Vol 49 Iss. 2

Re-reading Lomonosov's famous works - the treatise “On the Layers of the Earth” (1763) and “Word about the birth of metals from the shaking of the Earth” (1757), each time unexpectedly discover in them new details not noticed before, as if responding to the most burning questions of geological science of today. This has been repeatedly noted by the researchers of the great scientist's work. V.I. Vernadsky wrote: “In 1901, there was no geochemistry in our understanding and it was impossible to consider Lomonosov's thought from this point of view...”. On the amazing gift of Lomonosov's scientific foresight in the field of crystal structure it was written: “It is characteristic that as early as 1911, B. N. Menshutkin wrote about such a remarkable from the modern point of view Lomonosov's dissertation (“On the birth and nature of saltpeter”, 1749): “This dissertation I do not cite, as there is nothing interesting in it.” Only the discovery of X-ray diffraction in crystals (1912) and the subsequent rapid development of the latest structural crystallography revealed the full significance of Lomonosov's statements...” ...

The Keivsky area of about 10,000 km² is located in the central part of the Kola Peninsula between Efim Lake, the village of Kanevka, the northern foot of the Keiva Upland and the Ponoy River. Structurally, it corresponds to the Keiva synclinorium, stretching northwestward and joining the Voronyinsko‑Porosozersky in the northwest and the Imandra‑Varzugsky in the south ...

Volcanogenic formations of Maastrichtian and probably Danian age are part of the Upper Cretaceous-Paleogene volcanogenic-siliceous formation distributed in the south of the Koryak Plateau within the Olyutor Trough. Yu. P. Ershov and G. A. Zakrzhevsky, who first described these sediments in 1956 as the Achayvayam Formation, attributed them to the Paleogene and/or Neogene. It was only in 1962 that the Maastrichtian age of the volcanogenic formations of the Achayvayam Formation was established due to faunal finds. Its upper horizons were conventionally assigned by A. V. Ditmar to the Danian Stage. Now, when the Maastrichtian fauna is known in a number of new locations, we can speak about a wide distribution of Maastrichtian sediments between the valleys of the Achayvayam and Apuka in the northwest and the Bering Sea coast in the southeast. The length of this northeasterly elongated strip is 120 km. This article is devoted to the description of the sediments developed in its northeastern part in the basins of the Kadekkun, Villeikin, Kachestan and Anivayam rivers ....

The term formation was first introduced into geological literature in 1762 by the German scientist G. Füchsel to designate a complex of strata formed under similar conditions. Since then, the term has been widely used by American geologists as one of the basic units of local stratigraphic subdivision. Most Soviet geologists, led by N. S. Shatsky, understand formations as certain lithologic parageneses of rocks. Other geologists, led by V. V. Belousov, associate formations with certain stages of the geotectonic cycle ...

The study of the Upper Permian and Triassic sediments of the Caspian Depression has recently become increasingly important: the research area is located in the eastern near‑marginal zone of the salt dome area of the Caspian Depression. As it is known, the intensity of the salt tectonics processes decreases as we approach the sides of the depression, up to complete attenuation in the marginal part of the basin. This is caused by the reduction of the initial thickness of the Kungur saline sediments as they move from the central parts of the basin to the periphery; changes in the petrographic composition of the sediments, in particular, enrichment of the section with terrigenous, carbonate and sulfate interlayers; the time of manifestation of the most active phases of tectonic movements ...

In the complex history of Mesozoic magmatism and ore formation in Eastern Transbaikalia, the latest stages of the history, associated with the formation of numerous linearly elongated depressions of northeastern strike, are the least studied. They are bordered by large faults and are filled with Late Mesozoic sedimentary and volcanogenic rocks. It is to the depressions that the areas of the strongest manifestation of young tectonic movements and occurrence of the latest magmatic formations gravitate. Accordingly, the latest manifestations of hydrothermal mineralization in Eastern Transbaikalia are closely related to the depressions themselves or to the systems of faults surrounding them (gold deposits of the Baley type, deposits of fluorspar, ferberite‑antimonite ores of the Barun‑Shivey type, ore occurrences of antimonite, cinnabar, barite, etc.). The overwhelming majority, if not all these ore occurrences, belong to the type of low‑temperature hydrothermal formations of shallow depths. Both the source of this mineralization and its age are still controversial. However, in recent years the opinion has been expressed that this mineralization is related to the Lower Cretaceous volcanogenic complexes. Therefore, it is very important to study the history of Lower Cretaceous volcanism of Eastern Transbaikalia, in particular, to investigate various subvolcanic, vent, etc. formations, since in a number of geologically similar areas their location largely determines the distribution of mineralization ...

The Tannuol magmatic complex unites large granitoid massifs of Cambrian age, widely distributed in Central and especially Eastern Tuva. The idea of the Tannuol complex as a complex multiphase intrusion was first formulated by V. A. Kuznetsov. The history of development of the complex is not yet unambiguously established. Some researchers develop the idea of multiphase intrusion formation process, while others explain the diversity of rocks composing the complex massifs by hybridization processes during single-act magma intrusion of granitoid composition. The recently published monographs of G. V. Pinus and G. V. Pinus and T. N. Ivanova ...

The Cambrian metamorphic strata of the Atasuysky area are characterized by complex intense folding and abundance of tectonic discontinuities. They include the following strata (from bottom to top): lower shale (50-500 m), quartzite-shale (130-350 m), quartzite (100-600 m), upper shale (500 m), porphyroidal (more than 1000 m). These strata are folded into systems of narrow linear folds, forming in plan an extended (about 100 km long) arc facing westward. In the northern part of the arc, in the Alabas Mountains and at the northeastern end of the Aktau Mountains, the general strike of the folds is close to latitudinal. As one moves southward, still within the Aktau Mountains, it changes to northeastern and meridional and remains in this direction up to the latitude of the Atasu River. In the Zheldytau and Kushoko mountains, the strike of the folds changes to northwestern. In the southeastern part of the arc, in the Sarykulja and Uzuntau Mountains, it again becomes almost meridional ...

The main ideas about the tectonics of the Mountainous Crimea were obtained as a result of the works of K. K. Focht, A. A. Borisyak, A. S. Moiseev, V. F. Pchelintsev, M. V. Muratov, G. A. Lychagin, G. Kh. Dikenshtein and many other researchers. The material presented in this article was collected by the author during ten years of research in the Mountainous Crimea and route thematic works in the Western Caucasus. On the tectonic zoning of the Crimea. The Mountainous Crimea is a fragment of a large inherited arch uplift of Neogene age. The southeastern part and southwestern pericline of this uplift are cut off by northeastern and northwestern faults and are submerged in the Black Sea. The northwestern wing of the Neogene uplift dips gently towards the Plain Crimea and, judging by the occurrence of Upper Cretaceous and Tertiary sediments, is associated with the marginal structures of the platform part of the peninsula – the Alma Syneclise and the Simferopol uplift – without significant disjunctive faults ....

Over the last few years, many works on metallogeny of Eastern Transbaikalia have raised the question of the relationship between volcanism and hydrothermal formations. In some cases, volcanic structures are considered to be the most favorable sites for localization of mineralization, while in other cases, a closer (genetic and paragenetic) connection between volcanic and hydrothermal processes is assumed. Proponents of the latter point of view in support of their ideas refer to the age proximity of Late Mesozoic volcanogenic complexes and Late Mesozoic mineralization, to the confinement of volcanic formations and ore fields to the same regional structures, to the characteristic near‑surface appearance of ores of a number of deposits, to analogies with other ore districts, in particular, with the classical regions of development of "subvolcanic" deposits. While these arguments are convincing, they lack more direct, geochemical data on the links between volcanic and hydrothermal formations. The identification of such relationships is an important but very laborious task, involving the need to perform and compare a large number of diverse analyses. However, some characteristic petrographic features of the effusive formations of Priargunya can already be used in solving the question about the potential ore‑bearing capacity of those magmatic centers with which the effusives are associated ...

It is known that in the Mamsko-Chuyskaya pegmatite province - the main supplier of industrially valuable large-crystalline muscovite - there are several types of mica deposits, different in the form of ore bodies, structure and geological conditions of occurrence. Among them, of special interest are mica-bearing zones developed in large bodies, mainly composed of granite-pegmatite material. The bodies of these rocks are found in gneisses and crystalline schists in the form of isolated interlayered deposits and secant dykes or form a suite of converged interlayered deposits connected by a network of secant apophyses. N. V. Petrovskaya called such formations of convergent bodies of granite-pegmatite separated by interlayers of metamorphic rocks giganto-migmatites ...

The basis of the geological and industrial classification of deposits consists of the following main indicators: the shape and size of mica‑bearing bodies, the conditions of their occurrence, the host rocks, the degree of saturation of the host rocks with mica veins, the scale of deposits, content and quality of mica, the complexity of deposits, the industrial importance of deposits, features of their genesis. These are the determining indicators for the choice of exploration methods, industrial evaluation of the deposit and its development. We distinguish only four geological and industrial types ...

The study of the structure of vein quartz can greatly facilitate the identification of the prospectivity of vein bodies for ore-bearing potential. Most industrially valuable minerals in veins are formed later than quartz, so quartz bears traces of ore mineralization processes. Thus, vein quartz structures have been identified at gold deposits that were formed during the development of later metasomatic mineralization. One of the latest and most complete summaries of these structures is given by N. V. Petrovskaya ...

According to the existing theory, rock crystal deposits are formed in at least two consecutive stages: a) formation of quartz bodies; b) formation of crystal nests. For the formation of quartz bodies, the source of SiO₂ is magmatic , for the formation of crystal nests - host rocks or previously formed quartz bodies .

The main ore body of the Osenneye deposit is confined to the crushing zone in granodiorites and is represented by quartz and quartz-feldspar with tourmaline molybdenite-bearing veins, which dip westward at an angle of 35° in meridional strike. The body has been penetrated along the dip for about 60 m, and from the surface up to 35 m by adits, drifts and crosscuts, and in the interval of 50-60 m it is undercut by a mine. The data of sampling and study of material composition of ores made it possible to identify the oxidation zone up to 40 m deep, where the most oxidized ores are confined to the surface with a gradual decrease of oxide forms of molybdenum at depth.

Much data on the internal structure of pegmatite deposits of Kolotovka, Bolshoy Severny, Vitimskoye, Maximikha, Lugovka have been accumulated in recent years. They allow us to refer fine-grained biotite granites to independent structural varieties. It is advisable to consider some features of interrelations of these rocks with coarse-crystalline varieties of pegmatites and to supplement the existing data on the forms of transition of typical vein granites into pegmatite-like rocks ...

In geological literature, the conditions of formation of agate deposits are covered very one-sidedly. Most of the published works devoted to the genesis of agate mainly consider the mechanism of chalcedony filling of voids in rocks and formation of agate banding. However, search criteria are necessary for finding agate deposits, which can be developed only on the basis of clear ideas about the conditions of deposit formation. The host rocks for all agate deposits in Transcaucasia are volcanogenic formations, mainly of andesite composition. Agate deposits of the Akhaltsikhe region of the Georgian SSR are localized either in glassy andesite flows or in the sequence of andesite tuff-breccias and tuff-conglomerates. In terms of age, the rocks belong to the Upper Middle, Lower Upper Eocene ...

Endogenous deposits of technical agate are rare. Geologically they are poorly studied and many questions about conditions of their formation remain unclear. One of such questions concerns the problem of influence of host rocks on the process of formation of deposits of this type of mineral raw materials. Geologists who studied endogenous agate deposits usually note one side of the influence of host rocks: host rocks by virtue of lithological and textural features contributed to the deposition of chalcedony from hydrothermal solutions. At the same time, as a matter of course, it is assumed that the main mass of components, including silica, necessary for crystallization of chalcedony and accompanying minerals, hydrothermal solutions brought to the host rocks from the magmatic chamber.

The importance of the correct solution of the question of rational density of the exploration network does not require explanation. The literature devoted to it is extensive and is continuously being supplemented. The factors determining it are most clearly formulated in a general form by V. I. Smirnov [1957]. Many methods of calculating the necessary and sufficient number of exploration workings have been proposed and they continue to be developed. Usually the proposal of a new method is accompanied by a mention of previously proposed methods. But in the literature there is very rarely a systematic and comparative consideration of at least the best‑known methods of determining the rational density of the exploration network with respect to one and the same specific object. No one seems to object to the general statement that all methods of calculating the density of the exploration network are auxiliary to the geological method, but what this means exactly – nowhere is it clearly shown by anyone. Not surprisingly, there is no complete agreement even on the way to solve the problem. Usually, the practitioners determine the network density according to the tradition accepted at each field. If they take the path of theoretical calculations, they use several methods. The decision is made on the basis of sufficient convergence of the results of such calculations. At the same time, they are often given dogmatic value without proper geological analysis. Meanwhile, they can sometimes lead to errors and miscalculations. This article does not offer new ways to determine the density of the exploration network. By comparing a number of known methods in the conditions of a particular object, we are trying to establish the true value of each and the general way of solving the problem. It would be desirable to receive specific comments and suggestions on the question raised, in order to arrive finally at a generally accepted optimum solution.

The regularities of germanium distribution and causal relations of mineralization with the peculiarities of peat bog formation are shown on the example of a stratum of complex structure. The latter is represented by one complex coal seam or split into two, and the distance between them gradually increases from 10-15 cm to 10-12 meters. The areas with low thickness of the interbed are composed mainly of mudstones and less frequently siltstones. In areas with increasing interbed thickness, sandy-silty sediments appear ...

In the north-west of the European part of the USSR the mineral and raw material base of the refractory industry is the Borovichi-Lyubytinsk deposits of refractory clays in the Novgorod region. Out of 26 explored deposits of refractory clays six are exploited: Proletary, Bolshevik, Volgino, Ustye‑Brynkino, Sherekhovichi and Artem. All of them are confined to the Tula horizon of the Visean Stage of the Lower Carboniferous, which crops out close to the surface within the so‑called Carboniferous escarpment ...

Widespread development of the oxygen-converter method of steel production poses before the refractory industry the task of providing converter shops with cheap high-strength refractories made from widely available raw materials. In domestic steel converters, the best resistance is possessed by lining made of fired periclase‑spinel brick made of fired magnesite and chromite ore. However, the experience of foreign countries using the oxygen-converter method of steel production shows that the greatest durability of lining and high economic effect are achieved with unfired dolomite and dolomite‑magnesite refractories made of calcined dolomite (or dolomitized magnesite) on a binder of coal tar, pitch or tar. Since tar‑dolomite refractories are cheaper than periclase‑spinel ones and have a higher resistance, they are accepted as lining material and for the oxygen‑converter shops designed in the USSR ...

The method of imprint has been known for a long time. For the first time it was proposed in 1906 by V. Bauman and E. Gein for the determination of iron and manganese sulfides in various grades of steel, and later – by R. O. Zhirkovsky and a number of Swiss researchers for diagnosis of opaque minerals in polished slides. In the Soviet Union, further development and improvement of the method was carried out by S. A. Yushko and I. S. Volynsky, and recently – V. I. Tikhomirov ...

When evaluating the results of analyses of the contents of any components in ores, as with any physical measurements, it is necessary to establish: 1) the level of random errors of analyses; 2) the presence and magnitude of systematic errors of analyses ...

The main discrepancy in the views of the author and B. Ya. Yufa consists in a different approach to check analyses. The author considers basic and check analyses as observations of unequal precision; B. Ya. Yufa believes that there should be no systematic errors in check analyses. The conclusion about the magnitude of systematic error is usually made on a limited batch of samples, and the magnitude of systematic error is essentially random, since it depends on the sample volume, sampling method, time of production of analyses, etc. In other words, while recognizing the absence of systematic error in check analyses (a controversial position, by the way), we must also recognize that the true magnitude of the systematic error of the main analyses compared to the check analyses cannot be determined ...