pdf № 318, June

DOI: 10.19110/geov.2021.6.1

The article is dedicated to the memory of Vsevolod Georgievich Olovyanishnikov (Getsen), an outstanding researcher of geology of the European North-East, Candidate of geological and mineralogical sciences, who worked at the Institute of Geology from 1960 until the end of his life (1936—2006). The article analyzes his creative path and shows main scientific achievements in three most significant areas of activity: stratigraphy of Precambrian deposits, tectonics (geodynamics) and rock metamorphism.

Keywords: Kanin-Timan Ridge, northeast of the European Platform, Upper Precambrian, stratigraphy, tectonics, metamorphism.

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DOI: 10.19110/geov.2021.6.2

Northern Timan is an uplifted block of the Upper Precambrian basement of the Timan Ridge, where intrusive rocks of various compositions cut Neoproterozoic metaterrigenous rocks of the Barmin Group and are overlain by Lower Silurian limestone. Syenites are widespread in the Cape Bolshoy Rumyanichny pluton and compose the Krayny Kameshek and Malyi Kameshek plutons. To determine the age of the syenites, U—Pb dating of zircons was carried out using secondary ion mass spectrometry (SIMS). The age of zircons from syenite of the Cape Bolshoy Rumyanichny pluton is 613 ± 7 Ma, Krayny Kameshek pluton — 602 ± 5 Ma, and Malyi Kameshek pluton — 598 ± 17 Ma. Similar zircon ages are known for other alkaline igneous rocks that occur within the Cape Bolshoy Rumyanichny pluton: olivine-kersutite gabbro — 614 ± 2 Ma, granites — 614 ± 11 Ma. Zircons from subalkaline granites of the Bolshoy Kameshek pluton are of the same age — 613 ± 6 Ma. The location of the plutons in the area of the Late Riphean passive margin of Baltica, the close association of subalkaline and alkaline granites, syenites, and alkaline gabbros indicate the anorogenic nature of these magmatic rocks and possible relationship with mantle plume activity. Ediacaran magmatic rocks of 614—600 Ma located in the Northern Timan could be associated with the final stages of Rodinia breakup, accompanied by plume-related magmatism, the products of which are also known in the eastern part of Laurentia and in the Scandinavia.

Keywords: syenite, Northern Timan, zircon, U—Pb isotopic age.

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DOI: 10.19110/geov.2021.6.3

The results of studies of metal-carbon composites, unique in composition and origin, in which the metal component is a tin-aluminum alloy with an admixture of In, Cu, Fe, Cr, Se, are discussed. The morphology and internal structure of particles, variations in the chemical composition, and the isotopic of carbon impurities are analyzed. Based on the diagram of the eutectic type, a conclusion was made about the crystallization of alloys in the temperature range 650—150 °С. The question of the indium content of volcanic products in Kamchatka as a new and possibly industrially promising type of phase-diverse indium mineralization is discussed.

Keywords: Kamchatka, volcanism, fumarole mineralization, indium-containing metal-carbon composites.

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DOI: 10.19110/geov.2021.6.4

Fenitized Precambrian carbonate rocks (Middle Timan) are parent rocks for bauxite — phosphate weathering crusts. Therefore, the mineral composition of fenites, characterized by rich and varied mineralization, is of great interest. Titanium minerals especially attract attention, since their high concentrations are noted in bauxite-phosphate weathering crusts. For example, in the bauxites of the Verkhne-Shchugorsk area, the amount of rutile may reach 6000—7000 g/t. Titanium mineralization is represented by titanite, rutile, anatase, and cassite.

Keywords: Middle Timan, Riphean, fenitization, carbonate deposits, titanium mineralization.

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