GEOLOGY
General features of the basement tectonics of the East European platform (EEP) have been considered. The important role of the long-lived Paleoproterozoic tectonic zones has been noted. They were formed due to the cyclic processes of rifting and compression combined with the strike-sleep shearing. They include different structures often superimposed in space: systems of rifts and collisional orogenic belts, transtensional and transpressional zones, ensembles associated with tectonic-plate processes. A special role belongs to the non-linear structures: different scaled rotational structures, concentric and spiral shaped shears, the arcuate orocline belts and horizontal protrusions. Long-lived Proterozoic zones form a giant vortex structure twirled in a clockwise direction, the pole of which is located in the center of the Upper-Volga geodynamic node. The rotational processes of this giant structure can explain many tectonic features of the EEP development.
A new data on the geological structure, conditions of formation and faunal composition of the Early Cretaceous site of the terrestrial vertebrates by Shestakovo village (Kemerovo Region, Western Siberia) has been presented.The consolidated geological section has been constructed along the line Shestakovo-1 — Shestakovo-4 — Shestakovo-3 in which five lithologic members have been identified. A distribution of the vertebrates fauna taxons has been carried out along the selected lithologic members composing the Shestakovo series of the Ilek formation. A new data obtained during fieldwork in 2017 has made it possible to distinguish two main bony levels (lithologic members 3 and 5), which contain whole skeletons of reptiles. Lithofacies analysis has shown that the formation of the sites occurred under the conditions of the fluviolacustrine plain, where the channel, delta and floodplain facies were replaced by lake and lake-marshy facies, forming a series of sedimentation cycles. The latter are the evidence of the increase in the aridization of the climate upwards along the section. The given data calls into question previously expressed point of view about the coastal-marine or lagoon genesis of the Shestakovo series.
HYDROGEOLOGY AND ENGINEERING GEOLOGY
Currently, an interest in the underground waters of the Cenomanian-Albian horizon has increased significantly. And this is mainly due to the fact that numerous centers of discharge of the groundwater are the object of recreation, places of worship and are actively used by the population for drinking purposes. The geological and hydrogeological features of the studied horizon in the area between the rivers of the Pazha and Torgosha has been reviewed, still poorly understood. We have investigated the formation of the groundwater resources of the Cenomanian-Albian horizon and hydraulically related waters of Quaternary deposits that are the between the rivers of the Pazha and Torgosha. For the first time, based on the actual material, a map of hydroisohypses of the groundwater have been made, the parameters of filtration and capacitive properties of the Cenomanian-Albian horizon have been pointed out, an actual data on the quality and salt composition of the groundwater has been presented. The lack of study of this issue, the importance of further research in this direction, the need of monitoring the quality of groundwater and regulating the attendance of sources by tourists and local people to create safe conditions for their use have been notified.
The methodical aspects of the processing and interpreting the results of the experimental filtration tests of the layered strata by the constant-rate pumping tests have been developed. Determination of the filtration and volumetric characteristics of the tested pressure aquifer has been proposed on the basis of the author's method based on the results of tracking the drawdown of the piezometric level of the groundwater in the wells of the experimental cluster at the initial stage of the pumping. Methods for interpreting the experimental data of the second and third stages of the constant-rate pumping test for the calculation of the flow parameters have been proposed.
USEFUL MINERALS, METHODS OF THEIR PROSPECTING AND EXPLORATION
On the example of Mesozoic deposits of one of the main diamondiferous regions of the Siberian platform, basic suppliers of terrigenous material into the ancient diamondiferous placers under formation and their occurrences have been characterized. Special attention has been paid to characteristics of local sources of allothigenous material removal to sedimentation basins of the said period, the main of which were Middle-Late Triassic crusts of weathering on terrigenous-carbonate rocks, formations of trappean origin (dolerites, tuffs, tufogene thick layers) and kimberlites. Comparatively short transfer of weathering products and their accumulation mainly in freshwater continental basins determined weak hydrothermal effect of environment on allothigenous minerals. The received specific features of the mineral composition of various rocks' crusts of weathering have been recommended for application during paleogeographical reconstructions in diamondiferous regions, to determine source areas of terrigenous material, in particular. The stated recommendations have been implemented when assessing material from local sources of drift (including diamondiferous material as well) to continental (Irelyakh and Ukugut suites) and coastal (Pliensbachian and Toarcian stages) deposits of MaloBOtuobinsky region, where primary and placer diamond deposits are successfully mined.
On the example of a number of domestic and foreign gold vein deposits it has been shown that the system of gold-ore bodies is located along some narrow local ore controlling displacements in a shape of veins. These veins are located at approximately equal distances from each other - at allocation step. This step varies from 30—70 m to 100— 250 m for different deposits. It allows forecasting of ore bodies at the flanks of the displacements and exploration by drilling. On the example of near-surface deposits it has been confirmed that such ore bodies can be formed at two vertical ore-bearing levels — upper and lower (deep). The upper level appears at very narrow vertical range of depths (100-300 m) near the paleosurface, presumably in the alumstone-adular-kaolinic metasomatites. Here the rhythmically-banded ores with low-grade gold are formed. At the lower (deep) level, the ore bodies can be formed in the interval of 600-1000 m and deeper from the paleosurface in the zones of tectonic breccia, crossing the metasomatites of the secondary quartzites type. They are more often to be the place of the localization of breccia structure ores with comparatively high-grade gold. So, at the near-surface deposits it is possible to explore the new (in particular, blind) ore bodies in allocation step distance from each other at two levels of mineralization, and, moreover, at the significant depth.
MINERAL AND GEOLOGICAL EXPLORATION ECONOMICS
The current state of the mineral resource base of gold, silver, platinum and palladium for different geological and industrial types of deposits has been shown. For each of the given metals reserves, probable reserves and allocated fund of deposits in Russia have been given. For all bank precious metals volumes of the market offers have been given. Special attention has been paid to the use of the metals both in the world and in Russia. In the practice of market relations, the demand for precious metals can be divided into two types: fabrication (industrial) and hoarding (investment). Precious metals are used in jewelry, electronic, glass, nuclear, pharmaceutical, chemical, petrochemical and other industries. They find their application in medicine and biomedicine, automotive, microelectronics, aerospace instrument making, the manufacturing of lasers and nuclear tests. It has been noted that in our country a great disadvantage is the weak industrial use of precious metals.
FROM THE HISTORY OF SCIENCE
The history of the geological and paleontological study of Bolshoye Bogdo mountain, as well as the evolution of the views on their geological structure, has been considered.The first descriptions of the rocks composing the Bolshoye Bogdo mountain, published in the 18th century by academicians S.G. Gmelin and P.S. Pallas, have been given. A particular attention has been paid to the results obtained during the expedition conducted under the guidance of the English geologist R.I. Murchison in 1841. A great contribution to the knowledge of the geological structure and paleontological characteristics of Bolshoye Bogdo mountain was made by A.B. Auerbach, who discovered here the remains of Triassic temnospondyl amphibians and fish for the first time for the territory of European Russia. A new stage in the study of the paleontology of the Bolshoye Bogdo mountain, which began in 1912, has been characterized. A well-known paleontologist and writer LA. Efremov worked there in the 1926th and 1928th years and conducted scientific research and searches for vertebrate remains. Later, the study of the geological structure of the Bolshoye Bogdo mountain was carried out by the staff of the Saratov State University, Borissiak Paleontological Institute and other scientific institutions of Russia.
BRIEF REPORTS
Concretions with fossils of the Ulyanovsk region are a new kind of jewelry and ornamental raw materials. Concretions are located in the middle part of the section of the Hauterivian sediments, which formed by dark gray dense clays. Concretions are dense, of dark gray or black colour, abundant with fragments of bivalves shells, less often with ammonites, and consist from, wt. %: calcite 85, aragonite 8, quartz 2, apatite 2, pyrite 2 and aluminosilicates 1. From the trace-elements there is Sr with a content of 0,08 wt. %. The contents of radioactive and carcinogenic elements are at background level. Aragonite constitutes the walls of the shells. Calcite is a cement of marl, and also constitutes fragments of shells. Pyrite constitute significant zones mainly in the outer parts of the concretions. In the central parts, it is presented as a rare dissemination. Quartz and aluminosilicates are minerals of bottom sediments. Calcite, apatite and pyrite are secondary minerals formed during the process of diagenesis of marine sediments. Contents of the trace-elements in calcite, wt. %, are: Mg from 0,52 to 2,19 and Mn from 0,34 to 2,13. There is no Fe, which is concentrated in pyrite. The structural features and chemical composition of minerals have been established. Concretions with fossils of the Ulyanovsk region are a technological high-decorative jewelry and ornamental material which allows producing of a wide range of jewelry and souvenirs.
CHRONICS
ISSN 2618-8708 (Online)