Thickness Of Rocks Research Articles

Main geological and mining factors affecting ground cracks induced by underground coal mining in Shanxi Province, China

As one of the largest coal-rich provinces in China, Shanxi has extensive underground coal-mining operations. These operations have caused numerous ground cracks and substantial environmental damage. To study the main geological and mining factors influencing mining-related ground cracks in Shanxi, a detailed investigation was conducted on 13 mining-induced surface cracks in Shanxi. Based on the results, the degrees of damage at the study sites were empirically classified into serious, moderate, and minor, and the influential geological and mining factors (e.g., proportions of loess and sandstone in the mining depth, ratio of rock thickness to mining thickness, and ground slope) were discussed. According to the analysis results, three factors (proportion of loess, ratio of rock thickness to mining thickness, and ground slope) play a decisive role in ground cracks and can be respectively considered as the critical material, mechanical, and geometric conditions for the occurrence of mining surface disasters. Together, these three factors have a strong influence on the occurrence of serious discontinuous ground deformation. The results can be applied to help prevent and control ground damage caused by coal mining. The findings also provide a direct reference for predicting and eliminating hidden ground hazards in mining areas.

Moho modeling of the Yellow Sea (West Sea) from spectrally correlated free-air and terrain gravity data

Moho estimates for the Yellow Sea and Bohai Basin were developed from the EGM2008 gravity, ETOPO1 topography/bathymetry, and NOAA’s sedimentary thickness databases. Spectral correlation analysis between the free-air gravity anomalies (FAGA) and the terrain’s gravity effects (TGE) at 20 km altitude was made to estimate the terrain-correlated FAGA, which can provide information on the isostatic status of the study area. This study included the additional terrain gravity effects due to density contrasts from sedimentary rock thickness variations over the Yellow Sea. Spectral correlation filtering of the FAGA with the TGE estimated the terrain correlated FAGA, which were subtracted from the TGE to infer isostatically compensated gravity effects for inversion constraints on the Moho modeling. The derived Moho estimates show considerable sensitivity to the sedimentary thickness variations and tectonic features of the Yellow Sea region. In addition, the gradients in the dynamic crustal topography inferred from the terrain-correlated FAGA show apparent associations with the distribution of the Yellow Sea’s earthquakes with predominantly strike-slip focal mechanisms.

Investigation of the cosmic ray angular distribution and the East–West effect near the top of Etna volcano with the MEV telescope

An experimental investigation of cosmic muons has been carried out with the Muography of Etna Volcano (MEV) tracking telescope, installed at an altitude of about 3100 m a.s.l. in front of the North-East Etna crater. The analysis of a statistically significant data sample ($$\sim 10^7$$ events), taken during a period of approximately 2 months, has been carried out to investigate the angular distribution of cosmic muons originating both from the open sky side and from a large solid rock thickness (Etna side). Due to the geographical orientation of the MEV telescope, anisotropies caused by the East–West effect could also be observed, extracting the asymmetry factor in small steps of the zenithal angle.

Soil, regolith, and weathered rock: Theoretical concepts and evolution in old-growth temperate forests, Central Europe

Evolution of weathering profiles (WP) is critical for landscape evolution, soil formation, biogeochemical cycles, and critical zone hydrology and ecology. Weathering profiles often include soil or solum (O, A, E, and B horizons), non-soil regolith (including soil C horizons, saprolite), and weathered rock. Development of these is a function of weathering at the bedrock weathering front to produce weathered rock; weathering at the boundary between regolith and weathered rock to produce saprolite, and pedogenesis to convert non-soil regolith to soil. Relative thicknesses of soil (Ts), non-soil regolith (Tr) and weathered rock (Tw) can provide insight into the relative rates of these processes at some sites with negligible surface removals or deposition. Scenarios of weathering profile development based on these are developed in current study. We investigated these with ground penetrating radar, electrical resistance tomography, and seismic profiling at three old growth forest sites in the Czech Republic, on gneiss, granite, and flysch bedrock.We found that the geophysical methods – which generated thousands of separate measurements of Ts, Tr, Tw – to produce good estimates. The weathered rock layer (sensu lato) was generally the thickest of the weathering profile layers. Mean soil thicknesses were about 0.64–0.75 m at the three sites, with typical maxima around 1.5 m. Non-soil regolith thicknesses averaged about 2.5 m on the gneiss site and 1.2–1.4 at the other sites. Weathered rock had a mean thickness of 7 m at the gneiss site (up to 10.3), 4.6 at the granite site, and 3.4 on flysch. Results indicate that weathering at the bedrock weathering front is more rapid than conversion of weathered rock to regolith, which is in turn more rapid than saprolite-to-soil conversion by pedogenesis on all three bedrock types. No evidence was found of steady-state soil, non-soil regolith, or weathered rock thicknesses or evolution toward steady-state. Steady-state would require that weathering rates at the bedrock and/or regolith weathering fronts decline to negligible rates as profiles thicken, but the relative thicknesses at our study sites do not indicate this is the case.

Decompression boiling and natural steam cap formation in high-enthalpy geothermal systems

Many high-enthalpy geothermal systems exhibit vapor-rich boiling zones at shallow depths (<1 km), commonly known as steam caps. While the spatial extent and vapor content of steam caps often increases in response to fluid extraction and subsequent pressure decline, the geologic factors controlling steam cap formation and development are poorly understood. Numerical simulations of groundwater convection driven by a transiently cooling intrusion elucidate a natural mechanism by which steam caps can develop from initially liquid-dominated boiling zones. In the simulations, intensive decompression boiling and steam cap development occurs after the heat of a subsurface magmatic intrusion is exhausted by prolonged hydrothermal convection. A reduction in the strength of the upflow leads to a fluid pressure decrease of 2–4 MPa in boiling zones beneath an impermeable cap rock. As the vertical pressure gradient decreases, approaching vapor-static, zones of liquid-vapor counterflow (i.e., heat pipes) develop at the base of steam caps, efficiently isolating overlying vapor-rich zones from underlying liquid. The reservoir rock permeability and the cap rock thickness are main controls on the enthalpy and spatial extent of steam caps, with thicker and higher enthalpy (potentially superheated) steam caps developing in intermediate permeability reservoir rocks (∼ 10−15 m2). Due to the importance of transient changes in geothermal system structure to steam cap development, the dynamics of natural steam cap formation may not be captured in standard approaches to natural state reservoir modeling, which express the role of the heat source in terms of fixed boundary conditions.

Growth of Paddy Rice Seedlings Using Controlled Fertilizers in 13 mm and 16 mm Thick Rock Wool Molding Medium

Growth of Paddy Rice Seedlings Using Controlled Fertilizers in 13 mm and 16 mm Thick Rock Wool Molding Medium

ПЕРСПЕКТИВИ ВІДКЛАДІВ НАДЗАПЛАВНИХ ТЕРАС ДНІСТРА НА ЗОЛОТУ МІНЕРАЛІЗАЦІЮ

The article clarifies the stratigraphic binding and origin of silicon nodules, which served as the main raw material for the manufacture of tools for mammoth hunters of the Mezhyrich Late Paleolithic site. In archaeological publications, these nodules are often mentioned to be confined to the "Vyrzhikovsky layer" (the Albian layer of the Lower Cretaceous), which was formed under continental conditions and consists of sand-clay (kaolin, in particular) deposits. The analysis of the necessary conditions and possible mechanisms for the formation of silicon nodules indicates the erroneousness of such ideas. Most likely, the source of silicon raw materials was the marine deposits of the Cenomanian (Upper Cretaceous), or, in accordance with the modern stratigraphic division of the Mesozoic-Cenozoic sequence, deposits of the Burim suite (upper Albian – lower Cenomanian). The paleogeographic setting, sedimentological conditions and lithological composition of the "Vyrzhikovsky layer" did not ensure the formation of silicon nodules in it in the form of inclusions. The latter are diagenetic in origin and could only form in the thickness of carbonate rocks, free of clay minerals. The region of Kaniv dislocations was the optimal region from the silicon production point of view, which was determined: firstly, by the tectonic dislocation of the sedimentary sequence, which contributed to the removal of deposits containing silicon nodules in the thickness of younger rocks; secondly,the erosion activity of temporary streams, which brought these deposits to the level of the denudation cut-off. The most convenient place for collecting flints was not the outcrop of bedrock in ravines but the cones of their removal, which overlook the floodplains of the Dnipro and Ros'. The possibility of collecting flint in the immediate vicinity of the Mezhirich site, in the ravines and gullies between the Ros and Rosava rivers, does not find confirmation, since the chalk deposits here lie much lower than the local erosion base and are not exposed by ravines. Therefore, the leading role in the formation of the raw material supply of the Late Paleolithic site of Mezhirich was played by the region adjacent to the Kaniv mountains of the alluvial-proluvial plain.Despite long-term geological study of the Dniester River basin, we still have no clear evidences about gold-bearing potentiality of this area as well as origin of gold. The leading role of geological, geochemical and mineralogical criteria is proved for defining the prospects of substantial gold deposits finding within the Dniester river basin. Gold was found here in the crystalline basement and in the sedimentary cover rocks. Study of mineralogy and lithology of the terraces above the flood-plain and typomorphic peculiarities of native gold shows that palaeogeographic conditions and alimentation zones of debris vary at the different tectonic stages of this area development. Gold-bearing potential of the Pliocene-Quaternary sediments in the Dniester River basin is related to the Pliocene (VI-IX terraces above the flood-plain) and Quaternary (I-V terraces above the flood-plain) terraces complex of the Dniester river, as well as this river and its inflows recent alluvia. Our study of the Mid-flow part of the Dniester river basin allow to conclude that native gold was found in geologocal strata of all ages, from Proterozoic up to the recent alluvium. This fact points the necessity of further prospecting to find the mother lodes of gold. Our field study, samples analyses made as well as publications observation allow highlighting the principal directions of further prospecting and evaluation works. The main among that are: 1) comprehensive study of river Dniester alluvia and its terraces complex (previously VI–VII terraces), that will allow to specify their material composition, to assess real gold-bearing potential and to define the history of denudation areas changes; 2) lithogeochemical prospecting of primary and secondary dispersion haloes to clear the principal gold-bearing regularities; 3) definition of prospect plots within the area described; 4) modern analytical approach study of typomorphic peculiarities of native gold from alluvia and terrace deposits to define its ore formational affinity and mineral type.

ПРО ВІК І ПОХОДЖЕННЯ КРЕМ'ЯНОЇ СИРОВИНИ ІНВЕНТАРЮ ГЕОАРХЕОЛОГІЧНОЇ ПАМ'ЯТКИ МЕЖИРІЧ (КАНІВСЬКЕ ПРИДНІПРОВ'Я)

The article clarifies the stratigraphic binding and origin of silicon nodules, which served as the main raw material for the manufacture of tools for mammoth hunters of the Mezhyrich Late Paleolithic site. In archaeological publications, these nodules are often mentioned to be confined to the "Vyrzhikovsky layer" (the Albian layer of the Lower Cretaceous), which was formed under continental conditions and consists of sand-clay (kaolin, in particular) deposits. The analysis of the necessary conditions and possible mechanisms for the formation of silicon nodules indicates the erroneousness of such ideas. Most likely, the source of silicon raw materials was the marine deposits of the Cenomanian (Upper Cretaceous), or, in accordance with the modern stratigraphic division of the Mesozoic-Cenozoic sequence, deposits of the Burim suite (upper Albian – lower Cenomanian). The paleogeographic setting, sedimentological conditions and lithological composition of the "Vyrzhikovsky layer" did not ensure the formation of silicon nodules in it in the form of inclusions. The latter are diagenetic in origin and could only form in the thickness of carbonate rocks, free of clay minerals. The region of Kaniv dislocations was the optimal region from the silicon production point of view, which was determined: firstly, by the tectonic dislocation of the sedimentary sequence, which contributed to the removal of deposits containing silicon nodules in the thickness of younger rocks; secondly,the erosion activity of temporary streams, which brought these deposits to the level of the denudation cut-off. The most convenient place for collecting flints was not the outcrop of bedrock in ravines but the cones of their removal, which overlook the floodplains of the Dnipro and Ros'. The possibility of collecting flint in the immediate vicinity of the Mezhirich site, in the ravines and gullies between the Ros and Rosava rivers, does not find confirmation, since the chalk deposits here lie much lower than the local erosion base and are not exposed by ravines. Therefore, the leading role in the formation of the raw material supply of the Late Paleolithic site of Mezhirich was played by the region adjacent to the Kaniv mountains of the alluvial-proluvial plain.

Строение баженовского резервуара и прогноз нефтеносности горизонта Ю0 баженовской свиты в юго-восточных районах Западной Сибири

For the South-Eastern regions of the West Siberian oil and gas province, a model of the structure of the Bazhenov reservoir and criteria for selecting areas that are promising for detecting oil accumulations in the productive level of the South-West Bazhenov Formation are proposed. According to the our criteria, the following characteristics of the object of research are given: the thickness of rocks of the Bazhenov Formation, the thickness of rocks with a Corg content &gt; 7%, catagenesis degree of organic matter, the thickness of the underlying and overlying fluid barriers, current reservoir temperatures of rocks and reservoir pressures in the Bazhenov Formation. Based on a comprehensive analysis of the materials that characterize the above criteria, promising zones of two categories are identified. The Central-Nyurol zone is assigned to the 1st category (the most promising), and the North-Nyurol, East-Nyurol, South-Nyurol, West-Parabel, and Ust-Tym zones are assigned to the 2nd category.

Distribution Features of the Minimum Rock Cover Thickness of the Surrounding Rock Self‐Stability of the Metro Tunnel in the Soil‐Rock Dualistic Stratum

Based on the maximum value of the self‐stability of surrounding rock, the key issues affecting the distribution of the minimum mock cover thickness of the surrounding rock self‐stability (MRCT‐SRS) of the metro tunnel in the soil‐rock dualistic stratum are discussed. The MRCT‐SRS was studied for different soft stratum thicknesses Hs and excavation spans D based on cusp catastrophe theory. Moreover, the 3D spatial distribution was determined, and the fitted curves were constructed according to the MRCT‐SRS, Hs, and D. This facilitated the assessment of the stability of the surrounding rock in the excavation of a metro tunnel. Combined with the construction practices used for the Qingdao metro project, the validity of the obtained MRCT‐SRS has been verified by the inverse analysis of the monitored data from the metro tunnel. Furthermore, the application of the MRCT‐SRS in determining the reasonable buried depth of a metro line has been explored. The research results have provided theoretical support and scientific basis for the preparation, revision, and improvement of the relevant codes, standards, and guidelines for metro tunnel planning and design.

Numerical investigation on overburden migration behaviors in stope under thick magmatic rocks

Quantification of the influence of the fracture of thick magmatic rock (TMR) on the behavior of its overlying strata is a prerequisite to the understanding of the deformation behavior of the earth\'s surface in deep mining. A three-dimensional numerical model of a special geological mining condition of overlying TMR was developed to investigate the overburden movement and fracture law, and compare the influence of the occurrence horizon of TMR. The research results show that the movement of overlying rock was greatly affected by the TMR. Before the fracture of TMR, the TMR had shielding and controlling effects on the overlying strata, the maximum vertical and horizontal displacement values of overlying strata were 0.68 m and 0.062 m. After the fracture, the vertical and horizontal displacements suddenly increased to 3.06 m and 0.105 m, with an increase of 350% and 69.4%, respectively, and the higher the occurrence of TMR, the smaller the settlement of the overlying strata, but the wider the settlement span, the smaller the corresponding deformation value of the basin edge (the more difficult the surface to crack). These results are of tremendous importance for the control of rock strata and the revealing of surface deformation mechanism under TMR mining conditions in mines.

A Short Note on the Petroleum Potential of the Sokoto Basin in North-western Nigeria

The stratigraphy of the Sokoto Basin has the Illo/Gundumi Formation at the bottom, followed successively upward by the Taloka, Dukamaje, Wurno, Dange, Kalambaina, Gamba and GwanduFormations. Re-mapping of the basin carried out in this studyshows that the geological framework remainslargely as previously outlined except that some hitherto unreported tectonically controlled structures have been documented. The basin is generally shallower at the margin and deepens towards the centre such that the areas around the border with Niger Republic are deepest and hence most prospective on the Nigerian side. Geophysical aeromagnetic interpretation has assistedto analyze the depth to basement configurations. Organic geochemical studies show that the dark shales and limestones of the Dukamaje Formation constitute the source rocks in the potential petroleum system. With averages for source rock thickness of 50m, area of basin of 60,000km², TOC of 7.5wt%, and HI of 212mgHC/gTOC, charge modeling indicates 808.10 million barrels of oil equivalent extractable hydrocarbons in the Sokoto Basin, at current knowledge of the geology and if the appropriate maturity has been attained at deeper sections. The sandstones of the Illo/Gundumi Formation as well as in the Taloka and Wurno Formations and carbonates of the Kalambaina Formation provide potential reservoir packages. The paper shale of the Gamba Formation and the clays of the Gwandu Formation provide regional seals. If the presently mapped tectonic structures are ubiquitous in the whole basin, structural and stratigraphic traps may upgrade the petroleum system. Other petroleum systems may exist in the basin with either or both the Illo/Gundumi and Taloka Formation (s) providing the source and reservoir rocks.

Simulation Research on the Load Transfer Mechanism of Anchoring System in Soft and Hard Composite Rock Strata under Tensile Loading Conditions

Soft and hard composite rock strata are frequently encountered in transportation, geotechnical, and underground engineering. However, most of the current support is designed for homogeneous rock masses, which ignores the different anchoring effect in soft and hard composite rock strata. A numerical study is presented in this paper on the pull‐out behavior of fully grouted rock bolts in soft and hard composite rock strata. The nonlinear bond‐slip relationship of bolt‐grout interface that is anchored in soft rock and hard rock is obtained from laboratory test, respectively. Then, the nonlinear bond‐slip relationship is put into the numerical model. The numerical result shows a close match with the experiment tests and the proposed model. Lithological sequence, layer thickness ratio, and layer numbers are taken into consideration in numerical simulation models. Under the same layer number, the shallower‐soft and deeper‐hard composite rock strata (SHCRS) have a higher bearing capacity and deformation resistance than the shallower‐hard and deeper‐soft composite rock strata (HSCRS). As the soft‐to‐hard thickness ratio in SHCRS increases, the initial stiffness of the load‐displacement curve and peak load decreases continuously. The load‐displacement curve shows the same initial stiffness for different hard to soft thickness ratios in HSCRS. As the hard to soft thickness ratio increases, the load peak and the displacement at the peak load increase. Therefore, the closer the hard rock is to the loading end, the greater the initial stiffness of the load‐displacement curve is. The greater the hard rock thickness, the larger the peak load. Under the same anchor length, the peak load and the displacement at the peak load decrease with the increase of layer numbers, but the reduction magnitude decreases. This paper leads to a better understanding of the load transfer mechanism for the anchoring system in soft and hard composite strata and provides a reference for scientific support design and evaluation method.

Updates on the Geology and Potential Petroleum System of the Bida Basin in Central Nigeria

The Bida Basin is one of Nigeria’s inland frontier basins. The conventional stratigraphy of the Bida Basin has the Bida Formation at the base in the northern sector, followed successively upward by the Sakpe, Enagi, and Batati Formations. In the southern sector, the Lokoja Formation is at the base, followed by the Patti Formation and ending with the Agbaja Formation at the top. Detailed field mapping carried out in this study has not identified the Batati Formation at the previously assigned Type Locality at Batati village. A new formational name of “Pattishabakolo Formation” has been proposed. The Patti Formation is also not mappable at the previously assigned Type Locality of the Mount Patti in Lokoja but mappable at Gegu, Ahoko and midway on the Agbaja Plateau. A new Type Locality at Ahoko has been proposed. Sediment thicknesses in the Bida Basin are shallower at the margin and generally deepen towards the centresuch that the central portions constitute the most prospective areas. Geophysical aeromagnetic interpretation has assisted in the interpretation of the geology of the basin. Organic geochemical studies show that the Kudu Shale in the Northern Bida Basin equivalent to the Ahoko Shale in the Southern Bida Basin constitutes the source rocks in the potential petroleum system. With averages for source rock thickness of 40m, area of basin of 45,000km2, TOC of 9.0wt%, and HI of 220mgHC/gTOC, charge modeling indicates 623 million barrels of oil equivalent extractable hydrocarbons in the Bida Basin, at current knowledge and if the appropriate maturity has been attained at deeper sections. The Bida/Lokoja Formation sandstones as well as the well sorted sandstones in the Enagi Formation constitute potential reservoirs in the basin. Regional seals are provided by the clayey members of the Enagi and Batati Formations. Potential traps are both structural and stratigraphical.

The influence of magmatic rock thickness on fractureand instability law of mining surrounding rock

The influence of magmatic rock thickness on fractureand instability law of mining surrounding rock

Optimized Selection of Construction Scheme for Huiqing Expressway Tunnel

In view of the complex construction environment of the mountain tunnel, the construction method conforming to each project is adopted, which is beneficial to avoid blind spots during the construction process. For poor surrounding rock conditions, the thickness of different soils will lead to the joint of the plastic zone of the excavation face, which will cause the overall settlement. Taking Maple Ridge, Daping and Fengshuao Tunnels as an example, comprehensive analysis of different surrounding rock thickness conditions, through the comparison of three construction methods of double side wall method, CD method and three step method, using FLAC finite element software results Analysis gives the most advantageous deformation control method. The results show that the larger the thickness of the overburden, the larger the displacement of the arch and the arch, the double-wall method does not extend to the slip zone in the plastic zone of different soil thickness, and the surrounding rock also maintains the self-stability, compared with the other two methods. Good stability. Therefore, it has a good guiding significance for the construction method in the same situation in the future.

Stability study and optimization design of small-spacing two-well (SSTW) salt caverns for natural gas storages

Abstract A small-spacing two-well salt (SSTW) cavern is a relatively new type of cavern. As this type of cavern is less frequently used in underground natural gas storages, study on its stability is quite limited. To promote the application of this type of cavern and accelerate the construction of underground salt cavern gas storages, stability analysis and optimization design of this type of cavern are indispensable to the security of underground natural gas storages. In this paper, numerical calculation and parameters analysis were performed to analyze the effects of internal gas pressure and ratio of long axis to short axis (RLS) on the stability of SSTW caverns. The results show that internal gas pressure has an influence on the stability of SSTW caverns and low pressure should be limited in terms of duration and magnitude. And the ratio of long axis to short axis (RLS) has limited influence on the stability of a SSTW cavern by ways of volume loss rate and roof settlement. Overall, the SSTW cavern behaves similar stability state with that of a SW cavern. In addition, a flatter roof shape appears under greater Ratio value (RLS) and thus a thicker roof salt rock thickness is suggested for engineering design. The most different between them are the waist displacement along short axis, therefore the pillar width close to the adjacent cavern should be a certain lengthened at this direction.

ПАЛЕО- ТА СУЧАСНІ ГІДРОГЕОЛОГІЧНІ УМОВИ БІЛЬЧЕ-ВОЛИЦЬКОЇ ЗОНИ КАРПАТСЬКОЇ НАФТОГАЗОНОСНОЇ ПРОВІНЦІЇ

On the basis of paleo- and modern hydrogeological sings it was possible to establish a space-time mechanism of formation and reservation of gas and oil deposits in the Bilche-Volytsa zone of the Carpathian oil- and gas-bearing province. The time interval of their forming applies on the last cycle of the hydrogeological time. Geodynamic and secondary geostatic loadings, that manifested themselves during the dynamo-elision stage (Late Badenian – up to the present) the development of which was caused by thrust motions of the covers, turned out to be the factors of migration of aqueo-hydrocarbon mixtures deep underthrust structures of the Inner zone. Time calculations for reservation of deposits of gas fields have determined their age which does not exceed 6 million years. The south-western trend of motion of paleo- and modern infiltration waters in combination with reversed dynamo-elision have caused here the existence hydrodynamically balanced system squeezed between them which differs by favourable conditions for the formation and reservation of hydrocarbon deposits. We have ascertained the connection between piezomaxima and areas of tectonic dislocation, mainly transverse, that points out the ways of transsference of hydrocvarbon mixtures from deep-seated horisons. Discharge areas (perspective on a plane of searching for new deposits) are limited by local piezomaxima on the background of regional fields. Areas of paleopiezominima in the near-fault part of the Ugerske-Kosiv blocks at the boundary with the East European Platform are favourable for localization of hydrocarbon deposits. Results of the baroosmotic analysis of hydrogeological conditions of gas and oil fields have revealed baroosmotic flows of waters molecules in the thickness of clay rocks, their intensity and directions of motion and connections with deposits.

Quantitative Evaluation of Karst Developmental Differences Based on Improved Analytic Hierarchy Process and Multidimensional Extension Matter Element Model

In this study, limestone solubility, rock thickness, burial depth, hydrodynamic cycle, and geological tectonic of mine No. 13 in the Pingdingshan coalfield (China) were selected to evaluate the degree of karst development. The weight of each index factor to the karst development was determined by using the improved analytic hierarchy process. The multidimensional extensional matter model was used to determine the degree of karst development of the four mining areas (named 1st to 4th) of the Pingdingshan mine No. 13. The results show that the degree of karst development differs zonally, with 1st and 2nd mining areas presenting the lowest degree of karst development (grade II-IV, for an average quantification value of 3.0) and 4th mining area having the highest degree (grade IV-V, for an average quantification value of 4.7). In the vertical direction, the development degree of the vertical layer L1-L4 karst in the Carboniferous Taiyuan Formation is grade IV-V, with an average quantitative value of 4.5, whereas the layers L5-L7 in the Taiyuan Formation had a III-V grade, with an average quantitative value of 3.75, and the Cambrian limestone grade was II-IV, for an average quantitative value of 2.75, i.e., the development degree of karst gradually decreases from shallow to deep.

Динамика показателей поглотительной способности почв после пирогенного воздействия

Статья посвящена мониторингу показателей почвенного поглотительного комплекса (ППК)дерново-лесной глеево-элювиальной почвы подвергшейся пожару в 2010 году. В 0-10 см слое произошло уменьшение в содержании илистой фракции на 3.25%, уменьшилось содержание средней пыли на 0.07% и мелкой пыли – на 0.48%.Установлено, что в первый год, после лесного пожара, повысилось значение pHH2O почвенного раствора с 5.21 до 5.93. В 2018 году реакция среды возвращается к исходному значению и составляет 5.34. Гидролитическая кислотность снизилась с 5.08 до 3.14 [ммоль (экв.)/100 г почвы]. Произошло снижение в ППК содержания суммы обменных оснований с 8.99 до 7.90 [ммоль (экв)/100 г почвы]. С 2011 по 2018 год произошло их увеличение с 7.90 до 8.27