during the introduction of the Vladimir granitoid massif. Later associations were formed at the temperature ~250–350 °C as a result of the episodic circulation of the mobile fluid phase in the zones of increased permeability against the background of cooling of the Vladimirsky massif.
Elena V. Perevoznikova (Wed,) studied this question.