Abstract The paper is dedicated to gas hydrate fields and active underwater gas seeps found in the Sea of Okhotsk. The study of geological conditions of the generation and dissociation of gas hydrates and their relations with methane fluxes is of great importance both for the Sea of Okhotsk and for understanding these processes in the World Ocean. The paper reports data on the distribution of natural

Abstract The paper presents the results of multidisciplinary studies in the carbonate–barite mineralization area revealed on the western slope of the Kuril deep-water basin in the Sea of Okhotsk. Findings of carbonate concretions and barite in different age (Miocene–Holocene) deposits indicate that the bottom of this area hosted a long-lived center of gas–fluid emanations over several million years

Abstract Oil- and gas-bearing reefs are widespread in the Paleozoic of ancient (North American, East European, and Siberian) platforms. Two main types of reefs have been identified according to their morphology and paleogeographic position. Single isolated reefs formed in the setting of more or less deep-water reservoirs represent relatively symmetric (in cross-section), dome-type (pinnacle reefs)

Abstract A comparative analysis of the composition and structure of the surface facies of carbonatite weathering crusts (profiles) in the Chuktukon (Russia) and Seis Lagos (Brazil) deposits and ultra-rich rare metal ores in the Tomtor deposit (Russia) is presented. It is shown that the main geochemical trends in the formation of the Tomtor-type ultra-rich rare metal ores and the surface facies of weathering

Abstract A model of the Ba geochemical cycle in the ocean is discussed based on a few own and published data. Barium ion reacts with the sulfate ion in various fluids (pore water, gas–liquid and methane-bearing cold solutions, hydrothermal sulfate–sulfide solutions of rift zones) to form the poorly soluble diagenetic barite. Based on the Ba distribution in the water column, one can judge the value

Abstract The article analyzes the position of individual and average data points of the Archean and Early Proterozoic metaaleuropelites (Isua and Akilia associations, West Greenland; Beit Bridge Complex, Limpopo Province, South Africa; Moodies, Mozaan, and Pretoria groups, Barberton Mountain Land, South Africa; Kola Group, Baltic Shield, Russia; Nurmes paragneisses, Eastern Finland; Onot greenstone

Abstract New data were used to analyze the distribution of polycyclic aromatic hydrocarbons (PAH) in the lithological complex and soils of the Siljan impact crater area (Scandinavian Shield, central Sweden). Ten individual unsubstituted PAHs were identified, including diphenyl, fluorene, phenanthrene, anthracene, pyrene, chrysene, fluoranthene, benzo[a]anthracene, benzo[a]pyrene, benzo[ghi]perylene

Abstract The chemical and isotopic compositions of manganese carbonate and oxide ores and host dolomites of the Porozhinsk deposit are studied. Manganese carbonates are characterized by low values of δ13C (–19.0 to –8.4‰, PDB) and δ18O (8.8 to 27.3‰, SMOW). These data indicate the participation in their formation of the isotopically light carbon from oxidized organic matter, and the water of ore-depositing

Abstract Vietnam is a country with diverse and abundant mineral resources with nearly 5000 mines and ore spots of about 60 different minerals. Mining and processing of mineral resources have contributed about 9.6–10.6% of the country’s GDP since the year of 2000. However, the exploitation and processing of mineral resources have been leading to a certain soil and sediment contamination by heavy metals

Abstract The typomorphism and chemical composition of garnets and zircons were studied in the Pechora (Dnieper) and Vychegda (Moscow) Middle Neopleistocene moraines in the Laya and Vychegda river valleys of the northern and southern Timan–Pechora–Vychegda region, respectively, to substantiate a detailed subdivision and correlation of Quaternary sections. The moraines contain garnets of two color groups:

Abstract Platform carbonate formations in various climate zones differ with respect to not only composition and structure of the composing rocks and but also the internal structure of rock sequences. Rock formations in humid zones are composed mainly of the biomorphic and bioclastic limestones. Vertical sections of formations are relatively heterogeneous. The composition and structure of formations

Abstract This paper addresses for the first time the internal structure of lens 2 of the Shulepovo refractory clay deposit. The SEM study of representative samples from the entire lens section revealed relationships between the major minerals: kaolinite, halloysite, illite, and quartz. The lens was previously considered homogeneous, but its detailed study revealed a clear internal zonality. The structural

Abstract The paper presents the mineral and chemical compositions of carbonate, metalliferous, and ore-bearing sediments developed within the Pobeda ore cluster based on the materials of stations 37L244g, 37L245g, and 37L184k by the chemical, optical, electron microscopic, electron probe, and X-ray methods. The compositions are compared with those of background biogenic carbonate sediments developed

Abstract Altered ash tuff and tuffite layers in the Jurassic–Cretaceous boundary rocks (Bazhenovo Formation) were studied in detail. These layers represent an interval ranging from the upper part of the middle Volgian substage to the uppermost Ryazanian and cover a huge area (more than 400 000 km2). Despite small thickness (10–3–10–2 m), these layers are prominent in borehole cores and correlated confidently

Abstract In the lower part of Upper Vendian deposits on the East European Platform, packs of chocolate-brown clayey rocks/tuff-argillites containing intercalations of volcanic tuffs (products of acid volcanism) are widespread. Upper Riphean–Vendian sections on the western slope of the Middle and Southern Urals include packs of the red-colored clayey rocks. Among them, volcanic tuffs (clay-type rocks)

Abstract Studying with precision methods the mineral composition of bauxites in the Kursk Magnetic Anomaly (KMA) made it possible to reevaluate the conditions of their formation. Occurring among Early Proterozoic jaspilites in the Belgorod ore region, they are confined to the upper part of the Early Carboniferous lateritic weathering profile on the biotite–muscovite schists. The northern part of the

Abstracts The results of studying the material composition of sandy rocks from Cenozoic deposits in the West Sakhalin Terrane are considered. It has been established that sandstones in the terrane correspond to graywackes and petrogenic (“first cycle”) rocks. They are characterized by a low maturity degree of the detrital material formed mainly due to the mechanical destruction of source rocks. Paleogeodynamic

Abstract A new reference section of the Okhotsk seaside of Kamchatka in the Mitoga 2 River area is studied and dated for the first time (14C and 230Th/U). Sedimentary deposits were correlated with the previously known sections in the Khomutina‒Mitoga interfluve. It has been established that the sequence of “gray silts and clays” represents deposits of a large lake-type estuary, which began to swamp

Abstract Although the characterization of depositional conditions of Vendian sedimentary successions in the northwestern, central, northern, northeastern and eastern parts of the East European Platform is available at present, issue of the types of catchment areas and the ratio of crystalline complexes, sedimentary, and metasedimentary sequences therein remains somehow debatable. Location of the clayey

Abstract Lithological features of intermoraine aquatic sediments were studied to assess the possibilities of their application for the stratigraphic subdivision and correlation, as well as paleogeographic reconstructions and localization of the terrigenous provenances during the formation of these sediments. Results of the lithological study of Quaternary aquatic sediments in the European subarctic

Abstract The alluvial-fan sediments play a very important role in mineral reserves and underground water resources, though a comprehensive study on such sediments, especially from a geochemical point of view, is still lacking. In this research, a total of 22 particularly important alluvial fans across the Khuzestan Plain in the southwestern Iran were studied through field surveys, petrographic evaluations

Abstract Gas-geochemical studies of the methane, helium, and hydrogen concentrations in the water of thermal and mineral springs, as well as the subsurface atmosphere, of northern Vietnam showed that the region is in the hypabyssal degassing zone of hydrogen and helium flowing to the surface through a fault system in the Earth’s crust. A joint transit of these gases through the fault structures was

Abstract We studied the composition and isotopic characteristics (δ13C and δD) of hydrocarbon gases from the Kotelnikovsky, Zmeiny, and Goryachnisky hot springs located in the coastal zone of Lake Baikal. Of greatest interest is the Zmeiny Spring located on the eastern coast, where the methane has abnormally high values of δ13C (up to +11‰) and δD (up to +267‰). These values are related to the fractionation

Abstract The mineral composition and depositional environments of the Konkian in eastern Georgia (Kura trough, eastern Paratethys) corresponding to the Kosovian (13.65–12.829 Ma) in the Central Paratethys and the final Middle Miocene marine transgression in Paratethys are considered. Jurassic and Cretaceous volcanic rocks of the Lesser Caucasus (Adzhar–Trialet and Artvin–Bolnisi zones) were identified

Abstract The Ushkatyn-III deposit is located 300 km west of Karaganda (Central Kazakhstan). It is classified as a weakly metamorphosed Atasu-type hydrothermal-sedimentary ore deposit. Stratiform iron, manganese, and barite–lead orebodies occur in the Upper Devonian (D3fm2) carbonate sequence of this deposit. The Fe- and Mn-bearing rocks were studied. Iron ores are composed of hematite, calcite, and

Abstract For the first time, mineralogical, structural, crystal-chemical and isotope-geochronological data were obtained for a glauconite sample from the Lower Riphean Ust-Il’ya Formation on the Magan River (western slope of the Anabar Massif, northern Siberia). It has been established that glauconite from the lenticular layer of friable glauconitite (glauconite grains ≥80%) contains two populations

Abstract Signs of extensive migration of gas-bearing fluids from the sedimentary cover into the water column were identified in the northern Barents Sea during Cruises 25 and 28 of the R/V Akademik Nikolai Strakhov. The existence of a chain of interrelated processes has been revealed: upward migration of gas-bearing fluids, increase of gas concentration in bottom sediments, deformation of the bottom

Abstract Cretaceous and Paleogene sedimentary sequences of the eastern Caucasus show the traces of vertical migration of gel-type diagenetic products (silica, iron sulfides). Signs of the migration of SiO2 compounds were recorded in the carbonate rocks with an admixture of biogenic silica; the traces of sulfide migration are confined to the alternation of limestone and OM-rich clayey marls. The migration

Abstract Several barite deposits have been reported to occur in Nigeria within the Benue Trough, one of the West Central African Rift Systems (WCARS) considered variously as an aulacogen, strike-slip or pull-apart basin. In spite of these occurrences and the high local and international demand for barites, Nigerian barite is yet to find a place even in its local market probably due to the poor knowledge

Abstract The paper considers factors that determined the geochemical features of the Jurassic terrigenous complex of the northern Caucasus. It is shown that at the initial stages of sedimentation, source rocks were the pre-Mesozoic crystalline basement. The geochemical composition of the Jurassic rocks was also affected by weathering crusts developed on serpentinite massifs. The formation of large

AbstractThe Kolyma Terrane is one of the long-developed regional structures in Northeast Asia. Specifics of its neotectonic evolution promoted the wide distribution of Cenozoic overburden rocks, weathering crusts included. We studied the spatial distribution, mineralogy, chemistry, grain size composition, and morphology of native gold in this region. Only relicts of lower horizons of the weathering

AbstractBased on the data from long sediment cores retrieved by R/V Eltanin (United States) during the 1950s–1960s, Neo- and Eopleistocene lithofacies maps of the southern Pacific Ocean (scale 1 : 20 000 000) and Scotia Sea (scale 1 : 10 000 000) were compiled for the first time. For the Scotia Sea, schemes of isopachites are shown on the respective lithofacies maps. All maps are processed with the

AbstractThe work is based on extensive factual material, including a core collection and GIS data on 84 deep wells drilled in the southeastern Nepa–Botuoba anteclise (Siberian Platform). Lithological studies of the Vendian basal deposits formed in the postglacial epoch were carried out. These deposits characterized by significant vertical lithological heterogeneity include layers of highly radioactive

AbstractDinosaur footprints were found in Pliensbachian terrigenous rocks in the central North Caucasus. Tracks of different sizes (12‒35 cm) were identified at three levels of the Mizur Formation section. The sediments accumulated on the wide (15‒20 km) shelf of a paleobasin. The coastal land was covered with abundant vegetation. The warm and humid climate favored the development of weathering crusts

AbstractsExpeditionary studies in the last decade yielded new data on the sedimentary layer structure in northeastern Barents shelf. Based on the constructed spatial model of deep temperatures and heat flow distribution, depths of the catagenetic transformation of hydrocarbons in the sedimentary cover of the northeastern Barents shelf are determined, as well spatial and quantitative correlation of

AbstractThe Vema Fracture Zone orthogonally intersecting the Mid-Atlantic Ridge along 11° N is a complex tectono-sedimentary system, through which bottom water is transferred from the western to the eastern Atlantic. The southern surrounding of the fault valley is an extended (about 320 km) transverse ridge. At the early stages of the Vema System evolution, the ridge was located at shallow depths in

AbstractThe paper reports geochemical and mineralogical data on ores of the Briketno-Zheltuhinskoe U–Mo–Re deposit, which is confined to the Visean paleochannel coal-bearing sandy sediments of the Moscow lignite basin. In addition to main ore elements (Re, Mo, U, and Se), the ores have elevated contents of the following metals (in order of decreasing abundance): Zr, Zn, Mn, Ni, As, Co, V, Pb, Y, Cu

AbstractThe paper presents the results of studying the Pesochansk brown coal deposit located in the central Dnieper–Donets coal-bearing area. The sedimentary cover of this area is characterized by the presence of salt structures, one of which is the Pesochansk stock. The subsidence trough of this pre-Paleogene structure was filled with the Paleogene–Neogene sediments containing three brown coal seams

AbstractThe article characterizes some geochemical proxies of endo- and exospheric processes in sedimentary sequences and analyzes their average values in Upper Precambrian clayey rocks in the South Urals. It is shown that a gradual decrease of the Th/Scaver value in Lower Riphean (Mesoproterozoic) ~1750–1300 Ma ago rocks correlates to a certain extent with the assembly and disintegration of the Columbia/Nuna

AbstractOrganogenic buildups named as carbonate mounds are widespread in Lower Permian deposits in the northern Timan–Pechora basin and are of great interest to the oil-and-gas industry as natural hydrocarbon reservoirs. Their distribution and textural features were controlled by seabed morphology, sea level changes, and specific paleoecology of the Early Permian period. In contrast to classic reefs

AbstractNew data on the 87Sr/86Sr ratio variations in carbonate rocks of the Dal’nyaya Taiga Group in the Vendian reference section (Ura Uplift, Central Siberia) are presented. The 87Sr/86Sr variations correlate with the sequence-stratigraphic scheme reflecting evolution of the paleobasin, δ13C variations, and paleontological data. Limestones with a high (>1050 µg/g) Sr concentration, which do not

AbstractThe Briketno-Zheltukhinskoe U–Mo–Re deposit is located in the southern sector of the Moscow lignite basin (central East European Platform). It is restricted to the paleochannel and deltaic coal-bearing sandy sediments of the Visean Bobrikov horizon lying on the Famennian limestone. They are overlain by the younger Neogene–Quaternary sands and clays. Tectonically, the deposit is ascribed to

AbstractA complex of lithological-geochemical studies was carried out in rocks of the Upper Jurassic–Lower Cretaceous Bazhenov Formation and their transition zones to host rocks: composition of rocks, ratio of organic carbon and sulfide sulfur (C/S values), and distribution of several redox indicators (degree of pyritization, content of the authigenic uranium, and values of Mn/Al and Mo/Mn ratios)

AbstractThe article presents data on numerous findings of authigenic K-feldspars in the Lower–Upper Carboniferous carbonate and terrigenous rocks in the southern limb of the Moscow syneclise, including the Oka–Tsna bar. In terms of the composition and crystalline structure, all feldspar morphotypes (idiomorphic monocrystalline fringes on the surface of sandy clastic grains, fine-crystalline aggregates

AbstractMorphology of the Rio Grande Rise and the acoustic structure of different types of deposits in its uppermost sedimentary cover were discussed based on high-resolution seismoacoustic profiling of cruises #32 (2010) and #52 (2016) of R/V Akademik Ioffe. Slopes of the Rio Grande Rise are composed mainly of landslide deposits and gravitites, but contourite sedimentation is possible on its southern

AbstractThe Haléo-Danielle Plateau bauxite deposit forms the largest part of the 15 km long Minim-Martap Bauxite ore district in the Adamawa Region of Cameroon. The plateau is covered with thin Upper Pleistocene to Holocene alluvial layer. It covers by laterites and bauxites formed on Tertiary-Quaternary basalts. Gibbsite and boehmite are the aluminum oxide found in the bauxite, while goethite is the

AbstractIn 13 out of 14 samples of carbonate xenoliths from mud volcanic breccias of Azerbaijan, the 87Sr/86Sr values (0.70675–0.70823, 87Sr/86Srmd = 0.7073 ± 0.0005) are within the same limits as in the volcanic waters (Bujakaite et al., 2019). Genetically, they can be associated both with Mesozoic carbonate and saline deposits or with Cenozoic volcanosedimentary strata. Similarity of the Sr isotopic

AbstractThe coastal-marine rare metal–titanium placers of the West Siberian megaprovince were formed in a relatively short Eocene–Late Oligocene interval. A similar formation mechanism and commonality of primary sources of ore matter were responsible for the single type and similarity of mineral composition of placers in the megaprovince. Based on the comparison of various characteristics of these

AbstractThe results of lithological, petrographic, and C–O isotope studies of various types of the diagenetic and postdiagenetic carbonate cement in silty mudstones, as well as coeval limestones, in postglacial deposits of the Dal’nyaya Taiga Group (Patom Basin, Siberia) are presented. Evidence of methane generation but not its anaerobic oxidation has been obtained. High δ13C (up to 14.9‰) values of

AbstractThe geothermal and hydrochemical parameters of a large hydrogeothermal system located in the city of Velingrad and its environs (southwestern Bulgaria) are discussed. The article summarizes the results of its research, including those obtained by 2019. Temperature of the discharging thermal waters varies from 37 to 94°C. The hotter mineral waters have SO4–HCO3/Na composition with pH ≈ 8.0,

AbstractThe study of structural features along with carbon and oxygen isotope compositions made it possible to discriminate lithological rocks in deposits of the Karatau phosphorite basin (Kazakhstan) into the following types: high- and low-grade phosphorites; unaltered and altered dolomites (with and without phosphate) hosting phosphorites of the Chulaktau Formation (lower dolomite and Fe–Mn horizons);

AbstractDistribution of carbonate sediments of different composition in the Precambrian section is reviewed. It is shown that calcium carbonates prevailed in the Archean–initial Early Proterozoic, and iron carbonates dominated in the banded iron formations. Dolomites and magnesites were more widespread in the Proterozoic. Such distribution suggests an acid reductive geochemical environment in the Archean–Early

AbstractClay minerals in basalt sills from the northern East Pacific Rise, covered by Upper Pleistocene clayey–sandy–silty sediments (turbidites, hemipelagites, and diatom oozes) sampled from DSDP Holes 477, 478, and 481A, were studied by X-ray methods based on the modeling of diffraction patterns. Trioctahedral smectites formed in thin (0.1–0.5 and 1.8–4 m) fissured sills that are well permeable for

AbstractThe behavior of stable carbon and oxygen isotopes in carbonates during the deposition and diagenesis of sediments in the bioproductive Upper Famennian Pripyat Trough (southern Belarus) is discussed. Limestones and clayey limestones (Corg 0.92 ± 0.11%) are characterized by very low δ13C values (–9.6 ± 0.3‰). Parental sediments of these rocks were deposited in the shallow-water zone during slow

AbstractData on the mineral and chemical composition of samples of sulfide deposits from the Broken Spur and TAG (Mid-Atlantic Ridge) are presented. The main minerals in the Broken Spur field are marcasite, pyrrhotite, pyrite, chalcopyrite, and sphalerite; in sample from TAG: chalcopyrite, pyrite, and marcasite. It has been established that these sulfide minerals of Fe, Cu, and Zn are natural ion exchangers

AbstractThe article presents a brief lithological description of modern bottom sediments collected in the Barents Sea during Cruise 67 of the R/V Akademik Mstislav Keldysh at test sites: (1) “Pechora Sea”; (2) “Western slope of the Kanin Shoal”; (3) “Central Barents Sea (Shtokman area)”; (4) “Russkaya Gavan Fjord”; (5) “Medvezhinsky Trough”; (6) area south of Spitsbergen; (7) “Kola Meridian”; (8) “Spitsbergen–Franz

AbstractData on the concentration of rare and rare-earth elements in the Devonian manganese-rich metasediments of the Polar Urals and Pai-Khoi Ridge are presented. It is shown that Sc, V, Rb, Zr, Nb, Hf, Th, and U represent elements delivered to the metalliferous sediments as a part of the detrital material. Excess (relative to the background detrital material) concentrations are established for Li

AbstractNew data on the structure and formation conditions of the Anabar–Lena sedimentary basin in the Nordvik facies region at the beginning of the Early Jurassic (Hettangian–early Pliensbachian) are presented. Based on a detailed lithofacies analysis, coastal-continental, coastal-marine, and shallow-marine sedimentation conditions were reconstructed. Ichnofacies studies were carried out for the first

AbstractThe results of integrated study of the Cretaceous/Paleogene transition in the northeastern Caucasus are reported. The lithological, geochemical and micropaleontological characteristics of the sediments from two sections (Okhli and Gubden, Mountainous Dagestan) accumulated in different parts of paleobasin are displayed. An analysis of nannofossil distribution at the Cretaceous/Paleogene transition

AbstractBased on materials obtained during Cruise 37 of the R/V Professor Logatchev in the Russian exploration area, the species composition, distribution, and preservation of nanno- and microfossil carbonate shells in biogenic bottom sediments within the Pobeda hydrothermal cluster (17°07.45′–17°08.7′ N MAR) were studied. Physicochemical parameters and total carbonate content were measured and their