编号 1 (2024)
Scientific articles
Stages of formation of quartz-albite-allanite-fuchsite veins at the Chudnoe Au-Pd deposit (Subpolar Urals)
摘要
The gold-palladium mineralization of the Chudnoe deposit is represented by mineralized veined zones in fractured and brecciated rhyolites of the Riphean-Vendian age. Native gold and palladium minerals are concentrated mainly in veins of Cr-containing muscovite (fuchsite), in which allanite is present in small amounts; quartz, albite, calcite, potassium feldspar, titanite, apatite, zincochromite and other minerals are also found. Veins of allanite-albite-quartz composition are found in ore zones, in some cases containing abundant fuchsite secretions. It has been established that quartz-albite-allanite-fuchsite and other fuchsite-containing veins are the result of the superposition of quartz-albite vein execution on previously formed gold-bearing fuchsite veins. Quartz-albite vein material fills central parts of the combined veins and cements fragments (xenoliths) of fuchsite, while in some cases part of the gold was redeposited and fixed in the quartz-albite part of the veins. Based on the study of the decomposition structures of solid solutions in native gold, it was previously established that the temperature of gold formation in fuchsite veinlets exceeded 220 °C. The deposition temperature of the main part of the quartz-albite veins was noticeably lower. The homogenization temperature of fluid inclusions in vein minerals (quartz, albite, allanite, calcite) was mainly in the range of 96—168 °C, solutions were enriched with magnesium and calcium chlorides. Under these conditions, allanite, apatite, monazite, xenotime, and molibdosheelite were formed and redeposited, and fuchsite recrystallized.
4-15
Geological structure of Quaternary sediments in the lower Pechora river valley
摘要
The geological structure of Neopleistocene deposits was specified along a 19-kilometer section of the right bank of the lower Pechora between the villages of Garevo and Sergeevo-Shchelya. The presence of three glacial and two interglacial horizons was revealed in coastal outcrops, and the material composition of the composing sediments was studied. The formation of the most ancient moraine horizon was associated with Fennoscandinavia and occurred in the early Quaternary Pomusov (Oka) time. The Pomusov moraine was overlain by Chirva (Likhvin) interglacial alluvial and lacustrine sediments. In the Middle Neopleistocene glacial complex, two morainic strata of different ages were distinguished: Pechora (Dnieper) and Vychegda (Moscovian), separated by a pack of predominantly coastal-marine littoral sediments, and alluvial and lacustrine sediments, the age of which was determined as Rodionov (Shklov) by the palynological method. Differences in the lithological composition of moraines confirmed a double glaciation of the European North-East of Russia in the Middle Neopleistocene.
16-23
Groundwater of Middle Jurassic deposits of the southern regions of the Komi Republic
摘要
The features of the chemical composition of fresh groundwater of the Middle Jurassic aquifer complex in the southern regions of the Komi Republic, which is the main source of drinking water supply, are shown. Groundwater is mainly confined to the sole, composed of quartz sands, of the Sysol formation of the Middle Jurassic (J2ss) and is distributed at depths from 13.7 to 119 m. The waters are confined to the zone of active water exchange, to the areas of infiltration of atmospheric precipitation in the territory with a humid climate. The waters have a bicarbonate-calcium composition, a near-neutral medium, mineralization up to 0.58 g/dm3 and after preliminary water treatment (degreasing, demanganation) can be used for drinking purposes. Based on the conducted geochemical studies and statistical data processing, the main patterns of the distribution of macro- and micro–components in the groundwater of the Middle Jurassic sediments have been established, the leading processes of formation of the main components of the chemical composition of groundwater — oxidation, hydrolysis, cation exchange and sulfate reduction — have been identified.
24-33
Seismic events in the Vorkuta coal industrial district in 2023
摘要
In 2023, regional seismic stations recorded 25 seismic events in the Vorkuta coal industrial district of the Komi Republic, with a local magnitude ML from 1.8 to 2.8. A significant contribution to the detection of weak, ML ≤ 2, events was made by data obtained from the temporary seismic station of the IG FRC Komi SC UB RAS, installed as part of expeditionary work in the summer of 2023 in the Polar Urals.
Among them the seismic event on August 1, 2023, which had a macroseismic effect, is of particular interest. Residents of several districts of Vorkuta felt tremors similar to an earthquake. Seismic records from 5 stations with epicentral distances from 40 to 1070 km were processed. The following parameters of the epicenter were obtained: t0 = 18:39:07, 67.529N, 64.001E, h = 0 km, Rminor = 3.9 km, Rmajor = 6.7 km, AzMajor = 90°, Kp = 9.0, ML = 2.8, Ms = 2.35. The instrumental epicenter of the event is located in Vorkuta, near the mine field of the Vorkuta mine. We classified the seismic event as a rock burst. Macroseismic intensity calculated in accordance with the Seismic intensity scale-2017 using 57 questionnaires and 163 definitions of sensor categories was I0 = 4.73 ± 0.02. The calculated value of the macroseismic depth of the source was H = 0.5 ± 0.4 km, which corresponds to the instrumental definition and to the range of depths of mine workings of the Vorkuta coal deposit.
34-42
From teaching experience. 13. Name of crystal polyhedron. On the occasion of the 130th anniversary of A. F. Losev's birth and the 100th anniversary of «Philosophy of the Name»
摘要
The article is timed to the 130th anniversary of the birth of the outstanding Russian philosopher A. F. Losev (1893—1988) and the 100th anniversary of his work «The Philosophy of Name». Against the background of his ideas, the article considers the nomenclature of polyhedral crystalline simple forms, developed by the scientific school of the «Fedorov Institute» under the leadership of A. K. Boldyrev in the walls of the Leningrad Mining Institute. A general algorithmic approach to the nomenclature of convex polyhedra, convenient for computer data processing, is proposed. It opens an extensive research programme on the frontier of combinatorial theory of convex polyhedra, linear algebra and number theory. The aim of the article is to improve the teaching of crystallography in Russian universities and to broaden the outlook of students in related fields of knowledge.
43-49