Titre du document / Document title

Pge minerals in gold placer province of the Algiyak River in northern Tuva : Their new ore occurrence

Auteur(s) / Author(s)

LESNOV F. P. ; OYDUP Ch. K. ;

Résumé / Abstract

The studied PGE minerals have been found in the mined gold placer at the Kurtushibin Ridge area (the Western Sayan). From the general amount of several hundred grains collected by final slime processing of gold concentrate, 30 representative grains have been studied by the electron microprobe with 72 analyses made for Os, Ir, Ru, Rh, Pt, Pd, Fe, Ni, Cu, and As, Sn, Sb also. Grains of PGE minerals vary in size (from 1.4 X 1.1 to 3.4 X 2.7 mm), weight (from 5.15 to 53 mg), and the degree of their rounding - from very weak to quite significant one. Most of them were represented by rutheniridosmine of silver-gray color. Several grains were composed of iridosmine and ruthenium iridosmine. Numerous rutheniridosmine grains contained also reddish-yellow inclusions of iridium isoferroplatinum varying in shape and size. All the studied compounds of Os, Ir, Ru belong to the hexagonal series. By their chemical composition, the rutheniridosmines are relatively homogeneous, with a very weak Ru trend. Analyses of central and edge zones of grains have shown their zonal structure marked by certain depletion of edge zones in Os together with their weak enrichment in Ir, Ru and Fe. It may be looked as an evidence for some trends in crystallization of rutheniridosmines - the trends related to changes in the crystal growth conditions, including a decrease of the mineral-forming medium temperature. In some rutheniridosmine grains the iridium isoferroplatinum inclusions have the shape of thin-plate accretions; that could be considered as a pattern of decay of PGM solid solutions. By the total scope of its typomorphous features, the studied placer PGE mineralization relates to rutheniridosmine mineralogical-geochemical type. As for its primary source, it might be supplied by the neighboring massifs of restitogeneous ultramafites participating in Kurtushibin ophiolitic belt.

Revue / Journal Title

Zapiski Vserossijskogo mineralogičeskogo obŝestva   ISSN 0869-6055 

Source / Source

2004, vol. 133, n^o6, pp. 49-65 [17 page(s) (article)]

Langue / Language

Russe

Editeur / Publisher

Nauka, Sankt-Peterburg, RUSSIE, FEDERATION DE  (1992) (Revue)

Localisation / Location

INIST-CNRS, Cote INIST : 4673, 35400013476271.0040