Subpolar Urals Research Articles

Heterochlamydomonas uralensis sp. nov. (Chlorophyta, Chlamydomonadaceae), New Species Described from the Mountain Tundra Community in the Subpolar Urals (Russia)

This paper describes a new species from the class Chlorophyceae, Heterochlamydomonas uralensis sp. nov., isolated from the soil of the carex-moss-lichen tundra in the Subpolar Urals Mountains, Russia. The taxon is studied using morphological methods and DNA identification. Heterochlamydomonas uralensis differs from other Heterochlamydomonas spp. by cellular morphology, detected on light and ultrastructural levels, and 18S and ITS2 rDNA sequences. These results support the separation of the species Heterochlamydomonas uralensis sp. nov. This study is important for connecting data from DNA metabarcoding with species described on the basis of morphological characteristics.

Vodorazdelny Granite Massif (Subpolar Urals) and Correlation Problems of the Pre-Ordovician Granitoids and Volcanic Rocks from the Northern Part of the Lyapinsky Anticlinorium

Petrogeochemical features of the Vodorazdelny massif granites (Subpolar Urals, Lyapinsky anticlinorium) indicate these rocks are close to I-granites and were formed in suprasubduction environment. The ratios of the key elements (Rb, Ba, Th, Sr, Y, Nb) suggest that the basites of the melting slab and the fluid separated during their dehydration could participate in the granite generation. The U–Pb age of the main population of magmatogenic zircons is 593 ± 4 Ma and corresponds to the Vendian (Ediacarian). It coincides with the age of the granites from the nearby Vangyr massif (598 ± 5 Ма), as well as with the age of zircon cores from the granites of the Kozhim massif located to the north. Values of εHf(t) from –2 to 0 in magmatogenic zircons with an age corresponding to the age of Vodorazdelny granites indicate a heterogeneous source of melts. The zircons of these granites also contain ancient cores with U–Pb ages from 2200 to 700 Ma, where the values of εHf(t) from +0.8 to +13 indicate the presence of a crust component in the substrate (the substance of the ancient platform basement). Petrogeochemical and isotope-geochronological parameters of granites (and their zircons) do not confirm the validity of attributing of Vodorazdelny granite massif (and its analogues – the Vangyr and Kozhim massifs) to the Cambrian Salner-Mankhambo complex. We consider there are the possibility of separating of independent complex (about 598 Ma, Vendian?) during geological mapping. The presence in the Lyapinsky anticlinorium of several stages of granite generation (Middle Riphean–Vendian–Cambrian), accompanied by metamorphism, and complicate composition of ancient metamorphic strata from this structure basement led to varying isotopic parameters characterizing the heterogeneity of the source of melts, on the one hand, and the convergence of a number of geochemical features, on the other.

Native Gold of the Chudnoe Gold–Palladium Deposit (Subpolar Urals, Russia)

Abstract ––The Chudnoe gold–palladium deposit, located within the Central Ural uplift, is confined to the axial zone of an anticlinal structure complicated by faults. Veinlet mineralization is localized in fractured and brecciated Late Riphean–Vendian rhyolites. Native gold and palladium minerals are concentrated mainly in veinlets of Cr-containing muscovite (fuchsite) and, more seldom, at local sites of rhyolite metasomatism, almost free of sulfides. Using a representative material, we studied the composition and texture of native gold and the regularities of their spatial variations. Native gold has composition Au–Ag–Cu and contains Pd and Hg impurities. The proportion of elements varies significantly: The content of Au ranges from 65.8 to 92.7 wt.%, the content of Ag varies from 0.4 to 33.8 wt.%, the content of Cu reaches 12.7 wt.%, and the content of Pd is up to 2.9 wt.%. Gold formed as a homogeneous Au–Ag–Cu solid solution at temperatures above 220 °C. The presence of copper in native gold is probably due to the absence of sulfide ion from the ore-forming hydrothermal solution. With decreasing temperature, Au–Ag–Cu solid solution containing more than 1.1–2.5 wt.% Cu disintegrates into two or three phases, forming characteristic plate–lattice and tabular exsolution textures. In the case of two-phase exsolution, the final phases are Au3Cu and Au–Ag solid solution or AuCu and Au–Ag solid solution; and in the case of three-phase exsolution, these are Au3Cu, AuCu, and Au–Ag solid solution. In some cases, the exsolution was accompanied by the recrystallization of gold with the formation of grain intergrowths. The composition of native gold in the deposit varies significantly, showing a discrete character at different sites of the ore zones, which is consistent with the veinlet ore mineralization. At the final stages of mineral formation, native gold was partly replaced by secondary highfineness gold.

U-Pb (LA-SF-ICP-MS) dating and probable provenance of detrital zircons from terrigenous deposits of the Upper Precambrian of the Subpolar Urals

Research subject. Upper Precambrian metaterrigenous deposits of the northern part of the Lyapinsky anticlinorium in the Subpolar Urals.Material and methods. From the metaterrigenous rocks of the Upper Precambrian section of different stratigraphic levels, monofractions of zircons were isolated and their optical and isotope-geochronological (U-Pb LA-SF-ICPMS) studies were performed.Results. Age boundaries of the formation of the Puivinskaya, Khobeinskaya, and Moroinskaya Formations in the Subpolar Urals were specified. A comparison was carried out of age populations of detrital zircons from metaterrigenous deposits of the Subpolar Urals and terrigenous sequences of adjacent regions similar in age. The age boundaries and the proposed location of crystalline complexes, the probable provenance areas of terrigenous material, were established.Conclusions. The lower age limit of the formation of the basal layers of the Upper Precambrian of the Subpolar Urals does not go beyond the Late Riphean. The north-eastern periphery of the East European Platform, including the Subpolar Urals, in the Late Precambrian belonged to the same continental margin, and the accumulation of the Middle-North Timan and Subpolar Ural Upper Riphean sediments occurred in the common sedimentation basin. The lower age boundary of the formation of the Puivinskaya Formation (about 1000 Ma) determines the probable formation time of the Timan passive margin.

Morphology, Structure, and Composition of Zircon from Metasandstones of the Alkesvozhskaya Sequence (Polar Urals)

A description of the features of morphology, internal structure, and analysis results of Th/U and Zr/Hf ratios in zircons from sandstones of the gold-bearing Alkesvozhskaya sequence, located at the basement of the Paleozoic section in the Subpolar Urals, is presented. It has been established that most of the studied zircons are primary igneous grains of the first weathering cycle. The detrital zircon source was probably in formations close in age, underlying or located nearby felsic and basic volcanics of igneous complexes of different stages of formation of Timanides-protouralides, associated granitoids, and intrusive mafic formations. Small part of well-rounded zircon Pre-Riphean grains can be redeposited from the Riphean metasedimentary formations, which, in turn, inherited it from the rocks of the ancient basement of the East European Platform.

Growth of the Whitefish Coregonus lavaretus (Salmonidae: Coregoninae) in the Ural Tributaries of the Pechora River

For the first time, we represent a comparative characteristic of the growth of, presumably, the freshwater form of the whitefish Coregonus lavaretus in the Ural tributaries of the Pechora River. The growth rate of the whitefish in the studied rivers varies significantly, which testifies the assumption of existence of several local groups in the Pechora river system, confined to different parts of the river basin. In the Ilych and Kosyu rivers as well as in the upper reaches of the Pechora River (Northern Urals), the calculated body lengths and linear growth rates do not differ significantly. Similar growth rates have been observed for the whitefish from the plain tributaries of the Pechora (lower reaches of the Kosyu and Usa rivers). In the rivers of the Subpolar Urals, the variability of whitefish growth rates is significantly higher. The specific growth rate of the subadult whitefish positively correlates with the benthos biomass in the watercourse (ρs = 0.57 according to Spearman, p = 0.04), while the dependence on climatic conditions is less significant.

Новый вид остракод рода Leperditia из силурийских отложений западного склона Приполярного Урала

The article describes a new species of ostracods of the genus Leperditia from the Upper Silurian deposits of the western slope of the Subpolar Urals (Shchugor River basin). Leperditia unituber Saldin sp. nov. differs from all other species of Leperditia by the presence of a tubercle near the ventral margin of the right valve, a stable diagnostic character.
 The shell is truncated-oval, elongated, widening towards the posterior end. The ventral margin is gently and asymmetrically arched. Longitudinal axis at a slight angle to the length. A narrow marginal border is observed along the ends of the shell. The posterior dorsal swelling on the left valve is pronounced. On the right valve near the ventral part, where the greatest height of the shell is observed, there is a tubercle or spiny outgrowth.

Parasitic Arthropods of Small Mammals in the Subpolar Urals (Eastern Macro-Slope)

Surveys of small mammals (insectivorous and rodents) and their ectoparasites were carried out in the Subpolar Urals (eastern macro-slope) near Mount Neroyka (Berezovsky district, Khanty-Mansi Autonomous Okrug Ugra) in different altitude zones (from 407 to 1018 m above sea level) in 2020 and 2021. A total of 15 species of parasitic gamasid mites, 1 species of ixodid ticks, 11 species of fleas and 1 species of lice were identified. Two counting methods, ditch with pitfalls and trap-lines, were used to better reveal the composition of small mammals (feeders of ectoparasites). Specific parasites of Eurasian water voles, Laelaps muris and Hyperlaelaps amphibius, dominated among gamasid mites regardless of the method of trapping insectivores and rodents. At the same time, the proportion of the Eurasian water vole in the small mammal community of the Subpolar Urals (eastern macro-slope) did not exceed 7%. The group of dominant species also included Laelaps algericus, which was recorded in only three species (of 16 small mammal species recorded in the Subpolar Urals): the Eurasian water vole, the field vole and the Middendorff's vole. Among rare species of gamasid mites, Haemogamasus dauricus is of particular interest, a species not previously recorded in the Urals and Western Siberia. Ixodes persulcatus is a single occurrence in the area. The find of this tick is one of the most northerly in the Asian part of the Russian Federation. Among representatives of flea and lice groups the share of specific species (shrews and red-backed voles) is high. This is probably due to the high mobility of shrews, their close contact with rodents, and the specificity of animal counting methods.

Золото из аллювиальных отложений Пуйвинского района (Приполярный Урал)

In the Puyva region, located in the southeastern part of the Subpolar Urals, several gold-bearing placers and placer occurrences are known; however, information on gold itself is not complete enough, which makes the research relevant. The study of stream gold from the alluvium of the Khartes, Sertynya, Oika, Dorozhny, and Borovoy areas, has revealed that the gold is predominantly small; the particle shape is lamellar, thickened-lumpy, and complex. Gold roundness is medium; the portion of unrounded and well-rounded particles is insignificant. Silver is almost always present in gold, copper is less often noted. In some samples, electrum of a high silver content is found along with gold. Single gold particles have narrow, discontinuous high-fineness rims due to the removal of silver under exogenous conditions. Placer gold is gold of close wash-down; its original sources are probably represented by hydrothermal gold-sulfide-quartz veins localized in rocks of different composition and age.

Региональная кривая изотопов углерода и биотические события в силуре западного склона Приполярного Урала и поднятия Чернова

We present a new regional event scale based on a generalized analysis of results of determination of event-stratigraphic boundaries of biotic events of various levels and 13C isotope anomalies in studied reference sections of the Subpolar Urals and the Chernov Uplift.
 The combined regional curve of carbon isotopic composition allows finding out several isotopic events in the Silurian.

FLORA OF BARKOV MOUNTAIN (FLORA OF MOUNT BARKOV (SUBPOLAR URALS) AND ITS ROLE IN THE CONSERVATION OF RARE PLANTS

A list of vascular plants of the Barkova Mountain in Subpolar Urals (1320 m above sea level) made up of 237 species from 124 genera and 45 families is published. The high taxonomic diversity of the flora is predicated on a number of factors: mountainous relief and significant altitudinal range (670 m), the presence of several altitudinal vegetation belts and a vast mountain-top plateau, heterogeneous bedrocks, climatic conditions of subarctic highlands, and the general history of the flora formation during the Late Pleistocene. The flora of the Barkova Mountain occupies a transitional position, with both arctic montane and boreal features, and is classified as hypoarctic montane with regional characteristics. Two taxa (Sedum roseum and Castilleja arctica subsp. vorkutensis) are included in the Red Data Book of the Russian Federation, 27 taxa - in the Red Data Book of the Komi Republic, and 13 - in the Appendix to the regional Red Data Book. Many protected species are represented by marginal populations in the study area. Two species (Ranunculus kamchaticus and Draba pauciflora) have single records for the Komi Republic. Despite the recent significant human impact, the Barkova Mountain is important for the conservation of the floral diversity of the region, the Yugyd Va National Park and the Virgin Komi Forests UNESCO World Heritage Site.

Manifestation of the Late Aeronian event in the Silurian section on the western slope of the Subpolar Urals

Research subject. The article presents the results of studying traces of the global Late Aeronian biotic and isotopic (δ13Ccarb) events preserved in a new reference section of the Lower Silurian in the Subpolar Urals.Materials and methods. The samples of sedimentary rocks and microfauna, the results of isotope analysis, as well as the collections with remains of benthic fauna collected by the authors in different years during fieldwork were investigated. The studies were confirmed by sedimentological, biostratigraphic and chemostratigraphic data obtained by the authors.Results. The The event-stratigraphic interval, established in the upper part of the Lolashor stage (Aeronian) of the Silurian, is characterized by increasing regressive tendencies, decreasing biodiversity, disappearance of Pranognathus tenuis conodonts and brachiopods of the genus Pentamerus, as well as by δ13Ccarb anomalies in the upper strata of the Lolashor stage.Conclusions. The obtained data indicate a eustatic drop in the sea level, a major ecosystem restructuring, and a sedimentation gap at the end of the Lolashor time. The boundary between the Lolashor and Philippel stages (Aeronian and Telychian) records a sharp negative isotopic shift of δ13Ccarb, which was first observed in the Lower Silurian section in the European Northeast of Russia.

The First Data on Mosquitoes (Diptera: Culicidae) in the Yugyd-Va National Park (Komi Republic, Subpolar Urals)

The First Data on Mosquitoes (Diptera: Culicidae) in the Yugyd-Va National Park (Komi Republic, Subpolar Urals)

Formation Conditions of Quartz‒Lazulite Mineralization of Mount Chernaya, Subpolar Urals: Evidence from Study of Fluid Inclusions

Formation Conditions of Quartz‒Lazulite Mineralization of Mount Chernaya, Subpolar Urals: Evidence from Study of Fluid Inclusions

Riphean–Vendian–Cambrian Magmatism of the Mankhambo Block (Subpolar Urals): Geochemical Typification, Correction of Geodynamic Concepts, and the Role of Plume–Lithosphere Interaction

Riphean–Vendian–Cambrian Magmatism of the Mankhambo Block (Subpolar Urals): Geochemical Typification, Correction of Geodynamic Concepts, and the Role of Plume–Lithosphere Interaction

Первые U/Pb-данные о возрасте детритового циркона из песчаников золотоносной верхнекембрийско-нижнеордовикской алькесвожской толщи (Приполярный Урал)

The paper presents the novel isotope data on the age of sandstones of the gold-bearing Alkesvozhskaya sequence at the base of the Paleozoic section in the Subpolar Urals. The analysis of U/Pb dating of detrital zircons confirmed that the sandstones had been formed no earlier than in the Late Cambrian-Early Ordovician. The predominant part of dating is in a narrow Late Riphean-Late Cambrian age interval, and zircons are represented by unrounded or weakly rounded crystals. The composition of the sandstones of the Alkesvozhskaya sequence are dominated by the destruction products of the underlying rocks of igneous complexes at various stages of the formation of timanides-protouralides.

Morphological features, ontogenetic changes and stratigraphic range of conodonts <i>Siphonodella belkai</i> Dzik (Tournaisian, Mississippian)

Research subject. Multidisciplinary characteristics of the Siphonodella belkai Dzik conodonts, which an index species in the Tournaisian (Mississippian) conodont zonation. Materials and methods. Data on conodonts collected from the North Cis-Urals and Subpolar Urals sections was used. In total, 89 specimens of Siphonodella belkai were found in the Kozhim Eiver basin sections (Subpolar Urals) and the Vangyr River section (Tchernyshev Uplift). The histology, morphology and ontogeny of platform elements of this species were studied using SEM, optic microscope and X-ray micro-CT. In total, 45 complete specimens were biometrically studied. Results. Siphonodella belkai can be reliably distinguished by having a smooth lens-like platform and bearing developed rostral ridges. The paralamellar tissue occurs in the platform and rostral ridges; distribution of the albid tissue is restricted by carina denticles in the cusp neighborhood. Sinistral and dextral P1 elements of the species compose asymmetric pairs and differ by the position and number of rostral ridges (Class III of symmetry). The element outline remains constant in ontogeny. Rostral ridges appear at early ontogeny stages, when an element is of 0.4-0.5 mm in length, thus allowing reliable taxonomic diagnostics. Conclusions. Siphonodella belkai is known from the moderately deep-water deposits of the Central and Eastern Europe and South China. The base of the S. belkai zone, marked by the first appearance of the eponimic taxon, coincides with the base of the Upper duplicata zone. Distinguishing the S. belkai zone as a standard zone seems unreasonable due to the rarity, restricted area and specific ecology of S. belkai. This zone is of low correlation potential.

Earthworms (Oligochaeta, Lumdricidae) in the Komi Republic

The article presents information about 11 species in 8 genera of earthworms (Oligochaeta, Lumbricidae) in the Komi Republic. They belong to three morpho-ecological groups inhabiting different soil horizons (litter, litter/soil, soil). The species distribution maps have been compiled. The density of each species and their habitat affiliations in different flatland subzones and altitudinal zones of the Ural Mountains are shown. The number of species tends to decline in a regular manner from southern taiga to shrub tundra, from the Northern to Polar Urals. Boreal zone soils are inhabited by members of the genera Aporrectodea, Dendrobaena, Bimastos, Eisenia, Eiseniella, Lumbricus, Octolasion. Four species: Aporrectodea caliginosa, A. rosea, Eisenia fetida, and Octolasion lacteum, prefer meadows and farmlands. The species Bimastos rubidus and Eiseniella tetraedra inhabit meadows, willow carrs and forests in southern and middle taiga; they are absent in the extremely northern taiga and forest tundra; their habitats in the tundra zone are hydrogen sulfide springs. Three species (Dendrobaena octaedra, Eisenia nordenskioldi, Lumbricus rubellus) have been found in all natural zones and subzones. They compose the Lumbricidae fauna in the tundra zone. Northern Urals harbored the same earthworm species as the boreal zone. Two more species, Rhiphaeodrilus diplotetrathecus and Eisenia atlavinyteae, are representatives of the montane Urals Lumbricidae complex. Five species: R. diplotetrathecus, D. octaedra, E. nordenskioldi, L. rubellus, and O. lacteum, are known for the Subpolar Urals. The species D. octaedra, E. nordenskioldi, L. rubellus have been detected in the Polar Urals as in the tundra zone. The altitudinal distribution of earthworms in the Urals is characterized by the presence of ‘soil’ species in the montane forest zone and a decline in the species diversity in the subalpine and alpine tundra zones, mostly at the expense of the litter/soil group

IMPURITY LUMINESCENCE CENTERS IN FLUORAPATITE FROM QUARTZ-BEARING PARAGENESIS ACCORDING TO PHOTO-, CATHODE- AND SYNCHROTRON-INDUCED LUMINESCENCE

Apatite is typically characterized by a wide variety of spectrum and kinetic characteristics of luminescence; luminescent images of grains are often zonal. A variety of conditions for the formation of the mineral in various types of associations and in many types of host rocks contributes to the occurrence of impurities of various luminogen ions in its structure. The variety of luminescence is associated with impurities of d-metals, REE, different types of anions, as well as with the effects of co-activation in various combinations. The paper presents the results of a comparative study of photo-, cathode- and synchrotron luminescence of apatite (by the example of samples from crystal-bearing deposits of the Neroi region, Subpolar Urals). Using a Jeol JSM6390LV SEM equipped with a Horiba H-CLUE iHR500 attachment, cathodoluminescence spectra of apatite were obtained in the 200–800 nm range. The spectra and kinetic characteristics of apatite luminescence upon excitation by synchrotron radiation at 10 and 300 K have been analyzed for the first time; the physical nature of the excitation bands of the three main luminescence centers Ce3+, Eu2+ and Mn2+ has been examined; it is shown that the luminescence excitation with the energy transfer can be carried out in processes initially initiated by interband transitions or photoionization. The data obtained are important for expanding the possibilities of mineral cathodoluminescence with spatial and spectral resolution and its use in applied problems.

Mineral Phases of the Pd–Bi–Se System in the Ores at the Chudnoe Au–Pd Deposit (Subpolar Urals, Russia)

Mineral Phases of the Pd–Bi–Se System in the Ores at the Chudnoe Au–Pd Deposit (Subpolar Urals, Russia)