pdf № 265, January

Hydrogeological prerequisites of Kizil oil-region
in the Southern Urals
V. G Popov, R. F Abdrahmanov

The article discusses a debatable problem of oil-bearing Kizil structural facies zone of Magnitogorsk megasinclinorium in Southern Urals from a hydrogeological point of view. The discussion is based on the results of exploration deep drilling (up to 5010 m) in the Urals profile involving information on ore and hydromineral deposits. We present the analysis of the abyssal hydrogeochemical zoning and our ideas concerning the formation and genesis of ground waters. We showed that the oxygen-nitrogen fresh waters at the depth of more than 1000 m were replaced by salty waters and > 2000—3000 m — by methane brines of chlorine-calcium type. They are associated with fractured reservoirs of sedimentary and volcanic-sedimentary Carboniferous strata and occur in a very complex hydrogeodynamic regime and shielded from the effects of supergene factors by regional thrusts. The brines are the product of sedimentation in Carboniferous evaporite paleobasins and subsequent metamorphism in the rocks due to epigenetic processes. The tangential forces affected not only the style of tectonics and hydrogeodinamics of the Southern Urals, but also played a key role in the formation of filtration-capacitive properties of the rocks. The prospects of the oil-bearing zones are associated with Kizil buried anticlinal structure, particularly with its eastern subthrust part. The exploration works are complicated due to anisotropism and irregular fractured reservoirs.

Keywords: Southern Urals, Kizil zone, hydrogeological conditions, oil.

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DOI: 10.19110/2221-1381-2017-1-8-15

Petrophysical characteristics of geological bodies at the present stage of geological knowledge is considered as a «record» of the geodynamic conditions of the past and used for the development of new or refining existing models of structure and evolution of the lithosphere. The objects of this study were igneous, metamorphic and sedimentary-volcanogenic rock complexes of different age in the north of the Urals. A comparative analysis of geophysical, petrophysical, geological and geochronological data was used for detailed petrophysical systematization of structural-material complexes of the Earth's crust and upper mantle in the north of the Urals. It is proposed to differentiate the three regional petrophysical zones within the northern part of the Urals according to the petrophysical properties of rocks and characteristics of the gravitational and magnetic fields as a result of comprehensive interpretation of physical fields. Petrophysical zone of «paleocontinental» type, combines petrophysical group of formations represented by the pre-Riphean metamorphic associations. The «paleooceanic» petrophysical zone includes ultramafic rocks of ophiolite complexes and mafic rocks of Kershor and Lagorta associations. The most eastern zone of «paleo-island-arc» type consists of intrusive rocks of Sobskiy and Kongorskiy complexes, as well as volcano-sedimentary sequence.

Keywords: physical fields, gravitational field, magnetic field, anomaly, petrophysical characteristics, the north of the Urals.

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DOI: 10.19110/2221-1381-2017-1-16-21

The article presents results of research of typomorphic features of garnets from the Middle Neopleistocene tills in the valleys of Laya and Vychegda Rivers due to necessity of valid and reliable subdivision and correlation of the deposits. Two sorts of garnets, different in color, are the most widespread – orange and pink. The pink garnets dominate in the valley of the Laya River, their content in the Pechora horizon is higher than in the Vychegda horizon. In the Vychegda River valley the tills are enriched with orange garnets, but their concentration is higher in the Vychegda till.

Pyrope-almandine prevails among the pink garnets in the Pechora till. In the valley of the Laya River it accounts for 90 %, in the Vychegda River — 60 %. Half of grains among orange garnets in the Vychegda till of the Laya River are pyrope-almandine-grossularite and grossularite-pyrope-almandine, but in the valley of the Vychegda River they make up 100 %. The portion of pyrope-almandine among pink garnets in the Laya River valley is 56 %, in the Vychegda River valley — 44 %. Single garnet grains with high content of calcium (up to 90 %) and spessartine minal (more than 50 %) are found in the Vychegda till in the valley of the Laya River.

Keywords: Middle Neopleistocene, till, typomorphic features, garnet, minal composition, color group.

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DOI: 10.19110/2221-1381-2017-1-22-28

Tectonic relationship of the shale allochton and the carbonate parautochton of Pay-Khoy is subject of debates. Detailed study of the geological composition of the area of allochton and parautochton junction in the North of Pay-Khoy (Cape of Pyrkov, Lake of Khaenato, village of Khabarovo) demonstrates the presence of a number of klippes composed of deep-water sediments of the Early Palaeozoic age. Analyses of morphology and orientation of folds and faults show that the Main thrust fault of Pay-Khoy is accompanied by the formation of overthrust with minimum amplitude of movement on subhorizontal surface of more than 5 kilometers. The indications of the nature of the thrust suggest the presence of the deep-water facies sedimentary klippes in the south of the island of Vaigach. Carbonate parautochton was heavily deployed and undergone the same complicated way of tectonic transformations, as the allochton. 

Keywords: Main thrust fault of Pay-Khoy, carbonate parautochton, shale allochton. 

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DOI: 10.19110/2221-1381-2017-1-29-36

Prospects of development of the mining industry in the Komi Republic are associated with the largest deposits of titanium — Yaregskoe and Pizhemskoe. New data on the mineralogical and technological properties of titanium ores will allow accelerating the development of these deposits and proposing effective technologies of titanium ore processing and enhancing the list of commodity products. The set of mineralogical and analytical methods was used (optical and electron microscopy, X-ray and X-ray fluorescence analysis). Ilmenite-leucoxene ores of Pizhemskoe deposit are of complicated character, different metals (isomorphic impurity, autonomous mineral phases) are present along with main ore components. The morphometric characteristics of grains of ilmenite-leucoxene ore point to the need to use combined methods of enrichment and utilization.

Keywords: Pizhemskoe deposit, ilmenite-leucoxene ore, morphometric characteristics, technological properties.

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