pdf № 324, December

DOI: 10.19110/geov.2021.12.1

General information on the distribution of vertebrate remains in the Phanerozoic successions of the Komi republic is presented. A short description is given for some localities which are the most important and interesting for the evolution of the group and for biostratigraphy. The most productive sites of fossil vertebrates are confined to the Devonian, Permian, Triassic and Quaternary deposits. The oldest vertebrate remains represented by thelodont scales come from the Upper Ordovician. The Silurian – Middle Devonian marine deposits yield microremains only, among which acanthodian scales are dominant. A rich series of Upper Givetian – Frasnian sites are known in Timan. The following vertebrate taxa were originally described from these localities: Tartuosteus? ornatus, Asterolepis radiata, Janiosteus timanicus. Of particular note is the Lower Famennian section of Sosnovsky Geological Monument. Numerous remains of the earliest reconstructable tetrapod Parmastega aelidae as well as semiarticulated fish skeletons are known there. Vertebrates are quite rare in the Carboniferous deposits and are mainly represented by elasmobranch teeth. An unusual find from the Lower Tournaisian of the Podcherem River, named Proamphibia problematica, was described by A. P. Karpinsky as an amphibian shed skin turned inside out. The Permian deposits yield quite diverse tetrapod and fish remains, among which many taxa were originally described from the territory of the Komi Republic: Clamorosaurus borealis, C. nocturnus, Intasuchus silvicola, Syndyodosuchus tetricus, Parabradysaurus silantjevi, Timanosaurus ivachnenkoi, Koinia silantjevi, Koinichthys ivachnenkoi, etc. Complete skulls of Angusaurus tsylmensis and Vladlenosaurus alexeyevi are known from the Lower Triassic of the Tsilma and Luza rivers, respectively. In the Jurassic deposits, the most important finds are the tooth plates of chimeroid fishes from the Kargort locality and an incomplete skeleton of the ichthyosaur Arthropterygius lundi from the Izhma River. Single finds of mosasaurid remains were recorded from the Upper Cretaceous of the Lemva River. The Quaternary deposits generally contain single finds of bones of large mammals of the so-called «mammoth fauna»: mammoth, woolly rhinoceros, steppe bison, musk ox, wild horse, reindeer, cave bear, etc. About 20 localities are known in alluvial deposits yielding bone remains of the cold-adapted lemming fauna of voles. Among all the localities of the Quaternary vertebrates, the following two stand out: the Medvezhya Cave with the most diverse mammal fauna of the Late Pleistocene, and the Byzovaya Paleolithic site yielding numerous remains of mammoth.

Keywords: fossil vertebrates, Paleozoic, Mesozoic, Quaternary, Komi Republic.

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DOI: 10.19110/geov.2021.12.2

New data on the lithological structure of the stratotype section (Outcrop 14) of the Ust-Yarega Formation of the Frasnian Stage in the Southern Timan are presented. Sedimentary cyclites are identified and relative sea level curve are reconstructed. Local erosion has been identified inside the sediments of the Ust-Yarega Formation, as well as a sharply transgressive unit, which are a good regional reference level and a reflection of the Genundewa event.

The boundary of the Timan and the Ust-Yarega formations is located at the base of a unit of the fine-grained sandstones and siltstones, the lower part of which is represented by the oil-bearing bed I. On the surface, we have established only the upper part of this oil-bearing bed.

Keywords: Southern Timan, lithology, Timan Formation, Ust-Yarega Formation, Frasnian.

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DOI: 10.19110/geov.2021.12.3

The article presents the results of studying the material composition of Lower Paleozoic metaterrigenous rocks in the contact zone between the Riphean-Vendian Preuralide complex and the Caledonian-Hercynian Uralide complex. These deposits are the most promising object for the search for gold and rare-earth-rare-metal mineralization in the northern part of the Northern Urals. Based on geochemical data, it was established that the formation of quartzite sandstones and siltstones composing the section took place in a cold climate in the coastal-marine zone of the passive continental margin. Metaaleurolites and, to a lesser extent, quartzite sandstones contain unchanged volcanoplastics. The siltstones inherited the composition and geochemical features of the acidic volcanites of the Sablegorskaya formation, which are widely developed in the region. Quartzite sandstones are distinguished by the best sorting and maturity of the detrital material, and their composition is dominated by the products of erosion of ancient metamorphic formations. The main factor influencing the formation of the sediment composition was the mechanical destruction of metamorphic and igneous rocks that were slightly weathered in a cold climate. The level of REE contents and the nature of their distribution are typical for sedimentary rocks formed in shallow coastal-marine conditions with low-amplitude fluctuations in sea level. Sediment accumulation took place in a basin with a calm hydrodynamic regime in the immediate vicinity of sources of terrigenous material.

Keywords: metasandstones, chemical composition, clastic material, sources of drift, conditions of sedimentation.

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DOI: 10.19110/geov.2021.12.4

The first results of the determination of boron content in igneous rocks of the Morozov (RF₃mr) and Sokolninsk (RF₃–Vsk) Formation and the Morozov (bRF₃mr) subvolcanic bodies of the northwestern Pay-Khoy are reported. Elevated boron concentrations may indicate the presence of sedimentary material in the magma source, where boron can be introduced during the dehydration of oceanic sediments that enter the subduction zone along with the slab material. Transverse geochemical zoning in the island arc system of the Morozov paleoarc is expressed by increasing concentration of boron in magmatites from the frontal zone (boron content 12–18 ppm) to the rear (boron content 19–45 ppm), which is due to the ingress of a larger volume of sedimentary material by the time of the formation of melts in the rear part of the arc. The boron concentration in the basalts of the Sokolninsk Formation varies from 17 to 22 ppm, which indicates the entry of a smaller volume of sedimentary material into the magma generation area during the formation of the Sokolninsk paleoarc.

Keywords: boron, Morozov Formation, Sokolninsk Formation, island arc, Late Precambrian, Pay-Khoy.

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DOI: 10.19110/geov.2021.12.5

The article presents the results of the work of the temporary seismic station Zhelannoe in the Subpolar Urals. The calculation of the power spectrum and its daily variation showed that the seismic records of the station were characterized by a relatively low level of microseismic noise in comparison with the Peterson noise curves and stationary stations in the Komi Republic. The Zhelannoye station registered twice as many events in 13 days of operation than the Syktyvkar station during the same time. It is necessary to open a new seismic station in the north of the Komi Republic, this will allow monitoring natural seismicity, technogenic load on the geological environment of the mining regions of the republic, and will also form a primitive regional seismic network on its territory.

Keywords: earthquake, rock burst, seismic station, Subpolar Urals.

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DOI: 10.19110/geov.2021.12.5

The article is dedicated to the memory of Boris Alekseevich Goldin (1931—2011), an outstanding scientist, Doctor of Geological and Mineralogical Sciences, Professor, Honored Scientist of the Komi ASSR and the Russian Federation. He made a great contribution to the study of geology and the development of the mineral resource base in the north of the Urals. He is also known as a prominent specialist in the field of inorganic chemistry, crystal physics, crystal chemistry and materials science. The analysis of B. A. Goldin’s creative path requires deep knowledge in many areas. At the modern level of development of science, when a scientist generally achieves success by studying a lot about small things, it is extremely difficult to study B. A. Goldin’s comprehensive phenomenon. Therefore, the article shows an analysis of only one, but a very significant area of his research – magmatism in the north of the Urals and associated mineralization.

Keywords: northern Urals, magmatism, minerageny, intrusive and volcanogenic complexes, geochronology.

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