Continuous exploration works and investigations of mercury, mercury-antimony and gold-sulfide mineralization in Donetsk metallogenic province resulted in identification of promising gold-mercury ore formation. Dokuchaev-type (Carlin-type) gold mineralization is confined to the Lower Carboniferous limestones, dolomitic limestones and dolomites of the Pavlodar-Donetsk metallogenic belt. Predictive Dokuchaev gold ore district comprises three ore clusters totaling seven ore fields. Geology of the district, position of predicted ore fields, preliminary characterization of potential gold deposits and ore bodies are discussed. Some proposals for methodology of exploration works are presented.
On the south-eastern edge of the Baltic Shield in the north-western part of the Onega structure, dislocations previously attributed to slump folds were identified in the sand unit, and their detailed description was carried out. It was established that these formations form a paragenesis of soft sediment deformation structures. Possible hypotheses are considered and a seismogenic model of their formation is proposed.
Ammonites have been found in the upper Campanian deposits of the type locality of “Ammonites Baeri” Simonovich, Bacevich et Sorokin, 1876 in the city of Essentuki. This species is almost unknown in the literature due to the uncertainty of its features and the lack of type material. The study of the ammonites found allows us to classify “Ammonites Baeri” as belonging to the Coniacian-Maastrichtian subgenus Hauericeras (Gardeniceras).
3D modeling of the history of hydrocarbon systems formation in the North Chukchi Basin has been performed. A thermal history model has been constructed and calibrated using well data, and the possibility and scale of hydrocarbon generation have been estimated. Sedimentation modeling data have been used to estimate probable reservoir layers. The areas of probable hydrocarbon accumulation in the basin reservoirs have been estimated. The time of active generation of Cretaceous source rock is the Eocene, and of Eocene source is the Miocene-present. The localization and preservation of hydrocarbon fields significally depend on the quality of the seals and the configuration of the clinoform complex bodies.
Nannoplankton was first discovered in the core of the Lower Berezovo subformation from the Russian 5_05 well at a depth of 674.8 m in flaky clay-siliceous siltstones. The presence of Arkhangelskiella cymbiformis suggests that the age of the host sediments is not older than the Late Santonian, and the age range can be defined as Upper Santonian-Campanian-Maastrichtian Stage. The radiolarian complex indicates the Campanian Age. The composition of foraminifera is typical for the upper part of the Lower Berezovo subhorizon.
The present article is a study of hydrodynamical conditions that existed in the water area of Phanagoria in the second half of the I millenium BCE, during the construction and the following operation of a large pier structure. Its unusual shape and size is hard to explain without taking into account its local surroundings — wave and wind patterns, directions and strength of the currents. Models created using modern data and a paleogeographic reconstruction of the outlines and depth of the water area determined the hydrodynamic conditions of said area and confirmed the practical necessity of the ancient pier’s shape.
The vertical geochemical zonation of the Tutkhlivayam epithermal gold-silver ore occurrence (Ossora ore district, Kamchatka) has been studied. The chemical composition of the ores was studied based on the results of chip sampling, the concentration coefficients of chemical elements and geochemical associations in horizon samples were determined. The vertical series of geochemical zonation was determined (bottom to top): Cd-Pb-Zn-Cu-Ag-Mo-SbAs-Hg-Fe-Ba-K-Mn-Au-Sr-Ca. The indicators for estimating the level of erosional truncation of the Tutkhlivayam ore occurrence, other gold-silver objects of the Ossora ore district and similar deposits of volcanogenic belts are proposed.
The article discusses the conditions of formation, patterns of placement, compositional features, zoning, prospecting features and criteria for gold mineralization associated with granitoids of a large igneous uplift (Western Chukotka).
The currently available factual data, analysis of the existing oil and gas potential of the surrounding territories indicate high oil and gas prospects in the Arctic regions of Western Siberia and in particular the South Kara Basin. The general wedging out of the Mesozoic-Cenozoic and possibly Paleozoic deposits and the decrease in the thickness of the sedimentary fill in the southwestern part of the Kara Sea, and in connection with this, the tendency to decrease paleotemperatures and stages of catagenesis, led to other boundaries of the depths of detection of hydrocarbon (HC) accumulations relative to the fields of the northern part of the West Siberian oil and gas basin (OGB). The oil and gas complexes (OGC) of the north of Western Siberia produce both oil and gas accumulations, are characterized by different catagenic transformations, and are associated with different lithofacies and tectonic settings. The prospects and possible generation activity of the pre-Jurassic, Jurassic and Cretaceous oil and gas fields of the southwestern part of the Kara Sea are considered.
Ecological-geological systems are the main object of research in a new scientific field — ecological geology, which studies ecological functions of the lithosphere. Those functions of carbonate bioliths of the Crimean Mountains are characteristic. The main characteristics of abiotic (lithotope, edaphotope) and biotic (microbiocenosis, phytocenosis and zoocenosis) components of ecological-geological systems developed on limestone massifs of the Crimean Mountains are described. It has been demonsrtrated that the features of the lithotope are related to their high porosity and relatively high strength, which allows using limestones as a building stone. The specificity of the edaphotope of limestone massifs consists in the possibility of forming short-profile soils with a poorly developed humus horizon on slopes, and carbonate chernozems at the base of slopes on limestone wood. It is shown that the features of the lithotope and edaphotope of limestone massifs determine in whole the characteristics of phyto- and zoocenoses. The flora is dominated by calciphyte vegetation. Zoocenoses on the surface of limestone massifs are characterized by a relative diversity of fauna, in contrast to cave faunal complexes.
Offshore seismic data acquisition using simultaneous shooting has significant advantages over a classic single source seismic survey. However, it is necessary to eliminate the interference of multiple sources — to perform deblending. The paper discusses current state of deblending techniques and suggests that application of sparse inversion is the best option to suppress the blending noise.
The article presents the results of a study on the spatial distribution of thawed and frozen grounds in the permafrost zone using three-dimensional electrical resistivity tomography. The aim of the research was to determine the boundaries between frozen and thawed rocks, as well as to identify the groundwater level. The study utilized data from electrical resistivity tomography, drilling, and borehole thermometry. Based on the obtained data, a three-dimensional geoelectrical model was constructed, which aligns well with the available geological information. It was found that anomalous zones with elevated temperatures correlate with areas of reduced electrical resistivity, indicating the presence of taliks. Maps of the groundwater level and the top of permafrost were created, reflecting the geological features of the studied area. The results confirm the effectiveness of the three-dimensional model for data interpretation in complex geological conditions and can be applied to solve similar problems.
In sand-clay ground, the depth variations were established between lithological boundaries and the contrast of electromagnetic properties of the soil. As a result, GPR reflections diverge in depth from the lithological boundaries, complicating geological interpretation. The forward problem is solved using a model constructed from measured electromagnetic parameters. The modeling results made it possible to reasonably relate lithological boundaries to GPR reflections and to determine the cause of their depth variations. Consequently, the geological interpretation of GPR data is enhanced.
The article presents the results of comparing the spectral density of the MT field components in a wide frequency range and solar activity. The calculations used the MTS data obtained by a group of employees of the Department of Geophysics of the Faculty of Geology of Moscow State University and GEMRC IPE RAS in the central part of the East European Platform in the period from 2020 to 2024. Measurements were carried out both in summer and in winter with the same type of equipment. The processing of all MT data was performed in the EPI-KIT program. The obtained correlations are important for taking into account the forecast of sun weather when planning field work.
This article examines the geological features of Cretaceous terrigenous deposits in the Arctic gas-bearing province of Western Siberia, formed under diverse facies conditions. Based on macroscopic descriptions of well cores and lithological analyses of rock thin sections, the main sedimentary environments — ranging from continental to marine — have been identified. The factors influencing the development of reservoir and fluid-sealing properties of the rocks are analyzed.
This study examines post-sedimentation changes in sandstone reservoirs within Cretaceous deposits of the western part of the Gydan Peninsula. Using the method of stage analysis, structural-mineral associations formed under background burial catagenesis and superimposed fluid catagenesis were investigated. The focus is on the mechanisms of material redistribution that lead to changes in the reservoir-filtration properties of the rocks. The key processes contributing to secondary porosity formation include leaching and decompaction, driven by fluid activity. The obtained data can be used to predict the hydrocarbon potential of reservoirs and to identify optimal zones for development.
