Abstract Petrogeochemical and geochronological studies were conducted on the main varieties of granitoids from the Sedelga and Berezovsky batholiths in the eastern Bureya continental Massif of the Central Asian Fold Belt. SHRIMP-II U–Pb zircon dating of granitoids constrained the time of formation to the Late Triassic and Early Jurassic between 208 to 193 Ma. Our studies revealed that the batholiths

Abstract The activity of polyvalent elements in the geochemical processes is to a considerable extent determined by the valence state. A change in the valence is dependent on many factors, but the redox conditions of the medium where magma is generated are considered the main factor. The ratio between divalent and trivalent iron in magmatic rocks is a reliable and an accessible indicator of the redox

Abstract The results of P-wave velocity measurements in the basement and sedimentary cover rocks of the submarine Vityaz Ridge and surrounding morphostructures, used for age correlation of the geological complexes, are presented. The numerical values of the seismoacoustic parameter were obtained under laboratory conditions by direct measurements of the samples collected in the area of the Central Kuril

The Middle (?) to Late Paleozoic ophiolite association of West Chukotka comprises the large Aluchin, Atamanov, and Gromadnen–Vurguveem mafic–ultramafic massifs, which are spatially associated with Late Paleozoic volcanic rocks of the Yarakvaam terrane. This paper is devoted to the dikes of the Gromadnen–Vurguveem massif, which form two spatially isolated complexes: “dikes 1” and “dikes 2.” Both complexes

Abstract The paper presents the results of U-Pb and Lu-Hf isotope studies of detrital zircons from the terrigenous the Lan 410 Ma (Lower Devonian), Terrane in the eastern part of the Mongol-Okhotsk fold belt. The lower age rocks limits are for the Nivakh formation ~ for the Verkholan series ~332 Ma (Mississippian), for the Ugokhan series ~239 Ma (Middle Triassic). The evidences were obtained for the

This paper presents new data on rocks dredged from the Hahajima Seamount during the cruise KH03-3 of R/V Hakuho-Maru in 2003. It is shown that the seamount is a tectonically displaced block of the Earth’s crust composed of island-arc ophiolites. The basement of the ophiolite complex is made up of highly depleted mantle residue (dunites and harzburgites). Upward, they grade into cumulate lherzolites

Abstract The gravity field stresses caused by density inhomogeneity of the Earth’s crust in the Central Kuriles area are calculated. The general spatial variation trend of the stress field and its local perturbations via structural and density differentiation of the Earth’s crust are revealed. We conclude that areas with gravitational instability exist within the crust. The hypocenters of the Simushir

The scale and age of extreme hydrological events that have been manifested over the past 2000 years on the coast of Valentin Bay is established based on stratigraphic study and radiocarbon dating of different facies deposits. The deposits of four major historical tsunamis (1993, 1983, 1644, and the 12th century) and a paleo-tsunami, which occurred between 1700–1800 cal yr BP . BP, were found. Sedimentation

Abstract A model of the geological evolution of the Sea of Okhotsk is presented based on data from radioisotope age determinations and the mineral and isotope-geochemical composition of Late Mesozoic–Cenozoic volcanic rocks. We discuss the probable interrelationship between gas geochemical manifestations of gas fluxes with anomalous methane concentrations and the formation of gas hydrates, along with

Abstract This paper presents geochemical, microprobe, paleomagnetic, and rock magnetic data from peat accumulated over the past 10 000 years in the area between the Khor and Kiya rivers (Khabarovsk krai). A horizon ranging in thickness between 75 and 100 cm with elevated concentrations of Ni, Zn, Bi, and Se is identified as a result of comprehensive studies. Magnetite and carbon spherules, as well

Based on statistical processing of gravity anomalies and tectonic interpretation of 3D distributions of density contrast in the crust and upper mantle of Southeast China, new features of rheological layering of the tectonosphere are revealed. Relations of near-surface geological structures with a deep tectonosphere structure in this region are defined. New data on deep relationship of lithospheric

The most studied sections of the Triassic sequences in the lithotectonic zones along the Mongol–Okhotsk fold system from Eastern Transbaikalia to the Sea of Okhotsk are described. Changes in the composition, thickness, and characteristic biota are traced. Transgressive and regressive evolution stages are defined. The presented modern ideas on the geology of this region can serve as a reliable basis

Abstract Consideration is given to the nature of mafic–ultramafic bodies in the southeastern part of the Aldan-Stanovoi Shield using the Kun-Manie ore field as an example. These bodies played an important role in the formation of the Kun-Manie sulfide copper–nickel deposit as conduits of sulfide-bearing magmas. A detailed mineralogical and geochemical study with interval sampling was carried out on

The 190Pt-4He age of isoferroplatinum from andesitic fluid-explosion breccias (fluidolites, a new type of platinum-bearing rock) of the Poperechnoye deposit (Malyi Khingan, Russia) was estimated as 125 ± 21 Ma. This age correlates well with peak magmatic activity in the eastern Central Asian orogenic belt caused by upwelling of slab-window asthenosphere in a transform continental margin setting.

Abstract Petrographic, mineralogical, and geochemical analyses were conducted on Cenozoic sandstones from the Dunhua Basin, which located in Dunhua-mishan fault zone of northeast China, to investigate the provenance of the sediments, as well as the weathering intensity and tectonic setting of the source region. Petrographic data indicate that average quartz-feldspar-lithic (Q-F-L) proportions in the

Abstract Geochronological dating was performed on the detrital zircons of 20 sedimentary rock samples from the Khabarovsk, Samarka, and Zhuravlevka–Amur terranes in the northern Sikhote-Alin Orogenic Belt to establish that (1) the isotopic 206Pb/238U ages of the youngest detrital zircon populations of two sedimentary rock samples from the Gorin (K1b) and Pioner (K1b-v) formations, as well as one sample

Abstract The results of gas-geochemical studies of the Chaun Depression and the Ayon sedimentary basin of the East Siberian Sea are presented. The natural gas composition in rocks, gas manifestations, and bottom sediments is determined. The indicators of the molecular mass of hydrocarbon fractions and weight concentrations of individual hydrocarbons, in which ratios are of correlation-genetic significance

Integrated geological and mineralogical–geochemical study of the ores of the Sredne-Golgotay gold–bismuth deposit using high-precision analytical techniques allowed new data reflecting the typical features and nature of the Au–Bi–Te mineralization. The ores of the Sredne-Golgotay deposit were formed at different stages of gold-forming process and comprise widespread minerals of the Bi–Te–S and Pb–Bi–Sb–S

Abstract New data are obtained on the age of the epithermal gold-silver mineralization of the Kubaka deposit (Omolon Massif, Northeast Russia). Our geological observations in the open-pit mine of the Zokol zone of the deposit allow us to conclude that the mineralization formed between the eruptions of Upper Devonian ore-hosting volcanites of the Kedon series (zircon U-Pb age ~ 370 ± 2.5 Ma, SHRIMP)

Abstract Ditrital zircon U-Pb and Lu-Hf isotopic data are reported for metaterrigenous deposits of Dzhagdy Terrane in the Mongol–Okhotsk Fold Belt. The youngest zircon populations in metasedimentary rocks of the Dzheskogon and Nekter formations is concluded to be of the Middle–Late Triassic and Early Jurassic Age, suggesting that the formations are Early Mesozoic and not Carboniferous, as was previously

Abstract Numerous phosphorite occurrences are located among the Riphean–Early Cambrian rocks of the Khingan Group (Lessr Khingan, JAO). They are associated spatially and genetically with uranium, iron, and manganese ore occurrences. The phosphorites of the Gremuchy occurrence are enriched in rare-earth elements (REE) and yttrium (up to 813.58 g/t), uranium (up to 52.23 g/t), and gold (up to 17.03 g/t)

Abstract The first paleomagnetic and petrochemical data on the Lower Cretaceous sedimentary rocks of the Komsomolsk Series from the Zhuravlevka–Amurian turbidite paleobasin are presented. The rocks are collected in coastal outcrops of Sakhalin Bay (54.09° N, 140.05° E). The studies reveal that (1) the petrochemical characteristics of the sedimentary rocks of the Gorinskaya and Pionerskaya formations

Abstract The quantitative processing of gravimetric data is performed and the 3D density model is calculated for the southern part of the Russian margin of Eurasian continent. Based on the density model, new patterns of disjunctive tectonics at different depth levels are revealed and the position of the region at the global tectonic level is shown. It is established that the transition zone is an integrated

Abstract The geodynamic setting of the Agnie–Afanas’evskaya auriferous rotational structure, genetically related to a transtensional left-lateral duplex zone which was formed against the background of the regional roughly north–south lateral contraction (transpression), is discussed. Regional dislocations are accompanied by local dislocations caused by internal stresses, which account for the details

Abstract The paper reports the results of 40Ar/39Ar geochronological studies of the muscovite–quartz–albite metasomatites of the ore bodies and host rocks of the Albyn deposit located in the Selemdzha–Kerbi structural zone of the eastern part of the Mongol–Okhotsk Fold Belt. To a first approximation, the age of the hydrothermal ore process responsible for the formation of the Albyn deposit can be estimated

Abstract Based on the data of relief analysis, the gravity and magnetic anomaly axes, earthquake foci sequences, and Vp/Vs ratio values, tectonic fracturing of the lithosphere is studied and tectonic submeridionally and sublatitudinally oriented fracturing zones are distinguished in the Priamurye region. Separate segments of extended submeridional and sublatitudional fracturing zones are evidenced