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Oceanology - This paper reports the results of investigations on the radioecological state of bottom sediments of the Ob–Yenisei shoal area and Ob and Yenisei estuaries. Materials were... 相似文献
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En. E. Asadulin A. Yu. Miroshnikov V. I. Velichkin 《Geochemistry International》2013,51(12):1005-1018
This paper reports the results of a study of the geochemistry of bottom sediments from the zones of mixing between the freshwater of the Ob and Yenisei rivers and the saline water of the Kara Sea by means of neutron activation analysis. Using separate datasets for the sediments of the Ob and Yenisei estuaries accumulated under identical facies conditions, some characteristic features of the distribution of a number of chemical elements (mostly lithophile group elements) were established. The differences between them were attributed to distinctive regional geological and geochemical features of the catchments of the Ob and Yenisei, which are inherited by the geochemical characteristics of terrigenous material transported to the sea. The choice of the most informative indicator elements and their grouping on the basis of the character of behavior demonstrated that bottom sediments of the Ob or Yenisei origin can be identified in the marine region studied using the geochemical characteristics of a small group of samples. 相似文献
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Nikolay P. Laverov Vasily I. Velichkin Ai Fujiwara Naotatsu Shikazono Alexey P. Aleshin Enver E. Asadulin Vyacheslav N. Golubev Tatiana L. Krylova Alexander A. Pek Igor V. Chernyshev 《Resource Geology》2009,59(4):342-358
It has been shown that the main uranium ore mineral, pitchblende (uranium dioxide), is a natural analog of synthetic uraninite (also uranium dioxide), which constitutes 96% of spent nuclear fuel (SNF). Geochronological studies of the U‐Pb isotope systems in unaltered pitchblende from the orebodies reveal that these systems remained completely closed over the entire period (approximately 135 Ma) since the formation of the deposits. The bulk of the primary uranium ores within the Streltsovskoye ore field was influenced to various degrees by post‐ore hydrothermal solutions that led to pitchblende spherulites being replaced by pseudomorphs of an amorphous phase with a U‐Si composition; this phase also re‐precipitated in veinlets proximal to the pitchblende pseudomorphs. A technique specially developed by the authors was used to carry out quantitative counts of the abundance of uranium minerals by calculating the uranium mass balance in one of the orebodies subjected to hydrothermal alteration. The calculations reveal minimal uranium loss from the orebody. Uranium liberated in the process of the pseudomorphic replacement of pitchblende was immediately fixed, in situ, in the newly formed coffinite‐like amorphous U‐Si phase as a result of the development of an efficient geochemical barrier that prevented the long‐distance migration of uranium. In assessing the long‐term safety of underground SNF repositories, the results of the present study give us confidence that SNF uraninite, in terms of the preservation of its integrity as a mineral phase, provides for the reliable long‐term isolation of uranium, transuranium elements, and fission products that are “sealed” in the uraninite matrix. In the case of the mineral transformation of the uraninite matrix by hydrothermal solutions, the liberated uranium would be efficiently immobilized by the newly formed amorphous U‐Si phase. 相似文献
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N. P. Laverov V. I. Velichkin A. Yu. Miroshnikov En. E. Asadulin I. N. Semenkov 《Doklady Earth Sciences》2016,468(1):532-535
The density of global radioactive contamination was the most reliable estimated in marine regions and less accurate for intracontinental areas with semi-arid and arid climatic conditions. This work presents the results of using a new method developed for estimating the density of global radioactive contamination based on the calculation of 137Cs concentration in closed lake catchments. An average density of of 137Cs contamination in the model closed lake catchments of southwestern Siberian steppe landscapes is 0.80 ± 0.24 kBq m–2 that is 2–3 times lower than the levels calculated on the basis of the published data. 相似文献
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N. P. Laverov V. I. Velichkin A. Yu. Miroshnikov V. V. Krupskaya En. E. Asadulin I. N. Semenkov A. A. Usacheva S. V. Zakusin E. V. Terskaya 《Doklady Earth Sciences》2016,467(1):320-324
This work considers terrestrial coastal landscapes of Abrosimov and Stepovoi gulfs and Yuzhnii (Southern) Island in the Novaya Zemlya Archipelago in the Kara Sea. These areas are dominated by horizons of slightly acidic leptosols and lithic leptosols of 10 cm thick (Stepovoi Gulf) and those of weak skeleton acidic lithic leptosols of 10–15 cm thick (Abrosimov Gulf) covered by moss–shrub assemblages. Kaolinite is formed in a rhizosphere fine earth layer; illite is formed along the leptosol sequence. The studied coastal landscapes are characterized by low accumulation potential of chemical elements, including radionuclides, at higher contents of them. Elements such as Fe and Ti are dispersed in sols, whereas P, S, Cl, Cu, Pb, and Zn are accumulated in soils in minor amounts. Plants accumulate S, P, Cl, Sr, Zn, and 137Cs in minor amounts as well. Elements such as Ti, Mn, Fe, Cr, V, Co, Ni, Cu, Rb, Zr, Ba, Th, Y, Nb, Pb, and As are attributed to the group of weak biological adsorption. The specific 137Cs activity (Bq kg–1) amounts to 10–150 in plants, 10–300 in moor leptosol horizons, and 1–40 in mull horizons. 相似文献
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Miroshnikov A. Yu. Flint M. V. Dubinina E. O. Asadulin En. E. Shchuka S. A. Usacheva A. A. 《Doklady Earth Sciences》2018,483(2):1582-1586
Doklady Earth Sciences - This paper reports on the results of radiation monitoring of bottom sediments in Yenisei Gulf for the period from 1995 to 2016. Clear positive trends in changing the... 相似文献
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A.?Yu.?MiroshnikovEmail author N.?P.?Laverov R.?A.?Chernov A.?V.?Kudikov A.?A.?Ysacheva I.?N.?Semenkov R.?A.?Aliev E.?E.?Asadulin M.?V.?Gavrilo 《Oceanology》2017,57(1):204-214
Multidisciplinary investigations carried out in the Cape Zhelaniya area and on the Severny ice dome of Severny Island in the Novaya Zemlya Archipelago during cruise 63 of the R/V Akademik Mstislav Keldysh in September 2015 included a study of the environmental radiation level. The landscape?geochemical and radiation?glaciological data show that the Severny ice dome serves as a secondary source of radionuclides on the surface of the ice sheet; this source originated from past nuclear weapons testing in the atmosphere over the Severnaya Zemlya test site. Some samples taken from the periglacial zone near the edge of the Severny ice dome yielded specific activity levels of radioactive cesium of 450–650 Bq/kg. The study of ice cores obtained by shallow (up to 5.4 m) drilling of three boreholes revealed no significant activity values. At the same time, glaciological investigations made it possible to obtain the first data on the previously unexamined glacier, which indicate that the radioactively contaminated layer is located at a depth of 15?20 m at the boundary of the glacier alimentation zone. No similar investigations had been conducted earlier either by Russian or international scientific teams. 相似文献
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B. T. Kochkin N. N. Tarasov O. V. Andreeva En. E. Asadulin V. N. Golubev 《Geology of Ore Deposits》2017,59(2):141-155
The unique combination of several exogenic processes augmenting uranium mineralization followed one another in time at deposits of the Khiagda ore field and gave rise to the formation of uranium resources exceptional for the paleovalley geologic and economic type. The specific geological evolution, volcanic activity, and regional climatic conditions taken together became the main cause of local occurrence of these deposits. 相似文献
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A. V. Mokhov P. M. Kartashov T. A. Gornostaeva En. E. Asadulin O. A. Bogatikov 《Doklady Earth Sciences》2013,448(1):61-63
During the study of tea-colored impact glass fragments from the sample of lunar regolith delivered to Earth by the Luna 24 automatic station by transmission electron microscopy, the composition variations of the previously described high-carbonaceous film, the presence of at least three composition types of glasses, and unusual nanospherulites with Zn-B-N-O composition were discovered. As a part of a nonuniform high-carbonaceous oxygen-bearing film, sites enriched in either Na, S, Si, or Ca were detected. All these sites, as well as the whole film, are electron-amorphous; however, crystalline graphite was also found. Two types of nanospherulites are composed of amorphous ZnO and regular interstratifications of crystalline ZnO and amorphous boron layers with insignificant participation of adsorbed nitrogen. It is supposed that the formation of zinc-boron nanospherulites was caused by a fast-flowing explosive process and probably was modulated by high-frequency acoustic oscillations in a cloud of evaporated high-temperature ionized gas during the impact event. 相似文献