The research was conducted under the "Science" State Assignment FSWW-2023-0010 on the subject "Integrated research on the basis of natural geological laboratories".
The findings of the study were published in Scientific Reports (Q1; IF:4,9).
The Norilsk group of deposits is unique: it has the largest reserves of nickel, palladium and copper. Geologists from Tomsk Polytechnic University have been studying these sites for several years. Their current focus is on the layered silicates, which are understudied in these ores.
Scientists have found inclusions of cronstedtite when examining samples of massive ores with contents of oxides and silicates of no more than 1-3 volume percent of the total mass of the sample. Cronstedtite is an iron-rich layered silicate. It is quite rare for Earth Group deposits and is most commonly found in meteorites, i.e. bodies of extraterrestrial origin. Minerals are mainly identified by two parameters - chemical composition and crystal lattice structure. The scientists used transmission electron microscopy, Raman spectroscopy and diffraction analysis.
"The unique location of this discovery is what makes it special. The conditions for the formation of cronosthene are specific. It is a relatively unstable mineral that quickly changes to the magnesian phase. We think that the presence of massive sulfide ores at a relatively shallow depth - less than two kilometers - contributed to its formation. Earlier, our colleagues from Moscow State University had discovered another mineral from stone meteorites - ferrotochilinite - in the Oktyabrsky deposit. This fact makes the Norilsk deposit group even more interesting from the point of view of its formation conditions, in contrast to other copper-nickel deposits of global importance," says Tamara Yakich, Associate Professor at the Department of Geology.
Until now, crostedite has not been mentioned in the literature on the mineralogy of the Norilsk region. The results of the TPU scientists' research suggest that the formation of the mineral could have taken place in the conditions of isolated cavities of massive sulfides in the deep horizons of the Talnakh intrusion. The researchers do not exclude that the active participation of fluids - liquid or gaseous easily mobile components of magma - in relatively near-surface conditions could be an additional factor.