Для характеристики минералогии россыпного золота Южного Урала проведены поиски и исследование микровключений рудных минералов в зёрнах самородного золота. Изучено 110 неокатанных и слабо окатанных зёрен в 1-2 мм из восьми россыпных зон. Микровключения рудных минералов выявлены в шести россыпях Миасской зоны. Список включает сульфиды, арсениды, медистое золото, платиноиды. Для всех микровключений установлена связь с конкретными месторождениями рудного золота и хромитопроявлениями. Отмечено, что северные фланги Таловского, Нуралинского массивов, к которым приурочены золотые россыпи с платиноидами, требуют опоискования в отношении платиноидной минерализации.

The analysis of Early Iron Age gold jewelry from Hankarinsky Dol and Inskoy Dol in the Altai, Arzhan II royal mound in Tuva, and Filippovka I and II royal mounds in the Southern Urals, has detected platinoid inclusions similar to those in artifacts from the Near East. Their morphology and composition suggest that gold was mined from placer deposits located near the gold and platinum bearing ultramafi c belts. Microinclusions consist of solid solutions of osmium, iridium, and ruthenium. Their nomenclature was evaluated by the proportion of these components. Triangular plots of microinclusions in artifacts from the Urals reveal four clusters: principal (ruthenium and iridium-osmium) and secondary (osmium-ruthenium and iridium-ruthenium), the latter relating to nanoscale particles surrounding larger ones. Their emergence is due to the impact of gold melt on microinclusions. During melting, heated air in micropores could cause oxidation of osmium with subsequent assimilation of oxidation products by melt. Micropores, 1–0.4 μ in size, were revealed in 5–10 %. This should be taken into account when comparing the composition of microinclusions and minerals from tentative placer sources. Artifacts from Siberia show a mostly ruthenium tendency. Osmium-ruthenium and iridium-osmium trends were also detected, but not the iridium-ruthenium trend, possibly due to small sample size relating to Siberia. The presence of PGE microinclusions in ancient gold artifacts may suggest that these were manufactured locally.

The results of study of the Ishkinino Co-Cu massive sulfide deposit hosted in ultramafic rocks of the Main Ural Fault Zone are discussed. The ore field is localized in a fragment of Early Devonian accretionary prism composed of oceanic and island-arc tectonic sheets. The antiform structure of the ore field was formed at the collision stage in the Late Devonian. The primary ore was deposited near the bottom in the environment of the accretionary prism at the island-arc stage of evolution, whereas the superimposed ore mineralization was related to the collision stage. The primary ore is composed of massive, stringer - disseminated, and clastic varieties with two mineral assemblages of sulfides and oxides. The superimposed stringer - disseminated ore mineralization is represented by Co-Ni-Fe arsenides and sulfoarsenides, native gold, Bi and Te minerals, and late sulfides and oxides. Loellingite, safflorite, rammelsbergite, and krutovite were identified in the massive sulfide ore for the first time in the Urals. The geochemical attributes of Co-Ni minerals serve as indicators of superimposed processes. Chromites contained in rocks and ore correspond to Cr-spinel of suprasubduction ultramafic rocks in chemical composition. It is suggested that sulfide ore may be found in the accretionary prisms of the presently active island arcs composed of ultramafic sheets.