Ашық рұқсат Ашық рұқсат  Рұқсат жабық Рұқсат берілді  Рұқсат жабық Тек жазылушылар үшін

Том 515, № 2 (2024)

Мұқаба

Бүкіл шығарылым

Ашық рұқсат Ашық рұқсат
Рұқсат жабық Рұқсат берілді
Рұқсат жабық Тек жазылушылар үшін

GEOLOGY

Age constraints for the Zaonega formation of the Ludicovian superhorizon and the Shunga event in the Onega basin: new U-Pb zircon data for the Konchezero sill

Stepanova A., Samsonov A., Arzamastsev A., Larionov A., Larionova Y.

Аннотация

New U-Pb data for zircon in the Konchezersky Sill provide robust age constraints for the Suisari Fm in the Onega Basin and constrain the maximum age limit for the sedimentary successions of the Zaonega Fm and the Shunga isotope event.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):179-187
pages 179-187 views

New results of the U/Pb dating of cretaceous igneous rocks of the Komsomolsk ore district (Middle Amur River area)

Lebedev A., Alexandrov I., Ivin V.

Аннотация

The Komsomolsk tin ore district is located at the Miaochan Ridge in the Middle Amur River area (Khabarovsk territory) within the Badzhal accretionary terrane of the Sikhote-Alin orogenic belt. The paper presents new results of U-Pb zircon dating of tonalite of the Miaochan complex of the Silinka granitic pluton (99.7±1.1 Ma) and two rhyolites of the lower part of the Kholdami Formation (98.4±1.0 and 98.7±1.2 Ma) from the north-eastern part of the Komsomolsk district. The geochemical characteristics of rocks were also studied, which show that granitoids of the Miaochan complex are I-type granites, and coeval rhyolites of the Kholdami Formation are very peraluminous S-type rocks. New data on the geochemistry and early Cenomanian age of the igneous rocks allows us to consider the ore-magmatic system of the Komsomolsk ore district as part of the previously identified Albian-Cenomanian igneous province of Pacific Asia.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):188-195
pages 188-195 views

GEOLOGY OF ORE DEPOSITS

The age of the early stage formation of Ag-Bi-Cu-Ni-Co the Khovu-Aksyn deposit (Republic of Tyva): U-Pb (ID-TIMS) geochronological studies of garnet

Stifeeva M., Salnikova E., Kotov A., Nikiforov A., Plotkina Y., Tolmacheva E.

Аннотация

Mineralogical and U-Pb (ID-TIMS) geochronological studies of garnets from three types of scarn associations of the Khovu-Aksyn Ag–Bi–Cu–Ni–Co deposit (Republic of Tyva) were carried out. The U-Pb garnet age estimate (404±2 million years) is close to the Early Devonian stage of basitic and alkaline-basitic magmatism identified within the Tuva trough of the Altay-Sayan folded region. The age of the scarn formation and the associated with it early stage of mineralization of the Khovu-Aksynskoye Ag–Bi–Cu–Ni–Co deposit has been established for the first time.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):196-202
pages 196-202 views

GEOCHEMISTRY

Volcanites of neoproterozoic ophiolites Kalgyn massif (Northeast Asia): new geochemical and isotopic data

Ganelin A., Sokolov S., Maskaev M.

Аннотация

The Kalgan ophiolite massif is a unit of the ophiolite association of the Chersky collision belt. It is part of the Verkhoyano-Kolyma folded system on Northeast Asia. The Kalgan massif includes a complex of mantle peridotites, a lower-crust complex represented by ultrabasic cumulates, cumulative gabbro-amphibolites and amphibolites, and an upper-crust complex represented by metabasalts. New geochemical data obtained by the ICP-MS method, as well as data on the isotopic composition (Sm, Nd), made it possible to significantly clarify the geodynamic conditions for the formation of volcanites and to determine the features of the sources of parent melts.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):203-209
pages 203-209 views

Rifting in the Paleoproterozoic Onega Basin: geochemistry of volcano-sedimentary rocks of the Zaonega Formation

Samsonov A., Stepanova A., Guschina M., Silaeva O., Erofeeva K., Ustinova V., Maksimov O., Zhdanova L.

Аннотация

The study of the volcanogenic-sedimentary sequence in the lower part of the Zaonega Formation in the Paleoproterozoic Onega structure (Karelian craton, Fennoscandian Shield) has shown that tuffs and high-silica rocks predominate in its composition. High-silica rocks (SiO2 up to 94 wt. %) are depleted of all elements and probably representing chemogenic siliceous silt. Tuff rocks are close to N-MORB basalts in terms of major element content and rare element distribution character. This association is common to the early stages of continental rifting in the Phanerozoic and may indicate the formation of volcanogenic-sedimentary complexes of the Zaonega Formation in the environment of continental rifting. The mafic rocks in the lower part of the Zaonega Formation are geochemically identical to dolerite dikes and N-MORB-type basalts of 2.10–2.14 Ga age. Their formation was probably related to the same episode of large-scale stretching and thinning of the continental lithosphere of the Karelian craton in the mid–Paleoproterozoic. In this case, the age limit of the Zaonega and underlying Tulomozero Formations should be somewhat older than the 2.06–2.10 Ga interval accepted in modern regional stratigraphic schemes of the Paleoproterozoic of Fennoscandian shield.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):210-220
pages 210-220 views

Pacific waters in the East Siberian Sea: identification by δ13С(DIC) and [DIC]

Dubinina E., Kossova S., Osadchiev A., Chizhova Y., Avdeenko A.

Аннотация

The estimates of the scale and distribution of Bering Sea waters in the Pacific sector of the Arctic Ocean were made using the high-precision data on the isotopic composition and concentration of dissolved inorganic carbon. Despite the fact that δ13С(DIC) and [DIC] are not classic conservative tracers, in the East Siberian Sea, which is a zone of active interaction of river runoff with sea waters, these parameters can indicate the presence of sea waters not only of Atlantic, but also of Pacific origin, similar to the waters of the Bering Sea. Using a three-component mixing model, the spatial distribution of Pacific, Atlantic and river waters along two sections of the East Siberian Sea was estimated. The Pacific component extends from east to west to approximately 160 degrees east longitude, and possibly further west, skirting Wrangel Island not only from the north, but also possibly from the south. In the East Siberian Sea, waters similar to the open sea Bering summer surface waters are found, which are carried to the northern shelf by the circular Bering Sea Current, and upper intermediate waters, which can enter the zone of the northern shelf of the sea due to upwelling or active mixing.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):221-228
pages 221-228 views

PETROLOGY

Late devonian calc-alkaline high-k fractionated “Ferroan” I-type leucogranites (Rudny Altai)

Kruk N., Kuibida M., Sokolova E., Kotler P., Yakovlev V.

Аннотация

The paper presents the geological, geochemical and isotope-geochronological studies of the Rudny Altai granitoids in the west of Central Asian Orogenic Belt (CAOB) – the front part of the Altai convergent margin of the Siberian continent. Isotopic U–Pb dating of zircons showed an age range from 367 to 363 Ma. Geochemical characteristics indicate the relevance of leucogranites to calc-alkaline high-K series (SiO2 > 73 wt.%, Na2O+K2O = 6.9–9 wt.%, Na2O/K2O = 0.7–1.2), with calc-alkaline and alkaline-calcic affinities (MALI = 6.32–8.41). They bear meta- to weakly-peraluminous values (A/CNK = 0.9–1.2), high Fe* index (0.84–0.97) and high fluorine (0.04–0.17 wt.%) content. Variations of HFSEs, LILEs contents, Ga/Al ratios and strong negative A/CNK-P2O5 correlation indicate their affinity with fractionated I-type granitoids. Rare metal (beryllium) mineralization is spatially and genetically related to leucogranites. It is assumed that the formation of granitoids was associated with shearing setting at the convergent margin of the Siberian continent, as a result of oblique subduction of the Irtysh-Zaisan ocean plate.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):229-236
pages 229-236 views

Leucogranite intrusions in Eastern Kazakhstan: age, composition and mechanisms of formation

Khromykh S., Kotler P., Kruk N.

Аннотация

There are several large intrusions composed of 70–75% leucogranites within Eastern Kazakhstan. Information on the age of the intrusions is provided, the features of the composition of the rocks are considered, and conclusions about the petrogenetic mechanisms of forming of leucogranite magmas are drawn. Two stages of leucogranite intrusive magmatism have been established – in the Early Permian and in the Early Triassic. Their formation occurred in an intraplate geodynamic setting. Leucogranite magmas were formed as a result of partial melting of crustal substrates under the thermal influence of mafic magmas. Geochemical differences in leucogranites were due to different compositions of crustal substrates and different degrees of their melting.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):237-244
pages 237-244 views

MINERALOGY

A new untipical case of ferromanganese mineralization in the Sea of Japan

Kolesnik O., Karabtsov A., S”edin V., Kolesnik A., Terekhov E.

Аннотация

The first case of hydrothermal brecciated crusts composed of goethite with quartz veinlets for the Sea of Japan is described.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):245-251
pages 245-251 views

Features of isomorphism of post-spinel phases: result of computer simulation of the composition of inclusions in lower mantle diamonds

Buchinskiy V., Marchenko E., Iskrina A., Eremin N., Bobrov A.

Аннотация

The mixing properties of solid solutions of post-spinel phases of the composition CaCr2O4–CaAl2O4, CaCr2O4–CaFe2O4, MgCr2O4–MgAl2O4 and MgCr2O4–MgFe2O4 in the temperature range 1873– 2223 K and pressures 18–25 GPa were studied using the method of semi-empirical modeling. With these PT parameters, the energies of formation of impurity defects of trivalent metal ions (aluminum and iron) in isomorphic sites were estimated. It is shown that (1) the studied binary solid solutions are characterized by complete miscibility, (2) the incorporation of the Fe3+ impurity ion into the post-spinel phases of MgCr2O4 and CaCr2O4 is less favorable in terms of energy than the incorporation of Al3+ ions over the entire range of pressures and temperatures under study. The results obtained were used to interpret the composition of post-spinel phases forming inclusions in lower mantle diamonds.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):252-257
pages 252-257 views

GEODYNAMICS

West Siberian sedimentary basin. Crustal subsidence caused by rock contraction in its lower part due to prograde metamorphism

Artyushkov E., Chekhovich P.

Аннотация

The history of the crustal subsidence in the Mesozoic and Cenozoic in the West Siberian Basin – the largest sedimentary basin in the world – is considered. Most researchers associate its formation with post-rift subsidence of the crust, which followed an episode of strong lithospheric stretching about 250 million years ago near to the Permian to the Triassic transition. A characteristic feature of post-rift subsidence is a decrease in its rate in time. During the Mesozoic-Cenozoic history, in Western Siberia the rate of crustal subsidence should have slow down by an order of magnitude. However, the analysis of long (700–900 km) seismic profiles in the north of Western Siberia and in the Southern Kara Sea shows that since the beginning of the Mesozoic in these regions, on average, there has been an acceleration of the crustal subsidence. Under such circumstances, lithospheric stretching in them could be responsible for only a small part of the total subsidence of the crust of 6–7 km. In Western Siberia, the Earth’s crust is close to the isostatic equilibrium. Then, in the absence of strong stretching, the accumulation of thick sedimentary sequences in the basin could only have been caused by rock contraction in the lower crust due to prograde metamorphic reactions. To obtain the above results, we used, for the first time, some simple methods to analyze the structure of the sedimentary cover in the West Siberian Basin. Detailed seismic profiles have been published for many other deep basins on all the continents. The methods of their interpretation implemented in this paper can be easily applied to determine the role of lithospheric stretching in the formation of deep sedimentary basins on the global scale.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):258-273
pages 258-273 views

GEOPHYSICS

Geophysical effects caused by the bolide fall on September 02, 2023 (Turkey)

Spivak A., Rybnov Y., Riabova S., Tikhonova A.

Аннотация

We present the results of instrumental observations of acoustic oscillations, geomagnetic variations and variations of the atmospheric electric field during the fall and explosive destruction of the bolide in the southeast of Turkey on September 02, 2023. It is shown that the destruction of the bolide under the action of aerodynamic forces, which occurred in three stages, was accompanied by an acoustic signal of a characteristic shape and manifested in variations of the magnetic and electric fields in the near-surface layer atmosphere. The total energy of the event, estimated by the acoustic effect, was ~ 9×1012 J, which corresponds to about 2.15 kt in TNT equivalent. The maximum amplitude of geomagnetic variations caused by the explosion of the bolide ranged from 0.2 to 2.1 nT depending on the distance. At the same time, the amplitude of variations of the vertical component of the atmospheric electric field at the Mikhnevo observatory (distance ~1900 km) was ~70 V/m. The ionospheric effect of the event under consideration is demonstrated in the form of variations of the critical frequency f0F2 obtained as a result of processing ionograms of height-frequency sounding of the ionosphere at the Rome station.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):274-281
pages 274-281 views

OCEANOLOGY

Water budget of the Caspian Sea by numerical experiments with ocean circulation model INMIO-CICE in the last glacial maximum and pre-industrial period

Morozova P., Ushakov K., Semenov V., Volodin E.

Аннотация

We used the hydrodynamic model of the Caspian Sea, INMIO-CICE, to calculate equilibrium river runoff and evaporation from the sea surface over a wide range of sea levels (from –85 to +50 m asl) for different climatic conditions: the Last Glacial Maximum (about 21kyr) and pre-industrial climate (~1850 CE). Data from the climate model INMCM4.8 were used as boundary conditions. It was found that to maintain sea level at 35–50 m asl, corresponding to the maximum values of the Khvalynian transgression, a river runoff of about 400 km3/year was required in the Last Glacial Maximum. In the Last Glacial Maximum evaporation from the sea surface decreased by 105–170 mm (12–22%), and precipitation, according to the INMCM4.8 model, by 50–70 mm (15–30%). This caused the equilibrium runoff to decrease by about 10–20% compared to pre-industrial conditions. Smaller absolute and relative changes correspond to lower sea levels. The maximum decrease in evaporation occurred at 5 m asl.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):282-288
pages 282-288 views

Long–period trends in water temperature changes in the northern part of the Atlantic Ocean from ocean reanalysis data

Sukhonos P., Ivanov V., Diansky N.

Аннотация

The results of assessing long–period changes in water temperature in the North Atlantic Ocean (0°–70° N, 8°–80° W) based on data from ocean reanalyses and objective analyses for the periods 1961– 2011 and 1980–2011 are presented. The obtained estimates are based on the application of a nonparametric method of regression analysis (quantile regression) to the monthly ocean temperature for a quantile value of 0.5. During the period 1961–2011 warming was mainly observed in the upper 400 m layer in the region from the equator to 70° N. Over this 51-year period, the increase in the median monthly ocean temperature averaged over the analyzed water area ~0.5°C, and in the Gulf Stream–North Atlantic Current system ~1°C. During the period 1980–2011 warming in the North Atlantic Ocean mainly occurred in the upper 1 km layer at high latitudes (50°–65° N). Over this 32-year period, the increase in the median monthly ocean temperature in the subpolar gyre in the upper 400 m layer was ~1°C.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):289-295
pages 289-295 views

Analysis of fauna of mollusks, pollen assemblages and sedimentary environments in the Taganrog Bay of the Sea of Azov

Matishov G., Kovalenko E., Dyuzhova K., Polshin V.

Аннотация

The paper presents the results of a comprehensive study of well sections drilled on the coastal spits of the Taganrog Gulf of the Sea of Azov and bottom sediment columns selected in the water area. A detailed analysis of the early malacological communities, an important participant in the sedimentary process, made it possible to trace changes in their living conditions in the Holocene. Based on determining the absolute age (14C) from the valves of mollusk shells buried in situ, it is shown that at the beginning of the Phanagorian regression, in the area of the distal part of the Dolgaya Spit, there was a sea reservoir with an Azov-Black Sea complex of reference species. Based on the results of palynological analysis, changes in the natural conditions of the Azov region over the past few thousand years have been reconstructed and arid and humid climatic phases have been identified.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):296-303
pages 296-303 views

GEOECOLOGY

Neural network cognitive analysis of accumulation metals by marigold

Puhalsky J., Vorobyov N., Loskutov S., Chukaeva M., Sidorova V., Matveeva V.

Аннотация

The article presents the results of studies to assess the effect of humic acids, taken at a concentration of 250 ppm, on the process of induced phytoextraction of heavy metals from soils selected near Norilsk. Phytoxtraction was carried out by different types of marigold plants: Tagetes patula and Tagetes erecta. The studies were carried out in greenhouse conditions under controlled spectral illumination (light culture). The duration of the experiment was 21 days. A short vegetation period was chosen based on the conditions of a short summer period typical for this region, where it is more rational to keep records of the systemic removal of toxicants from contaminated soils by several cycles of their sowing/cutting per season, already at the juvenile phase of ontogenesis. For elemental analysis, the method of atomic emission spectrometry with inductively coupled plasma was used. To assess the level of efficiency of metal accumulation, the authors developed and used the original computing neural network CompNN, which allows calculating the cognitive significance index (CSI) based on empirical data on the accumulation of toxicants, both in shoots and roots of plants. The results of the study showed that the introduction of an organic additive in the form of humic acids into the soil led to inhibition of the growth of the above-ground part of T. patula. As for T. erecta, the rate of accumulation of green plant biomass did not change when humic acids were added. The decrease in the biomass of shoots of T. patula plants is explained by an increase in the accumulation of metals in them by an average of 91.6% for the variants. The content of metals in the shoots of T. erecta under the influence of humic acids, on the contrary, decreased by 17.3% on average. A similar result was observed in relation to the root zone: the trend of change in the fixation of metals for both plant species here was 40.8 and 10.8%, respectively. Calculation of CSI indices also showed that the addition of humic acids in T. patula increases the intensity of metal accumulation from the soil in its biomass in all variants, while in T. erecta, on the contrary, it decreases. The performed cluster analysis demonstrated the fixation of metals in the main buffer zone of plants, and also made it possible to isolate nickel into a separate homogeneous series. With regard to the distribution of this element in the shoots by variants, experience has shown that it has demonstrated here the proximity of convergence with copper. The correlation coefficients of their accumulation with the CSI index in the shoots of both plants were r = 0.82; 0.87 for Cu and r = 0.87; 0.83 for Ni. The proximity of these values indicates the priority nature of the accumulation of these metals in the plant biomass of marigolds, and also characterizes the manifestation of certain interactions between them in contaminated soil by the type of antagonism or synergism.

Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2024;515(2):304-314
pages 304-314 views