9 results on '"A. A. Bochneva"'
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2. Placer mineral deposits of Russian Arctic zone: Genetic prerequisites of formation and prospect of development of mineral resources
- Author
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A. V. Lalomov, William LeBarge, and A. A. Bochneva
- Subjects
Tectonics ,Supergene (geology) ,Placer mining ,Geochemistry and Petrology ,Geochemistry ,Economic Geology ,Geology ,Weathering ,Sedimentary rock ,Platinum group ,Placer deposit ,Mineral resource classification - Abstract
Placer deposits are an accumulation of valuable minerals both dense and resistant to weathering processes, formed by gravity separation during sedimentary processes. Placer deposits of the Russian Arctic zone (RAZ) include gold, platinum group minerals (PGM), tin, diamonds, rare metals, zircon-titanium mineral deposits and a specific type of related to placer deposits - fossil ivory. There are an insufficient number of scientific geological articles on placer deposits of RAZ in the English-language literature at present, especially of an overview nature. This review paper attempts to fill the gap and marshal on the regional scale all available data aiming to provide a framework for generating and testing new ideas on the placer deposits of RAZ. The focus is on main factors and conditions of generation of the placer deposits of industrial importance, details of key placer deposits, and perspectives of development of placer mineral resources in the region. Localization and scales of placer deposits are controlled by metallogenic, tectonic, climatic and geomorphological factors which have regional and local characters. The metallogenic factor specifies the primary sources of the placer minerals, especially for proximal (retained and partly transient) placers that have moderate transportation. Tectonics have a dual role: on the regional level it determines rate of the erosion and disintegration of the host rocks due to weathering process; while on the local level, tectonic dislocation forms structural traps of placer deposits. Climatic factor is determinative for the character of supergene processes: warm humid conditions (especially combined with stable tectonics) result in deep chemical weathering and disintegration of the host rocks containing primary mineralization which is favorable for the placer forming process; in frozen (periglacial) climate conditions, mechanical weathering processes are prevalent. Geomorphological factors are closely connected with the dynamic state of the placer forming area, from the source location to the final sedimentary accumulations. Industrial placer deposits are formed when an optimal ratio of the main factors of placer forming processes occurs. A special type of anthropogenic (technogenic) placers are formed as result of human mining activities. It is impossible to distinguish only one or two of the main universal factors which are responsible for the formation of placer deposits, as all types of placers will have one or more of these. However, the formation of placers of economic importance are always the result of an optimal combination of the metallogenic, tectonic, climatic and geomorphological factors, and the absence of even one of these may result in placers of weak or non-economic ore concentrations. As evidenced by the extensive historical mining of placer deposits and the presence of undeveloped inferred placer mineral resources, the Arctic region is a large polymineral and polygenic megaprovince with considerable placer potential.
- Published
- 2021
- Full Text
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3. Rare metal–titanium placer metal potential of Cambrian–Ordovician sandstones in the northwestern Russian Plate
- Author
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A. V. Chefranova, M. V. Platonov, A. V. Lalomov, A. A. Bochneva, and M. A. Tugarova
- Subjects
Placer mining ,Geochemistry and Petrology ,Heavy mineral ,Lithology ,Geochemistry ,Ordovician ,Economic Geology ,Baltic Shield ,Sedimentary rock ,Sedimentology ,Geomorphology ,Mineral resource classification ,Geology - Abstract
The geological setting of the region and lithology of Cambrian–Ordovician sandstones in the northwestern Russian Plate are generally favorable for the formation of associated rare metal–titanium (titanium–zirconium) fossil complex coastal-marine placers, but such deposits have not been discovered in this region so far. Investigation of reference objects in the Russian Plate, reconstruction of lithodynamic settings of the Cambrian–Ordovician paleobasin, and study of the geology, lithology, and mineralogy of rock sequence in this region made it possible to estimate prospects of the discovery of such placers and forecast promising areas with placer mineralization. Our data suggest the presence of shallow-marine placers beneath the unconsolidated sedimentary cover on the southeastern slope of the Baltic Shield.
- Published
- 2015
- Full Text
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4. Geological-geophysical criteria for the prospecting and exploration of rare metal-titanium placer deposits: Evidence from the Transural region
- Author
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A. A. Bochneva, A. V. Lalomov, A. V. Chefranova, O. P. Fedorov, R. M. Chefranov, and D. P. Khrushchev
- Subjects
Horizon (geology) ,Placer mining ,Sequence (geology) ,Geochemistry and Petrology ,Prospecting ,Economic Geology ,Geophysics ,Sedimentology ,Mineral resource classification ,Placer deposit ,Geology - Abstract
The results of study of the Umyt’ya rare metal-titanium placer in the Transural province of West Siberia (Khanty-Mansiisk autonomous district) are presented. Lithological features of the placer-hosting Oligocene sediments were used to identify three horizons with different formation conditions and placer metal potentials. Lithofacies analysis of rocks of the upper horizon was accomplished. Comparison of the obtained results with the geophysical information (gamma and electrical logging) makes it possible to determine geological-geophysical criteria for the prospecting and exploration of rare metal-titanium placer deposits. It has been established that the gamma activity of placer-hosting rocks have a high and stable correlation with their composition (the content of minerals of the Zr-Ti assemblage included) and makes it possible to recognize separate sectors with placer bodies of mainly shallow-marine type. Electrical properties of rocks are less representative for the local prospecting, but they provide insight into the placer metal potential of separate rock horizons. Based on the identified criteria, prognostic assessment is given for the placer metal potential of deep horizons in the productive sequence of the Umyt’ya placer.
- Published
- 2014
- Full Text
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5. Geostatistical approach for elucidating the potential titanium-zirconium placer areas: Evidence from the Transural placer district
- Author
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A. V. Lalomov, R. M. Chefranov, and A. A. Bochneva
- Subjects
Sedimentary depositional environment ,Placer mining ,Mineral ,Geochemistry and Petrology ,Facies ,Geochemistry ,Economic Geology ,Sedimentology ,Structural basin ,Geomorphology ,Placer deposit ,Mineral resource classification ,Geology - Abstract
Geostatistical analysis of the composition of mineral assemblages of Oligocene sediments in the Mansi and Severnaya Sosva areas of the Transural titanium-zirconium placer district was accomplished by the method of the principal components. High significance of the first principal component and its composition revealed by this analysis suggest the existence of an efficient placer-forming process that can produce commercial concentrations of ore minerals. Interpretation of statistical indicators is given. The results confirm the facies zoning of sediments revealed previously in the Oligocene basin. They show that the paleolittoral and shallow-water zones with a moderate hydrodynamic activity in the depositional environment have the highest potential of titanium-zirconium raw material. Analysis of the mineral potential revealed that the Mansi and Severnaya Sosva areas can accommodate a medium-scale placer deposit.
- Published
- 2013
- Full Text
- View/download PDF
6. Lithofacies zoning and titanium-zirconium potential of the Mansi and North Sos’va areas, Transural placer region
- Author
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R. M. Chefranov, A. V. Lalomov, V. A. Trofimov, and A. A. Bochneva
- Subjects
geography ,Placer mining ,geography.geographical_feature_category ,Geochemistry ,Shoal ,Structural basin ,Mineral resource classification ,Tectonics ,Geochemistry and Petrology ,Facies ,Economic Geology ,Epeirogenic movement ,Sedimentology ,Geomorphology ,Geology - Abstract
The lithofacies and morphostructural analyses of the Mansi and North Sos’va areas of the Transural placer region allowed us to establish factors of the spatial and lithostratigraphic control of titanium-zirconium placer potential. It was established that the placers are localized in sediments of the upper stage of the Oligocene-Miocene complex and rocks of Oligocene basin shows facies zoning. The most promising are the paleolittoral and shoal facies formed under moderate hydrodynamic activity. In tectonic aspect, the position of promising areas and their lithofacies composition are controlled by flank zones of local domes that experienced epeirogenic movements. Regressive regime in the Oligocene basin suggests the highest probability for the discovery of titanium-zirconium placers of the littoral type in inner zones of neotectonic domes.
- Published
- 2010
- Full Text
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7. Prerequisites for the formation of titanium-zirconium deposits in the transural placer region: A regional geological-evolutionary model
- Author
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N. G. Patyk-Kara, A. V. Lalomov, O. P. Fedorov, A. A. Bochneva, and R. M. Chefranov
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Placer mining ,Tectonics ,Geochemistry and Petrology ,Terrigenous sediment ,Geochemistry ,Period (geology) ,Economic Geology ,Sedimentary rock ,Sedimentology ,Cenozoic ,Mineral resource classification ,Geology - Abstract
In the Transural placer region of the western Khanty-Mansi autonomous district (KHMAD), Oligocene-Miocene rocks with titanium-zirconium potential are represented by mineralogically mature coastalmarine sediments. Source of placers are represented by both the Uralian weathering crust and placers of older sedimentary rocks. Sedimentation pattern of this period was governed by tectonic activation of the Uralian mountain system and sequential regressive dislocation of coastal lines from west to east. Location of perspective sectors was controlled by peripheral segments of local domes of the third order. Study of the mineral composition of sediments confirms the presence of two diverse (in mineralogy) Cenozoic terrigenous associations—(i) mature oligomictic association mainly composed of quartzose silty-sandy sediments with minerals of the titanium-zirconium assemblage (Oligocene-Miocene Complex) and (ii) polymictic (Neopleistocene) association dominated by unstable minerals and rock fragments. In terms of the set of lithofacies criteria, Oligocene-Miocene rocks are most perspective for the discovery of coastal-marine titanium-zirconium placers.
- Published
- 2009
- Full Text
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8. Mineral assemblages of titanium-zirconium sands at the Central deposit, the east European platform
- Author
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V. V. Barsegyan, I. A. Chizhova, E. N. Levchenko, E. A. Andrianova, V. T. Dubinchuk, A. I. Stekhin, N. G. Patyk-Kara, and A. A. Bochneva
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Placer mining ,Mineral ,Geochemistry and Petrology ,Subaerial ,Geochemistry ,Economic Geology ,Geology ,Mineral resource classification ,Titanium zirconium ,Geomorphology ,Marine transgression - Abstract
The study of mineral assemblages at the Central deposit allowed us to substantially refine the evolutionary model of the deposit and reveal the two main factors that control the variability of its mineralic space: (1) heterogeneity of the ore layer, consisting of a sublittoral bottom placer (the lower part) and a subaerial dune complex partly reworked in the course of a new transgression (the upper part), and (2) postore epigenetic alteration of the ore constituent of sands, which affected the quality of ore concentrates. The results obtained will be used in geological and technological mapping and development of the production program.
- Published
- 2008
- Full Text
- View/download PDF
9. Butterflies (Lepidoptera: Papilionoidea and Hesperioidea) from meadows of Vinogradovsky District, Arkhangelsk Region, northern European Russia, with notes on recent intense expansion of the southern species to the north
- Author
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Marina V. Podbolotskaya, Irina A. Bochneva, Vitaly M. Spitsyn, Ivan N. Bolotov, and Mikhail Yu. Gofarov
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Ecology ,biology ,species diversity ,QH301-705.5 ,Lycaena ,Northern European Russia ,Species diversity ,biology.organism_classification ,range shifts ,climate warming ,Geography ,Vanessa atalanta ,agricultural landscape ,Aglais io ,Papilionoidea ,Butterfly ,butterfly migration ,Cupido alcetas ,Nymphalis xanthomelas ,Biology (General) ,Ecology, Evolution, Behavior and Systematics - Abstract
The Vinogradovsky District is located at the center of the Arkhangelsk Region, one of the largest federal subjects of Northern European Russia. Boreal spruce forests are the prevalent ecosystem type in this area, but large expanses of agricultural land and herb-grass meadows are also presented there. Based on the studies of 1,699 specimens collected from three meadow sites during period 2011–2013, we provide the first data on the butterfly fauna of the district, which include 56 species, belonging to 35 genera and 5 families. Our data reveal an intense northward expansion of many southern butterfly species to the Arkhangelsk Region, including migrants (Pontia edusa, Issoria lathonia, Vanessa atalanta and Vanessa cardui) and species that have established resident populations there (Pararge aegeria, Nymphalis xanthomelas, Aglais io, Lycaena dispar, Cupido alcetas). Quantitative data on species diversity and phenology of butterflies are reported, including analysis of structure of butterfly assemblages and their seasonal changes.
- Published
- 2015
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