The content, preparation procedure and predictive-mineragenic component of the 1:2.5 M Map of distribution patterns of copper-gold-porphyry deposits in Russia, first compiled based on summarizing the results of work on compiling sets of State geological maps of the Russian Federation at a scale of 1:1 M, the 3rd generation are discussed. The Map has been prepared from 2017 to 2019 as part of the International project «Deep Structure and Metallogeny of Northern, Central and Eastern Asia». The Map is designed in the form of a GIS project (in ArcGIS 10.2) and includes as thematic “layers” geological, hydrothermalmetasomatic, geochemical, cosmostructural, geophysical and other criteria, represented on relevant specialpurpose geological maps, scale 1:2.5 M. The Map reflects the location of 297 ore and potentially ore clusters, including 205 clusters in the Russian Far East, promising for the discovery of ore mineralization of the goldcopper-porphyry type. The article provides recommendations on the direction of further exploration aimed at forecasting gold-copper-porphyry deposits.

Analysis of recent seismic materials resulted in the step-by-step reconstruction of the history of formation of the Eurasian Basin, the Arctic Ocean was performed. It is shown that according to geological and seismic data, the Eurasian Basin formed long before the beginning of spreading postulated by magnetostratigraphy, approximately 60–120 Ma earlier. In the part of Amundsen basin adjacent to the Laptev Sea, in the southern part of the Lomonosov Ridge, and the Eastern Lomonosov Basin, the sedimentary cover has appeared from the Aptian, overlapping the Late Cimmerian folded basement. It is quite possible that from the Taimyr Peninsula and Barents-Kara margin, the age of basal horizons of the cover is older, Jurassic – Early Cretaceous. The Miocene-Quaternary age of the Gakkel Ridge was established. Multi-age folded complexes of the Taimyr and Laptev Sea Shelf continuing into the ocean, as well as numerous protrusions which supplied subcrustal material to the cover and the basement have been identified in the acoustic basement of the Eurasian Basin adjacent to the Laptev Sea. These facts indicate the continental type of the crust in this part of the Eurasian Basin, which was subjected to the processes of scattered spreading and the initial stage of basification of the earth’s crust. The closest analog similar in age and morphology to the Eurasian Basin is the Red Sea region.

The origin and redistribution of U isotopes in the aquifer of Vendian sandy-clay deposits of a paleo-valley in northwestern Russia is described. Chemical weathering of Vendian deposits led to the formation of a thick oxidation zone developed above 250 m.b.s.l. The inverse correlation between U and Fe concentrations is a result of U removal from paleo-valley slopes under oxidizing conditions and its accumulation on the bottom under reducing conditions, and accumulation of Fe on the slopes and its removal from the bottom. Accordingly, the groundwater near the redox barrier is characterized by the highest U concentration and the activity of the 234U isotope that handicaps their use for drinking and medicinal purposes. Radiologically, the groundwater located near recharge zones is the safest.

The results of studying distribution patterns of trace elements (REE + Y, Hf, U, Th, Pb) in zircons from magmatic rocks of the Malmyzh and Pony Cu-Au porphyry ore fields based on geochemical SIMS measurements of zircons are discussed in the paper. Trace elements contents in zircons were determined at the same spots in which isotopic age of crystallization was measured by SIMS U-Pb method (SHRIMP II). ∑REE content in zircons from the Malmyzh granitoids varies from 217 to 1158 ppm, Y – from 718 to 732 ppm, Hf – from 4524 to 4928 ppm, Pb – from 1.2 to 1.6 ppm, U – from 89 to 112 ppm, Th – from 58 to 76 ppm. Geochemical characteristics of zircons from the Pony monzodiorite-porphyry are strongly differing from the Malmyzh granitoid zircons. Concentrations of most trace elements in the Pony zircons, especially LREE and MREE, as well as Y, Pb, U and Th are of two-three times higher than in zircons from the Malmyzh granitoids. Assessment of magmatic rocks fertility from the Malmyzh and Pony ore fields based on geochemical characteristics of zircons was carried out using Eu/Eu* vs. Dy/Nd and Eu/Eu* vs. (Ce/Nd)/Y plots. Analysis of these plots shows that zircons from the Malmyzh granitoids fall into the field of fertile porphyry systems whereas zircons from the Pony monzodiorite-porphyry fall into the field of barren suites. This result can be utilized during prognostic and metallogenic considerations not only within the limits of Sikhote-Alin territory but also within the whole Russian Far East region

Results of predictive assessment of gold-copper-porphyry mineralization based on combine approach to studying and mapping petrographic and geochemical characteristics of hydrothermally altered rocks within the Ryabinovoe ore field are discussed. It was established that emplacement and subsequent evolution of the Rybinovy alkaline stock were accompanied by the formation of hydrothermal-metasomatic zonation of plutonogenic type. The zonation is represented by haloes of aegirine feldspathitic and gumbeitic alteration within inner parts of the stock and by haloes of skarnification, fenitic and propylitic alteration in near-intrusion space. Main petrochemical and geochemical characteristics (specialization) of both wallrock metasomatite and weakly/moderately hydrothermally altered rock are recognized. It was indicated that gumbeitic alteration haloes in combination with positive multiplicative geochemical anomalies of AuAgCuBi, BaMoPb and AsSbHg composition could be used as main criteria for the prediction of gold-copper-porphyry ore mineralization within the Ryabinovoe ore field. The article provides recommendations on geological exploration within the located prospects.

Results of studies of Proterozoic gabbrodolerite intrusions of Motko (2274 ± 3 Ma) and Kuolisma (1960 ± 2 Ma) in Central Karelia are reported. A brief description of their geological structure, degree of differentiation and rock composition is given. It is shown that noble metal mineralization is spatially combined with titanomagnetite horizon and associated with the formation of copper-sulfide mineralization. Platinum group metal minerals are mainly represented by palladium and platinum bismuthotellurids, arsenids and stibioarsenids with kotulskite and sperrylite being dominant. Chalkopyrite, bornite and chlorine-containing (up to 5.5 %) ferrogastingsite are indicator minerals of noble metal mineralization. Ore occurrences can be economically significant after additional appraisal.

Information is given on the possibility of using thorium in domestic nuclear power industry that makes the problem of identifying and studying thorium deposits urgent. Features of thorium geochemistry and mineralogy, the genesis and formation epochs of thorium-oriented geological rock associations, as well as the petrological composition and geology of a number of important thorium-bearing targets with complex ores are discussed. Their classification based on studying ore formations of the domestic metallogenic school and the IAEA is proposed. Examples of ore deposits of major geological and economic types are given. Lines for further studies are recommended.