scholarly journals Gold-Bearing Brown Coal Deposits of the Zeya–Bureya Sedimentary Basin (East Russia): Fundamental Model of Formation

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 682
Author(s):  
Anatoliy Petrovich Sorokin ◽  
Andrey Alexeyevich Konyushok ◽  
Valeriy Mikhailovich Kuz’minykh ◽  
Sergey Vadimovich Dugin

The primary sources and the conditions for the formation of the Paleogene–Neogene coal-bearing deposits in the Zeya–Bureya sedimentary basin were identified and studied with the help of paleogeographic reconstructions and geochemical analyses. Based on the results obtained, we suggest a new basic model of element transfer into the coal, involving two mutually complementary processes to account for the introduction and concentration of gold and other trace elements in the sequences investigated. The first process reflects the system in which peatlands were concentrated along the basin’s junction zone and the passive internal residual mountain ranges. The second reflects the junction’s contrast-type (sharp-type) forms conditions along the external mobile mountain-fold frame. The eroded gold particles were transported over 10–20 km as complex compounds, colloids, dispersed particles, and nanoparticles, and remobilized into clastogenic and dissolved forms along the first few kilometers. The release of gold in the primary sources occurred due to weathering of gold-bearing ore zones, followed by transportation of gold by minor rivers to the areas of peat accumulation. This study considered the probability of the accumulation of high concentrations of gold and rare earth elements (REE) in coal due to the introduction of organic and inorganic materials during floods, with episodes of catastrophic events, and volcano–hydrothermal activities.

2019 ◽  
Vol 70 (3) ◽  
pp. 382 ◽  
Author(s):  
Nidia I. Tobón Velázquez ◽  
Mario Rebolledo Vieyra ◽  
Adina Paytan ◽  
Kyle H. Broach ◽  
Laura M. Hernández Terrones

The aim of the study is to determine the distribution of trace and major elements in the water and in the sediments of the south part of the Bacalar Lagoon and to identify the sources of the trace elements and their changes over time. The western part of the lagoon water column is characterised by high concentrations of Ca2+, HCO3– and Sr2+, derived from groundwater input. In contrast, the eastern part of the lagoon is characterised by high concentrations of Mg2+, Na+ and Cl–. The lagoon is not affected by present-day seawater intrusion. Water column and sediment geochemical analyses performed in Bacalar Lagoon show clear spatial distribution of different parameters. The saturation index of the water column indicates three main groups: (1) a zone oversaturated with regard to aragonite, calcite and dolomite; (2) an undersaturated area where all three minerals are dissolving; and (3) an area with calcite equilibrium and undersaturation with regard to the other minerals. Herein we present the first measurements of trace element (Ba2+, Mn2+, K+, Ni2+, Zn2+) concentrations in carbonates obtained from sediments in Bacalar Lagoon. In order to evaluate whether the trace elements are derived from natural or anthropogenic sources, four pollution indices were calculated. The results confirmed that Bacalar Lagoon sediments are not contaminated with Ni2+, K+, Mn2+ and Ba2+, and that the Zn2+ seems to have a predominantly anthropogenic origin.


2018 ◽  
Vol 84 (16) ◽  
Author(s):  
Christina Frick ◽  
Julia Vierheilig ◽  
Rita Linke ◽  
Domenico Savio ◽  
Horst Zornig ◽  
...  

ABSTRACTQuantitative information regarding the presence ofEscherichia coli, intestinal enterococci, andClostridium perfringensin poikilotherms is notably scarce. Therefore, this study was designed to allow a systematic comparison of the occurrence of these standard fecal indicator bacteria (SFIB) in the excreta of wild homeothermic (ruminants, boars, carnivores, and birds) and poikilothermic (earthworms, gastropods, frogs, and fish) animals inhabiting an alluvial backwater area in eastern Austria. With the exception of earthworms, the average concentrations ofE. coliand enterococci in the excreta of poikilotherms were equal to or only slightly lower than those observed in homeothermic excreta and were 1 to 4 orders of magnitude higher than the levels observed in the ambient soils and sediments. Enterococci reached extraordinarily high concentrations in gastropods. Additional estimates of the daily excreted SFIB (E. coliand enterococcus) loads (DESL) further supported the importance of poikilotherms as potential pollution sources. The newly established DESL metric also allowed comparison to the standing stock of SFIB in the sediment and soil of the investigated area. In agreement with its biological characteristics, the highest concentrations ofC. perfringenswere observed in carnivores. In conclusion, the long-standing hypothesis that only humans and homeothermic animals are primary sources of SFIB is challenged by the results of this study. It may be necessary to extend the fecal indicator concept by additionally considering poikilotherms as potential important primary habitats of SFIB. Further studies in other geographical areas are needed to evaluate the general significance of our results. We hypothesize that the importance of poikilotherms as sources of SFIB is strongly correlated with the ambient temperature and would therefore be of increased significance in subtropical and tropical habitats and water resources.IMPORTANCEThe current fecal indicator concept is based on the assumption that the standard fecal indicator bacteria (SFIB)Escherichia coli, intestinal enterococci, andClostridium perfringensmultiply significantly only in the guts of humans and other homeothermic animals and can therefore indicate fecal pollution and the potential presence of pathogens from those groups. The findings of the present study showed that SFIB can also occur in high concentrations in poikilothermic animals (i.e., animals with body temperatures that vary with the ambient environmental temperature, such as fish, frogs, and snails) in an alluvial backwater area in a temperate region, indicating that a reconsideration of this long-standing indicator paradigm is needed. This study suggests that poikilotherms must be considered to be potential primary sources of SFIB in future studies.


2019 ◽  
Vol 486 (6) ◽  
pp. 714-717
Author(s):  
T. P. Mayorova ◽  
S. K. Kuznetsov ◽  
V. N. Filippov

For the first time, silver nuggets were found in the gold-bearing placers of the Subpolar Urals. Galena, cassiterite, wolframite, cosalite, tetradymite, ferberite, cobaltine, joseite-B, native bismuth associate with silver and gold. Silver is mainly represented by poorly rounded and non-round gray lumpy, slightly flattened, elongated particles of 2-2.5 cm size. As part of silver, Au and Hg sometimes contain impurities. Inclusions are represented by small particles of gold, bismuth and tellurium mineral phases. Research results indicate a fairly widespread development of Au-Ag-Bi-Te mineralization, the primary manifestations of which are not yet known in the region. Relatively weak roundness of silver nuggets, presence of major and poorly rounded gold indicates the proximity of the primary sources to gold-bearing placers.


2021 ◽  
Vol 12 ◽  
Author(s):  
Patrizia Paganin ◽  
Chiara Alisi ◽  
Elisabetta Dore ◽  
Dario Fancello ◽  
Pier Andrea Marras ◽  
...  

In order to increase the knowledge about geo-bio interactions in extreme metal-polluted mine waters, we combined microbiological, mineralogical, and geochemical analyses to study the indigenous sulfate-reducing bacteria (SRB) involved in the heavy metal (HM) biomineralization processes occurring in Iglesiente and Arburese districts (SW Sardinia, Italy). Anaerobic cultures from sediments of two different mining-affected streams of this regional framework were enriched and analyzed by 16S rRNA next-generation sequencing (NGS) technique, showing sequences closely related to SRB classified in taxa typical of environments with high concentrations of metals (Desulfovibrionaceae, Desulfosporosinus). Nevertheless, the most abundant genera found in our samples did not belong to the traditional SRB groups (i.e., Rahnella, Acinetobacter). The bio-precipitation process mediated by these selected cultures was assessed by anaerobic batch tests performed with polluted river water showing a dramatic (more than 97%) Zn decrease. Scanning electron microscopy (SEM) analysis revealed the occurrence of Zn sulfide with tubular morphology, suggesting a bacteria-mediated bio-precipitation. The inocula represent two distinct communities of microorganisms, each adapted to peculiar environmental conditions. However, both the communities were able to use pollutants in their metabolism and tolerating HMs by detoxification mechanisms. The Zn precipitation mediated by the different enriched cultures suggests that SRB inocula selected in this study have great potentialities for the development of biotechnological techniques to reduce contaminant dispersion and for metal recovery.


Author(s):  
A. M. Nikishin ◽  
T. V. Romanyuk ◽  
D. V. Moskovskiy ◽  
N. B. Kuznetsov ◽  
A. A. Kolesnikova ◽  
...  

The first results of U-Pb dating of detrital zircons (dZr) from two samples characterizing the Taurica and Eski-Orda Groups of the Cimmerian structural complex of the Mountainous Crimea are presented. The strong similarity of the sets of ages of dZr from the Lower Taurica Formation of the Taurica Group and the Salgir strata of the Eski-Orda Group confirms the facial character of the primary relationships of these Groups. The studied Upper Triassic sandstones had a common feeding province and were formed, most likely, in different parts of the same sedimentary basin. It is most likely that this sedimentary basin was part of a continental margin of Baltica. The presence in samples of a significant number of dZr with very ancient ages >3.0 Ga (including 3 the oldest dZr grains with ages of ~3.9 Ga) makes the crystalline complexes represented in the present-day structure of the Ukrainian Shield as the very possible primary sources of these zircons. Crystalline complexes with such ancient ages are extremely rare over the world, but are widely represented in the Podolian and Cis-Azov blocks of the Ukrainian shield.


1985 ◽  
Vol 63 (3) ◽  
pp. 543-561 ◽  
Author(s):  
D. R. Engstrom ◽  
B. C. S. Hansen

Palynological and geochemical analyses of Holocene lake sediments are used to evaluate long-term interactions between vegetation and soils from four sites in southeastern Labrador, Canada. Changes in soil composition are inferred from the stratigraphy of humic materials and the elemental composition of authigenic and allogenic fractions of the sediment. Early Holocene lake muds deposited under tundra vegetation are predominantly inorganic and contain high concentrations of allogenic elastics derived from the erosion of barren soils. Concentrations of humic materials and redox–pH-sensitive elements (Fe, Mn, P, Al) of authigenic origin increase markedly with the subsequent invasion of spruce and fir (8000–7000 years BP). These changes represent decreased erosion of clastic minerals and increased mobilization of organometallic complexes from waterlogged soils produced through humus accumulation under coniferous vegetation. This transition of inorganic tundra inceptisols to humic-rich boreal spodosols contributed to the competitive replacement of Picea glauca and Abies balsamea by the more edaphically tolerant P. mariana between 6500 and 6000 years BP. A subsequent decline in sedimentary humic content and increase in allogenic components may signal a regional climatic cooling after 4000 years BP. Geochemical analyses of lake sediments reveal no stratigraphic changes in allogenic mineral composition that might indicate progressive soil weathering.


2021 ◽  
Vol 140 (1) ◽  
Author(s):  
Elena A. Jagt-Yazykova ◽  
Martin Košťák ◽  
John W. M. Jagt

AbstractA newly collected specimen of the enigmatic coleoid genus Longibelus is recorded from lower Turonian strata along the River Shadrinka in Sakhalin (Russian Far East). To date, this is the first record of Late Cretaceous coleoid cephalopods from the island and, in fact, from the entire Pacific coast of the Russian Federation. Lithological characteristics, coupled with published geochemical analyses (δ13C and Corg content), suggest the habitat of this coleoid taxon to have been the middle to outer (i.e. distal) shelf. Its provenance from the stratigraphical level that is known as the Scaphites Event, characterised by a mass occurrence of Scaphites and Yesoites, may be indicative of occasional or marginal overlap in ranges, rather than life in similar habitats. On the basis of lithological features and in view of the extremely rare occurrence of Longibelus in rich ammonite assemblages with clear ecological/bathymetric preferences, the natural habitat of Longibelus may have comprised neritic to mesopelagic zones over distal shelves and slopes.


2019 ◽  
pp. 33-45 ◽  
Author(s):  
A. P. Sorokin ◽  
A. A. Konyushok ◽  
V. M. Kuzminykh ◽  
T. V. Artyomenko ◽  
A. A. Popov

Distribution of noble metals, rare metals and rare earth elements in the Paleocene and Lower-Middle Miocene coals of Zeya-Bureya sedimentary basin was analyzed. Reconstruction of the basin formation in the Mesozoic and Cenozoic was performed with detailed paleogeographic analysis of the Cenozoic coal-bearing sequences from the position of geodynamic features of the adjacent regions development. Geological events at the turn of the Cretaceous and Paleogene are considered. Comprehensive analysis of the metal content in the basin frame carried out. We described conditions of migration and localization of trace elements. Given conditions arose mainly in the process of geodynamics developed on the northwestern flank of the Zeya-Bureya basin including the static orogens in the Paleocene — Miocene where the sedimentation was actively expanding. Microelements migration with capturing denudation plains occurred in stable processes of peat accumulation and localization of economically important components in streams associated with plains. Contrasting forms of conjugation in the flexure-uplift system and uneven localization of microelements are determined by high level of geodynamic activity on the south-eastern margin of Zeya-Bureya sedimentary basin. The presence of gold throughout the strata of the Paleocene and Lower-Middle Miocen coal-bearing sediments in the Sergeevskoe, Yerkovetskoe and Raychikhinskoe deposits is established. The Sergeevskoe deposit coals are enriched with Be, Sc, V, Ga, Rb, Nb, Ta, REE + Y.


Author(s):  
Victor N. Semenov ◽  
Aleksandr V. Naumov ◽  
Tatyana V. Samofalova ◽  
Nadezhda M. Ovechkina

Представлены результаты исследования пленок сульфидов кадмия и свинца, осажденных методом пиролиза аэрозоля из водных растворов тиомочевинно-тиосульфатных координационных соединений при температуре 400 °С. Исследование ТТКС показало, что в водных растворах, содержащих нитрат кадмия, тиосульфат натрия и тиомочевину с разными молярными соотношениями компонентов, образуются координационные соединения [Cd(SCN2H4)2(bi-S2O3)], а в соответ ствующих по составу растворах нитрата свинца формируются комплексы [Pb(SCN2H4)(bi-S2O3)(H2O)]. Методом инфракрасной спектроскопии установлено, что при образовании смешанных ТТКС свинца, а также кадмия, осуществляется монодентатная координация тиомочевины к катиону металла через атом серы, а тиосульфат-ион координируется бидентатно через серу и кислород. С помощью рентгенофазового анализа установлено, что независимо от соотношения компонентов в исходномрастворе пленки сульфида кадмия кристаллизуются в модификации вюртцита, а пленки сульфида свинца – в кубической структуре. Определена оптическая ширина запрещенной зоны синтезированных пленок, составляющая 2.4±0.01 эВ для сульфида кадмия и 0.50–0.56 эВ для сульфида свинца     REFERENCES Semenov V. N., Naumov A. V. Protsessy napravlennogo sinteza plenok sul’fidov metallov iz tiokarbamidnykh koordinatsionnykh soedineniy [Processes of the directed synthesis of metal sulfi de fi lms from thiocarbamide coordination compounds]. Proceedings of Voronezh State University. Series: Chemistry. Biology. Pharmacy, 2000, no. 2, pp. 50–55. (in Russ.) Semenov V. N., Naumov A. V. Thermal decomposition of cadmium thiourea coordination compounds. Russian Journal of General Chemistry, 2001, v. 71(4), pp. 495–499. https://doi.org/10.1023/A:1012306512566 Tuhtaev R. K., Boldyrev, V. V., Gavrilov A. I., Larionov S. V., Mjachina L. I., Savel’eva Z. A. Sintez sul’fi dov metallov iz serosoderzhashchikh kompleksnykh soedineniy metodom samorasprostranyayushchegosya goreniya [Synthesis of metal sulfi des from sulfur-containing complex compounds by self-propagating combustion]. Inorganic Materials, 2002, v. 38(10), pp. 1173–1180. (in Russ.) Markov V. F., Maskaeva L. N., Ivanov P. N. Gidrohimicheskoe osazhdenie plenok sul’fi dov metallov: modelirovanie i jeksperiment [Hydrochemical deposition of metal sulfi de fi lms: modeling and experiment]. Ekaterinburg, Ural Branch of the Russian Academy of Sciences Publ., 2006, 217 p. (in Russ.) Semenov V. N., Vlasenko N. V. Protsessy kompleksoobrazovaniya v sistemakh tiomochevina – kadmieva sol’ kislorodsoderzhashchey kisloty [Complexation processes in the systems of thiourea – cadmium salt of oxygen-containing acid]. Russian Journal of Inorganic Chemistry, v. 37(4), pp. 929–933. (in Russ.) Ugaj Ja. A., Semenov V. N., Averbah E. M., Shamsheeva I. L. Issledovanie vzaimodeystviya soley kadmiya s tiomochevinnoy pri poluchenii plenok sul’fi da kadmiya [Investigation of the interaction of cadmium salts with thiourea in the preparation of cadmium sulfi de fi lms]. Journal of Applied Chemistry of the USSR, 1988, v. 61(11), pp. 2409–2414. (in Russ.) Egorov N. B., Eremin L. P., Larionov A. M., Usov V. F. Prevrashchenie tiosul’fato-tiomochevinnykh kompleksov svintsa pri nagrevanii [The transformation of thiosulfate-thiourea lead complexes when heated]. Izvestija Tomskogo politehnicheskogo universiteta, 2010, v. 317(3), pp. 99–102. (in Russ.) Egorov N. B., Usov V. F., Fiterer I. P., Eremin L. P., Larionov A.M. Thiosulfatothiourea lead complexes. Russian Journal of Inorganic Chemistry, 2008, v. 53(1), pp. 117–122. https://doi.org/10.1134/S0036023608010166 Powder Diffraction File. Swarthmore: Joint Committee on Powder Diffraction Stan-dards, 1996. 10. Uhanov Ju. I. 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