Vol 510, No 1 (2023)

The article discusses the existing problems and original author’s solutions to the problems of 3D computer modeling of the processes of development of natural hydrocarbon deposits. The transition from laboratory experiments, 3D geological modeling to the creation of 3D filtration models of the reservoir, their subsequent adaptation to the actual data of the development history is considered. The use of a refined 3D model to optimize the economic performance of the operation of the developed field is discussed. In fact, the approach to the unpopulated management of oil and gas field development using a constantly adapting 3D model of the reservoir is justified.

U–Pb (LA-ICP-MS) geochronological studies of detrital zircons from diamond-bearing sandstones of the Khuzhir Formation of the Motskaya series of the sedimentary cover of the south of the Siberian platform were carried out. Similar spectra were obtained for two samples with the most representative peaks at 620, 780, 1860 and 2550 Ma and single data in the intervals 985–1000, 1400–1500, 1150–1190, 2700–2880 and 3225–3230 Ma. The maximum age of sedimentation is 605 ± 6 Ma, which corresponds to the Ediacaran and close to the time of the carbonatite and alkali-silicate magmatism in the region. Neoproterozoic data reflect the ages of the rocks of the Tuva-Mongolian terrane of the Central Asian Orogenic Belt, and the most ancient peaks are typical for the basement complexes of the southern Siberian platform. The obtained result supports the Ediacaran age the sediments studied and could be consider as first evidence of the presence of Precambrian diamond-bearing rocks within the Siberian platform.

For the first time, a detailed description of springs with alkaline waters (pH > 10) found within the ultrabasic massif of the Mt. Soldatskaya on the Kamchatsky Mys Peninsula in Kamchatka is presented. The chemical composition of the springs and the dependence of the ratios and concentrations of some components on pH correspond to the formation of these waters due to modern serpentinization of ultramafic rocks. The most alkaline springs (pH 12.3) contain dissolved hydrogen at a concentration of about 0.6 mmol/l. The behavior of the isotopic composition of carbonate travertines precipitated from these springs (δ¹³C and δ¹⁸O) differs from the known trend for “meteogenic” travertines, associated with serpentinization of ultrabasic rocks in Oman and California. The age of travertines, determined by the radiocarbon method is close to the modern.

Using the example of the Central Chadobets uplift deposit, the relationship of the crystallomorphological features of gibbsite with its position in the bauxite-bearing profile of the weathering crust is revealed. From the down up, in various parts of the profile, as a result of infiltration metasomatosis and various physico-chemical conditions, there is an increase in free space, contributing to the growth of gibbsite crystals. The higher the rock lies, the more porous it is. Thus, in the down-up section, the size of gibbsite crystals increases, its morphology becomes more complicated. By the method of thermal analysis, it was found that the larger the size of the gibbsite crystals, the more boehmite is formed when it is heated. These conclusions will help technologists to choose the most rational scheme for processing bauxite.

Trachyriolites and komendites of the Pechalninsky ore field contain high potentially industrial concentrations of a number of rare metals and REE. The enrichment coefficients vary from several times (Zn, Ga, LREE) to tens (Be, Y, Zr, Nb, Rb and heavy HREE). The REE distribution indicates a uniform enrichment of the HREE relative to the LREE, with a ratio (La/Yb)N in the range from 0.16–1.01). All samples show strongly negative Eu anomalies, with values of Eu/Eu* – 0.13. A comparative analysis with similar objects known in the world in alkaline volcanites has shown that the Pechalninsky ore field can become an unconventional large-volume source of HREE.

In the central part of the Vyatka belt, sandwiched between the Archean blocks in the northeast of the Volga-Ural segment of the East European craton, according to the core data from two deep wells, the following mineral parageneses were established in the metapelites of the Uni suite: (1) Pl + Ms + Bt + Qz + Kfs + And ± Chl and (2) Pl + Bt + Qz + Kfs + Grt + Sil ± Ms ± Chl (without staurolite and cordierite), corresponding to moderate pressure metamorphism of the amphibolite facies. To determine the P-T conditions for these parageneses a set of methods was used, including classical (Grt-Bt, GASP, Ti-in-Bt, Ms-Bt) and multi-equilibrium thermobarometry (winTWQ 2.34), as well as the isopleth intersection method on pseudosection diagrams (GeoPS 3.2.2.128). The calculated P-T values of metamorphism are 520–650°C (or up to 690°C according to the isopleth method) and 2–5.4 kbar. Paragenesis (2) rock was accompanied by anatexis in the water-saturated system. Zoning can be distinguished in the metamorphism of the rocks, it belongs to a relatively shallow type, to the andalusite-sillimanite subfacies.

The macroscopic fossils, an Ediacara-type composite moulds and casts, were found in the Dzhezhim Formation of the Timan Range for the first time. Among them, the representatives of palaeopascichnids, frondomorphs, chuariomorph colonies, arumberiamorph structures as well as trace fossils were diagnosed. Finding of a large number of various Ediacaran fossils on Timan Range both develops the understanding of their palaeogeographic range, and also clarifies the age limits of the deposition of the Dzhezhim Formation, whose stratigraphic position in the Upper Precambrian section was controversial.

Until recently, only the bone remains of the Don hares, extinct in the Holocene, were known. For the first time, the mummy of an adult hare, identified as the Don hare, has made it possible to expand the understanding of this species and its morphological adaptations to living conditions in the Arctic steppes of the Pleistocene of Yakutia: large body length, short ears and feet, powerful locomotor apparatus of the hind limbs, hard hair brushes on the feet, excellent heat-shielding properties of the fur, including the specific microstructure of the hairs.

The bottom morphology and thickness of bottom sediments of lakes Zapovednoye and Peyungda were studied by echo-sounding and seismic reflection profiling. The lakes are located in 60 km and 50 km from inferred explosion epicenter of “Tunguska event 1908”, respectively. We showed that both lakes have circular shape and funnel-like morphology with 60 and 34 m maximum water-depth, respectively, close to their geometrical centers. The shape of the lake is similar to famous Lake Cheko which is believed to be a secondary impact crater for Tunguska event of 1908. The shape of Lake Cheko was suggested to be highly unusual that was one of arguments to support the hypothesis of impact origin of Lake Cheko. We have shown that lakes Zapovednoye and Peyungda are examples of funnel-like deep lakes, and the age of both lakes exceeds are two thousand years. Therefore, we assume that all three lakes are most likely of karst origin. The similarity of the shape of the three reservoirs and their location in the riverbeds indicate the similar origin and testify against the hypothesis of the impact origin of Lake Cheko in 1908.

In large-scale smoke haze during mass fires in the boreal forests of Alaska in July 2019 in the visible and near infrared of spectrum intervals 440–1020 nm, according to monitoring data on the network of AERONET stations of the spectral dependences of the refractive index imaginary part, anomalous absorption of the fine smoke aerosol was found. Variations in the spectral dependences of the aerosol optical extinction and absorption depths, as well as the size distribution function of aerosol particles, are analyzed. With anomalous absorption, the imaginary part of the refractive index increased by a factor of 1.8–7.2 with increasing wavelength from 440 to 1020 nm, reaching a value of 0.315 for the wavelength of 1020 nm. A power-law approximation of the spectral dependence of the refractive index imaginary part with exponents approximately from 0.7 to 2.3 is proposed.

Ensemble simulations (taking into account uncertainty of paleoclimate reconstructions) with a models for ice sheets dynamics for the last glacial cycle (last 128 kyr) are carried out. The model realistically reproduces spatial structure of major ice sheets and heights of their domes in the Northern hemisphere as well as the associated changes in global sea level. Perturbations with a sufficiently large amplitude applied to the initial paleoreconstruction result in marked differences of the modelling, in particular, durimg the Last Glacial maximu and during 58–51 kyr before present (the initial part of MIS3). According to our simualtions, the uncertainty of temperature reconstructions durng the last galcial cycle is limited to 2°C in agreement with existing estimates.

For the first time for saline lakes of the Crimean Peninsula, the results of a comprehensive study of lacustrine sediments using litho-, bio- and chronological methods were obtained. For the first time, radiocarbon dating of the Crimean lake sediments was performed. In lakes Saki and Dzharylgach, sediment sequences of closed highly mineralized reservoirs, which overlay marine deposits, were retrieved. The surface of marine sediments is dated to 5610–5340 cal BP for Lake Saki and 5590–5350 cal BP for Lake Dzharylgach. By this time, sand barriers began to form, which subsequently completely separated the lagoons from the sea and led to the formation of closed reservoirs. Full isolation of Lake Dzharylgach occurred about 4600 cal BP. The vegetation change at the first stage of the lakes’ existence was controlled by changes in the sea level, as well as by fluctuations of salinity, later changes being mainly influenced by changes in climate humidity. The first Cerealia-type pollen occurs in the Subboreal period. Human settlements in the area of Lake Dzharylgach represent the Eneolithic, Bronze Age, as well as the Greco-Roman and medieval periods. A notable demographic change is observed in the period from the early first millennium to the end of the 5th century BC. The majority of archaeological sites in the vicinity of Lake Saki belongs to the Greco-Roman period.

The paper analyzes the effect of a promising additive (BAA) fulvic acid on the reproductive function of queen bees and the productivity of bee layers. A single dose of carbohydrate supplementation (40% sucrase) was 200 ml per family. A total of 12 feedings were carried out with an interval of three days. The effect of the drug on the reproductive function of queen bees was determined by counting the number of printed brood using a grid frame every 12 days. As a result of the research, a positive effect of fulvic acid on the reproductive function of queen bees was established. When using fulvic acid as a spring feeding of bee colonies, a significant increase was established on average by 22.5% over two years of research, and the honey productivity of bee layers increased by 17.7%.