Geophysical Work Research Articles

ERT, GPR, and magnetic surveying: the case study of Khayrabadtepa settlement (Southern Uzbekistan)

The use of geophysical methods has become an integral part of the work at all stages of archaeological research. Geophysics contribute to the efficient and rapid detection of buried objects. One of the effective methods for mapping archaeological sites is the magnetic survey that reveals anomalies associated with the residual magnetization of such objects. To study the deep structure of complex objects in conditions of variable relief, the method of electrical tomography (ERT) has been well recommended. Ground Penetrating Radar (GPR) measurements delineate buried structures in soil strata. Geophysical work was carried out within the boundaries of the settlement of Khayrabadtepa, which is a monument of the Kushan period in the territory of Northern Bactria. The settlement is located 1 km southwest of the city of Angor, 30 km northwest of the city of Termez.

Review of the current state of knowledge in forecasting and searching for gold deposits in the North-Western Balkhash region

The article provides an assessment of the degree of knowledge of the North-Western Balkhash region based on a priori information from the previously conducted complex of geological and geophysical studies. Today, much is known about the geological, tectonic structure of the North-Eastern Balkhash region, the metallogeny of the region, the main structural elements have been identified; there are characteristics of intrusive formations, the age of the main rock complexes has been determined, several mineralization points, ore occurrences and deposits have been discovered. Based on the results of the earlier work, the Dolinnoye, Pustynnoye, and Karyernoye deposits were discovered. They are characterized by promising gold reserves. The determining role when carrying out prospecting geophysical work is played by the degree of exploration of deposits, which makes it possible to formulate an optimal technology for detecting mineralization points and ore deposits and to reduce the risks of erroneous selection of production facilities to the minimum. The article analyzes the level and provides cartograms of the exploration of the North-Western Balkhash region territory by geological surveying, mining operations, sampling and geophysical methods. The geological and geophysical history of research in the territory of the Dolinnoye, Pustynnoye, and Karyernoye deposits was considered. Conclusions were drawn about the level of exploration of the research area and the need for further geophysical work in this territory, due to the high productivity of the area for copper mineralization.

An adaptive clustering constraint inversion method for gravity data

Clustering constraint is one of the effective ways to improve reliability of the inversion results by incorporating petrophysical information based on some mathematical techniques, such as the Fuzzy C-means clustering (FCM) algorithm. However, for most practical geophysical works, enough reliable petrophysical information is not available. In this way, the FCM inversion method is difficult to be performed. In order to solve this problem to some extent, we proposed an adaptive FCM inversion method (AFCM) in this study, with which the cluster information contained in the gravity data can be extracted adaptively and automatically, and then the FCM inversion can be executed without prior petrophysical information. We presented the detailed steps of the proposed method and illustrated its effectiveness on synthetic and field example tests. The obtained inversion results demonstrate that the AFCM method yields much better results compared with the conventional inversion methods without clustering information, as well as those obtained by using the FCM methods with wrong petrophysical information.

О роли АНО «НОИВ» в решении проблем горного и взрывного дела (итоги XXIII международной конференции по взрывному делу)

On the eve of the established annual holiday of explosive specialists – the DAY of the BOMBER from September 18 to 22, 2023, the XXIII International conference on mining and explosives was held. It was held in the nearest Moscow region on the basis of the chain hotel Amaks "Krasnaya Pakhra". A distinctive feature of this conference was the discussion of topical issues related to the production and supply of initiation means, ammonium nitrate and explosives to mining enterprises and objects of geophysical work, as well as the problems of the development of mining technologies under the conditions of sanctions and terrorist threat to dangerous production facilities, as well as one of the main problems under consideration, the problems related to development of the northern territories of the Arctic zone of the Russian Federation and construction of facilities in the development of the Northern Sea Route.

GEOLOGICAL AND GEOPHYSICAL STUDIES AND EXPLORATORY DRILLING OF PALEOZOIC SEDIMENTS IN THE TASBULAK GRABEN

Despite the half-century history of prospecting, the geological and geophysical knowledge of the Shu-Sarysu basin does not exceed 50%. At the same time, the Tasbulak graben remains the most unstudied. From 1941 to 1969 Regional and exploratory aeromagnetic surveys using Z-aerial magnetometers and fluxgate magnetometers at scales of 1:500,000-1:100,000 covered the areas of the western, northwestern and partially central parts of the Shu-Sarysu depression. From 1969 to the present, up to 70% of the area of the Shu-Sarysu depression has been covered with high-precision surveys using proton, fluxgate and quantum aeromagnetometers on a scale of 1:50,000-1:25,000. In fact, the entire territory of the Shu-Sarysu depression is covered by areal gravimetric surveys on a scale of 1:200,000, scales of 1:50,000-1:100,000 - about 70-75% of the area. In the west and southeast of this depression, individual areas were worked out by detailed surveying on a scale of 1:25,000. Over the entire period of satellite surveys (from 1972 to the present), a significant archive of high, medium and low-resolution images has been accumulated. Seismic exploration of the territory of the Tasbulak graben using the CDP and CDP methods was carried out in the period from 1968 to 1993. Seismic exploration using the CDP - 3D method was not carried out. With a total area of the basin of more than 150 thousand square kilometers, the degree of its drilling exploration is extremely low (about 1 well per 375-475 square kilometers). The degree of study of the Tasbulak graben is even less. As a result of prospecting and exploration work, 12 gas and gas condensate deposits were identified, including: 6 in the Moyynkum graben, 3 in the Kokpansor graben and 3 on the Talas uplift (helium). The totality of geophysical work carried out within the Tasbulak graben indicates a premature cessation of oil and gas exploration in the region and the need for detailed work to verify the presence of more complex structures and their reservoir properties.

Determining the location of the Bayan Obo rare earth elements mineralization body by the transfer learning method

Bayan Obo is the largest rare earth element (REE) deposit in the world. The occurrence of REE is closely related to the dolomite in this area. Dolomite serves as the mother rock of REE mineralization and the ore body. How to accurately locate and characterize dolomite is the key to determining the distribution of REE and estimating its reserves. A large amount of geophysical work has been conducted in this area, including a dense seismic array, various electromagnetic methods, gravity and aeromagnetic surveys, as well as numerous petrophysical property measurements. To fully leverage the results obtained by these geophysical methods and develop an understanding of the physical property structure, a multisource geophysical data fusion technology is developed. First, various physical property profiles obtained from inversion on the same profile are converted into images with identical resolution and dimension. Then, an image adaptive feature extraction technique based on transfer learning is used to extract features of different scales from multisource images. Subsequently, the fusion image is reconstructed based on the local nearest neighbor weighted average feature fusion rule to obtain the final fusion result. This aids in identifying the spatial appearance pattern of the target for detection. Given the physical characteristics of the mineralized dolomite, which has high density, high resistivity, and high magnetic susceptibility, its location and shape can be defined in the fusion image. The results indicate that the occurrence depth of dolomite can extend up to 1500 m and the dolomite has a southward tilt as one of its primary structural characteristics. The predicted range of dolomite distribution is consistent with the formation range revealed by drilling, making it a reliable basis for predicting the distribution of rare earth ore bodies.

An information theoretic Bayesian uncertainty analysis of AEM systems over Menindee Lake, Australia

SUMMARY Long-range, active-source airborne electromagnetic (AEM) systems for near-surface conductivity imaging fall into two categories: helicopter (rotary-wing) borne or fixed-wing aircraft borne. A multitude of factors such as flying height, transmitter loop area and current, source waveforms, aerodynamic stability and data stacking times contribute to the geological resolvability of the subsurface. A comprehensive comparison of the relative merits of each system considering all such factors is difficult, but test flights over well-constrained subsurface geology with downhole induction logs are extremely useful for resolution studies. However, given the non-linear nature of the electromagnetic inverse problem, handling transmitter–receiver geometries in fixed-wing aircraft is especially challenging. As a consequence of this non-linearity, inspecting the closeness of downhole conductivities to deterministic inversion results is not sufficient for studying resolvability. A more comprehensive picture is provided by examining the variation in probability mass of the depth-wise Bayesian posterior conductivity distributions for each kind of AEM system within an information theoretic framework. For this purpose, probabilistic inversions of data must be carried out. Each acquiring system should fly over the same geology, survey noise levels must be measured and the same prior probabilities on conductivity must be used. With both synthetic models as well as real data from over the Menindee calibration range in New South Wales, Australia, we shed new light on the matter of AEM inverse model uncertainty. We do this using two information theoretic attributes derived from different Kullback–Leibler divergences—Bayesian information gain, and a strictly proper scoring rule, to assess posterior probabilities estimated by a novel Bayesian inversion scheme. The inversion marginalizes fixed-wing geometry attributes as generic nuisance parameters during Markov chain sampling. This is the first time-domain AEM study we know of, that compares nuisance marginalized subsurface posterior conductivities from a fixed-wing system, with rotary-wing derived posterior conductivities. We also compare field results with induction log data where available. Finally, we estimate the information gain in each case via a covariate shift adaptation technique that has not been used before in geophysical work. Our findings have useful implications in AEM system selection, as well as in the design of better deterministic AEM inversion algorithms.

Разломная тектоника Ухтинской складки Тиманской гряды

he article deals with a model of the fault tectonics of the Ukhta fold in the Timan Ridge, created on the basis of reinterpretation of seismic data. By the results of constructions along the top of the Upper Proterozoic basement, the majority of the faults have a northwestern direction and extend both continuously and fragmentarily throughout the entire structure. Only north-west-directed faults are clearly traced over the surface of the Devonian deposits. The overlay of the obtained scheme onto the map of the anomalous magnetic field indicates that the identified faults are normally missed in the magnetic field when surveying at a scale of 1:50 000. For the detail site location of the faults and the continuous research of the geodynamic situation, a complex of field geophysical works is required to be conducted in the future.

Oil and gas prospects in deep deposits of the South Caspian water area

Background. In this paper, we present the results of geological and geophysical works and an analysis of the conducted simulation of the South Caspian Basin.Aim. Simulation of hydrocarbon systems of the Turkmen sector of the South Caspian basin.Materials and methods. Statistical generalization and systematization of data and materials from reference literature, fund sources, field data and published works of Sh.F. Mekhtiev, I.S. Guliyev, M.Z. Rachinsky, S.S. Djibouti, S.A. Aliev, V.Yu. Kerimov, V.V. Kolodiya and others. Simulation was performed in the PetroMod software.Results. The conducted simulation showed that the entire commercial oil and gas potential in the region is positioned mainly outside the outer perimeter of the deep-water area, in the form of an annular strip with the width 20–50 km. All the deposits were found to be genetically and spatially associated with the areas of high macro- and micro-seismicity of slip joints filled with hydrothermal aggregates.

Practice of geo-radar research in the Republic of Kazakhstan

The article considers the issues of applying ground penetrating radar (GPR) technologies for engineering purposes concerning subsurface research. It describes the field of application of GPR research during road construction and operation and the advantages and disadvantages of this type of engineering survey. It presents comparative data on the accuracy (inaccuracy) of existing GPR control methods applied to determine the thickness of the monolithic pavement layers in Europe, CIS, and the USA. The main provisions of the GPR survey procedure are described, including four main stages: the analysis of initial materials of surveyed section and equipment preparation; GPR survey; geological verification; processing and interpreting of radargrams; and the preparation of a report. Geophysical works were performed using the geo-radar of the OKO series as part of the road measuring complex DVK-05 on the section of the Astana-Petropavlovsk A-1 highway with cement concrete pavement and on the section of the R-12 "Kokshetau - Atbasar" with asphalt pavement. The example of a radargram and the core sample of a cement concrete pavement taken during geological verification of the thickness of a monolithic layer is presented. Graphs of variation in the thickness of pavement layers by radargrams of longitudinal passages in the indicated road sections with the assumptions about the nature of the heterogeneity of the obtained values are given. The obtained results on the thickness of monolithic layers (cement concrete and asphalt concrete) were assessed on the criteria of quantitative deviation from the required standard value. Recommendations were provided to address positive deviations in the thickness of monolithic pavement layers at various stages of the road survey.

ANALYSIS OF THE SINKHOLE FORMATION MECHANISM IN PERMAFROST ROCKS IN THE SITE OF INTRAPERMAFROST GROUNDWATER DEVELOPMENT WITH REGARDS OF DISSIPATIVE GEOLOGICAL STRUCTURES

The paper considers hazardous phenomena on the Earth’s surface such as sinkholes within the Lena River floodplain terrace, the Central Yakutia, in the areas of intrapermafrost groundwater development. Possible mechanisms for the formation of a dip based on thermosuffusion and the mechanism of formation of dissipative geological structures are investigated. The materials of monitoring and geophysical works in the areas of manifestation of failures are analyzed.

PROSPECTS FOR OIL AND GAS POTENTIAL OF THE MIOCENE-PLIOCENE AND MESOZOIC DEPOSITS OF THE ABSHERON ARCHIPELAGO

The article is devoted to the prospects of oil and gas potential of the Miocene-Pliocene and Mesozoic deposits of the Absheron archipelago. The geological information about the Absheron archipelago dates back to the middle of the 19th century, the century of the industrial revolution. The offshore area of the Absheron archipelago, located to the east of the Absheron peninsula, is abundant with islands, surface and underwater hidden rocks, ridges, ledges and sand banks. The largest islands of the archipelago Pirallahi and Chilov are located here. They are confined to the anticlinal folds of the same name and their formation is associated with large thrusts of the SW limbs of these structures. The North Absheron oil and gas zone, located in the northern part of the Absheron archipelago, covers a vast territory stretching from the northwest to the southeast and is the southern end of the Scythian-Turanian Epi-Hercynian platform. An interesting feature from the point of view of the geology of the North Absheron tectonic zone is a peculiar tectonic structure, lithofacies features and oil and gas potential. Local uplifts differ from other uplifts located in the fold zone by their indeterminate location (Fig. 1). Despite the geological and geophysical work and the drilling of numerous prospecting wells, the Miocene-Pliocene deposits of the study area have not been sufficiently studied in terms of their oil and gas potential. Drilling of numerous wells in the Miocene-Pliocene deposits did not completely open the section of these deposits. The drilling of oil and gas bearing formations with full penetration and development is mainly associated with the optimal conduct of drilling operations. The anticlinal zone begins with structure bank Absheron. In connection with the washout on the structure bank Absheron, the upper section of the Productive series (PS) comes out on the day surface, and the lower section of the PS, with the exception of Gala suite, participates in all stratigraphic units. The Gala suite was found on the southwestern limb of the structure. Recently, hydrocarbon accumulations have been identified by prospecting and exploration work on the structures of Novkhany, Ashrafi, Garabagh. From this point of view, the correct assessment of hydrocarbon accumulations in the Miocene-Pliocene deposits in the North Absheron tectonic zone is considered the main one and complements the understanding of the oil and gas potential of the study area. Keywords: Absheron archipelago, Mesozoic complex, Pliocene deposits, Caspian Sea, prospecting and exploration, tectonic zone.

Creation of a training ground for the complex geological and geophysical study of fracturing within the south-western Crimea (Cape Fiolent, Heraclea Plateau)

A complex of geological and geophysical work was carried out to study fracturing in the Jurassic-Neogene rocks of the Heraclea Plateau, which included a field study of the Georgievsky fault zone, structural and geomorphological analysis; the geophysical complex combined marine seismic and magnetometric studies in combination with ground-based studies using electrotomography, gravimetry and magnetometry. The main object of study was the zone of the deep Georgievsky fault and the feathering tectonic disturbances. As a result of complex studies, the main geological and geophysical criteria for the identification of dangerous fracturing sites have been established: the extremely heterogeneous structure of the upper part of the geoelectric section to depths of 30–40 m according to electrical survey data; seismic data indicate that Miocene limestones have extremely low strength properties in areas of increased fracturing; according to electrical survey data, the water content (humidity) of the upper part of the section changes sharply horizontally; in the karst areas at certain depths, there is a sharp variability in resistivity from the maximum values to the minimum; fracturing develops quite actively under the influence of landslide processes. Especially dangerous are the stretching cracks that occur in areas of positive relief of the base rocks, along which landslide bodies represented by limestones slide.

Mapping of Aquifer Potential in the Northeast Basement Rock of Burkina Faso: Using Remote Sensing and Geophysical Methods

The North-East of Burkina Faso is made up of formations of the Birimian basement rock. The region has a Sahelian climate where surface water resources are very limited. In order to assess the hydraulic potential of the existing aquifers, remote sensing and geophysical techniques (aeromagnetic and ground electric) were used. Satellite image processing and aeromagnetic survey data were used to generate a lineament map that was subsequently validated on the basis of existing geological, hydrogeological and topographical data, geomorphological field surveys and ground geophysical work. The resulting map displays a more or less dense network of 405 magnetic lineaments with a cumulative length of 1,787,676 meters as opposed to 94 lineaments from Landsat 8 images with a cumulative length of 970,054 meters. The average length of the magnetic lineaments is 4,414.01 meters while the average remote sensing length is 10,317.72 meters. The identified NE-SW and WNW-ESE fracture corridors are propitious for the presence of fracture aquifers. In addition to the lineament validation, the ground geophysics performed through electrical surveys allowed the characterization of the aquifers in the study area. Alteration thicknesses are generally less than 20 meters deep. The fractured horizon can reach 100 meters thickness under the alterites. The kernel density map highlights areas of good aquifer potential that could constitute significant groundwater reserves. Mapping aquifer potential is a crucial step in ensuring sustainable and efficient use of groundwater resources.

Digging Up Jericho: Past, Present and Future

Digging Up Jericho: Past, Present and Future

Anomalously light geological complex on the watershed plain of the Yano-Indigir lowland

The research method is a purposeful petrophysical interpretation of the gravitational field. The object under study appeared during prospecting geological and geophysical work as a hindrance to the solution of the main geological problem. Its density is 1 g/cm3, the height of the sole is 35 m, the area is 1420 km2, the volume is 20 km3. The object is defined as an abnormally light Ice Complex (ALIC). The revealed density is explained by peat-ice performance. In ALIC, a near-surface lenticular-layered formation ice has been uncovered, the structure of which indicates the generation of the mass of the complex ahead of sedimentation. The gravimetric data, the landscape and the details of the ALIC structure are interconnected and make up the first — the most complete view of the complex at the moment. The main elements of the presentation are the three phases of the development of the complex. The first is classical, generally accepted for polygonal—vein structures, the second differs from the classical one by the absence of frost-breaking cracking, the third is the growth of formation ice. The qualitative difference of the thermophysical components of the cryolithozone of the territory is given, which made it possible to introduce several concepts concerning the generation of peat-ice mass ALIC. Such as: heat dissipation capacity of the middle layer, stabilization of the zero isotherm at the petrophysical boundary; conditions for the beginning of the growth of lenticular-layered ice; accelerated lateral segregation growth of powerful ice veins; constancy of the thermal resistance of the cryolithozone. On the basis of these concepts, models of the development of the second and third phases of ALIC are compiled, and a view on the theory of the formation of cover glaciers is formed, which follows from the model of the third phase. The novelty of the research consists: in identifying a unique petrophysical object, in defining this object as ALIC, in identifying an ice massif on the territory of ALIC, in presenting the development of the complex as a sequence of three phases, in compiling models of the second and third phases of ALIC and in an original approach to the formation of cover glaciers.

Topographic data in the cartographic support of geological exploration: current state and prospects

The purpose of the current study is an attempt to characterize the scientific and practical issues of modern topographic data preparation and its use in geological exploration. The study is based on the long-term author’s experience in cartographic support of field and cameral geological and geophysical works and on the analysis of modern research in topographical mapping. The specifics of providing access to modern topographic data in the Russian Federation, the Republic of India and the Republic of Colombia, where the main experimental work has been carried out, are briefly described. The content features of the topographic map sheets of these countries are shortly summarized. Practical results of solving such exploration tasks as survey network design, creation of terrain sketch, processing and interpretation of geological and geophysical data, creation of digital terrain models, and preparation of base maps for web services are presented. The prospective directions for further research in improving the use of topographic data in geological exploration are given. It has been found that topographic maps and data are increasingly being used as base layers in the creation of the modern web map services. A balanced and critical approach to the use of global topographic data resources is need for geological exploration as a state’s strategic activity. The industry needs publicly available national multiscale topographic maps as well as theoretical and methodological foundations for the use of web mapping advances in mineral prospecting and exploration.

Geofyzikální mapování výskytu těšínitové asociace hornin v okolí Žermanic – slezská jednotka

Picrites, monchiquites, fourchettes, ouachitites, teschenites s.s. and teschenite clinopyroxenites are the representatives of major effusive and hypabyssal rock types of teschenite association rocks (TAR) of the Silesian unit of the Western Carpathians flysch belt. The geophysical image of TAR and their physical properties can be observed mainly in the magnetic and geoelectrical data, mainly from well logs and magnetic maps of different authors. Geophysical research of the TAH was carried out only in a limited scope of works due to unclear and complicated structural-tectonic conditions related to its development in space and time. This contribution provides a detailed overview of the methodology used in the mapping and interpretation of one of the geologically well-explored locality located in the vicinity of the abandoned quarry in Žermanice village. Geophysical works are part of research projects implemented at VŠB-TU in Ostrava. The aim is to verify the possibilities of geophysical methods in monitoring the extent, structural and tectonic position of the TAH. It also includes the creation of GRAV/MAG models based on which the reality of the measured effects caused by the given bodies is verified. At the Žermanice location, geophysical methods were used in the profile variant, namely gravity, magnetic and geoelectrical measurements in the ERT (electrical resistance tomography) variant. The results proved that this combination of methods enable comprehensively map individual TAH bodies and thus appropriately supplement geological and geochemical data and results.

Геолого-плотностные модели глубинного строения в районе локальных гравитационных аномалий севера Волго-Уральской антеклизы

Detailed geological and geophysical studies discovered intensive local gravimetric anomalies (Frolovskaya, Chetdinskaya, Lokchimskaya, Kynmemtila and others) in the south of the Komi Republic, which were promising for the discovery of bodies of the basic (ultrabasic ?) composition in the production of geological and geophysical works [8, 9].
 Within them, a database of XYZ (recorded and extrapolated) in arbitrary units of the gravity field and their rectangular coordinates was created in the Microsoft EXCEL program, with more than 1600 values, and formed grid files, based on them, formed the basis for calculations in the Golden Software SURFER program for constructing models of the deep structure. As a result of the interpretation of the gravity field, geological and geophysical models of the deep structure

Analysis of the results of geophysical work in the area of Eastern, Southern and Northern Bukantau (Uzbekistan)

Analysis of the results of geophysical work in the area of Eastern, Southern and Northern Bukantau (Uzbekistan)