The paper presents the results of a study of the structural configuration, properties, and character of wear of prototype samples of drill plates with ultradisperse additives of MgAl2O4 powders. It is found that the introduction of ultradisperse additives of magnesium spinel into the composition of the furnace charge of a VK8 alloy promotes the formation of a fine-grained structure and also affects the change in the character of fracture from brittle to quasi-brittle.

The results of Sr-chemostratigraphic study of carbonates of the Staraya Rechka and Nemakit-Daldyn formations which make up the upper part of the Precambrian cover of the Anabar Uplift in Northern Siberia are presented. A Pb–Pb age of the Staraya Rechka Formation dolostone has been obtained (549 ± 25 Ma, MSWD = 1.4) for the first time. An improved stepwise dissolution procedure was used to determine the 87Sr/86Sr, 206Pb/204Pb and 207Pb/204Pb isotopic ratios in carbonates rocks. The methodology for studying the Rb–Sr systematics included the chemical removal of about a third of the crushed sample [fraction L(Rb–Sr)1] by preliminary acid leaching in 0.2N CH3COOH and subsequent partial dissolution [fraction L(Rb–Sr)2] of the remaining part of the sample in CH3COOH of the same concentration. The Pb–Pb isotopic systematics of dolostones was studied by six to nine-step dissolution in 0.5N HBr. Chemical procedures resulted in the removal of secondary epigenetic carbonate material, which improved the quality of Sr-chemostratigraphic and U–Pb geochronological information. The initial 87Sr/86Sr ratios in the least altered carbonate material [fraction L(Rb–Sr)2] of the Staraya Rechka Formation dolostone are 0.70822‒0.70836, and in the Nemakit-Daldyn Formation limestone, 0.70854–0.70856. The Pb–Pb age of early diagenesis of dolostones of the Staraya Rechka Formation (549 ± 25 Ma) was calculated from fractions [L(U–Pb)2–L(U–Pb)n], where n for different samples varied in the range from 6 to 9. Epigenetic carbonate fractions L(U–Pb)1 are characterized by a Pb–Pb age of 360 ± 190 Ma (MSWD = 0.8). The obtained results prove that the Staraya Rechka Formation of the Anabar Uplift belong to the Late Vendian (Late Ediacaran), allowing them to be confidently correlated with the carbonate rocks of the upper part of the Yudoma Group of the Uchur-Maya region and to include the named strata into a single Yudoma Complex of Siberia.

The paper presents the results of study of Rb–Sr isotopic system of ore-hosting granitoids, metasomatites after granites, and hydrothermalites of the Upper Karalon gold deposit, as well as the Pb–Pb isotopic system of galena of low-sulfide gold–quartz mineralization of the Karalon gold field. Three groups of ore objects with various Pb isotopic composition of galena are distinguished. Different contribution of mantle and ancient crustal sources is identified for each group. The Pb isotopic composition of galena of the Upper Karalon deposit indicates its genetic link with ore-hosting granites, the age of which (∼600 Ma) could be close to the age of the earliest stage of formation of gold–quartz mineralization. The ancient crustal source is common for the leading gold deposits of North Transbaikalia and exhibits the continental crust parameters of the Siberian Craton at the period of 500–600 Ma. It is established that the Rb–Sr system of the studied rocks and minerals of the Upper Karalon deposit was reconstructed and the Pb isotopes of galena of the Vodorazdel’naya ore zone of the Karalon ore field were redistributed at the boundary of 290–250 Ma. The isotopic data show that the processes of the formation of gold mineralization in geological evolution of the Upper Karalon deposit and Karalon ore field were characterized by long multistage character and accompanied by the regeneration of primary ore concentrations.

Работа посвящена исследованию изношенных напаиваемых твердосплавных пластин резца буровых шнеков. Преимущество шнекового бурения заключается в мобильности, а также в совмещении операций бурения и извлечения грунта. В процессе эксплуатации в зависимости от природно-климатических и абразивной среды бурения буровой инструмент претерпевает изнашивание. Проведение исследовательских работ износа рабочих элементов из твердосплавных пластин необходимо для разработки рекомендаций увеличения ресурсных потенциалов и повышения работоспособности буровых инструментов. Объектом настоящей работы являются твердосплавные напаиваемые пластины для резцов бура шнекового бурения. Максимальное изнашивание поверхности твердосплавных пластин рабочих элементов резцов претерпевают те участки, где наблюдается повышение удельной мощности трения. Макрорельеф поверхности разрушения имеет неоднородную фактуру: наличие различного размера бороздок, сколы, отслаивания, трещины, лункообразования с элементами бороздок усталостного разрушения. The work is devoted to the study of worn soldered carbide plates of the drill screw cutter. The advantage of auger drilling is mobility, as well as the combination of drilling and soil extraction operations. During operation, depending on the climatic and abrasive drilling environment, the drilling tool undergoes wear. Carrying out research on the wear of working elements made of carbide plates is necessary to develop recommendations for increasing resource potentials and improving the performance of drilling tools. The object of this work is carbide soldered plates for auger drill cutters. The maximum wear of the surface of the carbide plates of the working elements of the cutters is experienced in those areas where an increase in the specific friction power is observed. The macrorelief of the fracture surface has an inhomogeneous texture: the presence of grooves of various sizes, chips, peeling, cracks, hole formations with elements of fatigue fracture grooves.

—The Novaya Zemlya Archipelago is an early Cimmerian folded structure located on the northern periphery of the Ural–Mongolian fold belt. The geologic development of the archipelago is well-studied and serves as a benchmark for interpolating its features to the shelf of the surrounding water areas, whose sedimentary cover contains large accumulations of hydrocarbon raw materials. In addition to the stratified section of essentially sedimentary rocks, it is of interest to study igneous formations, which clearly mark tectonic events in the geologic history of the archipelago. In the light of this, the age of these formations remains important. The age of some magmatic complexes of the archipelago is still debatable. This paper focuses upon a lamprophyre complex in the extreme south of Novaya Zemlya, which has been dated at the Late Proterozoic or Late Proterozoic–early Paleozoic(?) until recently. The results obtained for the U–Pb age of apatites contained in the rocks of this complex confirm the Devonian age of the lamprophyres, and it is suggested by estimates based on the presented data that the emplacement time lies in a range from 360 to 398 Ma. This means that they might be associated with riftogenic processes on Novaya Zemlya since the second half of the Early Devonian, when the stage of short-term stable carbonate sedimentation (in the first half of the Devonian Period) was replaced by the initiation of a new structural–formational zonal sequence.

An Erratum to this paper has been published: https://doi.org/10.1134/S0016702923200016

This paper presents new age estimates and results obtained by the chemostratigraphic study of dolostones of the Billyakh Group, which consists of the Kotuikan and the Yusmastakh formations. The Billyakh Group forms the upper part of the Riphean section of the Anabar uplift in northern Siberia. The stepwise dissolution technique was used for the first time to determine the 87Sr/86Sr, 206Pb/204Pb, and 207Pb/204Pb isotopic ratios in dolostones. The Rb‒Sr systematics was studied by the chemical removal of about a third of the crushed sample (fraction L1) by the preliminary acid leaching in 0.2 N CH3COOH and the subsequent partial dissolution (fraction L2) of the remaining part of the sample in CH3COOH with the same concentration. The Pb‒Pb isotope systematics of dolostones was studied by the six-step dissolution of crushed samples in 0.5 N HBr. These procedures led to the removal of secondary carbonate material and greatly improved the quality of Sr chemostratigraphic and geochronological information. The initial 87Sr/86Sr ratios of the least altered carbonate material (fraction L2) of the Billyakh Group dolostones are 0.70502 ± 0.00029 in the Kotuikan Formation, 0.70519 ± 0.00026 in the lower subformation of the Yusmastakh Formation, and 0.70511 ± 0.00018 in the upper subformation of the Yusmastakh Formation. The Pb‒Pb age of early diagenesis of Kotuikan and Yusmastakh dolostones (1519 ± 18 Ma at MSWD = 1.8) was calculated from the results obtained for carbonate fractions L3–L6. Secondary carbonate fractions L1‒L2 are characterized by a Pb‒Pb age of 1466 ± 54 Ma at MSWD = 0.6. The δ13C values vary from ‒1 to ‒0.4‰ in dolostones of the Kotuikan Formation and from ‒0.4 to +0.8‰ in those of the Yusmastakh Formation (from ‒0.1 to +0.4‰ in the lower subformation and from ‒0.4 to +0.8‰ in the upper subformation). Comparison of these variations, as well as variations in the initial 87Sr/86Sr ratios in dolostones of the Kotuikan Formation and the Lower and Upper Yusmastakh subformations (0.70460‒0.70499, 0.70450‒0.70525, and 0.70462‒0.70523, respectively), does not make it possible to distinguish these units on the basis of chemostratigraphic characteristics.

— Clay subfractions (SFs) with particles size of 2–5, 0.6–2.0, 0.3–0.6, 0.2–0.3, and 0.1–0.2 μm of two shale samples (Upper Riphean Inzer Formation, South Urals) are studied using transmission electron microscopy, X-ray diffractometry (XRD), and U–Pb, Sm–Nd, Rb–Sr, and K–Ar methods. The SFs are composed of low-temperature 1M d illite; quartz, chlorite, and 2M 1 illite are observed only in some coarse SFs. Irrespective of the size, the clay particles are equant. The standardized illite crystallinity indices (CIS) of all SFs are typical of the dia(cata)genesis zone. The CIS value increases, the I 002 /I 001 ratio of XRD patterns decreases, and the K content and K/Rb ratio increase with decreasing particle size of the SFs from 2–5 to 0.1–0.2 μm. Leaching with 1N HCl and 1N NH 4 OAc and U–Pb, Sm–Nd, and Rb–Sr analysis of untreated SFs, leachate, and residue allowed us to study the isotope systematic of mixing in mobile and silicate material of shales. The 208 U/ 204 Pb and 87 Rb/ 86 Sr ratios of leachates are lower and the 147 Sm/ 144 Nd ratio is higher than those of residues. The leachates are also characterized by less radiogenic Pb and Sr and more radiogenic Nd relative to residues. With decreasing size of SF particles, the U, Pb, Sm, Nd, and Sr contents of leachates gently decrease and the Rb content increases. The 87 Rb/ 86 Sr and 87 Sr/ 86 Sr ratios of leachates of fine SFs are significantly higher, whereas their 238 U/ 204 Pb ratio is lower in comparison with coarse SFs. What is more, the data points of residues of various SFs occur along the mixing lines in the 87 Rb/ 86 Sr‒ 87 Sr/ 86 Sr and 1/ 86 Sr‒ 87 Sr/ 86 Sr plots. The data points of corresponding leachates also form linear trends in 238 U/ 204 Pb‒ 206 Pb/ 204 Pb, 206 Pb/ 204 Pb‒ 207 Pb/ 204 Pb, 147 Sm/ 144 Nd‒ 143 Nd/ 144 Nd, and 87 Rb/ 86 Sr‒ 87 Sr/ 86 Sr coordinates. Apparent Rb–Sr ages calculated from slopes of “inner isochrons” (“leachochrons”) as well as K-Ar ages gradually decrease from 835–836 and 721–773 Ma, respectively, for SFs of 2–5 μm and to 572‒580 and 555‒580 Ma, respectively, for SFs of 0.1–0.2 μm. Thus, the XRD and isotopic data indicate that both clay and mobile shale constituents are mixtures at least of two components, and the silicate phase contains authigenic illites of various ages. First-generation illite abundant in the coarse SFs of 2–5 μm and 0.6–2.0 μm was formed immediately after the deposition of the Inzer sediments and its age of 803–836 Ma is consistent with stratigraphic age of the Inzer Formation. The formation of this illite was facilitated either by lithostatic burial or intense horizontal fluid flow caused by tectonic inversion in the eastern regions of the Uralian paleobasin. The age of the second-generation illite is 572–580 Ma; it was formed as a result of vertical movements or renovation of the composition of the pore fluids during deformations and metamorphism of the South Urals related to the evolution of the Beloretsk metamorphic complex.

The 2–5, 0.6–2, 0.3–0.6, 0.2–0.3 and 0.1–0.2 µm clay subfractions (SFs) separated from two shale samples of the Upper Riphean Inzer Formation, the southern Urals, were studied by the TEM, XRD, and U–Pb, Sm–Nd, Rb–Sr and K–Ar isotopic methods. All the SFs consist of the low-temperature 1Md illite; admixtures of quartz, chlorite and 2M1 illite occur only in the coarsest SFs. The clay particles are isometric, regardless of their size. The CIS (Crystallinity Index Standard) illite values for the all SFs are typical for the dia(kata)genetic zone. As the size of particles in the SF decreases from 2–5 to 0.1–0.2 µm, the CIS rises, the I002/I001 ratio on the XRD diagrams decreases, and the K content and the K/Rb ratio increase. Leaching with 1N HCl and 1N ammonium acetate (NH4OAc) and subsequent U–Pb, Sm–Nd and Rb–Sr analyses of the untreated SF, acid (acetate) leachate and residue made possible to study the mixing systematics in mobile and silicate materials of the shales. The 238U/204Pb and 87Rb/86Sr ratios in the acid and acetate leachates are below, and the 147Sm/144Nd ratio is above those in the residues. Less radiogenic Pb and Sr and more radiogenic Nd are also common for the leachates compared to the residues. As the size of particles in the SFs decreases, the U, Pb, Sm, Nd and Sr contents in the residues are smoothly reduced, whereas the Rb content shows an increase. The 87Rb/86Sr and 87Sr/86Sr values in the residues for fine-grained SFs are well above, and the 238U/204Pb value is well below those for coarse-grained SFs. What is more, in the 87Rb/86Sr–87Sr/86Sr and 1/86Sr–87Sr/86Sr diagrams, data points for the residues of variable size are arranged on the mixing lines. The data points of respective acid and acetate leachates also form linear trends in the 238U/204Pb–206Pb/204Pb, 206Pb/204Pb–207Pb/204Pb, 147Sm/144Nd–143Nd/144Nd, and 87Rb/86Sr–87Sr/86Sr coordinates. The apparent Rb–Sr age values, calculated from the slopes of “inner isochrons” (“leachochrons”), along with the K–Ar ages are smoothly lowered from 835–836 and 721–773 m.y. for the 2–5 µm SF to 572–580 and 555–580 m.y. for the 0.1–0.2 µm SF. Hence the XRD and isotopic data testify that the clay as well as the mobile material of the shale represent the mixtures of at least two components, the silicate phase containing authigenic illites of different ages. The first illite generation enriched in coarse-grained 2–5 and 0.6–2 µm SFs was formed shortly after deposition of the Inzer sediments, and its age of 803–836 m.y. is in agreement with the stratigraphic age of the formation. Simple lithostatic burial or intensive lateral fluid flow induced by tectonic inversion in the eastern regions of the Urals paleobasin may be considered as the geological processes responsible for the forming of this illite. The second illite generation was formed 572–580 m.y. ago. As the starting points for its formation, alternatively, may be concerned either vertical tectonics or renewal of pore fluid compositions during deformations and metamorphism on the southern Urals area related to evolution of the Beloretsk metamorphic complex.

Определен Pb–Pb изотопный возраст и получена Sr-изотопная характеристика осадочных известняков верхнего рифея юга Енисейского кряжа на западной окраине Сибирской платформы. Возраст карбонатных осадков дадыктинской свиты тунгусикской серии в Каменской фациальной зоне на востоке Енисейского кряжа составляет 1020 ± 20 млн лет. Возраст известняков горевской свиты широкинской серии в Глушихинской фациальной зоне на западе региона оценивается в 1020 ± 70 млн лет. Отношение 87 Sr/ 86 Sr в известняках дадыктинской свиты заключено в пределах 0.70536–0.70590, а горевской – 0.70552–0.70578. Это совпадает с понижением отношения 87 Sr/ 86 Sr в океане сразу после кульминационной фазы гренвильской орогении. Корреляция широкинской серии с ослянской серией Каменской зоны в сочетании с другими данными ограничивает время накопления тунгусикской, широкинской и ослянской серий интервалом 1030–950 млн лет. Изотопный возраст границы среднего и верхнего рифея в основании тунгусикской серии Енисейского кряжа оценивается как 1030 млн лет, что согласуется с возрастом этого рубежа в разрезах Туруханского поднятия и Учуро-Майского региона Сибири. Установлено, что большая часть верхнего рифея (неопротерозоя) в осадочной летописи Енисейского кряжа отсутствует. Наблюдаемая фациальная зональность рифейских отложений Енисейского кряжа отражает конфигурацию древнего осадочного бассейна, который существовал на западной окраине Сибирской платформы задолго до коллизионных событий, сопровождавшихся гранитообразованием и метаморфизмом, в неопротерозое.

Определены концентрации U и Pb и изотопные составы углерода, кислорода и свинца в доломитах билляхской серии (в 6 образцах котуйканской свиты и 15 образцах юсмастахской свиты), слагающей верхнюю часть рифейского разреза Анабарского поднятия Северной Сибири. Величины δ 13 С и δ 18 O в доломитах билляхской серии варьируют от –3.0 до +0.8‰ PDB и от 23.7 до 27.3‰ SMOW соответственно и согласуются с таковыми в карбонатных осадках, отлагавшихся 1600–1400 млн лет назад. На графике в координатах 206 Pb / 204 Pb – 207 Pb / 204 Pb 18 фигуративных точек всех образцов котуйканской и юсмастахской свит располагаются вдоль прямой линии, которая отвечает возрасту 1513 ± 35 млн лет. Полученный Pb – Pb возраст доломитов впервые дает прямую изотопно-геохронологическую характеристику осадочных пород чехла Анабарского поднятия и в сочетании с опубликованным ранее Rb–Sr возрастом глауконита нижележащей усть-ильинской свиты позволяет поместить всю осадочную последовательность билляхской серии в ранний рифей. Эти результаты указывают на относительно быстрое (в пределах ~10 млн лет) накопление терригенно-карбонатных отложений билляхской серии до внедрения долеритов котуйского комплекса и заложения мезопротерозойской куонамской магматической провинции на Сибирском кратоне. Новые данные ставят точку в дискуссиях о возрастном положении рифейских отложений, вскрытых на Анабарском поднятии.

Test flux-cored wires for arc spraying technology are developed. Tantalum and tungsten powders are selected as modifying additives. A PGSR-4 (Ni–Cr–B–Si) commercial powder is the basis of the powder material. The structure of the modified coatings is studied by metallographic analysis. Wear tests of the modified coatings are performed by slipping friction. The friction coefficients and the roughness characteristics are measured.

The U and Pb contents and C, O, and Pb isotopic compositions are determined for dolomites of the Billyakh Group (6 and 15 samples of the Kotuikan and Yusmastakh formations, respectively), which composes the upper part of the Riphean section of the Anabar Uplift of North Siberia. The δ13С and δ18O values of dolomites vary from –3.0 to +0.8‰ PDB and from 23.7 to 27.3‰ SMOW, respectively, and are in agreement with those of carbonate sediments 1600–1400 Ma in age. On the 206Pb/204Pb–207Pb/204Pb plot, 18 data points of all samples of both formations occur along a straight line which corresponds to the age of 1513 ± 35 Ma. The Pb–Pb age of dolomites is a first direct geochronological characteristic of sedimentary rocks of the Anabar uplift cover and, along with the previously published Rb–Sr age of glauconite of the underlying Ust’-Il’ya Formation, allows us to ascribe the entire sedimentary sequence of the Billyakh Group to the Lower Riphean. These results indicate relatively fast (~10 m.y.) terrigenous-carbonate sedimentation of this group prior to intrusion of dolerites of the Kotui complex and origination of the Mesoproterozoic Kuonamka igneous province on the Siberian Craton. New data close a discussion on the age position of Riphean sediments of the Anabar Uplift.

For the first time, the age of magnesite in the Lower Riphean Bakal Formation of the Southern Urals is determined by the U—Pb (Pb—Pb) method: it is equal to 1366 ± 47 Ma (MSWD = 18). The stage of magnesite formation of the Bakal ore field was associated with the Mashak rifting pulse and took place prior to the formation of industrial deposits of the Bakal siderite.

В работах различных авторов было показано, что многочисленные спонтанные повреждения ДНК (разрывы ДНК, изменение оснований), ежедневно возникающие в клетке в результате метаболизма организма человека, являются основой мутационной селекции. Мутантные клетки имеют определенные преимущества в микроокружающей среде, изменяющейся вследствие возрастных особенностей, что способствует образованию онкоклонов и диссеминации их. Значительная роль в этом процессе принадлежит наследственным факторам, при этом существует ряд наследственных болезней (пигментная ксеродерма и др.), которые в большинстве случаев приводят к возникновению рака. Описан ряд сопряженных генов, контролирующих клеточный гомеостаз и при этом являющихся генами-супрессорами, изменение активности которых или мутации в их структуре способствуют канцерогенезу. Рассмотрена роль эпигенетических факторов, к которым относятся некодирующие регуляторные РНК, организация структуры хроматина, метилирование в процессах канцерогенеза. Модуляция функциональной активности генов осуществляется некодирующими РНК, каждая из которых может иметь несколько генов-мишеней и, в свою очередь, быть подвержена влиянию различных генов. К регуляторным РНК относятся микроРНК и длинные некодирующие белки РНК, изменения активности которых могут служить биомаркерами начала заболевания, иметь прогностическую ценность и использоваться как мишень для терапии. Представлены новые данные о роли некодирующих РНК, метилирования и организации хроматина при канцерогенезе. Приведены данные авторов по использованию уровня экспрессии ряда генов и некодирующих РНК как прогностических показателей, пригодных для оценки эффективности терапии ряда опухолей. Специальное внимание уделено структурной организации хроматина и метилированию в канцерогенезе, а также взаимодействию клеточных структур, влияющих не активность генов и их регуляцию в канцерогенезе. Дана краткая оценка канцерогенного действия экзогенных факторов: природных (космические факторы, некоторые природные соединения) и антропогенных (радиация, химические вещества, онкогенные вирусы).

The geochemistry, geochronology, and isotope geochemical systematics (Nd, Sr, Hf, and Pb) of the granitoids of the Pozdnestanovoy complex of the Dzhugdzhur–Stanovoy superterrane of the Central Asia fold belt were investigated. It was shown that their age is Mesozoic (142–138 Ma) rather than Early Precambrian, as was previously supposed. The main sources of parental melts for these granitoids were the Neoarchean and Paleoproterozoic rocks of the lower continental crust of the Dzhugdzhur–Stanovoy superterrane and the rocks of the Late Paleozoic–Early Mesozoic continental crust of the Amur microplate. They were formed at depths of >40 km and temperatures of 700–800°C, most likely through the melting of mafic feldspar granulites under the conditions of aqueous fluid infiltration without any significant contribution from a juvenile heat source. The granitoids of the Pozdnestanovoy complex were emplaced during the closure of the eastern segment of the Mongolia–Okhotsk Ocean owing to the collision of the Siberian and Sino-Korean continents.