Petrographic Composition Research Articles

ПРИМЕНЕНИЕ НЕОРГАНИЧЕСКИХ РЕАГЕНТОВ-МОДИФИКАТОРОВ ДЛЯ ИЗВЛЕЧЕНИЯ СЕРОСОДЕРЖАЩИХ ПРИМЕСЕЙ ПРИ ФЛОТАЦИИ ГАЗОВЫХ УГЛЕЙ

The relevance of the research lies in the need to remove sulphur-containing compounds from coal raw materials at the lowest cost to reduce the environmental load in the areas of coal use. The object of the study is coals of the “G” brand of the Kuznetsk basin of the Kirov mine. The subject of the study is the petrographic and chemical composition of coals, the content of sulphur impurities. The aim of the study is to develop selective reagent flotation modes using inorganic reagents-modifiers. Research objectives: – to determine the petrographic and chemical composition of coals; – to conduct flotation studies using the foam flotation method; – to evaluate the effect of inorganic reagents-modifiers on the φ - potential and hydration of the coal surface; – to determine the mechanism of modifiers’ action on the depression of sulphur-containing impurities of coals. Methodology and methods of research. A complex of physical, chemical and physico-chemical research methods has been used in the work. The degree of scientific development of the topic. A promising direction for reducing sulphur-containing emissions is to increase the selectivity of the flotation process by modifying the coal surface. Results: petrographic analysis of the studied coals has showed that the main micro-component is vitrinite (85 %); chemical analysis indicates that the humidity of the coals is 2.27 %, the ash content is 17.82 %, the yield of volatile substances is 32.90 %, the mass fraction of inorganic sulphur is 0.38 %, organic sulphur is 0.43 %. A comparative analysis of qualitative and quantitative indicators of coal flotation shows that the use of non-organic reagents-modifiers can significantly increase the extraction of sulfur into flotation waste. The analysis of the kinetics of changes in the electrode potential of pyrite indicates an increase in the potential values in the presence of these reagents and a decrease in the hydration of the pyrite surface. The obtained results indicate the expediency of using inorganic salts as modifier reagents that contribute to reducing the sulfur content in coal concentrates due to the depression of pyrite-containing impurities due to an increase in the hydration of their surface

ПРО РОЗРОБКУ ЗАГАЛЬНОЇ МЕТОДИКИ ДЛЯ ПРОГНОЗУ НЕБЕЗПЕЧНИХ ВЛАСТИВОСТЕЙ ВУГІЛЬНИХ ШАХТОПЛАСТІВ

Purpose: to establish a quantitative effect on the dust-generating ability of mine layers of the degree of metamorphic transformations of fossil coals, mining-geological and mining conditions of mining operations and to provide proposals for the development of a general methodology for predicting other hazardous properties of mine layers. Methodology: research is based on the experience of using regulatory documents and analysis of the results of experimental and calculated data on dust formation of fine fractions for various observation conditions. Results: based on the analysis of statistical models of shallow and steeply dipping mine layers by groups of their dustiness, the effect of specific dust release, dust content in broken coal, moisture and thickness of the seams was established. Of all the possible factors that determine the specific dust release, the main ones are the design features of mining machines. The yield of small grades when tested by the falling weight method can serve as an indicator of the strength of coal. The use of such methods eliminates the errors caused by determining the degree of coal change during the transition from its actual destruction by a coal mining machine to the reference mode. The use of carbon content as one of the main indicators of the degree of metamorphism makes it possible to analyze the level of influence of both the sum of the remaining main components of the organic mass (hydrogen, nitrogen, sulfur, oxygen) and their separate influence. In order to bring the state of coal as close as possible to production conditions, it is necessary to additionally take into account moisture, mineral inclusions and their composition. The petrographic composition and some physical and mechanical properties are reliably characterized by the vitrinite reflectance index. The extreme limits of influence on dust formation of the design features of mass-produced combines differ by 43.4 times. The influence of metamorphic transformations at the extreme limits of the yield of the 1-0 mm class when testing coals in a pile driver is estimated by a difference of 5.6 times. The release of volatile substances taken as the main indicator of the degree of metamorphism in the normative base for the safe conduct of mining operations does not unambiguously characterize the gradation of mine layers according to their dustiness groups. The thickness of the mines being developed and the angles of occurrence do not determine their tendency to dust formation, but are the main criteria for choosing mining equipment for crushing coal in the massif. The general methodology for predicting the hazardous properties of coal mine layers, using the example of their dust-forming ability, should take into account the influence of factors of three blocks – metamorphic transformations, mining and geological and mining technical conditions. Scientific novelty: for the first time, a quantitative assessment of the effect on the dust-generating capacity of mine layers of a combination of factors of metamorphic transformation of fossil coals, mining-geological and mining-technical conditions of mining operations has been established. Practical value: the results obtained make it possible to substantiate and develop a general methodology for predicting the hazardous properties of mine layers, which will contribute to improving the regulatory framework for the safe conduct of mining operations.

Горно-геологические и физико-химические показатели, определяющие успешность применения блочного подземного и кучного выщелачивания

The success of the physico-chemical technologies’ application in the development of ore deposits, such as underground and heap leaching, depends on the petrographic and mineral composition of the ores and their host rocks, type of reagents leaching the useful component, technology of ore preparation and irrigation modes of lumpy ores. The efficiency of leaching of uranium-ore minerals is determined by the physico-chemical laws of the interaction of reagents with the ore material. In the course of the research, the relationship between the silica content in the rocks containing mineralization and their physical and mechanical properties was established. This makes it possible, knowing the type of rocks, to predict the conditions of ore preparation by drilling and blasting to obtain the optimal piece size for leaching. In addition, the influence of the ore texture on the leaching efficiency was proved experimentally. Previous researchers found that the rate of conversion of uranium to the mobile state during leaching depends on the rate of penetration of the leaching reagent into the piece, displayed by the effective diffusion coefficient (Kef). The analysis of mining and geological information made it possible to establish the relationship between the Kef and the type of host rocks through the SiO2 content and the type of uranium minerals through the uranium content. The obtained knowledge makes it possible to predict favorable conditions for the use of physico-chemical geotechnologies in the development of rock-poor uranium deposits

Deciphering the Reservoir Rocks Lithology by Mineralogical Investigations Techniques for an Oilfield in South-West Romania

An important element of the geological modeling of oil reservoirs is represented by determining of the mineralogical composition and rock types as part of the reservoir characterization process. In the paper we provide a comprehensive mineralogo-petrographic study based on petrographic observations and X-rays diffraction investigations made on several Miocene rock samples collected in the wells spudded in an oil field belonging to the Getic Basin. Getic Basin is a prolific petroleum province in Romania and belongs to petroleum systems of the Carpathian Foredeep. The oil exploration in the Getic Basin started more than 100 years ago and resulted in thousands of wells drilled and tens of fields discovered. The oil field is located in the Gorj County, geologically belongs to the internal zone of the Getic Basin, and is a faulted anticline with hydrocarbon accumulations in Burdigalian and Sarmatian deposits. The petrographic study led to the interpreting of the rock samples analyzed as epiclastic sedimentary rocks represented by conglomerates, breccias, sands, sandstones, claystones and marlstones, and carbonate rocks (limestones). X-rays diffraction investigations indicated the phyllosilicates (smectite and illite) as main minerals in the Sarmatian samples, while in the Burdigalian samples were found as main minerals: quartz, feldspars and carbonate minerals. The paper provides detailed information (like petrographic types, composition and microtexture) on the Miocene reservoir rocks belonging to the Getic Basin. Also the data obtained may be used as basis for future reservoir modeling studies in the region.

Отложения среднего неоплейстоцена в нижнем течении р. Печоры

The results of lithological studies of Quaternary deposits in the coastal outcrops of the valley of the lower course of the river are presented. Pechora. In the latitudinal section of the Pechora, two horizons of boulder loams (moraines) and underlying horizons, dividing or overlapping the moraine strata, are exposed to intermoraine sediments of fluvial genesis. Based on the results of lithological studies of textural, granulometric and mineralogical features of fine earth of deposits and petrographic composition of coarse material, it was concluded that material was supplied during the formation of moraines from different terrigenous-mineralogical provinces. The formation of the lower Pechora (Dnieper) moraine is associated with the North-Eastern feeding province, and the upper Moscow (Vychegda) moraine, with the North-West Fennoscandian center of glaciation. The glacial genesis of boulder loams has been confirmed.

Сырьевая база каменных индустрий раннего палеолита на территории Юго-Восточного Дагестана

This article presents the results of petrographic studies into collections of artifacts from the Acheulean complexes located in the Darvagchai Geoarchaeological District in Southeastern Dagestan. Throughout the entire Stone Age, raw stone was a crucial resource for subsistence of ancient humans. The lack of high-quality flint raw materials had been previously considered to be the main factor for concluding that this area was rarely visited by ancient humans. Archaeological research over the past decade has shown the opposite. During the exploration works, over ten Paleolithic sites were discovered and studied. Analysis of raw material sources has revealed that there are several main types of rocks in the area of the sites. The petrographic composition of the collections indicates that the overwhelming majority of artifacts were made of flint, while sporadic artifacts were made of limestone and sandstone. Flint raw materials which were used at the sites are distinguished by large number of internal defects, primarily, fracturing. The raw material factor played a very important role in the area. All large, carefully shaped macro-tools were made of sandstone and limestone, while mostly poorly shaped small artifacts were made of flint. Thus, sizes, methods, and intensity of processing stone tools demonstrate direct dependence on the type of raw material.

Late Jurassic-Early Cretaceous sandstones of Algan formation: composition, genesis, sources (North-West of Koryak Highland)

The article presents the results of studying the petrographic and mineralogical compositions of the sandstones of the Algan formation. Sandstones represented by pelitic-fine-medium-grained quartz-feldspar lithic arenites. Two tectonically combined sandstones lithotypes found. Lithotypes were formed in two heterochronous basins by high-speed and medium-speed turbidity flows, in moderately deep marine environments, in a relatively small distance from the coast. Sedimentation was near the deltas and prodeltas. The sources of these basins were different, related to the heterochronous volcanic areas in the north of the researched region.

Experimental Study of Fluorine Mobilization from Igneous Rocks

The paper presents experimental data on fluorine leaching from igneous rocks (dacite, rhyodacite, and trachyrhyolite) and greisen with distilled water and 0.01 M HCl, CH3COONa, NaHCO3, and Na2CO3 solutions. Fluorine leaching is proved to be proportional to its content in the rocks and depends on pH of the aqueous solution: the equilibrium concentrations of fluoride are minimal in the near-neutral solutions and increase in acidic and alkaline ones. The spatial variability of fluorine concentrations in waters of the hypergenesis zone is likely controlled primarily by the petrographic composition of rocks and processes that determine pH of the aqueous solutions.

Petrography of the Mesozoic Alkaline Rocks of the Medvedev Massif (South Yakutia, Aldan-Stanovoy Shield, Leglier Ore Cluster)

The article considers petrographic compositions of the Mesozoic alkaline magmatic rocks of the Medvedey massif. The latter is a part of the Central Aldan ore district and is spatially located in the central part of the Nymnyr block. The massif is a multiphase structure, of the most productive stage of development of the territory – the Mesozoic tectonic-magmatic activation of the Aldan-Stanovoy shield. The main purpose of this work was to identify qualitative quantitative-mineralogical characteristics of the massif rocks, potential for gold mineralization, using crystal-optical methods. As a result of the field works and petrographic studies of the Mesozoic alkaline magmatic rocks, it was determined that, The Medvedev massif has a zonal structure and is represented by three phases of intrusion with distinct contacts between the latter, which rocks differ in structural and material features. The rocks of the first phase of the massif are composed considerably of leucocrate (the content of dark-colored minerals is up to 9%) syenite-porphyry with elements of the monzonite structure. Magmatic formations of the second phase of the massif differ from those of the first phase primarily in structural features and are represented by hypidiomorphic granular differences with an increased content of dark-colored minerals in the rocks up to 15%. The rocks of the final phase have a noticeable difference from the first two phases and are represented by mesocratic monzonite porphyry with a clearly expressed monzonite structure with a dark-colored mineral content up to 20%. Within the Central Aldan ore region, the large Samolazovskoye gold deposit is associated with similar multiphase massifs, in particular with the Yukhtin massif. During field works, it was found that gold-ore mineralization is associated with the massif, which formation is related to an intensively occurred contact-metasomatic effect on the host rocks. Hydrothermal-metasomatic transformations of the latter are the products of multi-stage alkali-silicate metasomatism, associated with the second and especially the first phases of intrusion of the massif, as well as with further weathering processes, disintegration of gold-ore metasomatites and formation of an oxidation zone. Based on the petrographic study of the material composition of the rocks of the massif, it is concluded that gold ore occurrences of commercial scale can be associated with such massifs of multi-phase intrusion.

Provenance and production technology of late medieval \u2018Beszterceb\xe1nya/Bansk\xe1 Bystrica\u2013type\u2019 high-quality stove tiles

A unique collection of high-quality late medieval (fifteenth–sixteenth century) glazed and unglazed stove tiles from the northern part of the Carpathian Basin is of great interest to archaeologists and art historians. It is yet to be determined if these products, which are characterised by similar features, were produced in a single workshop, perhaps in Besztercebánya/Banská Bystrica (in present-day Slovakia), or in several workshops throughout the region. The first systematic multi-analytical investigation was carried out on the ceramic body and glaze of one hundred and seventeen tile fragments from six sites (Besztercebánya/Banská Bystrica, Fülek/Fiľakovo, and Csábrág/Čabraď in Slovakia; Salgó, Eger, and Szécsény in Hungary) using polarising microscopy, X-ray diffraction, electron microprobe, and Raman microspectroscopy analyses to determine the raw materials and production techniques used. Based on the petrographic characteristics, phase and chemical composition of the ceramic body, and the chemical composition and colourants of the glazes, the stove tiles can be classified into three primary groups. Tiles from different sites are different to each other, only the tiles from the Hungarian sites and from Fülek/Fiľakovo are similar. Thus, it is probable that the tiles were produced in several (at least three) workshops in the region from where they were then dispersed. The technological knowledge of the master(s) producing the polychrome Csábrág/Čabraď tiles with tin-opacified glazes was higher than that of the master(s) producing the other tiles. However, the exact location of the workshops as well as their existence through time is still in unknown.

Estimation of Coal's Sorption Parameters Using Artificial Neural Networks.

This article presents research results into the application of an artificial neural network (ANN) to determine coal’s sorption parameters, such as the maximal sorption capacity and effective diffusion coefficient. Determining these parameters is currently time-consuming, and requires specialized and expensive equipment. The work was conducted with the use of feed-forward back-propagation networks (FNNs); it was aimed at estimating the values of the aforementioned parameters from information obtained through technical and densitometric analyses, as well as knowledge of the petrographic composition of the examined coal samples. Analyses showed significant compatibility between the values of the analyzed sorption parameters obtained with regressive neural models and the values of parameters determined with the gravimetric method using a sorption analyzer (prediction error for the best match was 6.1% and 0.2% for the effective diffusion coefficient and maximal sorption capacity, respectively). The established determination coefficients (0.982, 0.999) and the values of standard deviation ratios (below 0.1 in each case) confirmed very high prediction capacities of the adopted neural models. The research showed the great potential of the proposed method to describe the sorption properties of coal as a material that is a natural sorbent for methane and carbon dioxide.

Lithological characteristics of moraine in Torhanovychi 2 section (Forecarpathians)

The main lithological characteristics of the moraine sediments discovered in the Torhanovychi 2 section are analysed. The capacity of the moraine is low (up to 35 cm), in the lower part it is built of the medium, fine-grained sands, and in the upper part, it is mostly coarse-grained. The sands are horizontally layered, and the capacity of the layers varies from 4–5 to 8 cm. The stratification is emphasized by the layered inclusion of coarse fragments, the maximum size of which (granite boulders) reaches 25 cm. Lithological analysis disclosed that the main component of the moraine is a sandy-clay material, the weight of which reaches 60% of the total mass of the sample. Almost a quarter (up to 24 %) is made of pebble and gravel material, and the remaining 16 % is formed by the hard gravel component of the moraine. The petrographic composition of coarse pebbles and gravel (100–40 mm) is represented by fragments of two types of sediments: light gray, gray Carpathian sandstones and pink granites, with a significant predominance of sandstone content. Granites are medium-rounded, and sandstones are medium and well-rounded. The petrographic structure of small pebbles and gravel (40–10 mm) is much more diverse and is represented by fragments of five types of sediments: Carpathian sandstones, silicites (Carpathian flints), siltstones, granites and quartzites. The most common are fragments of Carpathian origin: mainly medium-rounded light gray Carpathian sandstones and multi-coloured medium-rounded silicates. Their total part reaches 74,2 % of the total amount of fragments of the fraction. The second component is formed by erratics – pink, red, often very weathered granites with a variable shape and one well-rounded fragment of quartzite. The total part of erratics reaches 13,4 % of the total amount of fragments of the fraction. The least common in moraine are fragments of local sediments – light gray, gray, weakly cemented siltstones, as well as strong siltstones on siliceous cement with a conchoidal fracture. The total content of fragments of local sediments reaches 12,4 % of the total amount of fragments of the fraction. Medium-rounded siltstones predominate. The petrographic spectrum of hard gravel sediments is generally identical to the composition of small pebbles and gravel. They also contain fragments of five types of sediments: Carpathian sandstones, silicites (Carpathian flints), granites, siltstones and quartz. In addition, fragments of Carpathian-origin sediments also predominate here: medium-, well- and very well-rounded gray sandstones; multi-coloured silicites and milky white, gray quartz, etc. Key words: granulometric composition, petrographic composition, roundness, grain shape, Carpathian material, erratics, sandstones, silicites, siltstones, granites.

Geodynamic Emplacement Setting of Late Jurassic Dikes of the Yana–Kolyma Gold Belt, NE Folded Framing of the Siberian Craton: Geochemical, Petrologic, and U–Pb Zircon Data

We present the results of geostructural, mineralogic–petrographic, geochemical, and U–Pb geochronological investigations of mafic, intermediate, and felsic igneous rocks from dikes in the Yana–Kolyma gold belt of the Verkhoyansk–Kolyma folded area (northeastern Asia). The dikes of the Vyun deposit and the Shumniy occurrence intruding Mesozoic terrigenous rocks of the Kular–Nera and Polousniy–Debin terranes were examined in detail. The dikes had diverse mineralogical and petrographic compositions including trachybasalts, andesites, trachyandesites, dacites, and granodiorites. The rocks showed significant similarities in distributions of REE, and their concentrations of most HFSEs were close to the intermediate ones between ocean islands basalts and enriched middle ocean ridge basalts. We propose that the subduction that was ongoing during the collision of the Kolyma–Omolon superterrane with Siberia led to melting in the asthenospheric wedge and in the lithosphere, which formed a mixed source for the dike systems from both an enriched and a depleted mantle source. The U–Pb SHRIMP-II dates obtained for the dikes corresponded to the Late Jurassic interval of 151–145 Ma. We present a geodynamic model for the northeastern margin of the Siberian Craton for the Tithonian age of the Late Jurassic.

Mineral-geochemical characteristics Cu-U-Au-manifestations in the Kon Ra region of the Kon Tum province, Vietnam

Background. Complex Au-Cu-U mineralization is found in the metamorphic rocks of central Vietnam in the zones of their contact with Triassic granite intrusions. It is localized in tectonic breccias and cataclasites, which affected Triassic granitoids and Precambrian metaskarn rocks. The greatest differentiation is observed for tectonically disturbed granites of the Hai Van complex and the metasomatically reworked zones of contacts of this complex with metacarbonate and metaultramafic rocks of the Kham Duc complex.Aim. To determine the mineral and elemental composition of complex occurrences of Cu, U and Au in Proterozoic rocks of the Kon Tum province of central Vietnam.Materials and methods. The work was based on the authors’ data obtained during fieldwork and analytical laboratory studies in the 2016–2019 period. The diagnostics of ore mineral composition was carried out using 60 polished sections. The chemical composition of ores was determined for 214 samples by ICP MS and for 374 samples by atomic absorption spectrometry at the Vietnamese Centre for Geological and Experimental Analysis in the city of Hanoi. The geochemical relationships of ore components were established by the method of multivariate statistical correlations.Results. The mineral composition includes pyrrhotite, pyrite, chalcopyrite, molybdenite, magnetite, martite, hematite, cubanite, marcasite, gold, xenotime, sphalerite, uraninite, chalcocite, covellite, goethite, malachite and limonite. According to the petrographic and petrochemical composition, the geological position and the data on isotopic age, the metamorphic formations of the Kham Duc complex can be considered as Neoproterozoic-Cambrian formations having experienced metamorphism in the Ordovician.Conclusion. A scheme of the sequence of mineral formation was outlined. ICP MS results of primary ores showed that, in addition to Cu, the formations under study contain concentrations of Co, Mo, U, Au, Zn, Ni, V, Y, La, and As. A positive correlation was found between Cu, U and Au. A model of hydrothermal ore formation was proposed.

Bottom Rock Material of Polar Seas: Distribution, Composition, and Genesis

We have summarized the results of studies of bottom rock material in Quaternary sediments in the polar seas of the Arctic, North Atlantic, and Antarctica, obtained by sieve washing on expeditions of the Shirshov Institute of Oceanology, Russian Academy of Sciences. We have compiled maps of the quantitative distribution of this material over water areas and created pie charts of the petrographic composition for various sites. A wide variety of petrographic types of rocks has been revealed, caused by their transport by glaciers, icebergs, and ice from glaciation centers on continents and islands. We have identified petrographic provinces based on the composition of the rock material and determined its sources. At the same time, great importance has been given to searching for marker rocks, making it possible to correlate the rock material of the seas with their land sources.

On the origin and significance of composite particles in mudstones: Examples from the Cenomanian Dunvegan Formation

AbstractDespite the fact that mud‐dominated composite particles have increasingly been recognized as important components of marine mudstones, the characteristics, types and origins of these composite particles remain poorly understood. This incomplete understanding of critical mudstone parameters (for example, depositional grain size, composition at the particle scale and provenance) severely limits the ability to accurately interpret the conditions (for example, depositional environment and climate) under which these rocks were deposited. Herein, detailed petrographic analysis was conducted in core samples from a transect of contemporaneous proximal to distal deposits from the Cenomanian Dunvegan Formation, a fluvial‐dominated delta system in the Western Canada Sedimentary Basin. Within the well‐developed depositional framework, mud‐dominated composite particles can be tracked along the depositional profile of the Dunvegan Formation from the fluvial to the marine realm (from incised valley to distal prodelta). By following these particles from source (hinterland erosion) to sink (offshore deposition), the origin and dispersal of various types of mud‐dominated composite particles in marine mudstones can be unequivocally determined. Mud‐dominated composite particles derived from a wide range of origins are differentiated. Allochthonous mud‐dominated composite particles, supplied by rivers draining the hinterland, comprise volcanic rock fragments (vitric or felsic in composition), chert fragments, shale lithics (clay‐mineral‐rich or quartz‐rich in composition), metamorphic rock fragments and chlorite/siderite clasts. Autochthonous mud‐dominated composite particles include rip‐up clasts (argillaceous, sideritic or siliceous in composition) formed from intra‐basinal erosion and contemporaneous floccules. The recognition of mud‐dominated composite particles shows that the Dunvegan prodelta ‘mudstones’ are much coarser grained and more heterogeneous in terms of their petrographic composition than the grain size of their component minerals would suggest. Results of this study call for a critical reappraisal of the composition and actual grain size of mudstones in general. Recognition of mud‐dominated composite particles can provide valuable insights to unravel their provenance, transport history and depositional setting, and will greatly enhance their utility as palaeoenvironmental archives.

Sediment-routing controls on sandstone bulk petrographic composition and texture across an ancient shelf: Example from Cretaceous Western Interior Basin, Utah and Colorado, U.S.A.

ABSTRACTSediment-routing controls on sandstone texture and bulk petrography have been evaluated in linked alluvial–coastal–shelfal deposits of the Upper Cretaceous Castlegate Sandstone, Blackhawk Formation, Star Point Sandstone, and Mancos Shale (Western Interior Basin, Utah and Colorado, USA) using thin-section analysis of representative outcrop samples in the context of a high-resolution sequence stratigraphic and paleogeographic framework. The studied strata record deposition from two styles of sediment-routing system within an overfilled foredeep and contiguous intra-continental seaway. First, multiple transverse drainages supplied sand to fluvial, shoreline, and shelf segments of sediment-routing systems characterized by down-dip transport distances of 150–450 km and significant strike-oriented sediment transport along the shoreline. Second, the distal shoreline–shelf segment of an axially supplied sediment-routing system was characterized by sand transport for a distance of c. 300 km.Bulk petrographic composition indicates that transverse sediment-routing systems were sourced from catchments that supplied quartz-rich sand with a subordinate lithic component, while the large axial sediment-routing system was sourced from a catchment(s) supplying slightly more feldspathic sand. Thin-section measurements of mean grain size, sorting, skewness, and ratio of minimum-to-maximum diameter (a proxy for sphericity) are similar for sandstones deposited in fluvial, shoreline, and shelf segments of the transverse sediment-routing systems and in the shoreline–shelf segment of the axial sediment-routing systems, although hydrodynamic sorting is important in locally segregating grain-size populations within each segment. Further, textural analysis of detrital quartz, feldspar, and lithic sand-grain populations shows little evidence of relative change in mean grain size or apparent grain sphericity with downsystem distance, implying that sand-grain populations of different petrographic composition did not undergo significant differential mechanical breakdown during transport. Instead, the textural characteristics of these sand-grain populations are inferred to have been controlled mainly by bedrock lithology and recycling in source catchments. The textural signal of sediment-source areas then propagated downsystem in the sand fraction of detrital sediment supply. This inference is supported by the fine- to medium-grained, well- to very well-sorted character of all sandstone samples, consistent with recycling of sandstones and quartzites from the Sevier fold-and-thrust belt.

Features of the coarse clasts (psephites) distribution in the Upper Quaternary sediments of the northern Barents Sea

The paper presents the characteristics of the coarse clasts (psephites, larger than 1 cm) sampled in the northern part of the Franz Victoria Trough (Barents Sea) during the “Transarktika-2019” expedition. The studied sedimentary section was formed during the transition from the last deglaciation environments to the marine Holocene settings. The amount of psephites in deglacial sediments is much higher than the one in Holocene sediments. The petrographic composition of the psephites, their roundness (according to Waddell and Khabakov classifications) and shape (according to Zingg classification) were studied in detail. It is shown that the majority of psephites is represented by non-rounded or poorly rounded varieties. Isometric and disc-type shapes are predominating among coarse clasts. Isometric psephites prevail in “deglacial sediments”, while disc-shaped, bladed, and rodlike, as a rule, are current in marine Holocene sediments. The petrographic composition of psephites is mostly represented with carbonate (limestone and dolomite) and sandstones. The amount of carbonates increases from the Holocene to the deglacial part of the sediment section. Other rocks found in smaller quantities are represented by quartzites, cherts, shales, basalts, crystalline schists, gneisses, granites, pyrite. During the last deglaciation at the Late Pleistocene the iceberg rafting was the main mechanism of psephites delivery to the sampling points. The major sources of the icebergs were Franz Josef Land and the Belyi — Victoria Islands region. Rocks of Franz Josef Land are represented mainly by Cretaceous gabbro-basalt complex and Triassic sandstones and siltstones. Upper Paleozoic terrigenous and carbonate rocks, as well as Proterozoic metamorphites, occur in the west of the studied area (the area of the Belyi — Victoria Islands). The results of studying the petrographic composition of psephites allow us to conclude that during the last deglaciation icebergs from both sources were heading north towards the Nansen Basin through the Franz Victoria Trough. Both streams of icebergs failed to reach the opposite sides of the Franz Victoria Trough, mixing with each other approximately in the axial part of the trough and leaving it in northern directions.

Ash Characteristics and Selected Critical Elements (Ga, Sc, V) in Coal and Ash in Polish Deposits

The chemical composition of coal ash and the content of the critical elements Ga, Sc, and V in coal and ash are examined herein. In this study, lignite and bituminous coal from Polish deposits were used. The coals were subjected to ultimate and proximate analysis; the petrographic composition was determined based on maceral groups. The chemical composition of ash and the content of critical elements were determined using ICP-MS. The obtained results were correlated and Pearson’s linear correlation coefficient was determined. Based on the correlation analysis, the relationship between the chemical composition of ash and the proximate and ultimate analyses was demonstrated. The content of selected critical elements in the tested deposits was lower than the Clarke value in coal. However, in some deposits these contents are much higher in coal ashes. The higher levels of Ga, V, and Sc in the ash are associated with Al2O3. Therefore, it can be stated that ashes can be a potential source of some raw materials. The highest concentrations of critical elements in coal and ash were recorded in the Lublin Coal Basin. Supra-Clarke contents of Ga, V, and Sc were recorded in the Bogdanka coal mine.

Beach Gravels as a Potential Lithostatistical Indicator of Marine Coastal Dynamics: The Pogorzelica–Dziwnów (Western Pomerania, Baltic Sea, Poland) Case Study

The petrographic composition and grain shape variability of beach gravels in the Pogorzelica–Dziwnów coast section (363.0 to 391.4 km of coastline), southern Baltic Sea, Poland were analyzed herein to characterize the lithodynamics and trends of seashore development. Gravels were sampled at 0.25 km intervals, in the midpart of the berm, following an early-autumn wave storm and before beach nourishment. Individual variations in petrographic groups along the shore were investigated. Gravel data were compared and related to coastal morpholithodynamics, seashore infrastructure, and geology of the study area. The contribution of crystalline rock gravels (igneous and metamorphic) was observed to increase along all coast sections, whereas the amount of less resistant components (limestones, sandstones, and shales) usually declined. This effect is explained by the greater wave crushing resistance of igneous and metamorphic components, compared with sedimentary components. Similarly, the gravel grain shape (mainly elongation or flattening) was observed to change, depending on resistance to mechanical destruction, or due to the increased chemical weathering in mainly the limestones, marbles, and sandstones. Observed increase in contribution of discoid and ellipsoid grains is a potential indicator of depositional trends along the coast sections investigated. On the other hand, increased contents of spheroidal and spindle-shaped grains may be related to erosional trends, where intensive redeposition and mechanical reworking of gravels occurs. However, due to the great number of coastal embankments, the petrographic composition and shape parameters of beach gravels do not always clearly indicate the dominant direction of longshore bedload transport. Increased amount of eroded limestone located east of Pogorzelica indicate increased erosion of glacial tills. These sediments are deposited, building the shallow foreshore, with additional redeposition of morainic material towards the shore.