Formation Of Horizons Research Articles

Formation of placic horizons in soils of a temperate climate – The interplay of lithology and pedogenesis (Stołowe Mts, SW Poland)

A placic horizon is a thin soil layer that is cemented or indurated by Fe, Mn, and/or Al compounds as well as by organic matter. The placic horizon is a hard, continuous, and nearly impermeable and impenetrable horizon that retards the vertical leaching of water and inhibits the growth of roots. Placic horizons can develop under different climates and in various ways. However, we do not fully understand the interactions between lithology and pedogenesis that might promote placic horizon formation. Therefore, to shed light on the mechanisms of placic genesis, we used an applied multiproxy approach (electrical resistivity tomography – ERT, XRD, 57Fe Mössbauer spectroscopy, bulk geochemistry, soil micromorphology and 14C dating) for three soils developed from sandstone–mudstone parent materials in mountainous areas of SW Poland, to shed light on the mechanisms of placic horizon genesis. The ERT inversion models and soil survey data indicate lithic discontinuities in the profiles. Soil micromorphology data confirmed that a placic horizons formed slightly below the discontinuity. Radiocarbon ages of the placic horizon span from 2.2 to 4.8 ka and suggest that more humid conditions were favorable for the formation of a placic horizon, which aligns with our mineralogical results. Ferrihydrite is the major Fe oxyhydroxide in the placic horizon. Micromorphological data showed that after the formation of the placic horizon, a phase of clay migration might have occurred, while later, podzolisation took over as the main soil-forming process. This sequence shows that thin iron pans can develop independently of other processes and can exist (at least some of them) before the development of a spodic horizon. A placic horizon causes severe hydrological changes in the topsoil and subsurface horizons. Thus, water stagnation in the soil transforms it into a Stagnosol or Planosol and it’s responsible for the evolution of local plant communities and the ecosystem.

Anisotropic gravastar as horizonless regular black hole spacetime and its images illuminated by thin accretion disk

A connection between regular black holes and horizonless ultracompact objects was proposed in Carballo-Rubio et al. (JHEP 08:046, 2023, arXiv:2211.05817 [gr-qc]). In this paper, we construct a model of a horizonless compact object, specifically an anisotropic gravastar with continuous pressure, that corresponds to regular black hole spacetime in the appropriate limit. The construction begins by modeling an equation of state that satisfies the anisotropic gravastar conditions and transitions to the de Sitter (p=-ϵ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$p=-\\epsilon $$\\end{document}) upon horizon formation. The spacetime structure is similar to the Quantum Horizonless Compact Object (QHCO) described in Chen and Yokokura (Phys Rev D 109:104058, 2024, arXiv:2403.09388 [gr-qc]). Within this model, we also generate images of the corresponding objects surrounded by a thin accretion disk. The resulting images reveal that assuming that the emitting matter exists only outside the object, the inner light ring structure closely resembles that of the horizonless configuration of a regular black hole and the QHCO, yet it exhibits a distinct light ring structure compared to the thin-shell gravastar model. However, the opposite occurs when emitting matter is taken into account inside the object.

Soil-forming factors controlling Technosol formation in historical mining and metallurgical sites in the high-alpine environment of the Tatra Mountains, southern Poland

The Tatra Mountains are a unique Central European alpine ecosystem where the non-anthropogenic soil cover and soil-forming processes are well recognized. However, the Technosols in the area’s high-mountain environment have not been studied in detail to date. Therefore the aim of this study was to identify the most important soil-forming factors controlling the properties of Technosols developed in historical mining and metallurgical sites in the Tatra Mountains of southern Poland active from the 15th Century until the end of the 19th. The present paper is one of the first attempts to study the genetic aspects of high-mountain Technosols in the temperate climatic zone. The study involved determining soil morphology and classification, soil properties, magnetic susceptibility, mineral composition, optical microscopic observations and total concentration of major elements. The studied Technosols were poorly developed soils with simple soil morphology (mainly A horizon in the topsoil and C horizons in the subsoil). There was a high content of rock fragments. The research has shown that the properties of Technosols in the Tatra Mountains were primarily determined by past human activities like mining and metallurgy as well as the type of anthropogenic parent material, which included mining wastes and metallurgical slags and determined soil properties together with mineral and chemical composition. Soil formation was significantly influenced by vegetation which was conditioned by the relief and climatic conditions dependent on altitudinal zonation. Vegetation and plant-derived soil organic matter shaped topsoil properties. The lengthy soil-forming process acting since a few centuries in some Technosols led to the formation of Bw horizons.

Controls of paleogeomorphology on organic matter accumulation as recorded in Ordovician–Silurian marine black shales in the western South China Block

The Ordovician–Silurian transition represents a critical period marked by the formation of marine shale gas horizons within the South China Block. However, the mechanism for organic matter enrichment of Paleozoic marine shales in the western South China Block remain contentious, primarily due to insufficient understanding of paleogeomorphological evolution. In this paper, we describe the sedimentology of the Ordovician-Silurian succession composed of the Wufeng-Longmaxi Formation in the western South China Block and report new paleontological, and geochemical data for this succession to explore the relationship between basin paleogeomorphology and water mass environment. Nine graptolite zones are identified, spanning from the WF1 (Linxiang Formation) through WF2–WF4 (Wufeng Formation) to LM1–LM5 (Longmaxi Formation) in this well. Based on sedimentological and geochemical analyse results, three distinct stages of redox and paleoproductivity conditions in the water mass have been identified: (1) suboxic environments and low paleoproductivity in WF2–WF4; (2) euxinic and stagnant water conditions in LM1–LM3 accompanying with high paleoproductivity; and (3) anoxic water and low paleoproductivity in LM4–LM5. By integrating marine redox fluctuation, paleoproductivity conditions and regional hiatus (LM1-LM3) observed across multiple successions, we interpret thatthe western margin of the South China Block have been significantly affected by a collision between the South China Block and Yanbian terrane. The results of this study indicate that the accumulation of organic matter in the western margin of the South China Block was predominantly controlled by paleogeomorphology being caused by this collision event.

Lead and Barium strata-bound deposits in eocene carbonate ramps of Iran: Implications for the influence of sedimentary environment characteristics on the distribution of Ore reserves

In the case of ore deposits that are formed in marine environments, including kuroko deposits, the effect of paleo-sedimentary environment parameters and microfacies changes is very important, but it is often neglected in economic geological research. These factors determine the dispersion and concentration of ore horizons in an ore deposit area, and recognition them leads us to the localization of high concentration ore horizons.In this regard, lead and barite ore deposit area in the southeastern of Tafresh city (the border of Markazi and Qom provinces, Iran) was investigated. This ore deposit is of the kuroko type and is of the early to middle Eocene epoch (Ypresian-Lutetian ages) and was formed in a relatively deep ancient carbonate ramp. Investigating the concentration of different minerals and ore minerals in the mentioned ore deposit area using by remote sensing techniques indicates that the distribution of minerals and ore minerals is non-uniform with a noteworthy correlation unto the carbonate ramp microfacies in the southeastern of Tafresh. The scrutiny of microfacies characteristics and paleo-sedimentary environment showed that the distance from hydrothermal smokers, the action of different seawaves, sedimentological changes, structural features and initial morphology of microfacies have a remarkable impressiveness in the dispersion of ore reserves and the formation of horizons with a high concentration of ore.

Soil Formation on Loamy Deposits in Technogenic Landscapes of the Taiga Zone in the North-Eastern Part of European Russia

The paper highlights the influence of moisture on the soil formation process on loamy deposits during the primary vegetation succession. The study was carried out in the north-eastern part of European Russia (Komi Republic) in the middle taiga subzone. The authors analyzed young soils on the territory of a quarry for extraction of loamy grounds and background soils in the vicinity of it. Planting the Siberian spruce cultures on the territory of the quarry activated formation of the tree layer and thereby accelerated formation of the zonal type soils. The third succession decade in drained conditions saw formation of organic soil horizons (litters), a decrease in soil density in the upper profile part, a tendency to redistribute and differentiate the silty fraction by one-and-a-half oxides, indicating the beginning of selective podzolization. The rise in soil moisture content increased conservation of organic residues (peat formation) and made gley formation active. The quarry soils, like background soils, increased in acidity, carbon and nitrogen reserves along with the soil moisture content increase. In automorphic soil formation conditions, the rate of organic carbon accumulation in the upper 0–20-cm layer is 0.4 t· ha–1·year1; the excessive soil moisture content further increased it (1.0–1.2 t·ha–1·year1). The reserves of Corg in the upper 20-cm soil layer of young soils are by 2–4 times less than those in background soils.

Clarification of the structure of the Parfenov horizon based on generalization of the results of regional seismic surveys within the Angara–Lena oil and gas region

The results of regional geological exploration at the expense of the federal budget in the territory of the Angara–Lena oil and gas region from 2006 to 2017 are analyzed. Based on a comprehensive interpretation of data from geophysical surveys of wells and seismic surveys, relief maps of the roof of the Chora Formation, thicknesses and sandiness of the Parfenov gas-bearing horizon were updated. Based on the interpretation of a complex of GIS data, seismic exploration and deep drilling, a conclusion was made about the nature of the change in the sand content of the Parfenov gas-bearing horizon.

Rapid characterization of soil horizons for different soil series utilizing Vis-NIR spectral information

The visible-near infrared (Vis-NIR) reflectance technique is a powerful tool, particularly for obtaining faster information about soil texture, organic matter, and calcium carbonate content. However, there is limited research on the characterization of soil horizons using Vis-NIR data in profiles of different soil series. This study investigated the relationship between soil properties and spectral reflectance (Vis-NIR) in eight soil profiles with varying genetic properties from Harran Plain, Türkiye, focusing on variations within profiles (A, B, and C horizons) and across different soil series. A total of 36 soil samples were collected from the A, B, and C horizons, and spectral reflectance was measured along with calcium carbonate, organic matter, and particle size distribution. High variability was observed in calcium carbonate (11.58–52.50%) and organic matter content (0.60–3.71%), reflecting complex soil composition influenced by parent material and land management. Distinct reflectance patterns were observed within profiles, reflecting variations in soil composition. Ap horizons with higher organic matter content often exhibited lower reflectance (visible region). Clay content influenced NIR reflectance, with higher absorption in clay-rich profiles. The Kaynakli series (Fine-loamy, mixed, mesic Typic Calcixerepts) showed differentiation in reflectance between A and B horizons after 700 nm due to horizon formation and clay/carbonate accumulation. Increasing calcium carbonate content in Ck horizons led to higher reflectance compared to other layers. Confirmed that Vis-NIR reflectance could explain a significant portion of the variance in soil properties (A: 87.7%, B: 88.3%, and C: 90.6%). PCA results supported the notion that spectral signatures captured by Vis-NIR reflectance measurements are indicative of inherent differences between A, B, and C horizons. This study contributes to the growing body of knowledge on the application of Vis-NIR spectroscopy for soil assessment and monitoring. However, future research should focus on understanding spectral reflectance variations under diverse soil and environmental conditions.

Formation and degradation of textural pedofeatures in soils of ancient tropical coastal plains in southeastern Brazil

Textural features in soils are defined as having a distinct granulometric composition compared to the surrounding groundmass. Among these, clay coatings are found in various pedo-environments, covering a range of climatic conditions, from wetter regions to semiarid areas. This study aimed to understand how textural features in ancient coastal plain soils can reveal mechanisms of their pedogenetic evolution and how this relates to environmental transformations. Three soil profiles were studied at different points in a toposequence, representing the upper, middle, and lower thirds. The study area is located in the municipality of Seropédica, in the state of Rio de Janeiro, southeastern Brazil. Morphological, physical, chemical, mineralogical, and micromorphological analyses were conducted on the selected profiles. Acrisols, formed in free-draining conditions, were later transformed into Planosols due to base level oscillation and the percolation of brackish solutions through the soils. The pedogenetic model proposed in this study involves the following stages: i) Clay formation by in situ mineral weathering, mainly of phyllosilicates, with pseudomorphization of the structures. ii) Destruction of the pseudomorphized structures by pedoplasmation with proximal migration of clay and genesis of textural features of coating and filling. iii) Partial and episodic saturation of the base of the profile with solutions enriched in sodium of a fluvial-marine nature. iv) Dispersion of the clays, leading to the destruction of the textural features and soil micromass, accompanied by relative sand enrichment and E horizon formation. v) Local lowering of the surface and smoothing of the base of the slopes. This transformation model is unprecedented for the southeastern region of Brazil, increasing the evolutionary complexity of soil genesis in areas of ancient fluvial-marine plains.

Geochemistry and microbiology of boreal alluvial soil under salinisation

Soil salinisation in taiga landscapes is in most cases caused by anthropogenic activities. The study was carried out in Perm region (Russia) on the territory of the Verkhnekamskoe Potash Deposit. The inflow of sodium chloride drainage water into ground and surface waters during the production of potash fertilisers contributed to the technogenic salinisation of river valleys in the taiga zone. The purpose of the research was to investigate the microbial composition and chemical properties of alluvial soils in the area affected by NaCl waters in the Lyonva River valley. The chemical properties of soils were determined standard methods such as potentiometric method, titration, and spectrophotometry. The microbial community was determined by 16 s rRNA gene metagenomic analysis. The soil's mineralogical composition was determined using a binocular microscope and diffractometer for XRD. The morphology and microstructure of the samples has been studied using an analytical scanning electron microscope. In Solonchaks, an interdependence of salinity and bacterial species composition was discovered, along with the bacteria's geochemical processes. The topsoil contains a considerable amount of toxic salts, ranging from 5.9 to 17%. The ratio of exchangeable cations in the soil absorption complex changes when exchangeable calcium is replaced by sodium. Salinisation caused the neutralisation of acidic alluvial soils. Bacteria originating from marine and highly mineralised environments predominate in the soil. The soils are dominated by bacteria originating from marine and highly mineralised environments, such as Proteobacteria, Shewanella (75–79%), Thiomicrospira (26%), Desulfuromonas, Marinomonas and Idiomarina (9–10%), Alicyclobacillus (4%). The correlation revealed the connection of some taxa with ions of aqueous extract, as well as with exchangeable sodium, mobile iron and total sulphur. Some bacteria promote azonal geochemical processes within alluvial forest soil, such as the reduction of iron and manganese, the production of sulphides, and the oxidation of sulphur, hydrogen, and iron. Sulphide accumulation resulting in the formation of a hydrotroilite horizon (FeS × nH2O) and iron-bearing formations were found on the soil surface. Studying the properties and degree of soil disturbance makes it possible to identify the contribution of enterprises to environmental pollution, as well as to apply new methods for monitoring, purifying, and storing potassium waste.

No Black Holes from Light.

We show that it is not possible to concentrate enough light to precipitate the formation of an event horizon. We argue that the dissipative quantum effects coming from the self-interaction of light (such as vacuum polarization) are enough to prevent any meaningful buildup of energy that could create a black hole in any realistic scenario.

Endopedon pada Tanah yang Berkembang dari Batuan Ultrabasa di Desa Kiram Kecamatan Karang Intan Kabupaten Banjar

Endopedon identification is very necessary to determine the development, physical and chemical properties of soil. The development of endopedons originating from ultramafic rocks around Kiram Village, Karang Intan District, Banjar Regency has not been studied much, therefore it is necessary to explore more about the results of soil development. This research was a descriptive method to identify diagnostic horizons that develop in the endopedon. South Kalimantan is one of the areas where ultrabasic rocks are distributed and is an area with a wet tropical climate. The weathering force of the parent material will be faster in the wet tropics. Ultrabasic rocks in each region have different mineral and chemical compositions. Based on the research results, the Oxic horizon in Profile-1 was found at a depth of 29 cm to 76 cm from the ground surface. While in Profile-2 the Oxic horizon was found at a depth of 19 cm to 110 cm from the ground surface. The formation of the oxic horizon is due to the Latosolization process. Such as the long laterization process is supported by environmental conditions, climate, and rainfall making this laterization process will be better.

THE VIEW FROM THE EAST ON THE PROBLEM FIELD OF WESTERN LITERARY AND THEORETICAL STU

The study aims to determine the status of modern theoretical literary debate within the context of scientific theorizing in China and Japan. Growing understanding of the crisis of Euro-Atlantic literary-theoretical thought in the first two decades of the 21st century took shape in the publication of works by venerable specialists in the field of literary studies devoted to the causes of its occurrence and the taxonomy of directions and theoretical tools to overcome it. What unites this whole corpus of extensive research is an indirect or direct recognition of the decline of productive literary theoretical research, which came after the literary theoretical breakthrough of the late 60s of the 20th century. At the same time, the refusal to recognize Western literature as a model, artistic and aesthetic norm caused the emergence of powerful voices of authors whose writings are not directly shaped by the Western literary canon. Simultaneously, the refusal to recognize Western literature as a model, artistic and aesthetic norm caused the emergence of powerful voices of writers whose work is not directly shaped by the Western literary canon. The polemic started with the postcolonial discourse regarding the epistemological perspectives of Western literary theory in a situation of clash with a non-Western literary text, which, at the turn of the 21st century, developed into a reflection of its ontological potential. Both intellectuals and artists of the age of Multiculturalism, who relied on the Poststructuralist “breakthrough to the transcendental” on the one hand and on the philosophical nature as well as poetics and aesthetics of art of the East on the other, demonstrated that a complex of issues related to the future existence of literary theory risen by the literature itself, is much more sophisticated. First of all, these processes are caused by the early formation of new future horizons of world literature, in which artists with Eastern artistic and aesthetic background and knowledge play a major role. Following the mastering of the Western literary and aesthetic canon – rather a long period when the writings of these authors were derived from the general paradigm of Western literature – the formation of a new literature takes place, protesting Bhabha’s idea of mimicry as a way of survival and adaptation of the colonized and demonstrating the non-Western canon as its artistic source. The era of posttheory should testify that the rumours of the “death of the theory” may be greatly exaggerated in case the overcoming crisis of theory, which is based on literary knowledge originating from the East.

Vegetation at the former open-pit Ningyo-toge mine, 36 years after closure treatment: Impact of soil cover on woody plant establishment and dominance of the perennial herb Miscanthus sinensis

Soil cover is a prevailing method used at mine sites to ensure the safety of hazardous materials and restore ecological functions when the base materials are unfavorable for plant growth. The former open-pit Ningyo-toge Mine was backfilled with overburden and neutralized smelting residues and covered with soil in 1987. After 36 years, the vegetation remained dominated by the perennial herb Miscanthus sinensis, and woody plant establishment did not progress successfully. This study investigated the factors that inhibited woody plant establishment at the site. The soil profile survey revealed that the soil cover formed Bg horizons (pseudogley soil) with cloudy mottling, representative of poorly drained soil. In the Bg horizon, woody plant roots of Pinus densiflora and Weigela hortensis exhibited growth inhibition. Elemental analysis revealed that in the Bg horizon the roots of P. densiflora and W. hortensis accumulated high Fe concentrations exceeding 10,000 mg/kg DW at critical levels. Our results suggested that woody plant roots in the Bg horizon may have suffered from chronic oxygen deficiency accompanied by excessive Fe stress in the soil cover. Topsoil water content (<50 mm) and microtopographic features were not critical factors disrupting woody plant establishment because some individuals were growing in areas with high soil water content, exceeding 60%. Considering that woody plant roots were developed primarily in the shallow A horizon, A horizon formation by M. sinensis is a key step in initiating woody plant establishment by improving the soil structure and physiochemical characteristics of the soil cover, such as carbon content, exchangeable nutrients, and air-filled porosity. For successful mine pollution control and vegetation recovery, implementing an appropriate topsoil system, such as native forest soil, loosely graded and minor infiltration layer above the overburden would be necessary.

Pedological Factors, Classification, Physical-Chemical Properties and Management Strategies of Inceptisols in the Boca Formation of Temanggung, Cetral Java, Indonesia (Study: Horticultural Land Management)

Abstract The purpose of this research is to see the development of soil and management strategy of the boca formation in the Temanggung, Central Java, Indonesia. The boca range in Temanggung are hills located in Danurejo, Central Java, which are part of the old Sumbing mountain formation. This area is thought to be an intrusion area of cracks from the old Sumbing mountain, located at the foot of the mountain between Sumbing and Sindoro mountains. The boca formation is located at 705.9 m above sea level (m asl), in general the Boca formation consists of breccia, andesite, anglomerate and tuff. Vegetation that grows in the boca range includes bamboo and cotton. Soil genesis in the boca range has not yet reached an advanced stage of development characterized by the formation of an argillic horizon. The observed soil shows a diagnostic horizon, the cambic horizon. The soil acidity level (pH 5-6.5), falls into the slightly acidic class, with a texture dominated by geluhan. Based on the data obtained through field survey and laboratory analysis, the soils in the boca range are classified into Inceptisols based on USDA, Cambisols based on PPT and Cambisols based on WRB with ustic regime.

Global Models of Collapsing Scalar Field: Endstate

The study of dynamic singularity formation in spacetime, focusing on scalar field collapse models, is analyzed. We revisit key findings regarding open spatial topologies, concentrating on minimal conditions necessary for singularity and apparent horizon formation. Moreover, we examine the stability of initial data in the dynamical system governed by Einstein’s equations, considering variations in parameters that influence naked singularity formation. We illustrate how these results apply to a family of scalar field models, concluding with a discussion on the concept of genericity in singularity studies.

Landscape history mirrored in colluvial profiles: A multi-proxy approach from a Luvisol region in Central Czechia

Colluvisols represent an important geoarchive widely used to reconstruct of a range of processes related to the evolution of soil cover. Interpretation of Holocene landscape evolution based on the study of Colluvisols is becoming more important in areas where other proxy data, particularly archaeological and paleoenvironmental records, are lacking. The present study provides a detailed insight into the characteristics and development of two deep Colluvisols located in the Luvisols pedogeographic region in Central Czechia. Based on a multi-proxy approach combining optically stimulated luminescence dating, anthracology, soil micromorphology, clay mineralogy and geochemical analyses, it identifies the main sedimentary periods and describes both the dynamics of upbuilding of Colluvisol profiles and post-depositional pedogenesis. The position in the slope system and the provenance of the material influence the energy of deposition. The upper part of the side valley is characterised by rapid sedimentation of poorly sorted material, whereas the end part of the valley is described by calm sedimentation followed by intensive depletion. The most pronounced post-depositional features were due to bioturbation and redox processes. Although the pedological features associated with the clay illuviation are mainly preserved in the form of redeposited fragments, the in-situ formation of argic horizons in the sedimentary layers has been documented at the base of one of the profiles. The peaks of sedimentation correspond to the Migration Period and the early mediaeval Slavic colonization, both rarely identified depositional eras in Central Europe. In contrast, the colluvial layers representing the High Middle Ages and the recent redistribution of material are less represented. The remoteness of the area, the later onset of human pressure on the landscape and the specific nature of the Luvisols in terms of erosion vulnerability have been identified as the main reasons for this sedimentation history.

Black hole formation in gravitational collapse and their astrophysical implications

In this study, we have explored the process of black hole (BH) formation occurring in the collapse of a self-gravitating configuration using an innovative approach. The exact solution of the Einstein field equations is obtained in a model-independent way by considering a parametrization of the expansion scalar (Θ) in the background of spherically symmetric space-time geometry governed by the FLRW metric. Smooth matching of the interior solution with the Schwarzschild exterior metric across the boundary hypersurface of the star, together with the condition that the mass function m(t, r) is equal to Schwarzschild mass M, is used to obtain all the physical and geometrical parameters in terms of the stellar mass. The four known massive stars namely R136a3, Melnick, R136c, and R136b with their known astrophysical data (mass, radius, and present age) are used to study the physics of the model both numerically and graphically. We demonstrate that the formation of the apparent horizon occurs earlier than the singular state that is, the collapse of massive stars in our model results in the eventual formation of black holes as their final state. We have conducted an analysis indicating that the lifespans of massive stars are closely related to their respective masses. Our findings demonstrate that more massive stars exhibit considerably shorter lifespans in comparison to their lighter counterparts. Thus, the presented model corresponds to the evolutionary stages of astrophysical stellar objects and theoretically predicts their possible lifespan. We have also shown that our model satisfies the energy conditions and stability requirements via Herrera’s cracking method.

Formation of saline soils in the dry steppe landscapes of the Western Manych Valley on different forms of microrelief

The results of studying the physical and chemical characteristics of dry-steppe saline soils of the Western Manych valley, confined to different forms of microrelief, are presented. The soil cover of the studied territory is characterized by pronounced complexity due to the interrelation of natural and anthropogenic factors. It was revealed that chestnut saline soils and chestnut saline soils are mainly formed on micro-slopes and micro-elevations, and typical hydromorphic salt marshes are formed in saucer-shaped depressions. The soil profile has both common features (the presence of a saline horizon, a heavy loamy granulometric composition, etc.) and differences (the depth of formation of a saline horizon, the degree and chemistry of salinity, the boundaries of boiling of carbonates, the occurrence of gypsum and iron oxide forms, etc.). All saline horizons have increased density values (1.43-1.64 g /cm3), reduced humus content (no more than 2.0%) compared to the upper horizons. Geobotanical studies have shown that specific vegetation, represented by xerophilous and halophilic species, is formed on micro-slopes and micro-elevations during the development of the saline process. Various meadow and halophyte communities are formed in micro-depressions.

SOLA INCOGNITA: UNSOLVED PEDOGENETIC CHALLENGES

For the anniversary of the Faculty of Soil Science of Moscow State University, the author examines the issues that have remained unresolved in the field of classical genetic soil science over the past half century, and offers a list of tasks that need to be solved in the near future. It is noted that against the background of decreased interest in pedogenetic research, problems are accumulating in related fields that require a clear understanding of the genesis of soils: soil classification, digital soil mapping, paleopedology and soil assessment. One of the unsolved issues remains the estimation of the rates of soilforming processes, without which it is dificult both to reconstruct the evolution of soils in the past and to predict the behavior of soil systems in the future. The mechanisms of textural differentiation have not been deciphered both in temperate regions and in the tropics; in many cases, soils clearly differentiated by the content of the clay fraction are adjacent to soils with a profile homogeneous in texture. The mechanisms of deep illuviation of humus are unknown in the absence of signs of spodic or natric properties. There is no clear understanding of the mechanisms of formation of compacted subsurface horizons of soils (fragipan) and horizons cemented with opal (duripan). It is proposed to create a bank of unresolved soilgenetic issues that require analysis and solution