Compositions of gneisses from the Early Precambrian crystalline complexes of the Aldan shield and of mantle xenoliths from kimberlites plot along the magmatic fractionation trends. Their isotope age and crystallization temperature decrease in according to the sequence of their formation during fractionation. This indicates that the crystalline crust and lithosphere mantle formed as a result of crystallization and fractionation of a layered magma ocean. Evidence of chemical disequilibrium between the mantle rocks and metallic iron suggests that accretion of the Earth’s core occurred before that of the silicate mantle under the effect of magnetic forces. In the silicate magma ocean, which originated through impact melting, the processes of compressional crystallization and fractionation of its near-bottom parts occurred. Due to a very low pressure in the incipient magma ocean, the early formed residual melts varied in composition from granites to tholeiites. This provided very early formation of the acid crystalline crust. An increase in temperature during the accretion process resulted in the higher temperature of the upper mantle compared to the lower one. For this reason the lower mantle plumes did not ascend in the Early Precambrian, and magmas in ancient platforms were forming mainly from residual melts of compositionally varying layers of the magma ocean. In the Phanerozoic, the temperature of the lower mantle became higher than that of the upper one. As a result, lower mantle plumes, oceans and lithosphere of platforms came into existence. In the ascending mantle plumes, basic eclogites were subject to decompression melting. Fractionation of the formed magma chambers led to the formation of acid magmas under low pressure conditions and of various alkali-basic magmas under high pressures.

The object of study is clastic Middle Triassic of the central part of the Pronchishchev Range. The territory of researches is located on the border of Ust’-Anabar and Lena-Olenek facies districts and has poor geological knowledge. During field study of outcrops and test pits new data for Triassic of the right bank of the Peschanaya River were obtained. Lithofacial analysis and analysis of cyclical structure of the Anisian and Ladinian were carried out. The stratigraphic subdivision of the strata was made according to the results of a comprehensive bio- and lithostratigraphic analysis. The succession includes the Karangatinskaya and the Tuora-Khainskaya (Anisian), the Ust’-Olenekskaya and Olimpiiskaya (Ladinian) formations. The lithofacial analysis showed that the sedimentation occurred in mainly sea-shallow conditions with constant exposure of normal waves. Upward the succession a part of coastal sediments increase. Stages of fast sea level rising took place. The analysis of cyclical structures showed that the studied deposits represent the series of regressive sedimentological cycles of decameter scale with а transgressive orientation. They form the large regressive sedimentary cycle with a pronounced binomial structure. It has been found that the Anisian part of the studied section has very similar features of a structure with Leno-Olenek type sections. The structure of the Ladinian part is also similar to the sections of the Lena-Olenek type and is characterized by a slightly reduced thickness of the Olympic formation. It is typical for the western part of the Lena-Olenek facies district. Structural features of the selected cycles allow you to use them in lithostratigraphic correlations of geological sections within the considered sedimentation basin. This is especially true for sites with rare and relatively uniform fossil fauna.

The microbial structures of various genesis are rock-forming components in limestones of the Kizelovian regional substage (the Tournaisian stage) on the Middle Urals eastern slope. Comprehensive petrographic analysis of distinct grains allowed to reconstruct the carbonate platform depositional environments. Microbial structures in this study include: 1) calcitarcha (calcite “spheres” and similar sub-circular microfossils), 2) bioclasts of calcareous green algae, 3) bioclasts of calcified cyanobacteria/calcimicrobes (or calcibionts), 4) most peloids and traces of grains micritization, 5) oncolites (oncoids) and intraclasts of other microbialites. Environmental indicators evidence that sedimentation throughout the Kizelovian time was carried out within the upper subtidal photic zone, in conditions of high salinity and limited water circulation. A distribution of microfacies shows that the basin depth at an average corresponded to the normal wave basis. Microbiota taxonomic composition and bottom configuration features largely determined differences in sediment deposition characteristics. Some carbonate sedimentology terminologic issues are also discussed in this article.

The arm of the present paper is to evaluate the significance of species from genus Nikiforovella for stratigraphy of Devonian-Carboniferous boundary from different regions of Eurasia. The study is based on author and museum collections of the Late Devonian-Early Carboniferous bryozoans from Southern Urals, western part of the Altai-Sayan Folded Area, south-western of the West-Siberian plate, Rhenish massif, and Namur-Dinant Basin. The material was studied using a binocular microscopic. The morphological descriptions for each species were prepared in result of researching oriented sections. The first phylogenetical scheme of the genus Nikiforovella are offered on the base of statistical analyses of species features in Famennian-Tournaisian. Bryozoans from genus Nikiforovella are distributed in Northern hemisphere of the Earth in Carboniferous predominantly. The genus is stratigraphical significant because presented by low amount of taxa with short time interval of development. The specific view of colony surface (formed by a combination of autozooecies and heterozooecies) allows easy identified these bryozoans on first steps of research. Totally conclusions are next: Uppermost Famennian from some regions of Eurasia consists of various bryozoans from genus Nikiforovella. The genus has distinctly morphological particularities; Genus Nikiforovella are characterized changing of morphological particularities and species composition on the lower boundary of the Carboniferous ( sulcata Conodont Zone); During Famennian-Tournaisian phase of evolution Nikiforovella demonstrated tendencies to increase of size, number and changing disposition of metazooecies and acanthostyles; Phylogenetical scheme of this genus may be used for division and correlation of Upper Devonian-Lower Carboniferous deposits in some regions of Eurasia. Species N. gracilis Ernst, Herbig, 2010 and N. cf. gracilis Ernst, Herbig, 2010 are typical for the Uppermost Famennian of Rhenish Massif and Southern Urals respectively. Species N. alternata Nekh., 1956 are spread in Lower Tournaisian of Rudny Altai and Eastern TransBaikalia.

This work presents first results on⁴⁰Ar/³⁹Ar dating by stepwise heating method, as well as geochemistry of rare trace elements by ICP-MS and isotopic (Nd, Sr) composition of metabasites from tributaries basins of Velmo and Bolshoi Pit rivers (Transangaria, Yenisei ridge). The studied rocks form small areas of concordant boudined plate-shape amphibolite bodies among Late Archaean marbles, calciphyres, schists, and are derived from a metapicrite-basalt complex. They have schistose and banded structure and consist of hornblende with andesine, biotite, zoisite, carbonate, quartz, as well as accessory аpatite, sphene, and ilmenite.Mineral paragenesis corresponds to the conditions of low-temperature metamorphism of amphibolite facies.Chemical composition of rocks (wt %): 44-49 SiO₂, 2-4 Na₂O + K₂O, 1.1-1.8 TiO₂, 12-17 Fe₂O₃, 8-11 CaO, 7-11 MgO; FeO(t)/MgO 1-2 correspond to basalts and trachybasalts of the tholeiitic series from the ocean floor. Rock-forming age of amphibole is Late Precambrian (≈700 Ma) that matches early stages of Paleo Asian Ocean development. According to distribution of LILE (ppm) (≈20-1000 Ba,≈100-635 Sr) and HFSE (ppm) (46-83 REE, 4-10 Nb, 0.3-0.7 Ta, 30-90 Zr, 0.6-1.1 Th, ≈0.2 U), studied rocks coincide with tholeiitic E-MORB, which formed in the setting of back-arc spreading and had enriched asthenospheric source. Isotopic specifics: ε_Nd(t)from +3.6 to -5.2; T_NdDM ≈ 1.4-2.2 Ga; 0.7046-0.7154⁸⁷Sr/⁸⁶Sr(t)) indicate that mantle diapirism could have been accompanied by mixing of plume, subduction and crust (DMM + PREMA + EM) material. High concentrations of HREE (La_N /Yb_N 1-3, LREE/HREE - 2.2-3.2) and Y allow us to assume absence of restite garnet and extraction of primary tholeiitic E-MORB magma under setting/conditions of ≈ 4-20 % equilibrium melting of spinel lherzolite from upper mantle.

In the article is presented data of mineralogy, petrography, geochemistry and isotope-geochronology study Nyashevo mafic-ultramafic massif in Ilmeny-Vishnevogorsk polymethamorphic shear zone. The ultramafic rocks consist of serpentine and chlorite (up to 90 %), accessory and rare minerals - talc, carbonate, tremolite, cromium-magnetite, amphibole, garnet, biotite, muscovite, kyanite, scapolite, potassium-feldspar, zircon and quartz. The microprobe analysis of the composition of minerals was performed with a REMMA-202M scanning microscope with a microanalyzer. The contents of petrogenic, rare and rare-earth elements are determined by the atomic absorption method and by the ICP-MS mass spectrometer. U-Pb age in zircon was obtained on microprobe SHRIMP II. The Nyashevo ultramafic rocks have variations of the content of SiO₂ from 38 to 42 wt % and of #Mg from 0.89 to 0.92, minor concentration of Al₂O₃ from 0.6 to 2.0 wt % and CaO from 0.3 to 2.8 wt %, increase contents Cr (550-2400) and Ni (800-2000 ppm), low - Ti (to 75), HSFE (6.0-117.4) и REE (∑ = 1.3-4.3ppm). Relatively high content Rb = 0.10-0.57, Sr = 3-42, Ba = 3-95 ppm and relation Ba/Sr = 0.4-7.7. The 1892 ± 23 Ma of zircons dating from ultramafic rocks of massif are the minimum age of the mantle substrate, probably is his restite. The appearance of pyrope-almandine ( Py_18-26 Grs_3-4) and almandine-grossular ( Py_6-8 Grs_54-57) garnets, high- aluminous and magnesian alumoenstatite (#Mg = 0.77) and spinel (#Mg = 0.72-0.75) in ultramafic rocks suggests formation-transformation occurred at Т = 900-1050°С и Р ≥ 9 kbar. The formations of Nyashevo massif is the age of the Late Ordovician (443 ± 12 Ma) and almost coincides with the maximum marks of age Buldym ultramafic alkaline-carbonatite massif. The Permian (275.8 ± 2.1 Ma) dating reflects the processes of serpentinization and scapolitization in ultramafic rocks and it correlated with the age parameters of zircons from late miaskites, carbonatites and pegmatites. Nyashevo mafic-ultramafic massif was formed in the deep zone of the Proterozoic continental rift, it undergone a multistage metamorphic transformation during decompression ascent in the lower crust and subsequent disintegration in regional post-collision shear zone.

Granitoid massifs of the northern part of the West Tagil structural-formational zone previously had not a reliable geochronological substantiation of age however, some of them are connected with skarn-magnetite deposits. One of such ones is the Yuzhno-Pomursky massif, to which the dedicated copper-iron ore deposit - Tretii Severnyi Rudnik. Authors performed the geological research of the massif, studied the composition of intrusive rocks, and accessory minerals of granitoids. There were determined the contents of petrogenic oxides and petrological-informative elements by ICP-MS; the age of magmatic rocks was determined by U-Pb LA-ICP-MS method in zircons and titanites. Using the microprobe SX-100 it was performed the analyses of the compositions of apatites, amphiboles, magnetites and ilmenites, feldspars and zircons. The studies showed that the Yuzhno-Pomursky massif consists of igneous rocks belonging to the two Silurian complexes - diorite-granodiorite Petropavlovsky and diorite-granite Severorudnichnyi. The characteristic of petrographic features and chemical composition of the intrusive formations is given, the data of their age is provided. The study of the evolution of the fluid regime that accompanied the crystallization of the melt, showed that in the early stages of the fluid has been enriched with chlorine, and the later - fluorine; so accordingly changed the metallogenic orientation of fluid-hydrothermal processes: from skarn-magnetite to gold and rare metal systems. In exocontact aureole of the massif are known ore manifestations and deposits of skarn copper-magnetite ores, mineralized gold-sulfide zones, some points with high content of tungsten. The conclusion about the possibility of the presence at the exocontact of Yuzhno-Pomursky massif not only copper-skarn-magnetite deposits similar to the known Tretii Severnyi, but the gold mineralized zones too is inferred.

There is a generalization of U-Pb age of zircons from the copper-porphyry deposits of the eastern slope of the Urals. Approved reserves of the largest ones are about 1.4-1.8 Mt of Cu (at an average content of 0.4-0.6 wt % of Cu). Porphyry mineralization is confined to the small massifs of quartz-diorite composition, localized exclusively within sub-meridional volcanic areas of island-type separated by sialic zones. U-Pb ages were determined by LA ICP-MS, Goethe University Frankfurt (Germany), by SHRIMP-II, VSEGEI (St.Petersburg, Russia) and by SHRIMP-IIe/mc, IBERSIMS, Granada University (Spain). In the South Urals lateral section from east to west (approximately 160 km) the age of some quartz diorite porphyry deposits decreased from D_1-2 (390 and 380 Ma, the Gumeshky and small Voznesensk deposits in Tagilo-Magnitogorsk Megazone) to D₂-C₁¹ (362 and 356 Ma, major Mikheyevsk deposit Tarutinsk deposit in the eastern part of the East-Ural volcanic megazone) and C₁² (336 and 335 Ma, Benkalinsk, Zhaltyrkol’sk deposits in Valeryanovka zone). In addition, in the western part of the East-Ural volcanic megazone (in Uvelka allochthonous tectonic structure) there are S_1-2 ore-bearing porphyry quartz-diorite massifs. They include the large industrial Tomino-Bereznyaki ore cluster with epithermal and porphyry mineralization (427-429 Ma) and of Zelenodolsk porphyric deposit (418 Ma) located at the distance of 25 km to the South. In indicated direction, ore specificity also changеs: Cu-(Au)- and Au-Cu-porphyric deposits are replaced by Cu-(Au, Mo)-porphyric ones. Within the Magnitogorsk zone from the early- to the late island-arc stage, the age of ore-bearing granitoids decreases (390, 381, 374 and 362 Ma), at that time their composition changes from diorite to shoshonite. Isotopic and petrogeochemical data suggest that considered island-type diorite is perhaps the result of selective melting of metabasalts of low crust or of depleted mantle (mantle wedge). This melting occurred repeatedly according to the displacement in time of its source from the west to the east of the Urals.

The subject of investigations were rodingites, whose outcrops were recently found inTaukha terrane of the Sikhote-Alin. The contents of the rock-forming oxides in rodingites were determined using the methods of chemical analysis as well as the gravimetry (SiO₂, H₂O, and Loi) and atomic-emission spectrometry with the induction-bound plasma at the iCAP 6500Duo spectrometer (Thermo Scientific Corporation, USA) (other oxides). The contents of the secondary elements were determined with the method of mass-spectrometry with the induction-bound plasma at the Agielent 7500 с spectrometer (Agielent Technologies, USA). Analyses of minerals were done using the JXA8100 microanalyser with three wave spectrometers and the INCAx-sight power-dispersion spectrometer. The contents of precious metals were determined with the atomic-absorption method. The paper presents the results of investigations of the geological conditions of occurrence, petrochemistry, geochemistry, and mineralogy of rodingites and the Au-Pd-Pt mineralization in them. The rock-forming minerals of rodingites of the Sikhote-Alin’ are pyroxene, garnet, vesuvian, epidote, prehnite, amphibole, chlorite, plagioclase, potassium-feldspar, apatite, zircon, titanite, and others. In rodingites of the Sikhote-Alin’ there were found the relatively high contents of Au, Ag, Pt, and Pd and the typical of such rocks “copper gold” and native forms and intermetallic compounds of diverse metals. The investigations carried out allowed the substantiation of the conclusion about the genetic relation of rodingites with the Paleocene ultrabasic-intermediate and alkaline-subalkaline complex of the Sikhote-Alin’. The rodingites were formed by metasomatic way on the basic and ultrabasic rocks of the vent and intrusive phases. They have preserved some geochemical characteristics of protoliths, in which they clearly differ from skarns with the boron, polymetal, and iron mineralization of the Dalnegorsky and Olginsky ore districts and from the contact-metamorphosed Triassic metal-bearing sediments of the Sikhote-Alin’. The Paleocene magmatic complex of the Sikhote-Alin’ is of a special interest because with it the precious-metal mineralization is genetically related that is localized not only in rodingites but also in other rocks of the Paleocene explosive structures and in the alluvium of the springs draining them.