Types Of Deposits Research Articles

Study on the Hydrothermal Superposition Period: Mineralization–Alteration Zoning Model and Zoning Mechanism of the Dahongshan Fe-Cu Deposit in Yunnan Province

The Dahongshan large-scale iron (Fe)–copper (Cu) polymetallic deposit is in the Proterozoic metallogenic domain on the western margin of the Yangtze Block. It is a typical representative of Fe-Cu polymetallic composite mineralization in the Kangdian area. The deposit comprises a group of layered orebodies formed by volcanic exhalation sedimentation and metamorphism, and a group of vein-like orebodies formed by hydrothermal superposition. The large-scale mapping of altered lithofacies in the deposit has resolved issues of weak links and unclear mineralization and alteration zoning of hydrothermal superimposed deposits within the study area. The mineralization type, hydrothermal alteration type and intensity, mineral assemblage, and mineral structure of the vein-type Cu polymetallic deposits during the hydrothermal superposition period are meticulously analyzed and studied. Finally, the zoning relationships of vein orebodies (mineralization) are summarized. On the basis of the results of the study of the distribution pattern of this mineral body, a mineralization alteration zoning model of the hydrothermal superposition period is constructed. The results show that the alteration is primarily silicification, carbonation, and chloritization, and the mineralization is chalcopyrite, bornite, chalcocite, and pyrite. The Dibadu anticline and the cutting layer faults and fractures strictly control the hydrothermal alteration zoning. The mineralization alteration zoning from the core to the flank is divided into coarse vein zone (I) → stockwork zone (II) → veinlet zone (III). The corresponding mineral assemblages are quartz–calcite–chalcocite–bornite–(native copper) (I) → calcite–dolomite–quartz–bornite–chalcopyrite–chlorite (II) → dolomite–quartz–chalcopyrite–(pyrite) (III), where the stockwork zone has the most substantial mineralization. The mineral assemblages of each alteration zone, the characteristics of rare earth elements of typical samples, and the test results on the fluid inclusions confirm that pH and Eh primarily control the zoning mechanism. This study has significance for deepening the understanding of the composite metallogenic system, guiding deep and peripheral prospecting, and providing significant enlightenment for the study of this type of deposit.

The Precambrian continental record: A window into early Earth environments

The Precambrian was characterized by unique palaeoenvironmental conditions in the Earth’s atmosphere, biosphere and geosphere. This study presents a global quantitative analysis of Precambrian sedimentary successions of aeolian, alluvial, fluvial, lacustrine and glacigenic origins, examined in the broader context of Earth evolution. In the Precambrian, an apparent scarcity of aeolian successions is observed. This may be linked to: (1) differences in atmospheric density, which controlled wind erosion and sedimentation; (2) different astronomical configurations, which may have influenced tides and atmospheric circulation, thereby affecting sand availability and the width of subtropical zones; (3) potentially hotter and more humid climates, restricting dry-sand availability; (4) a lack of vascular vegetation that could prevent reworking of aeolian deposits; (5) poor preservation potential; (6) misinterpretation of the Precambrian record. Mixed aeolian-alluvial strata are more abundant, perhaps because their preservation in the geological record was favoured by water tables sustained by incursions of alluvial systems into otherwise aeolian dominated environments. Aeolian deposits were preferentially accumulated during phases of supercontinental breakup, where rapidly subsiding rift basins provided accommodation suitable for preservation. Other than in the Neoproterozoic record, where glacigenic deposits dominate, alluvial strata are the most common and thickest type of continental deposit in the Precambrian. Precambrian braided alluvial systems were more widespread than in the Phanerozoic. Major alluvial systems formed preferentially during phases of supercontinent assembly, whereby alluvial systems drained major orogens, and long drainage pathways developed from supercontinent interiors to coastlines. In the Paleoproterozoic, ephemeral, saline to partly arid lakes developed extensively in the desertic interior of Columbia. Glacial deposits preferentially formed in the breakup phase of supercontinental cycles; this supports theories invoking enhanced chemical weathering of uplifted rift shoulders as a driver of carbon dioxide sequestration, global cooling, and glaciation. Overall, the number of identified continental successions increases towards the Precambrian-Phanerozoic boundary. This may be an artefact of an increasingly more complete stratigraphic record as time progresses. However, the abundance of continental successions varies on a quasi-periodic cycle of 500 – 700 Myr, with peaks coinciding with the tenure and breakup of Precambrian supercontinents.

Deposit type discrimination based on trace elements in sphalerite

Sphalerite can form in different geological environments and is the main ore mineral of most Pb-Zn deposits. Trace elements in sphalerite combined with machine learning (ML) methods have been used for deposit type discrimination. However, the performance of different multivariate and ML methods is not systematically compared. Here more than four thousand laser ablation inductively coupled plasma mass spectrometry data from more than one hundred deposits were compiled and investigated by different multivariate and ML methods. Unsupervised multivariate and ML methods including principal component analysis (PCA) and t-distributed stochastic neighbor embedding (t-SNE), and supervised multivariate and ML methods including partial least squares-discriminant analysis (PLS-DA), logistic regression (LR), support vector machine (SVM), K-nearest neighbors (KNN), random forest (RF), naïve Bayes (NB), and neural network (NN) are used to classify deposit types. The models are constructed for five deposit types, Mississippi Valley-type (MVT), Volcanogenic Massive Sulfide (VMS), sedimentary exhalative (SEDEX), Epithermal, and Skarn deposits, based on twelve elements in sphalerite, Fe, Pb, Mn, Co, Cu, Ga, Ge, Ag, Cd, In, Sn, and Sb.The PCA and PLS-DA methods show similar clustering results, where Epithermal, MVT, SEDEX, and Skarn deposits can be separated from other deposit types. The t-SNE method is only efficient in discriminating MVT, SEDEX, and Epithermal deposits. The KNN, RF, and NN methods show better performance than LR, SVM, and NB in terms of average accuracy and precision. The PCA, t-SNE, and PLS-DA methods have advantages in data visualization, whereas KNN, NN, and RF methods are more suitable for classification tasks. Feature importance analyses of the PLS-DA and RF methods show that the most important discriminant elements in the classification are Ge, Mn, In, Sn, Ga, and Sb. The models based on PCA, PLS-DA, KNN, NN, and RF are used to predict sphalerite samples with uncertain origins. All the models give similar classification results for deposit types, which are consistent with the ore-forming geological setting. The multivariate and ML models, including discrimination diagrams of PCA and PLS-DA, can be used as the first screening for the type of Pb-Zn mineralization in mineral exploration.

Fingerprinting Pb-Zn mineralization events in the SW Yangtze Block, South China: A case from Yuanbaoshan deposit

The southwestern Yangtze Block represents one of the world’s largest lead–zinc provinces, comprises more than 400 known carbonate-hosted Pb-Zn deposits and contains over 30 million tons (Mt) of total Pb + Zn reserves. The Pb-Zn deposits in this area have been studied extensively by economic geologists, but the origin and mineralization processes of these deposits are still controversial. The Yuanbaoshan deposit is a typical carbonate-hosted Pb-Zn deposit of medium scale (0.19 Mt P + Zn reserves @ 0.7–26.31 wt%), which is in the northern part of the Pb-Zn mineral belt in the southwest margin of the Yangtze Block. In this study, we have conducted LA-ICP-MS sulfides trace elements, S isotope analyses, together with gangue carbonate C-O stable isotope analyses and pyrite Rb-Sr dating. We present Rb-Sr isotopic data on the pyrite that yields an isochron age of 196.4 ± 2.3 Ma. The mineralization temperature at Yuanbaoshan, as determined by the Ga, Ge, In, Mn and Fe (GGIMF) in sphalerite geothermometer, ranges from 161 to 264 ℃ (Sp1) and 141 to 246 ℃ (Sp2). The δ13CPDB values range from −0.66 to 0.61 ‰, δ18OSMOW values range from 15.6 to 17.3 ‰. In situ S isotopes show that the δ34S values of sulfides range from −1.4 to 17.73 ‰. The field, petrologic, geochemical and isotopic data from our study lead to the following salient findings. (1) The dissolved carbon and oxygen of ore forming-fluids of these Pb-Zn deposits were mainly derived from sedimentary carbonate dissolution. (2) The reduced S in the sulfide of the Yuanbaoshan Pb-Zn deposit is mainly derived from the thermochemical sulfate reduction (TRS) and the reduced S produced by the pyrolysis of S-containing organic matter in the carbonaceous mudstone of the Ebian Group. (3) The large-scale Pb-Zn mineralization in the southwest margin of the Yangtze Block was influenced by the post-collision extension between the Indosinian Block and the South China Block during ca. 200 Ma.

Computational simulation of the hydrothermal ore-forming system associated with the Luziyuan Pb-Zn Deposit, Yunnan, China: An example of pore-fluid convection controlled mineralization

The giant Luziyuan Pb-Zn deposit is a typical hydrothermal ore-forming deposit in the southern Baoshan block of SE Tibet. Although extensive studies were conducted to understand the ore-forming system associated with the Luziyuan Pb-Zn deposit through using the traditional geoscience methods, the ore-forming process involved in this deposit has not been justified in a strictly scientific manner to date. In this paper, the hydrothermal ore-forming process of the Luziyuan Pb-Zn deposit is computationally simulated through using the dual length-scale approach associated with the finite element method (FEM). In the dual length-scale approach, the FEM is first used to simulate the regional model of a large length-scale in the geological region where the Luziyuan Pb-Zn deposit is located. Afterward, the FEM is then used to simulate the deposit model of the Luziyuan Pb-Zn deposit. Particularly, the boundary conditions of the deposit model are consistently determined from using the computational simulation results of the regional model. The related numerical results demonstrated that: (1) the pore-fluid convection provides a continuous source of ore-forming fluid and ore-forming material for the Luziyuan Pb-Zn deposit; (2) the convective pore-fluid flow is the main dynamic mechanism, which controls the temperature, pore-fluid velocity and chemical species distribution in the Luziyuan Pb-Zn deposit; (3) the localized structure is the main controlling factor for the localized pore-fluid flow pattern, which further controls the formation and location of the orebody in the Luziyuan Pb-Zn deposit; (4) the dual length-scale approach associated with the FEM is very useful for simulating the hydrothermal ore-forming process of the Luziyuan Pb-Zn deposit.

Short wavelength infrared (SWIR) reflectance spectroscopy of alteration minerals of Qibaoshan ore district, Shandong Province, China

Qibaoshan is a recently discovered ore district including a significant epithermal deposit; it has three different types of deposits that have been developed in the Qibaoshan subvolcanic complex, including Jinxiantou copper–gold deposit, Qibaoshan polymetallic epithermal deposit and Diaoyutai pyrite deposit.The characteristics of these deposits and geochronological studies indicate that they may belong to the same mineral system. To study the relationship between the deposits and to determine potential for deposits under cover, surface alteration mapping by short-wave infrared spectroscopy (SWIR) analyses was conducted on the ore field. The results showed that the Jinxiantou copper–gold deposit has illite ＋ chlorite alteration, and the Qibaoshan deposit has illite + chlorite alteration as vein halos and gradually transitions outwards to montmorillonite alteration. Illite alteration is widely developed in the Qibaoshan ore field.Study of the spectral characteristics of illite in the east of the ore district showed it has a lower wavelength Al-OH absorption peak position (Pos2200) and higher illite crystallinity (IC) value and shows a trend of gradually decreasing Pos2200 and increasing IC to the west, indicating that the inferred heat center in the eastern ore district may be the center of hydrothermal activity. The Qibaoshan ore district contains a porphyry-epithermal hydrothermal mineral system, and the east of the ore district may have potential for discovery of porphyry deposits.

Occurrence State and Enrichment Mechanism of Rhenium in the Qianjiadian Uranium Deposit in the Southwestern Songliao Basin, Northeast China

Rhenium is an extremely rare critical metal element in Earth’s continental crust. Owing to its extremely high melting point and heat-stable crystalline structure, rhenium is an essential component of alloy materials used in high-performance aircraft engines. Demand for rhenium resources is therefore growing. Currently, most rhenium is produced as a byproduct of molybdenum mining in porphyry copper–molybdenum deposits. Research has therefore focused on the enrichment characteristics of rhenium in this type of deposit, with little attention paid to rhenium in other types of deposits. This study reports the occurrence state and enrichment mechanism of rhenium in the Qianjiadian sandstone-type uranium deposit in the Songliao Basin, Northeast China. Sequential extraction revealed that the average proportions of different forms of rhenium are as follows: water-soluble (57.86%) > organic-sulfide-bound (13.11%) > residual (12.26%) > Fe/Mn oxide-bound (10.67%) > carbonate-bound (6.10%). Combining mineralogical analysis techniques such as SEM-EDS, EMPA, and XRD, it has been established that rhenium does not occur as a substitute in sulfides (e.g., molybdenite) or uranium minerals in various types of deposits. Instead, it is mainly adsorbed onto clay minerals and Fe-Ti oxides, and in a small number of other minerals (pyrite, organic matter, and pitchblende). Rhenium is similar to redox-sensitive elements such as uranium and vanadium, and it is transported in a water-soluble form by oxidizing groundwater to the redox transition zone for enrichment. However, unlike uranium, which generally forms as uranium minerals, rhenium is mainly adsorbed and enriched onto clay minerals (kaolinite and interlayered illite–smectite). Most of the rhenium in sandstone-type uranium deposits occurs in an ion-adsorption state, and is easily leached and extracted during in-situ leaching mining of uranium ores. This type of deposit demonstrates excellent production potential and will become a crucial recoverable resource for future rhenium supply.

Origin of the Filizchay ore field (the southern slope of the Greater Caucasus)


 
 
 he article deals with the origin of the Filizchay ore field, which is a valuable object for the extraction of zinc, lead, copper, silver as well as for the extraction of the associated com- ponents. The data and types (VMS, SEDEX, VMT) of the pyrite deposits in the world have been briefly presented. Their comparative analysis has been carried out and it has been revealed that the Filizchay ore field is very different from the VMS-type pyrite deposits and it belongs to the SEDEX type. A direct relationship with vol- canism has not been observed in this deposit. Unlike the containing rocks related to volcanism in the Filizchay field , there are fine-rhyth- mic flyschoids with packages of sandstones, clay shales and silt-clay shales . The ratio of the natural ore types composed of the different mineral associations, with stages of the folded and disjunctive dislocations, allows us to divide the process of the deposit formation into the following three stages of the ore formation: 1. deposits of the massive hydrothermal-sedimentary essentially pyrite ores; 2. formation of the hydrothermal-metasomatic ores of the pyrite-copper-polymetallic composition; 3. deposition of the hydrothermal-meta- morphogenic ores of the copper-pyrrhotite composition. The available data indicate a favorable environment for sedimentary pyrite ore formation subject to a significant role of Corg. and sulfate-reducing bacteria. Moreover, the hydrothermal-sedimentary processes played the main role in the accumulation of the main volume of the sulfide masses. On the basis of the sulfur isotopic composition (according to Zairi, 1992) of the main minerals (pyrite, galena, sphalerite, pyrrhotite, chalcopyrite) from various types of the Filizchay ore field ores it was concluded that the deposit formation occurred from several portions of the entered hydrothermal solutions. It was found that by the period of accumulation of sediments of the ore-bearing horizon in the northern block – there occurred outpouring of the spilites and basalts in the narrow trough-like depression. The iron sulfides supplying the more southern basin with stagnant waters can be associated with their post-volcanic exhalations (as primary sources). The Filizchay ore field being connected with basaltic volcanism is combined according to formation method. It has been formed due to components which have been carried out by hydrothermal flows and due to basalts, which are associated with underwater alteration. The temperatures of the primary pyrite-polymetallic ores formation are relatively low (200-100 0С).
 
 

Titanomagnetite, a new potential geochronometer for in situ U–Pb dating

Titanomagnetite occurs commonly in igneous and metamorphic rocks, and various types of deposits, and serves as a valuable indicator. Recently, it has been identified as a new geochronometer for U–Pb...

Temporal and spatial distribution and genesis of primary indium deposits around the world

Because rare dispersed elements including indium play an increasingly extensive and indispensable role in the field of modern high technology, the exploration, development and research of its resources are in full swing. The abundance of indium in the earth's crust is extremely low, and its original independent deposits have not been found so far. Indium is mainly parasitic in bulk non-ferrous metal deposits in the form of associated by-products. Because of its origin, the genetic types of indium deposits are as diverse as those non-ferrous metal deposits it parasitizes. The distribution of indium in geological time and earth space is uneven. The formation of indium ore deposit is closely related to tectonic-magmatic activity. It is the product of plate tectonic movement, continental rifts and mantle plumes or mantle hotspots in the interior of ancient continents. The emergence of indium ore deposit is inseparable from magmatic activity, especially granite magmatic activity. Ore-forming materials mainly come from the upper mantle and/or deep crust. Indium deposits formed under high temperature conditions have enrichment mechanisms. In addition to the enrichment factors of traditional metal deposits, the enrichment of nano-scale indium minerals through the nano effect is also a very important enrichment method. The indium deposits formed at the end of the differentiation and evolution of granite magma may not be enriched in one go, but is the result of multiple enrichments.

Energy and tellurium deposits

<abstract> <p>In this article, we focus on the next generation of green batteries that are closely related to semi-metallic tellurium and its deposits. We briefly summarize the chemical and geochemical characteristics of tellurium that ordinary readers are not familiar with or have never heard of, and its important role in many fields such as high-tech and medical care, current global resource distribution, major mineral extraction and purification technologies and market evolution, etc. The spatiotemporal distribution of the two main types of tellurium deposits, namely associated tellurium deposits and independent tellurium deposits, is introduced in detail. The geological and geochemical characteristics of the only independent tellurium deposit in the world are introduced in detail, so that relevant researchers can use this deposit as an example to discover more independent tellurium deposits around the world, meeting people's increasingly urgent demand for tellurium and realizing the sustainable development of human society. We believe that humans will discover more and more new energy metals in the near future to meet the dual goals of protecting the earth's environment and developing the economy, which are contradictory and mutually reinforcing. New generation of energy metal batteries must be small, compact, easy to carry, charge quickly, and have a long life.</p> </abstract>

Soil Survey and Lithogeochemical Techniques in Mineral Exploration

This paper investigates the critical roles of soil surveys and lithologic evaluation in identifying potential mineral resources. Soil surveys involve the systematic mapping, examination, description, and classification of soils within a defined area. Through targeted sampling and laboratory analysis, these surveys can reveal the concentration of metals in the soil. By analyzing these metal signatures, geoscientists can infer the underlying geology and identify areas with a higher likelihood of hosting valuable mineral deposits. Lithologic evaluation complements soil surveys by focusing on the physical characteristics of rock units exposed at outcrops, in hand samples, or cores. Observable with the naked eye or a magnifying lens, these characteristics include color, texture, and structural features. Lithogeochemistry, or rock geochemistry, builds upon this foundation by analyzing the chemical composition of the bedrock. This analysis aims to identify spatial patterns of elements typically associated with specific types of mineral deposits. By integrating the findings from soil surveys and lithologic evaluations, geoscientists gain a comprehensive understanding of the subsurface environment, enabling them to prioritize areas for further mineral exploration activities. This paper delves into the fundamentals of these techniques, highlighting their strengths and limitations in the context of mineral resource exploration.

Preliminary discussion on pyrrhotite, gold killer in Wells-Barkerville, British Columbia, Canada

The Wells-Barkerville area of the Cariboo gold mining district is situated within the Quesnel Highlands on the eastern edge of the Interior Plateau in central British Columbia, Canada of the eastern Circum-Pacific volcanicmetallogenic belt. Recorded gold production from the area totals more than 4.0 million ounces, including an estimated 2.7 million ounces from placer mining from 101 creeks and 1.3 million ounces from lode mining. There are five principal types of lode gold deposits in the district; namely, auriferous pyrite replacement, including replacement in limestone and that in calcareous clastic rock; pyrite-quartz vein/veinlet lode gold, including strike vein, diagonal vein, orthogonal vein, and quartz veinlets; basalt-hosted auriferous pyrrhotite-pyrite lode gold; and associated gold in porphyry copper styles. This area is historically a famous gold production area in western Canada, including the initial alluvial gold and later and current lode gold. This original short article uses drilling results to illustrate that pyrrhotite in this area is the killer of gold. Wherever there is pyrrhotite, the gold grade is very poor or even contains no gold. In other words, gold grade is inversely related to pyrrhotite content. Then, the spatial distribution characteristics of the pyrrhotite anomaly zone(s) existing in this area were summarized, including the approximate thickness of zone(s). On this basis, several deep drill holes are recommended to verify whether there is considerable gold mineralization beneath the pyrrhotite anomaly zone(s).

СЕЛЕКТИВНІ РИЗИКИ ВКЛАДНИКІВ ВІТЧИЗНЯНИХ БАНКІВ В УМОВАХ ВОЄННОГО СТАНУ

The article examines the essence and types of selective risks of bank depositors and their features in the conditions of martial state. The main types of selective risks of bank depositors are characterized. The expediency of improving the determination of the rating of banks when determining the risk of incorrect bank selection is substantiated. An approach to improving the determination of the rating of financial stability of banks by normalizing financial indicators taking into account their normative values is proposed. It has been established that an important factor in the depositor's determination of the bank's reliability in nowadays conditions is the level of its technologies. The essence of the risk of incorrect choice of the deposit currency by the depositor is determined and a method of its assessment based on the application of Value at Risk measurement technology is proposed. It has been established that the main source of risk of incorrect choice of deposit currency by the depositor is the level of devaluation or revaluation of the national currency during the deposit period. The expediency of using Value at Risk technology to assess this risk is substantiated. It has been established that in the conditions of martial state and increased turbulence of the foreign exchange market, it is advisable to assess the risk of incorrect choice of the deposit currency taking into account both the volatility and the trends in the exchange rates. The essence of the risk of the wrong choice of the term of the deposit is determined and the complexity of its assessment in the conditions of martial state is substantiated. Attention is focused on the importance of effectively managing the risk of the wrong choice of the type of deposit in the conditions of martial state by forming a so-called financial security cushion in the form of placing a certain amount of funds on demand deposits or time deposits with the right of early withdrawal. The necessity of developing a strategy for forming the optimal portfolio of a bank depositor in the conditions of martial state is substantiated, which can become the subject of further scientific researches.

Indium use, resource, market and ore deposit type

With the continuous advancement of science and technology, rare dispersed elements that have long been dormant in rocks and ignored by humans have become increasingly important. Indium is one of these rare dispersed elements, although most people know little or nothing about it. In fact, indium has a wide range of important uses in many aspects. Given the unique physical and chemical properties of indium, some uses are even irreplaceable. Therefore, many countries have included some rare elements, including indium, in the list of national strategic resources or critical metals for protection. This article not only popularizes the main uses of indium in modern society, briefly describes the distribution and current status of natural indium ore resources around the world, but also explores its market status in the past 10 years and future development trends. Finally, the main genesis types of associated or symbiotic indium ores around the world are summarized and briefly discussed. Because indium does not exist as an independent deposit and can only exist as a by-product of non-ferrous metals such as copper, lead, zinc and tin, it is very important to research and develop new sources of indium, including recycling and reuse. These new sources include but are not limited to waste rock piles and tailings from related abandoned old mines, etc.

Application of principal component analysis method based on machine learning to gold deposit type discrimination: A case study of the geochemical characteristics of pyrite

Application of principal component analysis method based on machine learning to gold deposit type discrimination: A case study of the geochemical characteristics of pyrite

Hydrothermal monazite and xenotime chemistry as genetic discriminators for intrusion-related and orogenic gold deposits: implications for an orogenic origin of the Pogo gold deposit, Alaska

Attempts to geochemically distinguish between metamorphic-hydrothermal systems that form orogenic gold deposits and both reduced and oxidized magmatic-hydrothermal systems using isotopes or metal associations have proven ambiguous, particularly for orogenic gold and reduced intrusion-related gold systems. The absence of conclusive geochemical discriminators and the overlap in geologic characteristics have led to gold deposit models being potentially incorrectly applied, which in turn negatively affect regional mineral exploration and mine planning. In this study, in situ electron microprobe geochemical analyses of hydrothermal monazite and xenotime crystals associated with different types of gold-bearing deposits are shown to be effective geochemical discriminators. There are notable differences in mineral chemistry such as rare earth element (REE) profiles, total light REE, Dy, Er, Pr, Y, Nd/Sm, and La/Sm that distinguish monazite precipitated from metamorphic-hydrothermal fluids that form orogenic gold deposits and those precipitated from magmatic-hydrothermal fluids that form both porphyry Cu-Mo-Au and reduced intrusion-related gold deposits. Notable differences in overall xenotime abundances and concentrations of heavy REEs, Ca, and Sc are distinctive between the different deposit classes for xenotime. The origin of the controversially classified Pogo gold deposit, Tintina gold province, Alaska, which has been characterized as both a reduced intrusion-related and an orogenic gold deposit, is tested based upon the noted chemical differences associated with these hydrothermal phosphates. The findings of this study have implications for exploration and mine development in the Tintina gold province and other areas that contain deposits that are controversially classified as either orogenic or as magmatic-hydrothermal gold deposits.

СРАВНИТЕЛЬНЫЙ МИНЕРАЛЬНО-СЫРЬЕВОЙ ПОТЕНЦИАЛ ТВЕРДЫХ ПОЛЕЗНЫХ ИСКОПАЕМЫХ СУШИ И МИРОВОГО ОКЕАНА

There are no analogues of the main types of ocean ores (IMN, CMC, DPS), taking into account their composition, conditions of occurrence and morphology of ore bodies on land. They represent new, industrial-genetic types of ore deposits. The degree of study of the IMN and CMC allows us to assess their ore potential between the categories of reserves C1 and C2, and GPS between the forecast resources P1 and P2. When assessing their resource potential, a new interval version of such categories was used.

Физико-химический анализ гидрофильных интраокулярных линз, эксплантированных в связи с помутнением материала

Relevance. Clouding and discoloration of intraocular lens (IOL) seems to be a multifactorial problem, directly related to the properties of each group of materials from which they are made. Since the exact combination of factors and the sequence of events are not yet fully known, there is reason to continue research in this direction, even though, unfortunately, such important points as the specifics of IOL production are information closed to the general public. It is also obvious that this problem is urgent and requires an integrated approach. Purpose. To determine the type of deposits on the surface of hydrophilic IOLs explanted due to a decrease in the transparency of the material. Material and methods. Visualization of the surface of 8 explanted hydrophilic IOLs was carried out in a digital inverted microscope Altami INVERT 3 (LLC Altami, Russia). Elemental analysis of surface deposits was carried out on a JCM-6000 electron microscope (Jeol, Japan) with a JED-2300 energy dispersive analysis attachment. The Raman spectra were measured using M532 Raman microscope (Enspectr, USA). Infrared absorption spectra (IR spectra) were recorded using equipment: Fourier spectrometer InfraLum FT-02 (Lumex, Russia) and an IR spectrometer with an attachment of frustrated total internal reflection IRTracer-100 (Shimadzu, Japan). The processing and interpretation of the obtained spectra was carried out using databases and software from the equipment. Results. The nature of the deposits is represented by various crystallites, in some places forming a completely continuous film. The main elements of deposits are carbon, nitrogen, and oxygen. The IR spectrum contains functional groups characteristic of proteins. Conclusion. Deposits on the surface of a cloudy IOL of a hydrophilic type are of protein nature. The fact that the deposits have a crystalline structure makes it possible to significantly narrow the scope of the search for those compounds that are capable of crystallizing at temperatures close to the normal temperature of the human body. Key words: IOL clouding, hydrophilic IOL, IOL explantation

Is the Invasive Plant Amaranthus spinosus L. More Competitive than the Native Plant A. tricolor L. When Exposed to Acid Deposition with Different Sulfur–Nitrogen Ratios?

The functional differences between invasive plants and coexisting native plants can affect the invasion process of the former because invasive plants and coexisting native plants are exposed to similar or even identical environmental pressures. Acid deposition is an important component of atmospheric pollution, and acid deposition with different sulfur–nitrogen ratios may affect the invasion process of invasive plants by shifting the functional differences and differences in the growth performance between the invasive and coexisting native plants. It is crucial to analyze the functional indices and growth performance of these plants when exposed to acid deposition with different chemical compositions to assess the ecological impacts of atmospheric pollution on the growth performance of invasive plants. This study aimed to evaluate the functional differences and growth performance between the invasive plant Amaranthus spinosus L. and the native plant A. tricolor L. in mono- and mixed culture when exposed to an acid deposition with different sulfur–nitrogen ratios, including sulfur-rich acid deposition (sulfur–nitrogen ratio = 5:1), nitrogen-rich acid deposition (sulfur–nitrogen ratio = 1:5), and mixed acid deposition (sulfur–nitrogen ratio = 1:1). The acidity of the three types of simulated acid deposition was set at pH = 5.6 and pH = 4.5, respectively, with distilled water as a control (pH = 7.0). The competition experiment between A. spinosus and A. tricolor was conducted in the greenhouse. Amaranthus spinosus exhibited a strong growth performance over A. tricolor in the mixed culture, mainly via the increased leaf photosynthetic capacity. The competitiveness for light acquisition, leaf photosynthetic capacity, and enzymatic defense capacity under stress of A. spinosus may be vital to its growth performance. The lower pH acid deposition had imposed a greater reduction in the growth performance of both Amaranthus species than the higher pH acid deposition. Sulfur-rich acid deposition was more toxic to the growth performance of both Amaranthus species than nitrogen-rich acid deposition. Amaranthus spinosus was more competitive than A. tricolor, especially when exposed to acid deposition, compared with just distilled water. Thus, acid deposition, regardless of the sulfur–nitrogen ratio, may facilitate the invasion process of A. spinosus via the stronger growth performance.