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DOI: 10.19110/geov.2024.3.1

The Paleozoic section on the Kozhim River of the Subpolar Urals is the best sequence of the northern Urals. The border of Carboniferous-Permian deposits are observed on the opposite banks of the Kozhim River and are represented by two types of sections: on the right bank — the Kozhym skeletal mound, on the left bank — depression deposits of mixed composition (Losinoostrov Fm.). The article presents the first information on the isotopic composition of carbon and oxygen in the Lower Permian limestones of the Losinoostrov Fm. It is shown that the obtained data on the isotopic composition on the d¹³C—d¹⁸O diagram are visually separated into three clusters. The first cluster with the lowest values of d¹³C (–0.3…1.1 ‰) and d¹⁸O (23.5…25.0 ‰) included the most intensively silicified rocks (siliceous bioclastic limestones, secondary silicitolites, siliceous-carbonate- argillaceous mixtolites and siliceous- argillaceous limestone). The third cluster, with the highest values of d¹³C (3.9…5.1 ‰) and d¹⁸O (26.0…26.8 ‰), includes bioclastic and peloid-micritic limestones. In this case, the d¹³С values correspond to the range of variations in the carbon isotopic composition indicated in review works on the chemostratigraphic correlation of Permian deposits. The second cluster occupies an intermediate position and is characterized by the values of d¹³C (2.0…2.8 ‰) and d¹⁸O (24.3…25.4 ‰). This cluster is predominantly represented by limestones enriched with terrigenous materials.

A comparison is made of the isotopic composition of the limestones of the Losinoostrov Formation with the coeval limestones of the Kozhim skeletal mound, which showed higher values of d¹³C and d¹⁸O in the latter.

Keywords: carbon and oxygen isotopes, Subpolar Urals, Upper Carboniferous–Lower Permian rocks, Losinoostrov Formation

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DOI: 10.19110/geov.2024.3.2

The purpose of this study is to study the microstructure and 3D modeling of Paleoproterozoic stromatolites Segosia columnaris and Sundosia mira in the eastern part of the Fennoscandian shield (Karelian craton). The premise of the study is the extensive paleontological material collected by researchers in the 1950s and 1980s. Modern methods, including SEM analysis, 3D modeling, and the results of Raman spectroscopy are used. As a result of studying the microstructure of stromatolites, possible remnants of cyanobacteria involved in the formation of these structures were identified, which potentially indicated the biogenic origin of the studied samples. The results of Raman spectroscopy obtained by other authors also indicate the biogenic nature of the studied samples.

For the first time, images of the spatial shapes of the studied stromatolites were obtained by 3D visualization software, which could be used to refine the classification of stromatolites by morphological features. 3D modeling of stromatolite buildings allowed restoring their original shape.

Keywords: stromatolites, paleoproterozoic, scanning electron microscopy, 3D modeling, carbonaceous matter

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DOI: 10.19110/geov.2024.3.3

Titanosilicates with the structure of sitinakite and ivanyukite were synthesized with the use of enrichment wastes of quartz-leucoxene concentrate (Yarega deposit, Komi Republic) by autoclave method. It was found that using a mixture of mineralizer KOH and NaOH at a concentration of 0.15 and 1 mol/l, K-Na sitinakite was formed. Increasing the concentration of KOH to 0.45 mol/L and decreasing NaOH to 0.7 mol/L led to crystallization of ivanyukite. The obtained titanosilicates are characterized by high sorption activity towards Sr²⁺ and Cs⁺ cations. Sorption capacity of K-Na sitinakite and ivanyukite for Sr²⁺ was 95–110 and 102–114 mg/g, respectively. The Cs⁺ sorption capacity for K-Na sitinakite is 240 mg/g, the sorption capacity for ivanyukite is much higher — 370–380 mg/g. It was shown that the differences in the sorption capacity of K-Na sitinakite and ivanyukite are caused by the features of the crystal structure.

Keywords: titanosilicates, sitinakite, ivanyukite, sorption, Cs, Sr

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DOI: 10.19110/geov.2024.3.4

This article completes the publication of the «Memories of Mineralogists» of the repressed Professor A. Ya. Mickey, found by the author in the Professor D. P. Grigoriev Archive, kept in the Russian Mineralogical Society. From the correspondence the motivations and life circumstances in which the texts were written become clear. A. Ya. Mickey’s letters are deciphered, attributed and briefly commented. The relevance of the article lies in the need to uphold the priorities of Russian science. The aim of the work is to cover as fully as possible the professional activities of repressed mineralogists as an important component of the history of Russian science. Mention of I. M. Beznarytny, A. K. Boldyrev, P. V. Bryantsev, V. I. Vernadsky, P. Groth, S. A. Zaborovsky, V. A. Zilbermints, L. L. Ivanov, E. P. Kastner, V. I. Kryzhanovsky, E. K. Lazarenko, N. I. Lebedev, A. V. Nechaev, I. I. Tanatar, V. V. Tikhomirov, E. K. Ustiev, N. M. Fedorovsky, G. K. Feldman, A. E. Fersman, P. N. Chirvinsky, and I. I. Shafranovsky should attract the attention of readers. Attention is drawn to the importance of personal archives in the study of the history of science. The of Professor D. P. Grigoriev Archive in letters and other documents reflects several decades of the pre-war and post-war history of Russian mineralogy.

Keywords: D. P. Grigoriev, A. Ya. Mickey, personal archives, history of mineralogy

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DOI: 10.19110/geov.2024.3.5

We have described jasper pebbles from gravelites of the Dzhezhim formation on the Zhezhimparma uplift in the Southern Timan. The chip has a zonal structure. The central part is composed of devitrified volcanic glass and is surrounded by the rocks with an oolitic and crustified structure, composed of hematite-pigmented microgranular hexagonal quartz aggregates. We made a conclusion that one of the sources of the detrital material was rocks of timanide (preuralide) orogen, which final collision stage was Late Vendian by the age.

Keywords: South Timan, Riphean, Dzhezhim formation, pebbles, jasper, ophiolites

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