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This article presents new data on the ionic, microcomponent, and isotope compositions of thermal waters of the Amgu group classified as sodium-bicarbonate waters with low mineralization (up to 0.2 g/L), high contents of silica (up to 24 mg/L), lithium, tungsten, and molybdenum, and pH = 8.5–9.7. The influence of neotectonics and Quaternary magmatism on the composition and conditions of formation of nitrogen–siliceous thermal waters is shown. Using δD and δ18O values in thermal and background waters, their atmogenic origin was proved, and the source area of mineral waters was identified. The calculated deep reservoir temperature of 77–81°С indicates the formation of water resources in the crust at significant depths (as much as 2.5 km). The efficiency of using the multicomponent geothermometry method for low-temperature reservoirs is shown. [ABSTRACT FROM AUTHOR]

Samples of ore and gravity concentrate from the Algama zirconium occurrence were studied. Concentrations of rare-earth elements (REE), and rare and noble metals were determined. The REE content is 200–300 g/t in the ore and reaches 400 g/t in the gravity concentrate. REE distribution patterns show a clear negative Ce anomaly and MREE and Y predominance. The ore and the concentrate have elevated Hf, W, U, Ta, Au, and Pt contents. Their source is the ancient weathering crust developed after ultra-alkaline rocks of the Ingili massif. The presence of a buried weathering crust enriched in valuable components is inferred in the studied area. [ABSTRACT FROM AUTHOR]

Original data on the isotope and chemical compositions of mineral springs, cold ground and surface waters, as well as hydrogenic deposits of the Antonovsky manifestation of hydrosulfuric mineral waters (the coast of the Tatar Strait, Sakhalin Island), are presented. The data on the contents of oxygen and hydrogen isotopes in ground and surface waters, as well as the volumetric activity of radon and rare-earth elements are obtained for the first time. Based on automatic monitoring of the physical parameters of the mineral water, its hydrogeological characteristics are determined and balneological properties are assessed. It is found that the mineral waters of the spring are weakly alkaline, hydrocarbonic–chloride calcium–sodium with total dissolved solids (TDS) of up to 1 g/L. According to the isotope data, the genesis of the waters is atmospheric and the circulation time is less than 60 years. The gas composition is dominated by nitrogen of atmospheric genesis (δ15N = 0.0). High contents of organic carbon (Corg = 56.6 mg/L) are explained by the processes of interaction between groundwater and organic matter in water-bearing rocks. When organic matter is decomposed in the presence of sulfates and without access to oxygen, hydrosulfuric acid is released, producing several intermediate and stable sulfur compounds in hydrogenic sediments and bacterial mats. Elemental, sulfide, and sulfate forms of sulfur have been detected in the bottom sediments and in the new formations of the mineral spring, using electron microscopy. The interaction of waters with organic matter of rocks plays a significant role in the formation of the elemental composition of hydrogenic and biogenic deposits of the Antonovsky hydrosulfuric mineral spring and their enrichment with such metals as Zn, Ge, As, Sr, Ba, U, and Th. One characteristic feature of the mineral waters is the presence of a markedly pronounced positive europium anomaly, which is typical of waters with low Eh values. [ABSTRACT FROM AUTHOR]

The analysis of features of the geological structure of the Adycha gold placer region shows that flat structures of the early collision stage control the setting of the ore fields. The ores are similar to host rocks in the main components, lithofile trace elements, and REEs. The features of the trace-element pattern and indicative ratios agree with the suggested metamorphic origin of the main volume of fluids, their weakly reduced and almost neutral conditions, and sorption rock–fluid interaction. A group of elements, the distribution of which is significantly distinct from those of the host rocks, is determined. The geochemical type of the ore region is caused by Mo, Au, Bi, and Sb, the contents of which are higher in all studied ore objects. Chromium, As, Pb, and Te are present in all ore fields, but not in all objects. The Co–Ni–W–Zn–Cd–Ag, Co–Ni–W–In–Mn–Cu–Sr, and Sn–In–Mn–Cu–Zn–Cd–Sr–Ag associations supplement the geochemical type of the Delyuvial'ny, Lazo, and Sentachan ore fields, respectively. Our studies along with thermobarogeochemical data refine the metamorphic–magmatic model of the formation of the gold–quartz deposits of the Kular–Nera belt and outline approaches for the practical application of these features. [ABSTRACT FROM AUTHOR]

Graphitic and graphite varieties are distinguished in the carbonaceous shales of the Riphean Upper Nyatygran Subformation in the Melgin fragment of the Turan block, eastern Bureya Massif. The protolith of the graphitic shales had a terrigenous source related to island-arc volcanism. Pelagic sedimentation played a great role in the formation of the protolith of the graphite shale. These rocks were juxtaposed during the formation of an accretionary wedge on an active continental margin. The carbonaceous shales are characterized by high (>600 ppm) REE + Y contents, especially in the zones of brecciation and hydrothermal reworking. Detrial monazite enriched in LREE and MREE is the main carrier of REE mineralization in the graphitic shales. The main REE carrier in the graphite shales is REE phosphate (xenotime) formed during lithogenesis of sediments. Preliminary experimental treatment of the graphite shales of the Upper Nyatygran Subformation by ammonium hydrofluoride shows their potential for economic extraction of REE and Y. [ABSTRACT FROM AUTHOR]

This paper presents original data on the content and distribution of major and rare-earth elements in the modern hydrothermal systems of the Paratunka and Bol'shebannyi thermal water deposits. In spite of the similar geochemical type of the waters, the individual sites of the hydrothermal systems differ in the major component composition, which is caused by the time of water-rock interaction, temperature control, and the possible influence of seawater intrusions. The REE concentrations in the studied thermal waters are extremely low (a few tenths of ppb). A distinctive feature of these thermal waters is the presence of a positive Eu anomaly. The possible reasons for its appearance are discussed. Calculation of REE speciation shows that the main parameters controlling the formation of the REE complexes in the Paratunka and Bol'shebannyi hydrothermal systems are their individual chemical properties, as well as pH, Eh, and temperature of the aqueous solution. [ABSTRACT FROM AUTHOR]

The paper considers for the first time the morphology, composition, and conditions of formation of the greisens of the Solnechnoe deposit (Komsomol'sk ore district), a typical cassiterite-silicate assemblage. The greisens are localized in the root parts of the deposit and represent a system of veins and veinlets formed in the contraction fractures of the metasomatically altered roof of the monzogranite intrusion (age of 94-92 Ma). The cassiterite-chlorite-carbonate-muscovite-quartz composition of the greisens with admixture of topaz, fluorite, and apatite reflects the composition of the monzogranites. The greisens are close in age (85.3 Ma on muscovite) to the granitic aplites (80-85 Ma on the whole-rock and biotite) of the final phase of the intrusive magmatism. The fluid regime of their formation differs from that of the economic ores in higher temperature, pressure, and salinity. One distinguishing feature of the greisens is elevated contents of LREE, U, and Th, which are incorporated in the REE fluorcarbonates, thorite, and uranothorite crystallizing together with cassiterite. [ABSTRACT FROM AUTHOR]

Data on the concentrations of rare-earth elements and other metals in oils from Sakhalin fields were obtained by inductively coupled plasma mass spectrometry. The chemical preparation of the samples included the stages of acid digestion and ashing. In terms of the total metal contents; V, Ni, and Fe ratios; and Sr isotope ratios, the oil samples are divided into three groups. The crude oils from the extreme northeastern part of the island shelf, which are assigned to group I, differ from the other oils in the high contents of V and other metals, as well as the high V/Ni and V/Fe ratios. The crude oils of the group II fields located southward have elevated contents of REE and some other lithophile elements and moderate V/Ni and V/Fe ratios. Group III fields from the same area and from the Tatar Strait have low metal concentrations and low V/Ni and V/Fe ratios. The Sr/Sr ratio is comparatively low in the group II oil (0.70838-0.70858) and elevated in the group III oil (0.70854-0.70911). The Sr isotope ratio of the crude oils of the Kaigan-Vasyukan deposit (group I) originated from marine organic matter (0.70867-0.70884) is correlated with Sr/Sr ratios in sea-water with an age of 18.0-10.5 Ma. Based on the REE patterns, the V/Ni ratios, and the results of the multielement factor analysis, the crude oils of group III and, to a lesser extent, of group II are similar to the West Siberian crude oils. [ABSTRACT FROM AUTHOR]

This paper presents the results of the integrated study of ferromanganese crusts from the Belyaevsky (Central Basin) and Medvedev (Honshu Basin) seamounts from the Sea of Japan. The study of the mineral composition using powder diffraction and optical and electron microscopy showed that the crusts are made up of todorokite, birnessite, and pyrolusite minerals typical of hydrothermal ferromanganese deposits of the World Ocean. The composition of the ferromanganese crusts from the Sea of Japan was determined by ICP-MS and ICP-OES. The contents of Mn, Fe, Co, Cu, Ni, and other major and trace elements indicate the hydrothermal genesis of the crusts. The obtained data on the composition of ferromanganese crusts of the Sea of Japan, as well as their comparison with different types of deposits of the World Ocean, suggest the endogenic genesis of the studied crusts. However, the REE and Y distribution patterns testify to a significant admixture of hydrogenic matter, which participated in the growth of ferromanganese crusts from the Belyaevsky and Medvedev seamounts. [ABSTRACT FROM AUTHOR]

The chemical composition of the bottom sediments of the Amur River has been analyzed using modern analytical techniques. It was found that their composition and distribution patterns are controlled by several sources. The most probable sources for the bottom sediments of the studied area are siliceous magmatic or metasedimentary rocks. [ABSTRACT FROM AUTHOR]