At the beginning of the 1960s, a large body of funnel-shaped ore pegmatite composed of Cu–Ni sulfide ores and a gabbronorite matrix was discovered at the Nittis–Kumuzhya–Travyanaya ore vein field of the Northern Chamber of Monchepluton (Kola Peninsula). In terms of its localization conditions, size, structure, and enrichment in sulfides and platinum-group elements (PGEs), it is a unique formation that has no analogues among other Paleoproterozoic layered complexes of the Fennoscandian Shield. Ore pegmatite occurs in the upper part of the layered zone of Mt. Nittis, which is composed of harzburgites and orthopyroxenites. Its horizontal size is 9 × 16 m, and the vertical one is 15 m. Three zones are distinguished in the structure of the body: I, a core of continuous sulfides; II, coarse- and giant-grained gabbronorites, enriched in interstitial sulfides; and III, a contact zone with sideronite sulfides with gradual transitions into host orthopyroxenites. Petro- and geochemical, mineralogical, and isotope studies of rocks and ores were performed using modern analysis methods. Ore pegmatite is most recent product in the processes of fractional crystallization of a magmatic melt, which derived as a large schlier with a sulfide core and a silicate matrix with a high concentration of fluids. The hypsometric level of the termination of the melt upwelling was determined by the equilibrium of the internal pressure of the volatiles and the external pressure of the overlying rocks. The δ18O values (+4.9…+6.1‰) are close to mantle marks (δ18O = +5.7‰) that correspond to basic igneous rocks. Early, late, and postmagmatic stages of mineral formation with a consistent increase in the role of fluid components (H2O, CO2, Cl, F) are distinguished in the formation history of the ore pegmatite. According to the results of calculations performed using various mineral geothermometers, the melt crystallization at the magmatic stage occurred in the range of ∼1100–900°C at a pressure of about 5 kbar. The separation (liquation) of the immiscible sulfide liquid began at temperatures of 1100–1000°C. As the temperature decreases, the main silicate minerals (clino- and orthopyroxenes, plagioclase) were first to crystallize. In the interstitial space between these minerals, residual melt and sulfide liquid enriched in PGEs, Au, Ag, and chalcophile elements (As, Sn, Sb, Te, Bi, Pb, Zn) accumulated. A late magmatic association (pargasite, magnesian hornblende and phlogopite) was formed from the residual melt. During the cooling of the sulfide liquid to a temperature of ∼1000°C and below, a copper-bearing monosulfide solid solution (Mss) is detached. As a result of its solid-phase transformations, pyrrhotite, pentlandite, and chalcopyrite were formed. An intermediate solid solution (Iss) was formed from the residual sulfide liquid, which was enriched with Cu and noble metals. Under a temperature below 550°C, this solution was successively decomposed into chalcopyrite, pyrrhotite, and cubanite. The dominant PGE minerals are the following: michenerite PdBiTe, sobolevskite Pd(Bi,Te), froodite PdBi2, merenskyite PdTe2, and moncheite PtTe2. Au and Ag minerals are represented by electrum (AuAg) and hessite (Ag2Te). A rare mineral—cervelleite (Ag4TeS)—has been discovered. The Pd content in ore pegmatite varies in the range of 64.13–0.09 ppm, and that of Pt in the range of 2.70–0.004 ppm. The ore potential of Monchepluton is far from exhausted. Therefore, clarifying the genetic features of the origin of ore pegmatites and their connection with copper–nickel mineralization is of not only petrological, but also important practical significance, including for the purpose to develop prospecting indicators for the vein type of PGE–Cu–Ni ores.

At the beginning of the 60s of the last century at the Nittis-Kumuzhya-Travyanaya (NKT) ore vein field of the Northern Chamber of Monchepluton (Kola Peninsula), was discovered a large body of funnel-shaped ore pegmatite, composed of Cu-Ni sulfide ores and a gabbronorite matrix. In terms of localization conditions, its size, structure, enrichment in sulfides and PGE, it is a unique formation that has no analogues among other layered complexes of the Paleoproterozoic age of the Fennoscandian shield. Ore pegmatite occurs in the upper part of the layered zone of Nittis mont., composed of harzburgites and orthopyroxenites. Its horizontal size is 9 × 16 m, vertical – 15 m. Three zones are distinguished in the structure of the body: I – core of continuous sulfides, II – coarse- and giant-grained gabbronorites, enriched in interstitial sulfides, and III – contact zone with sideronite sulfides with gradual transitions into host orthopyroxenites. Petro- and geochemical, mineralogical and isotope studies of rocks and ores were performed using modern analysis methods. Ore pegmatite is most recent product in the processes of fractional crystallization of a magmatic melt, which separated in the form of a large schlier with a sulfide core and a silicate matrix with a high concentration of fluids. The hypsometric level of melt stop was determined by the equilibrium of the internal pressure of the volatiles and the external pressure of the overlying rocks. The δ18O values (+4.9–+6.1‰) are close to mantle marks (δ18O = +5.7‰) and correspond to basic igneous rocks. In the history of the formation of the ore pegmatite, early magmatic, late- and post-magmatic stages of mineral formation with a consistent increase in the role of fluid components (H2O, CO2, Cl, F) are distinguished. According to the results of calculations performed using various mineral geothermometers, crystallization of the melt at the magmatic stage occurred in the range of ~1100–900оC at a pressure of about 5 kbar. At temperatures of 1100–1000оC, separation (liquation) of the immiscible sulfide liquid began. As the temperature drop, the main silicate minerals (clino- and orthopyroxenes, plagioclase) initially crystallized, in the interstices of which residual melt and sulfide liquid enriched in PGE, Au, Ag and chalcophile elements (As, Sn, Sb, Te, Bi) accumulated, Pb, Zn). A late magmatic association (pargasite, magnesian hornblende and phlogopite) was formed from the residual melt. When the sulfide liquid cooled at a temperature of ~1000оC and below, a copper-containing a monosulfide solid solution (Mss) separated from it. As a result of its solid-phase transformations, pyrrhotite, pentlandite, chalcopyrite, precious metal minerals and an intermediate solid solution (Iss) were formed, which at temperatures below 550оC successively decomposed into chalcopyrite, pyrrhotite and cubanite. The dominant PGE minerals are: maychenerite PdBiTe, sobolevskite Pd(Bi,Te) frudite PdBi2, merenskite PdTe2 and moncheite PtTe2. Au and Ag minerals are represented by electrum (AuAg) and hessite (Ag2Te). A rare mineral in nature – servelleite (Ag4TeS) – has been discovered. The Pd content in ore pegmatite varies in the range (64.13–0.09 ppm), Pt – (2.70–0.004 ppm). The ore potential of Monchepluton is far from being exhausted, therefore, elucidating the genetic features of the origin of ore pegmatites and their connection with copper-nickel mineralization is not only petrological, but also of important practical significance, including to develop search signs on the vein type of PGE–Cu–Ni ores.

Model calculations were used to estimate the compositions of melts during fractional crystallization corresponding to the formation of the Malyi Zadoi massif, which is located in the Irkut block of the Sharyzhalgai uplift in the southwest of the Siberian craton. It is shown that the gabbronorites of the massif are comagmatic to the plagioperidotites and olivine gabbronorites. The estimates obtained for the composition of the model melts are used to characterize the composition of the mantle source of the parental melt. The geochemical characteristics led us to suggest that the parental melt of the Malyi Zadoi massif was formed by melting an enriched source, a conclusion consistent with isotope data that indicate that the mantle Sm/Nd ratio decreased in the Archean. The probable source of the parental melt could consist of depleted lithospheric mantle material metasomatized by felsic melts coming from rocks of a subducting oceanic plate.

The Lysan alkaline–ultramafic complex is located in the Sisim shear zone at the contact of the two largest tectonic structures of the accretion–collisional belt in the southwestern frame of the Siberian craton. Intrusions of the complex consist of ore-bearing olivinites, kaersutite clinopyroxenites, and banded kaersutite gabbro, which have been «cut» by albitite dykes and veins. The veins and veinlets of the carbonate rocks are mainly associated with the albitites. The present paper represents the first detailed mineralogical study of carbonate rocks and albitites in the Podlysansky Massif of the Neoproterozoic Lysan alkaline–ultramafic complex. The mineral composition was determined in situ in a polished section by scanning electron microscopy, energy dispersive spectrometry, and electron probe microanalysis. The carbonate rocks of the Podlysan Massif have been found to contain minerals that are typical of siderite–carbonatites (senso stricto), including calcite, siderite, phengitic muscovite, apatite, monazite, REE fluorocarbonates, pyrite, and sphalerite. These rocks are enriched in light rare earth elements due to the presence of monazite-(Ce), bastnäsite-(Ce), parisite-(Ce), and synchysite-(Ce). The albitites were formed as a result of the fenitization of leucocratic gabbro by alkali-rich carbo-hydrothermal fluids in zones of intense development of tectonic fractures. Infiltration was the dominant mechanism of fenitization. The obtained data significantly enhance the current understanding of the geochemical and ore specialization of rocks in the Lysan Complex.

ABSTR A C T Several published Mesoproterozoic paleogeographic reconstructions suggest proximity of northern Laurentia and southern Siberia. However, the apparent absence of the traces of the ca. 1.27 Ga giant Mackenzie magmatic event in southern Siberia was somewhat contradictory to this hypothesis. Here we present geochronological, miner-alogical, geochemical, Nd isotopic, and paleomagnetic data from the Srednecheremshansk dyke-shaped intru-sion, which was recently found in the Sharyzhalgay uplift of the southern part of the Siberian craton and which can be related to the Mackenzie event. The plagioclase-bearing peridotite of this intrusion yielded U-Pb (ID-TIMS) baddeleyite concordia age of 1260 +/- 3 Ma, which is interpreted as the time of their emplacement. This age is close to the previously published baddeleyite age of gabbro from the same intrusion (1258 +/- 5 Ma). The Srednecheremshansk intrusion is composed of ultramafic and mafic rocks. The main rock-forming minerals of the intrusion are olivine, orthopyroxene, clinopyroxene, phlogopite, and plagioclase in various proportions. Sulfide mineralization of the intrusion is represented by pentlandite nodules. The chemical composition of Sredne-cheremshansk ultramafic and mafic rocks correspond to subalkaline peridotite gabbro and gabbro. These rocks are characterized by negative epsilon Nd(t) values range from-6.3 to-6.9. Ultramafic and mafic rocks have similar geochemical and isotopic characteristics, indicating their generation from a single subcontinental lithospheric mantle source. The chemical composition of the Srednecheremshansk intrusion is similar to those of the ca. 1.27 Ga Muskox mafic-ultramafic intrusion of the Mackenzie Large Igneous Province in northern Laurentia. Paleo-magnetic data permit a variety of possible Laurentia-Siberia reconstructions in Mesoproterozoic. The combina-tion of geochronological, geochemical, and paleomagnetic data allows the relation of the Srednecheremshansk intrusion with the Mackenzie magmatic event.

Mineralogical and geochemical study of the gabbro-peridotite sills located in the near-bottom part of the Yoko-Dovyren stratified massif among the host terrigenous-carbonate rocks showed that the thickуые (200–250 m) of them are differentiated from plagiolherzolites to olivine gabbronorites. Their formation is well described by fractional crystallization of the picrobasalt melt. When it entered the crystallization chamber, it had already contained some intratelluric crystals of high-magnesian olivine (up to 93 % Fo). The rock crystallization occurred in the temperature range 1234–985 °C at pressure 1.3–1.6 kb, corresponding to depth ~5–6 km. The calculated depth of separation of the initial melt from the mantle source was ~88 km, which corresponds to the lithostatic pressure ~28 kbar. In terms of geochemical parameters, the composition of the initial melt is characterized by dual nature: they are close to both the basalts of suprasubduction magmatism and the basalts of collisional volcanic-plutonic areas. We assume that formation of the Synnyr rift with the Dovyren intrusive complex is due to the destructive development of scattered spreading zones at the collisional-accretionary stage of the Baikal-Muya belt within 720–800 Ma.

This paper presents new ideas about the formational identity, as well as the first data on the age of formation of rocks within the Lysan intrusive complex located at junction of the Derbin block and the Sisim-Kazyr zone of the Central Asian folded belt. The study identified the similarities between the Lysan complex and intrusions of the alkaline-ultrabasic formation. It formed during the period of maximum intraplate activity along the edge of the Siberian craton.

The study is focused on metapelitic granulites of Cape Kaltygei (Western Baikal region) that contain a diagnostic mineral assemblage of ultrahigh temperature (UHT) metamorphic rocks (orthopyroxene+sillimanite+quartz). The pseudosection-based thermobarometry yields peak metamorphic temperature and pressure values (T=950 °C, P=~9 kbar) and suggests near-isobaric cooling (IBC) conditions during the retrograde evolution of the granulites. The U/Pb zircon age estimates for metamorphism (~1.87 Ga) support the data published by other researchers. The SHRIMP-II U-Pb dating of zircon cores yields a minimum protolith age of 1.94–1.91 Ga. Biotites and amphiboles from granulites of Cape Kaltygei show the 40 Ar/ 39 Ar isotopic ages that are close to the Early Paleozoic accretion-collision system of the Western Baikal region.

The relevance. The deposits of two formation types (apohyperbasire and apocarbonate) were discovered in the jade province of Siberia, the largest in Russia. Their bodies are usually formed on the contact of serpentinized rocks and dolomite marbles with the aluminisilicate rocks. It is necessary to identify the genetic differences in jade of various formational accessories that allows making a conclusion on the sources of the fluid phase and answering the actual question about the oxygen source in the minerals forming the jade.The main aim of the research is to justify the physiochemical conditions of jade formation with the help of a critical summary of the world's material on the geochemistry and petrology of jade.Objects: Kavoktinskoe deposit of apocarbonate jade and Osipinskoe deposite of apohyperbasite jade.Methods. Chemical composition of the rocks was determined by photometric, atomic absorption, potentiometric and flame photometric methods. Trace element analysis was done by inductively coupled plasma mass spectrometry. The isotopic compositions of oxygen and carbon were analyzed by laser fluorination, and carbon and oxygen in carbonates - by the method of decomposition with orthophosphate acid. The isotopic composition of hydrogen in hydroxyl-containing minerals was determined by the method of Vennemann, O'Neil.Results. It was found that apogiperbasitic jades were formed under the influence of magmatic and metamorphic fluids released during the deserpentization of rocks; and in apocarbonate jade occurrences, the fluid is meteoric water saturated with carbon dioxide formed during decarbonization of dolomite. The order of formation of mineral paragenesis during the expansion of metasomatic zonation on the contact of rocks of various compositions was considered. It was shown that the uniformity of the mineralogical types of jade of a various genesis depends on composition of the hydrothermal solution, and P-T conditions of the process. Apocarbonate jade belongs to the low-temperature facies of magnesian skarns by the mineral paragenesis. As a result, the following metasomatic zoning is formed: dolomite marble - calcite marble with jade - tremolite skarn - pyroxene - amphibole - clinocyoisite skarn - amphibolites. The deposits of apohyperbasite jade have the different metasomatic zonality: microantigorite serpentinite - tremolithite - jade - tremolite - quartz-diopside-clinocyosite rhodingite - cyosite-amphibole rock. The temperature varies in the range of 300-450 degrees C, the pressure is 2000-3000 bar. These data allow us to create a model that properly describes the characteristics of the physicochemical processes of both apocarbonate and apogiperbasitic jade formation.

The study is focused on metapelitic granulites of Cape Kaltygei (Western Baikal region) that contain a diagnostic mineral assemblage of ultrahigh temperature (UHT) metamorphic rocks (orthopyroxene+sillimanite+quartz). The pseudosection-based thermobarometry yields peak metamorphic temperature and pressure values (T=950 °C, P=~9 kbar) and suggests near-isobaric cooling (IBC) conditions during the retrograde evolution of the granulites. The U/Pb zircon age estimates for metamorphism (~1.87 Ga) support the data published by other researchers. The SHRIMP-II U-Pb dating of zircon cores yields a minimum protolith age of 1.94–1.91 Ga. Biotites and amphiboles from granulites of Cape Kaltygei show the 40Ar/39Ar isotopic ages that are close to the Early Paleozoic accretion-collision system of the Western Baikal region.

Composition variations of Cr-spinel in high-Mg rocks of the Primorsky Ridge (Western Baikal region, Russia) are reported here. A specific feature of Cr-spinels in ultramafic rocks of the Primorsky Ridge is their noticeably high Ti content (up to 6.5 wt.%) compared to spinels in mantle peridotites. The presence of high TiO2 content in Cr-spinels enclosed in olivine crystals may be a clear indication of the primary magmatic nature of Ti enrichment. Two types of Cr-spinel were identified in ultramafic rocks from all intrusions. Cr-spinels of Type I are enclosed in the inner part of olivine crystals and are homogeneous Al-rich chromites and Fe2+-rich chromites. They are characterized by variable content of TiO2 (1.0–5.3 wt.%), moderately high Cr# (0.7–0.83), and low Fe3+# (0.20–0.34). Cr-spinels of type II occur in the interstitial space and occur as homogeneous and zoned grains with Al-rich chromite and Fe2+-rich chromite cores. Al-rich chromite cores have a composition similar to that of the Cr-spinel enclosed in olivine crystals. Fe2+-rich chromite cores have relatively high MgO (3.8–6.2 wt.%), Al2O3 (8–9 wt.%), and TiO2 (2.6–2.8 wt.%) content, low MnO (0.34–0.52 wt.%) content, and a low Fe3+# (0.25–0.27) ratio.

Re sulfides were discovered in Cu–Ni–platinum-group elements (PGE) ores of the Zhelos and Tokty-Oi intrusions. These intrusions can be considered as products of the mantle superplume responsible for Rodinia’s break-up. The mineral compositions were determined in situ in polished samples. Electron microprobe analyses were mostly consistent with a general formula of (Cu,Fe,Mo,Os,Re)5S8, (Cu,Fe,Mo,Os,Re)4S7, and (Cu,Fe,Mo,Re)S2. One of the major features of Re sulfide from the Zhelos intrusion is its high osmium content. The ΣMe/S ratio for a part of our data is consistent with that of the tarkianite. Re sulfides from the Tokty-Oi have a ΣMe/S ratio similar to those in rheniite or dzeskazganite, but differ from them by the presence of Fe and Cu and the metal-to-metal ratio. The localization of the Re sulfide within the chalcopyrite suggests its crystallization from the residual Cu-rich liquid.

—We present results of study of sulfide ore occurrence in highly metamorphosed (granulite facies) Archean rocks of the Siberian craton basement. The host rocks and ore minerals are briefly described, and new data on the multiple sulfur isotope (δ33S, δ34S, Δ33S) composition of sulfides are presented. Application of high-resolution analytical methods enabling the assessment of the sulfur isotope behavior in situ made it possible to reveal mass-independent fractionation of sulfur isotopes in the rock samples. The isotopic composition of sulfur in the sulfides indicates its inflow from several sources, including the ancient Archean atmosphere, where primary sulfur has passed through a cycle of fractionation. Despite the high-gradient metamorphism, the subsequent ultrametamorphic and post-ultrametamorphic transformations accompanied by a change in the primary mineral composition of rocks and by chemogenic fractionation of sulfur, the signature of the sedimentary source of sulfur in sulfide ores has been well preserved. Analysis of the chemical composition of rocks and ore minerals and of sulfur isotopes has led to the conclusion that the studied rocks are metamorphosed Late Archean analogs of black shales and the sulfide mineralization is of stratiform pyrite type.

We study the behavior of a number of siderophile elements, including platinum-group elements, during the formation of the Medek dunite-wehrlite intrusion. Its structural position, internal structure, and mineralogical composition are presented; a 3D geochemical model is constructed. The forsterite content of olivine varies from 90 to 73% from top to bottom of the vertical cross section of the intrusion. In addition, there is a decrease in the volume content of olivine and the appearance of ilmenite instead of accessory Cr-spinel. The observed zonation in variations in the composition of rocks and minerals is consistent with magmatic differentiation in a sheet-like body, which changed its primary occurrence. A geodynamic scenario is proposed, which links the formation of the intrusion with the break-up of Rodinia and the further changes in the primary occurrence with subsequent accretion-collision events on the southern and southwestern margins of the Siberian craton in the period 600-450 Ma. (C) 2018, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All right reserved.

We report data on the geology, mineralogy, petrography, and chemistry of 733 Ma gabbro-peridotite sills from the Late Riphean Dovyren plutonic complex. Thick sills were differentiated into plagiolherzolite to olivine gabbronorite compositions by fractional crystallization of the K-Na series high-Mg low-alkali low-Ti picritic parental magma. The magma already contained up to 5% of intratelluric olivine crystals when entering the reservoir. The sills emplaced before the whole complex, judging by the presence of their fragments as plagiolherzolite xenoliths in the gabbro zone of the Yoko-Dovyren layered pluton. The gabbro-peridotite sills are products of high-temperature within-plate magmatism. High heat flow during the generation of the magma, evident from its high-Mg composition, was likely maintained by the activity of a mantle plume associated with the Neoproterozoic Franklin large igneous province. (C) 2018, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.

The mechanism for obtaining high-resolution X-ray images according to the scheme with a direct geometric increase in objects of imaging is described. The basis of the mechanism for obtaining pseudovolumetric images is given, which allows obtaining additional information on the relative position of the parts in the object. A model of a robotic installation is described that allows to realize the considered survey schemes and to carry out tomographic studies.

In the Chernorud granulite zone in the Olkhon region of West Pribaikalie, we studied gabbro‐pyroxenites composing tectonic plates (Chernorud, Tonta) and synmetamorphic intrusive bodies (Ulan‐Khargana), as well as nu‐ merous disintegrated boudins and inclusions embedded in the metamorphic matrix. Based on the results of compara‐ tive analysis of the chemical compositions, the gabbro‐pyroxenites are classified into a single island‐arc tholeiitic se‐ ries. The COMAGMAT software was used to simulate this series and to estimate the initial composition of the parent magma (magnesian basalt: SiO2=46.0 wt. %, TiO2=0.8 wt. %, Al2O3=15.3 wt. %, ΣFeO=9.0 wt. %, MnO=0.15 wt. %, MgO=10.5 wt. %, CaO=17.0 wt. %, Na2O=1.0 wt. %, K2O=0.2 wt. %, P2O5=0.05 wt. %, total = 100.0 %, Mg# = 67.5 %). It is concluded that the granulite metamorphism (P=7.7 to 8.6 kbar, T=770 to 820 °C) was due not only to dipping of the initial sedimentary‐volcanic series to a depth of 25–28 km, but also to the presence of a deep chamber of magnesian basalt magma. In our estimations, garnet‐pyroxenites (i.e. mafic rocks of the top facies in the above‐mentioned cham‐ ber) originated at P=8.0–8.3 kbar and T=900–930 °C. Considering petrology, the deep mafic chamber under the layer of granulite facies is evidenced by metamorphic magma mingling, as well as pipe‐shaped intrusions characterized by the specific morphology, internal structure and bulk rock compositions. Based on the data on the Ulan‐Khargana mas‐ sif and gabbro‐pyroxenite bodies involved in the structure of the marble melange, we propose a petrological model showing two stages of mafic injection – Stage 1: hydraulic fracturing of granulite series and the emergence of tubular structures and bodies, which are similar to kimberlite pipes or channels of different shapes; Stage 2: rising of the flu‐ idized residual alkaline melt through the emerging ‘pipes’ and fractures armored by hardened zones, which is fol‐ lowed by metamorphic magma mingling under viscous deformation conditions. The mafic magmas intruding to the level of the granulite facies facilitated the deep anatexis and formation of synmetamorphic hypersthene plagiogranites (U‐Pb isotope dating: 500–490 Ma) and high‐K stress granites. In the Chernorud granulite zone, intense ductile‐plastic and brittle‐plastic deformations accompanied the processes of metamorphism, intrusion and formation of gabbro‐ pyroxenites and the anatexis of the crustal substance. As a result, the intrusive bodies were fragmented, and specific tectonic structures termed ‘metamorphic magma‐mingling’ were formed. All the tectonic and magmatic structures were subsequently ‘sealed up’ by K‐Na synkinematic granites at the regressive stage under conditions of the amphibo‐ lite‐facies metamorphism (U‐Pb and Ar‐Ar isotope dating: 470–460 Ma).

This study aims at summarizing available geological and geochemical data on known Proterozoic platinum-bearing ultramafic-mafic massifs in the south of Siberia. Considering new data on geochemistry and geochronology of some intrusions, it was feasible to compare ore-bearing complexes of different time spans and areas and to follow their relationships with the recognized large igneous provinces. In the south of Siberia, the platinum-bearing massifs might be united into three age groups: Late Paleoproterozoic (e.g., Chiney complex, Malozadoisky massif), Late Mesoproterozoic (e.g., Srednecheremshansky massif), and Neoproterozoic (e.g., Kingash complex, Yoko-Dovyren massif, and massifs in the center of the East Sayan Mts.). In most massifs but Chiney the initial magmas are magnesium-rich. On paleogeodynamic reconstructions, the position of the studied massifs is the evidence that three most precisely dated events in North Canada continued into southern Siberia: In the period 1880-1865 Ma, it was the Ghost-Mara River-Morel LIP; at 1270-1260 Ma, the Mackenzie LIP; and at 725-720 Ma, Franklin LIP. In Siberia, the mostly productive massifs with respect to PGE-Ni-Cu mineralization are those linked with the Franklin LIP: Verkhny Kingash, Yoko-Dovyren, and central part of the Eastern Sayan Mountains, e.g., Tartay, Zhelos, and Tokty-Oy. (C) 2016, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.