Lower Triassic sandstones in the southern part of Belsky depression (Pre-Uralian foredeep) contain detrital zircons with concordant U-Pb isotopic ages ranging from Neoarchean to the boundary of the Carboniferous and Permian. The distribution of rare and trace elements in zircons suggests that the majority of them fall into the Triassic sandstones due to erosion of basic rocks (or, taking into account the possibility of multiple recycling, most of them are crystallized in the rocks of basic composition). These data indicate a much wider age range of rocks in provenances in the Early Triassic, than it follows from petrographic observations. The micropetrografic data testify that the magmatic complexes which are distributed at present in Sakmara area were the sources of zircons with the Early and Middle Paleozoic datings. Detrital zircons with the Proterozoic and Neoarchean ages are likely redeposited from Riphean-Vendian Ural-Tau zone, where they were brought due to erosion of East European platform base. A small proportion of crystals with Late Paleozoic ages taking into account the geochemical and petrographic data, permits suggest that granite massifs of the Main Granitic axis of the Urals, during the formation of Pre-Uralian molasses has not been involved into erosion. Perhaps they have not yet been withdrawn to the surface, or were placed to the East line of the watershed. At the same time, a significant number of zircons with Precambrian age indicates that the Ural-Tau metamorphic formations were in the erosion zone. Consequently, the orogen watershed at that time was to the east of the zone. This is also evidenced by the presence in the Lower Triassic sandstones few crystals of zircon with Carboniferous age, the source of which could be to the west of modern Magnitogorsk megazone. On the basis of these data we suggest that the forming of coarse clastic formations of the final stage of orogeny in the southern Urals occurred mainly due to erosion of sedimentary, igneous and metamorphic complexes from modern western slope of the axial zone of the Urals.

The article outlines five intervals of the wells drilled in Western Siberia, and covering the major part of the section (from lower Jurassic to lower Cretaceous). A detailed study of individual core samples permit to elaborate the common notions about the conditions of deposits formation. Implemented the holographic principle, recommended for use in a visual-practical purposes. For two intervals defined speed sedimentation, as 3.5-5 mm/year.

The plagiogneiss mineralogy from the Yangiyuganskaya parametric borehole (the West-Siberia north-western part) has been studied. The rocks are composed of quartz-oligoclase aggregate with presence of mica (muscovite and phlogopite), amphibole (edenite-ferroedenite-ferropargasite), clinozoisite-epidote, garnet (almandine-grossular series), clinochlore, microcline, magnetite, titanomagnetite, rutile and fluorapatite. It is shown that plagiogneisses have been formed from leucocratic plagiogranites under the conditions of the metamorphism of amphibolite facies. U-Pb, Sm-Nd, Rb-Sr plagiogneiss datings point with the biggest possibility to the following main events of geological history of these rocks formation: 1) magmatic intrusion of plagiogranites in Vendian; Sm-Nd isochrone 691 ± 58 Ma also points to neoproterozoic age of the plagiogneiss initial substance; 2) the metamorphism of plagiogranites and its turning into plagiogneisses involved in early Ordovician (486 Ma); 3) the latest tectonothermal events (292 ± 23 Ma), fixed by Rb-Sr system are associated possibly with collision processes.

It is conducted lithogeochemical investigation of Vendian fine-grained clastic sediments composed Talakh, Parshinsk (Nepa horizon) and Byuk suites (Tyre horizon) of some wells core material in Nepa dome of Nepa-Botuoba anteclise, Siberian Platform. Pelites of all three suites are characterized by variations in the composition from the sandstones to clays, with an increase in clay component up to the section, and have a common geochemical specifics. With moderately alkaline composition they belong to the class of high-K rocks, indicating similar environment of pelite formation due to bring in a shallow marine basin of Vendian passive continental margin the material of chemical weathering platform crusts in conditions of humid climate. Very likely, the source of sediments was the rocks crustal basement of the Siberian platform with possible participation Riphean sediments.

Fragments of the ophiolites of the Mariinsky complex of eastern and western framing of the Revdinskiy massif have been compared. At the eastern framing rocks of Mariinsky complex are main dolerites of sheeted dike complex, whch intruded basaltic pillow lavas, and were provenanced by back-arc spreading. This conclusion is confirmed by study of the composition of accessory chrome-spinels. Minor geochemical differences of dolerites of sheeted dike complex and basaltic pillow lavas have been demonstrated. In sheeted dike complex acide dikes of andesite-dacites were investigated. At the western framing of the Revdinskiy massif rocks of Mariinsky complex are main amphibolites and green schists, which were origin by metamorphism of basic rocks of the upper part of ophiolite section. Relic interlayers of cataclastic metagabbros differing from the host amphibolite by geochemical characteristics were found in the amphibolites at Mt. Lysaya. Amphibolites of the western framing of the Revdinskiy massif are intermediate position between the oceanic basalts and back-arc spreading basalts and differ from rocks of eastern framing by some geochemical characteristics (high TiO₂, absence of highly visible Ta-Nb-minimum etc.), that indicates its origin by different geodynamic settings and probably different age.

We present for the first time U-Pb age data and Hf-Nd-Sr-Cu-S isotope signatures for lithologies and associated sulphide ores from the Binyuda and Dyumtaley ultramafic-mafic intrusions located in the limits of the Taimyr Peninsula (Russian Arctic). Zircons are characterized by similar U-Pb ages (245.7 ± 12 Ma at Binyuda and 256.2 ± 0.89 Ma at Dyumtaley), indicating for their close temporal relationship with tholeiite-basalt magmatism of the Siberian Platform. Silicate materials show distinct Hf-Nd-Sr isotope signatures (εHf = -3.8 ± 1.3, ɛNd = -3.8±0.4 and⁸⁷Sr/⁸⁶Sr_i = 0.70588 ± 0.00013 at Binyuda and εHf = 9.5 ± 2.5, ɛNd = 4.2 ± 0.7 and⁸⁷Sr/⁸⁶Sr_i = 0.70474 ± 0.00020 at Dyumtaley). The determined Hf-Nd-Sr variability is interpreted to represent a primary source signature of the lithological units. An important role of the juvenile component is clearly pronounced for the Dyumtaley intrusion, whereas a major contribution from a subcontinental mantle or essentially crustal source is inferred for the Binyuda intrusion. These signatures clearly manifest deviation from those typical of the ore-bearing intrusions from the Noril’sk Province, characterized by protracted magmatic evolution with significant time span of zircon and baddeleyite U-Pb ages (from ca. 350 to 230 Ma), relatively constant εNd values (ca. +1 ± 0.5), highly heterogeneous εHf (from -2.3 to 16.3) and⁸⁷Sr/⁸⁶Sr_i (from 0.70552 to 0.70798). In terms of Cu-isotopes, the majority of the analyzed sulphide samples fall within a tight cluster of δ⁶⁵Cu values (-0.66 ± 0.24‰ at Binyuda and 0.4 ± 0.1‰ at Dyumtaley), characteristic of the ores from the economic Ni-Cu-PGE deposits at Talnakh. In contrast, notable difference in δ³⁴ S values typifies sulphide ores at Binyuda and Dyumtaley (1.5 ± 0.4 and 11.4 ± 0.6‰ respectively). We suggest that the Cu-S isotope characteristics of the sulphide ores reflect their primary signature rather than a result of mixed sources or magmatic fractionation of stable isotopes. However, the latter possibility cannot be ruled out for heavy S isotope composition of sulphide ore at Dyumtaley. Samples of the disseminated sulphide ore from the Dyumtaley intrusion approach δ³⁴S-δ⁶⁵Cu parameters of the economic ores at Talnakh (Noril’sk Province) and might be considered as the most prospective for targeting the massive Ni-Cu-PGE sulphide ores.

Bureja-Khanka uranium-bearing province is one of the long ago determined uranium provinces of Russia. Opening its and first geological prospecting and geological exploration for uranium-bearing objects of the territory took place in the early fifties of XX century. It was the initial stage of large-scale geological studies for uranium, when in a short time it was discovered many uranium deposits and uranium-bearing areas in different regions of the USSR. In Bureja-Khanka region were identified three major uranium-bearing area and a series of separate deposits of uranium. However, with the simultaneous opening of richer uranium-bearing areas, geological exploration for uranium within the study region were suspended. Therefore, many deposits and occurrences of uranium remained unexplored or opened only from the surface. Currently, the problem of оpening new industrial deposits in Russia has become very topical again, since large deposits of uranium in the Streltsovsky area is being finalized, and large gold-uranium deposits Elkon area have many complex geographical and economic problems, and not demand by industry. The major uranium-bearing areas of Bureia-Khanka region are in favorable geography-economic conditions and they have considerable interest for industry companies.

The litho-paleoecological characteristics of the Upper Ordovician reef Bol’shaya Kos’yu was given. The reef paleolandscape profile - reef plateau, reef internal lagoons, and frontal reef zone was determined, and reef facies were described. The distribution of fossils involved in the reef Bol’shaya Kos’yu formation was shown. The evolution of reef ecosystem was traced. The ecological succession fore stages were identified: stabilization, colonization, diversification and domination which reflex the complex ecosystem structure of this reef.

Subject of the study was molybdenite aggregate (0.9 × 0.5 cm) in granite from Cu ± Mo-porphyry mineralisation (Altynai Massif, eastern part of Middle Urals). Microprobe analysis and electron microscopy identified fine alternating microlayers of molybdenite and quartz in all 0.4-5.0 mm flakes of molybdenite. Thickness of normally discontinuous layers of quartz is 0.5-3 μ, distance between layers - 8-100 μ or more. Quartz layers are aligned only with the basal cleavage of molybdenite. In some molybdenite flakes or parts of flakes quartz layers are absent or very few in number. Large flakes of molybdenite are surrounded by fine-grained aggregate of quartz, chamosite and molybdenite. Occasional grains of fluorite and galena have also been found within this aggregate. Molybdenite flakes in such areas contain no quartz layers, have random orientation, and can be seen as fragments cemented by chamosite and quartz. Molybdenite has consistently low rhenium content of 29 ppm (according to ICP-MS). It is suggested that molybdenite-quartz rhythms are likely to correspond to primary oscillatory distribution which was subsequently subjected to deformations and redistribution of silica in crushed areas.

The data on C, O, Sr and S isotope composition of the carbonates, quartz and sulfides from the Tamunier and Vorontsovsk gold-ore deposits, localized in the Auerbakh volcano-plutonic belt are cited. It is established that on mineral isotope characteristics the nearest analogue of mineralization in beresites of the Tamunier deposit is the gold-polymetallic mineralization in jasperoids of the Vorontsovsk deposit. Calculation of the C, O and S isotope composition of the ore-bearing fluid testifies to a participation in ore-formation of two main substance reservoirs - the rock (sea carbonates and biogenic pyrite of host volcanogenic-sedimented series) and the fluid one (metalliferous magmatogene, as well as metamorphogenic fluids connected by the intrusive mass injection).