pdf № 286, October

DOI: 10.19110/2221-1381-2018-10-3-9

The geological position and age of the Shchokurya suite in the Subpolar Urals are considered, which in modern stratigraphic schemes refers to the Lower or Middle Riphean formations. For the first time the U-Pb-dating of zircons indicates the Early Proterozoic time of the early stages of the metamorphism of the rocks of the Shchokurya suite. The upper age limit for the formation of the terrigenous-carbonate substrate of the suite may be previously limited to the minimum age of the main population of terrigenous zircons (about 2.5 Ga). These data confirm the results of previous structural, petrological and mineralogical studies, on the basis of which the idea was formed that the Shchokurya suite with the Manhobeyu suite and the Nyartin complex belonged to the structures of one (Lower Precambrian) structural story, and the Upper Proterozoic section (the Upper Precambrian structural story) in the Subpolar Urals began with the Oisez stratum of the Puyva suite of Middle or Late Riphean age.

Keywords: Subpolar Urals, Upper Precambrian, metamorphism, zircon, isotope age.

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DOI: 10.19110/2221-1381-2018-10-10-16

The paper presents the results of studying the macro- and microstructural features of the metamorphic rocks average and top Low Precambrian (Hobein and Moroya suits) and the Lower part Paleozoic (Obeiz suite) sections in the North of the Subpolar Urals.

The macro and microstructural features of the rocks of the northern part of the Subpolar Urals, such as the Hobein, Moroya and Obeiz suites are studied in the article. The common structural features for all these formations are both the presence of the falling on the NW at medium and low angles, and the presence of similar orientations of the optical c-axes quartz fabric for rocks which quartz grains experienced translational (dislocation) sliding under compression and shear conditions. The distinctive structural features for the rocks of the Hobein and Moroya formations from the rocks of the Obeiz suite are, firstly, the presence of the early two asymmetric folds with axial planes of of the NE-falling at steep angles, and secondly, the presence of crenulation cleavage observed in the polarization microscope, and thirdly, the existence in these two sets of orientations of optical quartz axes characteristic of rocks that underwent intensive folded deformations. All this allows us to propose additional criteria for the dismemberment and correlation of the metamorphic formations of the Kozhim river basin.

Keywords: Subpolar Urals, Precambrian, Upper Riphean, Lower Ordovician, structural geology, folds, microstructure analysis, c-axes of quartz.

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DOI: 10.19110/2221-1381-2018-10-17-22

Lithological-facies zonality of Neopleistocene and Eopleistocene sediments from Antarctic continental margin off Wilkes Land and in the Ross Sea has been described for the first time. Processing of respective maps and isopach schemes, compiled by authors, by means of volumetric method by A. B. Ronov gave an opportunity to calculate quantitative parameters of sedimentation for mapped types of Pleistocene sediments. We revealed the dominance of terrigenous sediments. In Neopleistocene they accumulated more intensively than in Eopleistocene. In Eopleistocene, vice versa, siliceous sediments accumulated wider than in Neopleistocene.

Keywords: Wilkes Land, submarine continental margin, Ross Sea, Eopleistocene, Neopleistocene, areas, volumes, masses of dry sediment matter, masses of sediments per time unit, terrigenous sediments.

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DOI: 10.19110/2221-1381-2018-10-23-29

On the territory of the Republic of Komi new locations of a rare spore plant Lycopodiella inundata (Lycopodiaceae), have been identified. The species prefer warmer and moister environmental conditions. Spore images were obtained by scanning electron and light microscopes at the Institute of Geology of the Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences. An analysis of the species paleogeographical history based on our and another researcher palynological data made it possible to refer it to the allochthonous element of the flora in the region.

Keywords: Lycopodiella inundata, Pleistocene, the Komi Republic, flora.

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DOI: 10.19110/2221-1381-2018-10-30-34

Изучена морфология элементов конодонтов рода Ozarkodina из лландовери Приполярного Урала в бассейне р. Кожым. Из отложений верхнего аэрона р. Кожым установлены переходные формы между Ра-элементами вида O. kozhimica Melnikov и O. waugoolaensis Bischoff. Переходные Ра-элементы O. aff. waugoolaensis по сравнению с Ра-элементами O. waugoolaensis характеризуются более коротким и высоким листом и более регулярной зубчатостью на переднем отростке, а по сравнению с Ра-элементами O. kozhimica — хорошо развитыми главным и вторым зубцами.

Ключевые слова: конодонты, морфология, Ozarkodinida, ранний силур, Приполярный Урал.

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DOI: 10.19110/2221-1381-2018-10-35-38

The literature and author’s data on the standard free energy of ions and titanium complexes in aqueous solution are presented. To analyze the behavior of titanium in the process of weathering we used the method of PC physical and chemical modeling Selector software. We established that in the weathering profile (when accounting for 41 complexes and titanium ion) titanium in solution was represented by only one hydroxocomplex — Ti(OH)40. Its content was controlled by the solubility of rutile and rated 10^–7 mol/l.

Keywords: titanium, rutile, weathering, standard free energy, modeling, Selector software.

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DOI: 10.19110/2221-1381-2018-10-39-46

The first data on findings of small magnetic microspherules in calcite and dolomite carbonatites of the Southern Urals (Ilmeny Mountains) are given. The composition of the microspherules is predominantly ferrous with a small admixture of manganese. Their diameter does not exceed 1 mm. Their form is spherical or slightly elongated, sometimes hollow inside. The surface of the microspherules is smooth shiny, rarely matte, sometimes trickle in the crust. The inner structure of the microspherules is shell-zonal, with voids in the center. They are characterized by the presence of dendritic and columnar crystals, their dense packing. These microstructures are similar to those of iron ingots. There are joints of microspherules of different diameter. The presence of an unusual association of elements for carbonatites in the iron matrix (Pt, Ni, Cu, Zn, Cl, Ca) was revealed by energy-dispersion spectrums from the inner surfaces of some hollow microspheres. The absence of the actual Ni-phases in the composition of the balls distinguishes them from similar formations of cosmic origin.

Along with crystals of fluorapatite and fluorophlogopite, forsterite, garnet, pargasite, sadanagaite, ilmenite, rutile, diopside, which are equally rare in carbonatites, ferrous microspheres are scattered in the carbonate matrix of the rock, without detecting adherence to cracks or interlayers. As the microspherules of native iron in igneous rocks are crystallized at temperatures of about 1500 °С, their availability in carbonate rocks of the Ilmeny Mountains is another evidence of their igneous nature.

Keywords: carbonatites, ferrous microspherules, native iron, Ilmeny Mountains, Southern Urals.

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DOI: 10.19110/2221-1381-2018-10-47-55

Raman spectroscopy was used to study the inclusions of carbon substance in placer diamonds from the rivers B. Shchugor and B. Kolchim, (Perm Region, Krasnovishersky district, Russia). It is established that inclusions of carbon substance within natural diamonds could be presented by either graphite of different degree of crystallinity, or low ordered glass-like carbon. The correlation between a Raman shift of T2g diamond band (1332 сm^–1 at room conditions) from G and G+D` graphitic carbon bands in Raman spectra has been analyzed. The dependence of residual deformation of a diamond lattice of crystallinity degree of carbon inclusions was defined, the latter was marked with appearance of a D`-bands in Raman spectra. It was shown that correct estimation of the residual tension of carbon substance inclusions within diamond could be made only on the basis of Raman data of high ordered graphite (FWHMG = 12—20 сm^–1), or by nanocrystalline graphite (FWHMG = 20—40 сm^–1) having a D` band within a spectrum. It is not correct to use the inclusions of low ordered carbons (FWHMG = 40—70 сm^–1) for the residual tension with the standard graphite coefficient for calculations, at the case the residual pressure can be estimated only by residual deformation of a diamond matrix. Without the complex analysis of the carbon inclusions Raman features and initial wrong acceptance of nanocrystalline and glass-like carbons as high ordered graphite the residual pressure is overestimated up to 1.5—2 times.

Keywords: Raman spectroscopy, residual stress, diamond, carbon inclusions.

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DOI: 10.19110/2221-1381-2018-10-56-61

The results of this investigation of technogenic minerals — Zn sulfides and silicates formed as precipitate at the fittings of hydronic heating system — are presented. The morphology, mineralogy and surface chemistry of the matter were studied by X-ray diffraction, X-ray fluorescence spectroscopy, scanning electron microscopy and energy dispersive X-ray. The results of this investigation provide clear evidence that hydronic heating systems have been found to support a breeding ground for bacteria associated with microbiologically influenced corrosion (MIC). In the precipitate Zn minerals are presented by tabular crystals of several generations, spheres, spherical aggregates and biomorphs on the bacterial cells that probably activated fitting corrosion and promoted Zn precipitation as sphalerite, wurtzite and hemimorphite.

Keywords: ZnS spherical aggregates, city hydronic heating system, microbiologically influenced corrosion.

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