Sedimentation environments were reconstructed for the Early Vendian successions of the western slope of the Central Urals, which comprises one of the most complete sections of the terminal Precambrian system in northern Eurasia. It was shown that, despite the presence of several diamictite levels in the sections of the Serebryanka Group, mature and multiply recycled fine-grained siliciclastic materials (CIA = 65–77) were delivered into the sedimentation basin over the whole Early Vendian. Based on the lithochemical characteristics of shales, the climate of Serebryanka time can be estimated as semiarid-semihumid, similar to that dominating in Late Vendian paleocatchments. Based on relatively high Mo/Mn values (0.011–0.024), it was suggested that anoxic or similar conditions existed in the basin of Buton time, whereas other sedimentary complexes of the Serebryanka Group were formed in well aerated environments. The systematics of Sr, Ba, Zr, Cu, and V in fine-grained siliciclastic rocks and Sr isotopic data for carbonate rocks indicate that the sediments were accumulated in a fresh-water basin. The values of trace-element indicator ratios, e.g., Th/Sc, La/Sc, Th/Cr and others, in the shales of the Serebryanka Group and Nd model age estimates indicate that a variety of mainly Early Proterozoic complexes, ranging from granitoids to basic rocks, occurred in the Early Vendian paleocatchments. The basic rocks were eroded most extensively probably in the end of Serebryanka time. Based on the Ce/Ce* values of shales, it was concluded that submarine volcanism had no significant influence on sedimentation processes in the Early Vendian. An exception is Koiva and Kernos time, when hematite-bearing shales were accumulated in association with pillow basalts in some zones of the basin. The distribution of the compositions of shales from various formations of the Serebryanka Group in discrimination diagrams suggests that the Early Vendian sedimentary sequences were formed in passive geodynamic settings.

The alteration of platinum group minerals (PGM) of eluval, proximal, and distal placers associated with the Ural-Alaskan type clinopyroxenite-dunite massifs were studied. The Isovsko-Turinskaya placer system is unique regarding its size, and was chosen as research object as it is PGM-bearing for more than 70 km from its lode source, the Ural-Alaskan type Svetloborsky massif, Middle Urals. Lode chromite-platinum ore zones located in the Southern part of the dunite “core” of the Svetloborsky massif are considered as the PGM lode source. For the studies, PGM concentrates were prepared from the heavy concentrates which were sampled at different distances from the lode source. Eluvial placers are situated directly above the ore zones, and the PGM transport distance does not exceed 10 m. Travyanistyi proximal placer is considered as an example of alluvial ravine placer with the PGM transport distance from 0.5 to 2.5 km. The Glubokinskoe distal placer located in the vicinity of the Is settlement are chosen as the object with the longest PGM transport distance (30–35 km from the lode source). Pt-Fe alloys, and in particular, isoferroplatinum prevail in the lode ores and placers with different PGM transport distance. In some cases, isoferroplatinum is substituted by tetraferroplatinum and tulameenite in the grain marginal parts. Os-Ir-(Ru) alloys, erlichmanite, laurite, kashinite, bowieite, and Ir-Rh thiospinels are found as inclusions in Pt-Fe minerals. As a result of the study, it was found that the greatest contribution to the formation of the placer objects is made by the erosion of chromite-platinum mineralized zones in dunites. At a distance of more than 10 km, the degree of PGM mechanical attrition becomes significant, and the morphological features, characteristic of lode platinum, are practically not preserved. One of the signs of the significant PGM transport distance in the placers is the absence of rims composed of the tetraferroplatinum group minerals around primary Pt-Fez alloys. The sie of the nuggets decreases with the increasing transport distance. The composition of isoferroplatinum from the placers and lode chromite-platinum ore zones are geochemically similar.

The formation of snow-dirt sludge (SDS) via the mixing of snow and surface-deposited sediment by vehicles and pedestrians is one of the least studied sedimentation processes in urban areas. The aim of this study was to analyse the material, mineral, particle size, and chemical compositions of the SDS solid phase. The study was conducted using Ekaterinburg, Russia, as an example city with an intense anthropogenic impact and a long cold snowy period. The average content of the SDS solid phase was approximately 35 g L⁻¹ of meltwater on heavy traffic roads, of which the dust fraction (<0.1 mm) accounted for 23 g L⁻¹. On driveways and lawns, the contents of the SDS solid phase were 12 and 6.6 g L⁻¹, respectively. The mineral composition of the SDS solid phase was generally similar to the geology of the surrounding area, which is composed of a mosaicked combination of felsic and mafic complexes. The presence of building material fragments and other anthropogenic particles confirms the significant anthropogenic impact. The chemical composition contained major and minor elements specific to the minerals and materials that constitute the SDS solid phase. There was significant variability in the concentrations of Pb, Cu, and Zn in the granulometric fractions, indicating pollution. Intensive melting of SDS with a high particulate matter (PM) content is an important factor influencing the environmental quality of the urban environment.

The paper presents results of comprehensive studies of the rock association composing the lower zone of the northeastern part of the Monchetundra mafic massif in the Monchegorsk ore district. The zone consists of orthopyroxenite, plagioorthopyroxenite, and norite, which are variably amphibolized and host numerous gabbroid injections from the upper zone of the massif. The chemical composition of the dominant rock-forming minerals of the rocks was studied. The orthopyroxenes of the lower zone of the Monchetundra massif (LZMM) notably differs from those of the Monchegorsk pluton (Monchepluton) in containing lower aluminum concentrations because of differences in the P–T parameters of their crystallization. According to mineral geothermobarometric data, the LZMM rocks crystallized at 1200–1000°C and approximately 6 kbar, at a depth of about 20 km, whereas the Monchepluton rocks crystallized at an average temperature of 1230°C and a pressure of 3 kbar in shallow conditions. The LZMM rocks are characterized by moderate magnesium and silica contents and by elevated iron and low titanium concentrations, are enriched in the light rare earth elements (LREE) and LILE (Rb, Ba, and Sr) but are depleted by HFSE (Nb and Ta). The behavior of major components in the rocks is similar to that in analogous rocks in the bottom axial part of the Monchetundra massif, lying at its basement. Moreover, all petro- and geochemical parameters of the LZMM rocks are close to those of the analogical rocks of the Monchepluton. The paper presents new U–Pb isotope-geochronological data on individual zircon grains from the LZMM rocks. The age of the orthopyroxenite is 2496.3 ± 2.7 Ma, and that of the norite is 2500 ± 2 Ma, which indicates that these rocks crystallized simultaneously (within the error). The orthopyroxenite has an age of 2452 ± 85 Ma and positive ε_Nd(T) = +1.7, and the model age of the protolith T(DM) is 2.76 Ga according to data on the Sm–Nd of isotopic systematics. The possible parental melt of the rocks may have been komatiite contaminated with crustal material. The obtained results indicate that the Monchetundra massif is a composite intrusion, whose lower zone is similar to the layered intrusions and the upper one is made up of rocks belonging to the gabbro–anorthosite complex. The massif was formed by at least three pulses of magmatic activity (at 2.50, 2.47, and 2.45 Ga).

A complex mineralogical geochemical study of the bone detritus of large Pleistocene mammals inhabiting the Pechora Fore-Urals, the northernmost European part of their geographical range, is performed