Vol 35 Iss. 2

The problem of rare-metal mineralization of pegmatites is an object of lively discussion. One group of researchers, mostly sharing the genetic ideas of A. E. Fersman, continues to defend the idea of the existence of a specific “pegmatite melt-solution”. It is assumed that the main mass of rare-metal compounds was contained in this “melt-solution” during its introduction into the host rocks. The formation of pegmatites (and rare-metal minerals in them) is represented as a process of successive crystallization of the melt, sometimes accompanied by autometasomatic transformations of early crystallization products under the influence of still liquid residue. The possibility of new portions of postmagmatic solutions entering the crystallizing pegmatites is admitted. However, the participation of these solutions in the occurrence of rare-metal mineralization seems to be limited.

In recent years, many researchers have paid considerable attention to the study of tectonic factors in the formation of mica pegmatite deposits. The greatest number of studies is devoted to pre-mining tectonics, which determines the localization and shape of pegmatite veins. Less attention is paid to the study of intra-ore tectonics, which determines the character of muscovite distribution in the pegmatite body.

Crustalization of quartz veins. Three systems of tectonic fractures dominate in the rocks of the crystal province of the Subpolar Urals: consonant, secant and transverse fractures. Almost all crystal quartz veins of the studied area are confined to these fractures.

The Dzhaur tungsten-polymetallic deposit is located in the northern Sikhote-Alin in the upper reaches of the Dzhaur River, a left tributary of the Khungari River. Its study is of particular interest because it is the first skarn-type deposit in the northern Sikhote-Alin. Besides, the Dzhaurskoe deposit belongs to the category of few, but very important for understanding the genesis of skarn deposits of skarn type, deprived of connection with limestones.

Tungsten-cassiterite deposits in Jiangxi Province are the largest in the world (they account for more than 50% of the world's tungsten production). Great industrial value, rare association of minerals, peculiar genetic features make these deposits extremely important, interesting and fertile material for research. Nevertheless, there are almost no published works devoted to the questions of their genesis and mineralogy. In fact, the only one is an extremely general work by Ke-Chinsu, devoted to a regional overview of the deposits. Some additions to this work can be found in the monograph by Lee and Wang Chun Yu. In addition, a description of these deposits was given by V. A. Tokarev for the Mining Museum at the Leningrad Mining Institute.

In 1956-1957 in the Laboratory of Coal Geology of the USSR Academy of Sciences, the author participated in the processing of materials on germanium in Donbass coals.It seems interesting and useful to publish some of the conclusions of geological and coal-chemical order, which follow from the studied material, especially since these issues in the literature are covered very little.About 25 years ago, the issue of germanium distribution in Donbass coals was dealt with V.A. Zilbermints. The works published by him are considered in the domestic literature as the main ones on this issue and are widely quoted both in our country and abroad in relevant studies. The materials, which were at our disposal, allow us to supplement, clarify and partially modify the conclusions of V.A. Zilbermints.

Arkagalinskaya coal-bearing area is located within the Magadan region on the interfluve of the Indigirka and Kolyma rivers, 100 km north-west of Susuman settlement. Geological exploration works in this area have been carried out since 1935 up to the present time (V. I. Vronsky, G. V. Buryak, V. I. Baryantsev and others). Coal seams are developed by several mines.

The splitting of coal seams is an extremely characteristic phenomenon and is noted by numerous researchers for all coal basins and deposits. Already about 100 years ago, the phenomenon of splitting coal seams found a correct explanation in the works of C. Lyaille. For the initial position in explaining this phenomenon he took the following well-known principle: not the sea level rises, and the earth falls, and, conversely, not the sea level falls, and the earth rises. In other words, C. Leyel associated the splitting of coal seams with oscillatory movements of the Earth's crust of a differentiated kind. This point of view was later universally recognized. The splitting of coal seams is currently explained by the manifestation of differentiated movements of separate parts of the Earth's crust, distinguishing between plastic deflections and deflections as a result of clastic sinking and rising.

The Suputinskoye lignite deposit is located 35 km southeast of Voroshilov, near the village of Kondratenkovo. Administratively, it is part of the Voroshilovsky District of Primorsky Krai. The territory of the Suputinskoye field has the shape of an elongated oval stretching from southwest to northeast for a distance of more than 22 km, with a maximum width of 7 km. The depth of the depression exceeds 600 meters. The area of the deposit (about 100 km2) can be divided into three sections according to a number of features: southwestern, central and northeastern.

The Sadon-Unal anticlinal zone is one of the most interesting structural units of the Central Caucasus. Its place among other geological structures of the Central Caucasus is determined by the works of I. G. Kuznetsov, L. A. Vardanyants, S. S. Kuznetsov and other researchers. According to I. G. Kuznetsov's tectonic scheme of the Central Caucasus, it is part of the Baksano-Digorsky anticlinal-mountainous uplift of the main ridge zone. In the earlier scheme of tectonic zoning of the Central Caucasus by L.A. Vardanyants, this structure, along with other tectonic structures (Fiagdonskaya, Jimarai-Khokhskaya, Daryalskaya, Nuzalskaya), is included in the tectonic zone of the northern slope.

Fracture and displacement of the formation is a geological phenomenon, in each specific case, depending on the geological situation, possessing special geometric forms. Geometric classifications of fractures are numerous and their complexity is diverse, but all of them are only a way to make sense of the variety of fracture shapes. In order to search for a displaced part of the formation, not only normal but also displaced wing data are needed. Therefore, geologic setting data common to both wings are of particular importance to the search for the offset part of the reservoir.

Insignificant changes in the occurrence of declining seams often leads to losses of coal in the subsurface and. creates sometimes difficulties in the use of mining mechanisms, so the clarification of hypsometry of declining seams is one of the important tasks of mine geology.

The most complete schemes of the tectonic structure of Kamchatka were made by M. F. Dvali and B. F. Dyakov. F. Dyakov. A numerous group of volcanologists headed by A. N. Zavaritsky paid much attention to the issues of disjunctive tectonics of Kamchatka and the Kuril Islands. The works of the team of geologists and geophysicists of the expedition vessel “Vityaz” were of great importance in understanding the tectonic structure of the Kuril Islands. In addition to these works of regional importance, the issues of tectonics of certain areas were covered in various geological studies.

The first researcher who more or less fully classified the rocks composing the Middle Ridge was K. I. Bogdanovich. Based mainly on petrographic features, he divided the rocks into 13 groups. Metamorphosed rocks constituted 3 groups. Group 4 included various metamorphic shales of sedimentary and effusive origin. Group 3 included arch sandstones, schistose sandstones, etc., often indistinguishable from some rock varieties of group 4. Group 5 combined orthogneisses and intrusive rocks. The age of all these metamorphosed formations K. Bogdanovich attributed the age of all these metamorphosed formations to the Paleozoic, but it is not older than the Devonian.

The methodology of tectonic analysis of complex geological structures is still not exhaustively developed. Deciphering the geological structure and analyzing its development in time often cause difficulties for geologists not only in the course of geological survey, but also in the process of final interpretation of the totality of the actual material in the desk period. In practice there were and still are cases when the structure of the area, for which a conditional geological map was made, was interpreted inaccurately or even erroneously only because of the researcher's insufficiently clear idea of the tasks and content of tectonic analysis.

Ore Altai is one of the major areas of polymetallic deposits of the Soviet Union. Paleozoic volcanogenic rocks play a major role in its geological structure. Most of the industrial deposits are confined to volcanogenic and volcanogenic-sedimentary strata. Regardless of whether the formation of these deposits is related to volcanic activity or volcanogenic rocks are only host to ore deposits, the geological and petrographic study of these rocks is of scientific and practical importance. It makes it possible to clarify the nature and history of volcanism and, consequently, to present the geologic history of the area more fully.

In the southwestern part of the ore Altai, secondary quartzites are widely developed among volcanogenic rocks of the Lower Carboniferous. They compose most of the uplands located to the southwest of the Bukhtarma River valley. The outcrop of some secondary quartzite massifs is measured in several square kilometers. The contours of the massifs in plan are mostly irregular, somewhat elongated in some direction, less often isometric.