The results of a comprehensive detailed study of the vein structure, mineral zoning of veins, and mineral typomorphism of the Shakhtama deposit obtained on the basis of new samples from poorly studied horizons are given. The results obtained show that the Mo resources of the deposit are far from being exhausted, and the typomorphic features of ore minerals indicate that base metal mineralization associated with Au (Ag), also continues to a depth, along with Mo. The presence of rare Sr mineral, svanbergite, in the Shakhtamа deposit and the typomorphic properties of ore minerals testify in favor of the near-surface origin of the exposed mineralization. The succession of mineral formation has been established. Based on the study of ore and metasomatic zonality, fluid inclusions and isotopic data, as well as the composition of structural impurities in molybdenite, conclusions were made of the formation conditions of ore mineralization in a porphyry ore-forming system.

The results of a comprehensive detailed study of the vein structure, mineral zoning of veins, and mineral typomorphism of the Shakhtama deposit obtained on the basis of new samples from poorly studied horizons are given. The results obtained show that the Mo resources of the deposit are far from being exhausted, and the typomorphic features of ore minerals indicate that base metal mineralization associated with Au (Ag), also continues to a depth, along with Mo. The presence of rare Sr mineral, svanbergite, in the Shakhtamа deposit and the typomorphic properties of ore minerals testify in favor of the near-surface origin of the exposed mineralization. The succession of mineral formation has been established. Based on the study of ore and metasomatic zonality, fluid inclusions and isotopic data, as well as the composition of structural impurities in molybdenite, conclusions were made of the formation conditions of ore mineralization in a porphyry ore-forming system.

Tungstenite of unusual shapes (spheroids, rings, threads, spirals, etc.) was found in scheelite of gold-bearing quartz–carbonate–pyrite–chalcopyrite veins. It is crystallized in the veins in the final part of mineral deposition, after crystallization of sulfides, sulfosalts, and scheelite of several generations against the background of decreasing activity of sulfur. The issue concerning the type of the strong reducing agent of the W6+ → W4+reaction rarely occurring in nature is crucial for the formation of tungstenite. There are no traces of reducing agents, which could be solid or liquid hydrocarbons, in the veins. The unusual shapes of tungstenite aggregates similar to biomorphosеs may be evidence of the existence of microorganisms in the fractured anisotropic medium in scheelite at the boundary of the transition of the quartz part of the vein to the substantially carbonate part. The occurrence of the biomorphоsеs only in scheelite suggests that microorganisms have a W-dependent metabolism, which is observed in extremophiles of the Archaea domain producing a strong reducing agent H2; methanogens producing CH4 coexist in symbiosis with them.

The paper presents pioneering data on the composition, texture, and crystal structure of molybdenite from various types of molybdenum mineralization at the Bystrinsky Cu–Au–Fe porphyry–skarn deposit in the eastern Transbaikal region, Russia. The data were obtained using electron microprobe analysis (EMPA), laser ablation–inductively coupled plasma mass spectrometry (LA-ICP-MS), and high-resolution transmission electron microscopy (HRTEM). Molybdenite found at the deposit in skarn, sulfide-poor quartz veins, and quartz–feldspar alteration markedly differs in the concentrations of trace elements determined by their species in the mineral, as well as in its structural features. Molybdenite-2H from skarn associated with phyllosilicates occurs as ultrafine crystals with uniform shape and texture; no dislocations or inclusions were found but amorphous silica was. The molybdenite composition is highly contrasting in the content and distribution of both structure-related (Re, W, and Se) and other (Mn, Co, Ni, Cu, Zn, As, Ag, Cd, Sb, Te, Ag, Pd, Au, Hg, Pb, and Bi) metals. In the sulfide-poor quartz veins, highly structurally heterogeneous (2H + 3R) molybdenite microcrystals with abundant defects (dislocations and volumetrically distributed inclusions) are associated with illite, goethite, and barite. Some single crystals are unique three-phase (2H + 3R polytypes + amorphous MoS2). The mineral has a low concentration of all trace elements, which are uniformly distributed. However, individual domains with uniquely high Pd, Te, Ni, Hg, and W concentrations caused by mineral inclusions are found in some grains. Molybdenite from quartz–feldspar alteration is characterized by low concentrations of all trace elements except for Re and Se, which enrich some domains of the grains. Our data indicate that the compositional and structural heterogeneity of molybdenite from the Bystrinsky deposit are its crucial features, which obviously correlate with the types of Mo mineralization.

This article presents the new mineralogical, fluid inclusion, and isotopic data for ores of the Novoshirokinsky base metal–gold deposit. Mineralogical sequence is supplemented and specified. The mineral assemblages containing native gold are studied. Morphology, grain size and chemical composition of native gold are described. Major parameters and composition of mineralizing fluids of the main ore stages at the deposit are estimated: main base metal (mid-temperature conditions, fluid salinity 3.1–13.1 wt % equiv NaCl) and carbonate–base metal (low-temperature conditions, fluid salinity 1.0–12.9 wt % equiv. NaCl). Sulfur isotopic composition of sulfides from commercial mineral assemblages has been studied. The δ 34 S value (+10.5 ± 1‰) of mineralizing fluid has been calculated. The Novoshirokinsky deposit is similar to epithermal deposits and is spatially related to the Late Jurassic porphyry system. Evidence is provided on carbonate rocks of basement involved in the ore-forming process.

The structural state was determined for zero-valence molybdenum in the lunar regolith. The body- and face-centered molybdenum forms (BCC and FCC, respectively) were identified. Disruption of the structure down to complete amorphization was noted. This might be caused by the long-term influence of the solar wind.

Определено структурное состояние нуль-валентного молибдена из лунного реголита. Выявлены ОЦК и ГЦК его формы. Отмечен факт разрушения его структуры до полной аморфизации. Предполагают, что причиной этого послужило длительное воздействие солнечного ветра.

В статье представлены данные о размещении зон калиевых и пропилитовых гидротермальных изменений в купольной вулкано-плутонической структуре, контролирующей на Северо-Востоке России позицию Дукатского рудного поля с одноименным уникальным эпитермальным Au-Ag-месторождением. Комплексные минералого-геохимические данные для пород и минералов зон гидротермальных изменений и ассоциирующих интрузий показали, что кварц-ярозит-серицитовые, кварц-пирит-серицитовые, кварц-адуляр-хлоритовые изменения происходили при участии потоков флюидов, связанных со становлением пальцеобразных выступов крупнопорфировых интрузий лейкогранитов повышенной калиевой щелочности в условиях дивергентных плитовых границ рифтогенного грабена, а кварц-клиноцоизит-кальцитовые, эпидот-хлоритовые, гранат-кальцит-хлоритовые – со становлением аналогичных тел K-Na-лейкогранитов в условиях конвергентных плитовых границ, активизированных в связи с формированием краевого Охотско-Чукотского вулканического пояса. Процессы фазовой сепарации и коагуляции отдельных порций восходящих флюидов приводят к образованию и стабилизации малоразмерных частиц самородного серебра и других рудных компонентов, способных вовлекаться в потоки вторичных гидротерм и рудообразующих флюидов. Данные изотопного состава Sr, Nd и Pb пород и минералов зон гидротермальных изменений, ассоциирующих интрузий и продуктивных рудных тел месторождения Дукат показали, что их компоненты были заимствованы из областей ювенильной континентальной коры, преобразованной в домеловые периоды эндогенной активности. Компоненты нерудных минералов калиевых и пропилитовых гидротермальных изменений и ассоциирующих интрузий были заимствованы из глубинных областей, различающихся величинами 87Sr 86Sr и 143Nd/144Nd при близких значениях U/Pb, Th/Pb. Халькофильный свинец продуктов гидротермальной деятельности и меланократовых включений лейкогранитов был заимствован из областей с повышенными величинами U/Pb, Th/Pb.

The paper considers the localization of potassic and propylitic hydrothermal alteration zones in the domal volcanic-plutonic structure controlling the position of the Dukat ore field with the eponymous unique epithermal Au-Ag deposit. Comprehensive mineralogical and geochemical data on rocks and minerals in hydrothermal alteration zones and associated intrusions have shown that quartz-jarosite-sericite, quartz-pyrite-sericite, and quartz-adularia-chlorite alterations were formed with the participation of fluid flows related to a fingerlike projection of a high-K leucogranite porphyry intrusion with large phenocrysts. These hydrothermal alterations developed in the rifted graben under conditions of divergent plate boundaries, whereas quartz-clinozoisite-calcite, epidote-chlorite, and garnet-calcite-chlorite alterations were linked to K-Na leucogranite intrusive bodies and developed under conditions of convergent plate boundaries reactivated as a result of formation of the marginal Okhotsk-Chukotka volcanic belt. Phase separation and coagulation of specific portions of ascending fluids resulted in the formation and stabilization of small-sized particles of native silver and other ore components, which enabled involvement in flows of secondary geothermal solutions and ore-forming fluids. The Sr, Nd, and Pb isotopic compositions of rocks and minerals from the hydrothermal alteration zones, associated intrusions, and economic orebodies at the Dukat deposit indicate that their components have been derived from the juvenile continental crust, which was altered in pre-Cretaceous periods of endogenic activity. The components of gangue minerals of potassic and propylitic hydrothertmal alterations and associated intrusions have been taken from deep sources differing in 87Sr/86Sr and 143Nd/144Nd at similar U/Pb and Th/Pb ratios. Chalcophile lead in products of hydrothermal activity and melanocratic inclusions in leucogranite has been taken from regions with elevated U/Pb and Th/Pb ratios.

The Butarny gold deposit is situated in the central part of the Khurchan-Orotukan Zone of tectonomagmatic activation, which is traced for 150 km in the near-meridional direction, and localized in the slightly eroded Late Jurassic granitoid stock of the same name. The explored orebodies are quartz veins and pinnate veinlets with low-grade pocket-disseminated sulfide (mainly arsenopyrite) mineralization containing native gold. The Bi-bearing gold-pyrite-arsenopyrite and the quartz-löllingite-arsenopyrite-stibnitejamesonite stages of the veined low-sulfide ore formation have been distinguished. The main mineral assemblage consists of arsenopyrite, native gold, and native bismuth. The minerals-carriers of gold were deposited during the final stage of ore-bearing quartz crystallization at 334−245°C from low-concentrated pneumatolytic-hydrothermal carbonated fluid containing CO 2 and CH 4 (5.8−2.2 and 1.6−0.5 mol/kg of solution, respectively). The ore-bearing fluid had variable salinity (5.3−2.2 wt % NaCl equiv). It is quite probable that the gas-saturated fluid participated in transport and precipitation of ore matter. Its density varies from 1.02 to 0.77 g/cm 3 . The pressure is estimated at 1600 to 780 bar. The fluid regime of ore formation at the Butarny deposit is similar to that of typical intrusion-related gold deposits. The Au tenor of beresitized granodiorite, numerous quartz veinlets, and extensive Au-bearing weathering mantle allow us to suggest stockwork mineralization.

Месторождение золота Бутарное расположено в центральной части Хурчан-Оротуканской зоны тектоно-магматической активизации, прослеженной в субмеридиональном направлении на 150 км, и локализовано в пределах слабо эродированного одноименного гранитоидного штока позднеюрского возраста. Разведанные рудные тела представлены кварцевыми жилами и оперяющими их прожилками с убогой гнездово-вкрапленной сульфидной (главным образом арсенопиритовой) минерализацией, несущей самородное золото. Жильные руды месторождения малосульфидные, сформировались в течение двух стадий: золото-пирит-арсенопиритовой (висмутсодержащей) и кварц-леллингит-арсенопирит-антимонит-джемсонитовой. Главная ассоциация рудных минералов – арсенопирит-золото-висмут. Отложение минералов-носителей золота происходило при завершении кристаллизации продуктивного кварца в интервале температур 334–245°С. Продуктивные ассоциации характеризуются слабо концентрированными пневматолито-гидротермальными карбонатными растворами, содержащими СО2 и CH4 (5.8–2.2 и 1.6–0.5 моль/кг раствора соответственно). Для рудообразующего флюида характерна переменная соленость 5.3–2.2 мас. %-экв. NaCl. Вполне вероятно участие насыщенного газового флюида в переносе и отложении рудного вещества. Его плотность изменяется от 1.02 до 0.77 г/см3. Оценки давления составляют от 1600 до 780 бар. Флюидный режим формирования руд, установленный на месторождении Бутарное, сходен с типичными месторождениями золота, связанными с интрузивами гранитоидов. Данные по золотоносности березитизированных гранодиоритов и многочисленных кварцевых прожилков, а также развитие площадной золотоносной коры выветривания позволяют предполагать наличие штокверковой рудной залежи на месторождении.

Минералы рассеянной минерализации позднемеловых лейкогранитов Дукатского рудного поля составляют меланократовые сульфидные эпидот-полевошпатовые, пироксен-полевошпатовые и малосульфидные алланит-флюорит-полевошпатовые включения грейзенизированных интрузий. Серебро-полиметалличекая минерализация представлена пиритом, пирротином, малоразмерными частицами сульфидов, оксидов Pb, Zn, Sn, Ag, Sb, их самородных форм, интерметаллических соединений, а редкометальная – оксидами, силикатами, алюмосиликатами РЗЭ, Th, U, Ti, Zr, Nb, Ta, W. Данные изотопного состава Nd, Sr, Pb и геохимические характеристики минерализованных включений, породообразующих минералов гранитоидов, гидротермальных минералов предрудных пропилитов и рудных тел месторождения Дукат показали, что их компоненты были заимствованы из неоднородных областей палеозойской ювенильной континентальной коры Сибирской платформы.

There are good grounds to believe that the inherited development of ore bodies controls the most important regularities in the location of deposits, especially of large ones, and also explains quite clearly the relatively selective ore occurrence in different magmas. Giant silver deposits were identified among both Paleozoic bodies and their regenerated Late Mesozoic vein-disseminated analogues. Jointly they represent a unified polychronic ore formation range. The performed investigations of mineral composition and the isotopic Sm-Nd system of granitoids in the Dukat ore field and their gold- and silver-bearing melanocratic inclusions established the possible occurrence of the Paleozoic juvenile continental crust of the Siberian Craton in their composition and confirmed our complicated scheme of oregenesis at the Dukat silver giant. The occurrence of high-grade gold in the melanocratic mineral aggregates of granitoids in the Dukat ore field should be regarded as a feature of hypabyssal gold-bearing zones being of high commercial interest.

The dispersed mineralization in the Late Cretaceous leucogranite of the Dukat ore field comprises melanocratic high-sulfide epidote-feldspar, pyroxene-feldspar and low-sulfide allanite-fluorite-feldspar inclusions in greisenized intrusions. The silver-base-metal mineralization is composed of pyrite, pyrrhotite, small particles of Pb, Zn, Sn, Ag, and Sb sulfides and oxides, their native species, and intermetallic compounds; the rare-metal mineralization consists of REE, Th, U, Ti, Zr, Nb, Ta, and W oxides, silicates, and aluminosilicates. The isotopic Nd, Sr, and Pb isotopic compositions and geochemical characteristics of the mineralized inclusions, rock-forming minerals of granitoids, hydrothermal minerals of preore metasomatic propylites and orebodies at the Dukat deposit show that their components have been taken from heterogeneous domains of the Paleozoic juvenile continental crust of the Siberian Platform.