Abstract: The object of study in this publication is local cryogenic gas-dynamic geosystems, the development of which leads to pneumatic explosions and the formation of gas emission craters. The subject of the research is cryogenic formations recorded in frozen rocks composing the gas emission craters discovered in northern Western Siberia. The authors provide a detailed examination of the cryogenic formations found in various elements of the craters, analyzing their structure, morphology, plastic, and brittle deformations. Special attention is given to the processes that could have led to the formation of certain cryogenic elements, such as ring structures, cellular ice, and fracture structures on the crater surfaces. Due to the insufficient study of many cryogenic processes recorded in the craters, analogies from other fields of technical and natural sciences were widely used. Currently, researchers are primarily focused on searching for hypothetical schemes linking the genesis of gas with the formation of gas emission craters. The authors of this work have shown that without considering the cryogenic factor, it is impossible to address the problem of pneumatic explosions in permafrost, even in the context of gas genesis. The main method used in this article is the analysis of scientific publications on the topic under consideration, as well as data from laboratory modeling conducted by the authors. The synthesis of the analyzed materials was carried out based on a geosystem approach. The novelty of the research lies in the justification of the cryogenic basis for the staged development of the gas dynamic geosystem in frozen rocks, which conditions the preparation for pneumatic explosions and the formation of gas emission craters. For the first time, four stages of development of the cryogenic gas dynamic geosystem in frozen rocks have been identified. The first stage is the initial formation of a gas-saturated zone with increased pressure of the subsurface gas, located at the base of the gas dynamic geosystem. The second stage is the formation of a transit zone for the redistribution of subsurface gas. The concluding stage is where the gas pressure at its upper part reaches values exceeding the strength of the overlying soils. The final stage of development of the cryogenic gas dynamic geosystem is the pneumatic explosion that forms the gas emission crater. The main conclusions of the conducted research are as follows: the processes preparing for the formation of gas emission craters are cryogenic. They are determined by the structural-textural features of frozen rocks, mass transfer processes, and phase transitions occurring within them, as well as their strength and deformation properties.

Abstract: This publication is the second part of an article in which, based on an analysis of available data in scientific literature, the significant role of the cryogenic factor in the preparation of pneumatic explosions within permafrost rock layers is demonstrated. The subject of the research is local cryogenic gas-dynamic geosystems, the development of which leads to pneumatic explosions and the formation of gas emission craters. The focus of the study is the morphology and structure of cryogenic formations in frozen rocks that compose the gas emission craters found in northern Western Siberia. The authors discuss aspects of the topic in detail, such as the analysis and generalization of data on the cryogenic structure of various elements of gas emission craters. Special attention is paid to the examination of cryogenic formations associated with plastic deformations in the upper part of frozen layers and the formation of sub-vertically oriented structures outside the craters, related to the pressurized impact of gas. The primary method used in this article is the analysis of materials from scientific publications on the topic as well as data from laboratory modeling conducted by the authors. The synthesis of the analyzed materials was carried out based on a geosystemic approach. Significant interest is raised by the discovery of ring structures in several craters associated with shear deformations in the edge parts of gas-saturated stocks. The particular interest and novelty of the research lie in the study of cellular ice. These ices and the processes forming them have not been previously considered in geomcryology. They are traced in a narrow zone along the walls of the crater from its bottom to the upper edge of the narrowing part, significantly deformed and separated from the other rocks in the crater by fractures. In the upper part of the crater, the zone of cellular ice integrates into the layered ice-soil mass, forming a stiffness core in the shape of an ice block. Cryogenic formations in the form of cellular ice indicate the forceful impact of rising gas from below on the frozen host rocks. The main conclusion of the second part of the article is as follows: the local gas-dynamic geosystem preparing a pneumatic explosion consists of paragenetically related dynamic cryogenic subsystems, each possessing its own specific cryogenic structure.

Abstract: This publication is the first part of an article that demonstrates the significant role of the cryogenic factor in the preparation of pneumatic explosions within the body of permafrost rocks, based on an analysis of data available in scientific literature. The object of the study is local cryogenic gas-dynamic geosystems, the development of which leads to pneumatic explosions and the formation of gas blowout craters. The subject of the study is the morphology and structure of cryogenic formations in frozen rocks that make up the gas blowout craters found in the northern part of Western Siberia. The authors thoroughly examine aspects of the topic such as the analysis and generalization of data on the cryogenic structure of various elements in gas blowout craters. Special attention is given to the study of various deformations of primary ice formations, which allows tracking the history of the emergence and development of local gas-dynamic geosystems within permafrost rocks. The authors do not address questions related to the genesis of gas, as they believe that the pressure processes occurring in local gas-saturated zones with increased pressure do not depend on its origin. The main method used in this article is the analysis of materials from scientific publications on the subject, as well as laboratory modeling data conducted by the authors. The synthesis of the analyzed materials is based on a geosystemic approach. A significant contribution of the authors to the study of the topic is the identification of a common pattern in the structure of gas blowout craters. All craters that are not filled with water and are accessible for study exhibit a three-part structure. At the bottom of the craters, an expansion is observed, sometimes due to caverns and grottoes. In the middle part, the cross-section of the craters decreases, and the walls of the crater are most often steep and even. In the upper part, an expansion is observed in the shape of a flare. The novelty of the research lies in uncovering the paragenetic relationships between the morphological structure of the craters, the stages of development of the gas-dynamic geosystem that prepares conditions for pneumatic explosions, and the complexes of processes at each stage. The main conclusions of the research include the identification of the leading role of gas pressure in the transformation of the cryogenic structure of frozen rocks at all stages.

Abstract: The article is devoted to the consideration of surface and deep factors that trigger the mechanisms for the preparation of explosive processes that form gas emission craters. The study object is local zones of gas-saturated soils with abnormally high gas pressure and gas craters. The main method used in this article is the bibliography review. The synthesis of the analyzed materials was carried out based on the geosystem approach. In the proposed work, an analysis was made of the main hypotheses of the formation of gas-saturated zones with increased gas pressure in frozen soils: 1) due to the comprehensive freezing of taliks (completely dependent on surface conditions; 2) due to the inflow of warm gas from underlying rocks into the surface layers (depending on deep sources); 3) due to the decomposition of gas hydrates contained in the permafrost (the reasons can be both surface and deep); 4) due to the joint interaction of the freezing talik and the associated deep gas inflow channel. Possibilities of realization of these or those hypotheses in real conditions are revealed. The relevance of the topic is due to the reassessment of the role of frozen soils as a screen that protects the atmosphere from the emission of greenhouse gases from the lithosphere. Evidence has appeared that this role of the cryolithozone is significantly weakened with an increase in temperature, while the frozen soils themselves can be a source of gas release.

Abstract: The subject of this research is the cryogenic formations found in gas emission funnels in the north of Western Siberia. The object of this research is cryogenic processes that prepare the explosion, which forms a gas emission funnel. The study of cryogenic structures that shape the walls of gas emission funnels is based on the structural-genetic analysis, which reveals the peculiarities of the initial cryogenic structure of frozen rock, as well as the cryogenic textures modified as a result of dynamic metamorphism. The authors examine such aspects of the topic as the general orientation of plastic and explosive deformations under the influence of high pressure. Analysis is conducted on the role of intra-ground gas filtration in transformation of the initial cryogenic structure. Special attention is given to the patterns of emergence and development of the local geodynamic system that ultimately substantiates the formation of gas emission funnel. The novelty of this research consists in the establishment of paragenetic relations between the processes of gas filtration and deformations of gas-saturated ice surface material (from viscoplastic motion to brittle fracture). The main conclusions are as follows: such external influences as increase in the temperature or pressure change thermodynamic conditions, which lead to multi-phase structural transformation of the initial cryogenic structure of the cryolithic zone; a series of plastic and explosive deformations instigates the intense heat and mass transfer, redistributing the substance in the liquid, solid and gaseous state; in frozen rocks, ice is the most deformable component, thus, most information on the processes preceding the formation of gas funnels can be acquired by studying the morphology of cryogenic formations observed in the walls of the funnels, as well as in the unthawed fragments of frozen rocks thrown to the surface. The authors’ special contribution lies in examination of the complete lifecycle of the development of selected geosystems, from the initial stage –  formation of conditions for decomposition of the gas hydrates, to the final stage – explosion and emission of ice surface material.

Abstract: The object of this study is the geosystems of gas-saturated permafrost. Currently, the theoretical basis for examination of gas component in permafrost is practically not developed. At the same time, the theoretical and practical significance of this problem has rapidly increased in recent years. This is due to gas emissions during drilling of wells in frozen rocks, the identification of significant greenhouse gas emissions in the Arctic, the detection of previously unknown processes in the permafrost zone – the formation of craters due to gas emissions.The main method applied in the article is the analysis of research materials. The synthesis of the results was carried out on the basis of the geosystem approach. The authors are first to demonstrate that gas-saturated zones in seasonally and permafrost rocks have all the attributes of geosystems: localization in space, boundaries, morphology, individual structure and properties, development history, life cycle, hierarchy. Five types of geosystem were determined: active layer; genetic type; confined to geological structures; secondary, associated with the decomposition of gas hydrates in vivo; technogenic (due to thermal or mechanical effects on hydrated and gas saturated frozen rocks). The artcile describes promising directions in studying gas-saturated geosystems of permafrost zone, as well as  the advanced research methods.

Abstract: The subject of this research is the gas emission crater (Yamal crater), located in the southern part of Bovanenkovo deposit on the Yamal Peninsula. Generalization of data on the structure of crater soils components, natural conditions and laboratory results, allowed building a phenomenological model of the Yamal crater, with identification of different stages of its development. The cause for the emergence of the gas emission craters is the formation within the subsurface of permafrost rocks of the underground gas accumulation zones with the abnormally high pressure. The diverse geological and thermodynamic factors substantiate the various scenarios of their development. The main research method lies in consideration of the different structural elements of the Yamal crater as the phenomena that reflect the processes of its formation. In determination of the processes that form the gas emission craters, the authors apply the method of analogies. The conclusion is made that the gas emission craters eventuate the self-development of the fluid dynamics geosystems, which are the local ice-surface gas-saturated formations in non-equilibrium thermodynamic state in relation to the enclosing permafrost rocks. The development of the selected geosystems is defined by paragenetic links between gas filtration processes and deformations of gas-saturated ice-surface material (from viscoplastic motion to brittle fracture). The Yamal crater is a particular example of a full and complete life cycle of the development of selected geosystems: from the initial stage – the formation of conditions for decomposition of gas hydrates, to the final stage – the explosion and release of ice-surface material.

Abstract: The second part of the article is devoted to the consideration of the conditions for the development of two types of fluids in permafrost: frozen soils, and ice flows and gas flows. This work is hampered by the lack of a corresponding conceptual and terminological base, developed classifications, systematized features, differentiation of genetically distinct dynamic formations in frozen soils. In this work, the conceptual fluid dynamics terminology used in geology is analyzed and the possibility of its use in geocryology is considered. The main attention is concentrated on the construction of phenomenological models for the fluids formation in permafrost, supplemented by the structural method and by the method of actualism. The conditions for the development of various types of lithogenous fluids are analyzed: through the formation of a nucleus of rigidity, the motion of frozen soils along the slope, subaquatic landslides, and folding at the lateral surface of growing ice wedges. Based on the analysis of the structure of the gas emission crater (Yamal Crater), the possibility and conditions of gas filtration through icy frozen soils are considered. A mathematical model of the pressure filtration of gas fluids in structurally heterogeneous soils is proposed on the basis of the Brinkman equation applied to the frozen soils.

Abstract: This article is devoted to the consideration of issues related to the formation of local zones with signs of dynamic metamorphism in permafrost. Data on the cryogenic formation structures with traces of plastic and discontinuous deformations, as well as signs of flow in a solid, liquid and gaseous form are analyzed. The possibility of using the fluid dynamical approach in the study of dynamic processes in the cryolithozone is considered. The development of the fluid dynamic topic necessitates consideration of non-traditional geocryological objects associated with fluid formations in the cryolithozone. The main attention is given to the structural method associated with the analysis of the features of the cryogenic formations structure and the method of actualism associated with the analysis of the conditions for the fluids formation. In the first part of the article, the paragenetic relationships between the features of the frozen soils formations on the Arctic coasts, the formation of inland water flows and the structural and texture features of the cryogenic formations are considered. A section of marine sediments in the area of the Nei-To lake in Central Yamal was chosen as the research object.

Abstract: The subject of this research is the natural explosive processes into cryolithic zones. The object of this research is the Yamal Crater. The authors meticulously examine the groups of the natural explosive processes in the territory of distribution of permafrost. A new approach towards the theory of the crater of gaseous discharge is proposed. It is based on the migration mechanism of gas fluids from the zones of gas hydrates disassociation into the overlying thickness of permafrost. The dissociation zone forms in segments of the local heatup through the heat input from the top. The authors demonstrate the gradualism of processes of preparing the explosive process that formed the Yamal Crater, as well as calculate the pressure of ejection of the frozen layer in emergence of the Yamal Crater. The work provides characteristic to the four phases of preparation of the natural explosive processes, considers various scenarios of such in cryolithic zone, as well as creation of the model of the heat and mass transfer processes alongside tense and distorted situation in permafrost that contain gas hydrated in terms of temperature variation and pressure. The following conclusions were made: the explosions of hydrolaccoliths and emergence of the craters of gaseous discharge belong to the same group of processes – physical explosions of natural origin; preparation of explosive processes in permafrost passes through several stages; in preparing explosions of natural origin in permafrost, a significant role is played by the migration of gas fluids.