Long-Term Geochemical Monitoring of the Source of the Angara River (Runoff from Lake Baikal)

The long-term data (1950–2017) on the chemical composition of the water from the source of the Angara River, which is the only run-off from Lake Baikal, a large and clean fresh water reservoir, are presented. The absence of water contamination despite the anthropogenic influence is shown. The similarity and constancy of the current composition of the waters in the lake and the Angara River are recorded. It is recommended to continue geochemical studies of this unique world heritage site.     

Granitoid magmatism of the Lermontovskaya and Vostok-2 tungsten ore-magmatic systems: U-Pb (SHRIMP) dating and isotope characteristics (<Superscript>3</Superscript>He/<Superscript>4</Superscript>He) of ores

U-Pb (SHRIMP) isotope dating of magmatic complexes of tungsten ore-magmatic systems (OMSs) resulted in a conclusion about the close age (103–105 Ma) of their formation in the magmatic rock masses from the Tatibinsk plutonic series whose location is controlled by the Sikhote-Alin’ strike-slip fault system. The OMSs are formed within the zones of strike-slip fault extensions (“windows”) dipping into the mantle, which establishes the conditions for the participation of deep fluids in the generation of melts at the level of crustal-mantle interaction. The new data from the study of the isotope composition of helium in the fluid inclusions showed that the content of mantle helium in ores of tungsten OMSs is approximately 10%.     

Determination of Trace Elements (Ag, B, Ge, Mo, Sn, W, Tl) in Reference Samples of Soils and Bottom Sediments by Atomic Emission Spectrometry: A Traceability and Fitness-for-Purpose Study

Reference samples of soils from the Institute of Applied Physics, Irkutsk (RIAP), the Institute of Geochemistry, Irkutsk (IGI) and the United States Geological Survey, Reston (USGS) were analysed with the aim of determining Ag, B, Ge, Mo, Sn, Tl and W abundances by an atomic emission method with air-stabilised D.C. arc excitation. Two series of reference samples of soils and bottom sediments, GSS-1-8 and GSD-1-12 (IGGE), were used to ensure the traceability link for the analytical results. Traceability was also demonstrated through the comparison of measured results by AES and ICP-MS methods. It is shown that the reference samples GSS-1-8 and GSD-1-12 satisfied the "fitness-for-purpose" criterion (uncertainty U of the certified value should be one-third to one-tenth the magnitude of routine laboratory data uncertainty S (S/U > 3-10)) and can be applied for calibrating AES techniques.     

Hydrobiological conditions of sapropel formation in lakes in the south of Western Siberia

The results of studies of the hydrobiological regime of three sapropel lakes in Novosibirsk region in 2012 are presented. The biological production of the examined lakes, the composition and biomass of dominating species–producers of organic matter (phyto- and zooplankton, macrophytes) is determined, and the sedimentation rate of plankton and phytodetritus is estimated. The obtained results provide improved estimates of the contribution of aquatic organisms of different trophic levels to the processes of sedimentation and formation of sapropel in different types of lakes.     

Geochemical controls on the formation of unconformity-type Au–U deposits (Northern Transbaikalia)

This study provides geochemical, mineralogical, and isotope data for rocks and ores from Lower Proterozoic black shale formations of the Kodar–Udokan structural and formational zone, which host the Khadatkanda gold—uranium deposit. The results indicate that the uranium and gold mineralizations were formed at different times in relation to different geodynamic settings. The gold mineralization is associated with the inception of the Syulban fault and has a juvenile source. The later Th–U mineralization originated during tectonic rejuvenation of the Syulban fault zone, while the sources of radioactive elements were presumably the underlying sediments of the Kodar Group, which are widespread throughout the area of the Baikal mountain region (BMR). Based on the above results, the Au–U mineralization in the study area can be recognized as unconformity-type deposits, analogous to the well-known deposits of Australia and Canada. In this connection, the Baikal mountain region has a good potential for the discovery of Au—U deposits.     

Accumulation Properties of Major and Trace Elements of the Subcolloidal Fraction of Bottom Sediments in the Marginal Filter of the Razdolnaya River (Amur Bay,Sea of Japan) under the Influence of Increased Runoff

Oceanology - The study reveals the distribution of contents of major (Si, Al, Fe, Mn) and trace elements (Ga, V, W, Th, Mo, U, Be, Y, Cd), Сorg, and clay minerals in the subcolloidal fraction...     

Hydrochemical characteristic of sapropels in Novosibirsk oblast

Sapropels of lake systems in Novosibirsk oblast were studied to develop a scientific basis for their rational use. Sapropels from lakes in Novosibirsk oblast have been classified based on the ash content, chemical composition, and genesis. Organic–mineral and mineral–organic calcium and mixed sapropels of macrophyte and macrophyte–plankton genesis have been shown to be predominant by far among sapropel deposits in lakes in Novosibirsk oblast.     

Early Archean sialic crust of the Siberian craton: Its composition and origin of magmatic protoliths

This study demonstrates that the base of the Archean deep-seated granulite complexes within the Siberian craton consists of a metabasite-enderbite association. The major and trace element distribution patterns revealed that the protoliths of this association are represented by calc-alkaline andesites and dacites, containing several minor sequences of komatiitic-tholeiitic volcanic rocks. The origin of the primary volcanic rocks of the metabasite-enderbite association is inferred on the basis of a model of mantle plume magmatism, which postulates that both andesitic and dacitic melts were derived from the primary basitic crust at the expense of heat generated by ascending mantle plumes. The formation of the protoliths of the Archen metabasite-enderbite association of the Siberian craton began at 3.4 Ga and continued until the late Archean.