Epigenetic changes of acidic volcanites from the top of the Western Siberia Pre-Jurassic complex

Author(s):  
A. V. Krasnova ◽  
Yu. V. Rostovtseva ◽  
A. E. Gavrilov

The study of secondary changes of acidic effusives with reservoir properties from the top of the Western Siberia pre-Jurassic complex (Tomsk Region) was produced. Lithological, petrographic and mineralogical features of these rocks indicate their change by low-temperature hydrothermal solutions, while weathering products, which are widely spread at the top of the basement, have not been clearly defined. Reservoir properties of studied rocks were formed probably due to fracturing and leaching.

Author(s):  
A. V. Krasnova ◽  
Yu. V. Rostovtseva ◽  
A. E. Gavrilov

The carbon and oxygen isotopic composition of secondary carbonates from acidic effusives fro investigated. Ϭ13С (VPDB) and Ϭ18О (VSMOW) values of siderite vary from –6,6 to –2,4‰ m the top of the Western Siberia pre-Jurassic complex (Tomsk Region) was and from 7,8 to 12,3‰, while Ϭ13С and Ϭ18О values of calcite vary from –8,9 to –8,4‰ and from 2,5 to 3,7‰ respectively. Light oxygen isotopic composition indicates formation of studied carbonates from heated hydrothermal solutions.


2008 ◽  
pp. 68-75 ◽  
Author(s):  
G. S. Taran

In the Ob river floodplain between the mouths of its tributaries Vakh and Tym (within the limits of Aleksandrovskiy district of Tomsk region), phytocoenoses belonging to 9 associations and 2 communities of Braun-Blanquet classification vegetation classes are listed. Class Lemnetea is represented by associations Ricciocarpetum natantis (Segal 1963) Tx. 1974, Lemnetum trisulcae Soó 1927, Stratiotetum aloidis Miljan 1933; class Potametea is done by asso­ciations Potametum perfoliati Koch 1926, Myriophylletum sibirici Taran 1998, Myriophylletum verticillati Soó 1927, Potametum graminei Koch 1926, Potametum pectinati Carstensen 1955, Nymphoidetum peltatae (All. 1922) Bellot 1951, as well as Sagittaria natans and Potamogeton natans—Ceratophyllum demersum communities. The syntaxa distribution in Western Siberia and adjoining territories is characterized.


2008 ◽  
Vol 72 (5) ◽  
pp. 1083-1101 ◽  
Author(s):  
W. H. Paar ◽  
Y. Moëlo ◽  
N. N. Mozgova ◽  
N. I. Organova ◽  
C. J. Stanley ◽  
...  

AbstractCoiraite, ideally (Pb,Sn2+)12.5As3Fe2+Sn4+S28, occurs as an economically important tin ore in the large Ag-Sn-Zn polymetallic Pirquitas deposit, Jujuy Province, NW-Argentina. The new mineral species is the As derivative of franckeite and belongs to the cylindrite group of complex Pb sulphosalts with incommensurate composite-layered structures. It is a primary mineral, frequently found in colloform textures, and formed from hydrothermal solutions at low temperature. Associated minerals are franckeite, cylindrite, pyrite-marcasite, as well as minor amounts of hocartite, Ag-rich rhodostannite. arsenopyrite and galena. Laminae of coiraite consist of extremely thin bent platy crystals up to 50 urn long. Electron microprobe analysis (n = 31) gave an empirical formula Pb11.21As2.99Ag0.13Fe1.10Sn6.13S28.0 close to the ideal formula (Pb11.3Sn2+1.2)Σ=12.5As3Fe2+Sn4+S28. Coiraite has two monoclinic sub-cells, Q (pseudotetragonal) and H (pseudohexagonal). Q: a 5.84(1) Å, b 5.86(1) Å, c 17.32(1) Å, β 94.14(1)°, F 590.05(3) Å3, Z = 4, a:b:c = 0.997:1:2.955; H (orthogonal setting): a 6.28(1) Å, b 3.66(1) Å, c 17.33(1) Å, β 91.46(1)°, V398.01(6) Å3, Z = 2, a∶b∶c = 1.716∶1∶4.735. The strongest Debye-Scherrer camera X-ray powder-diffraction lines [d in Å, (I), (hkl)] are: 5.78, (20), (Q and H 003); 4.34, (40), (Q 004); 3.46, (30), (Q and H 005); 3.339, (20), (Q 104); 2.876, (100), (Q and H 006); 2.068, (60), (Q 220).


Author(s):  
A. S. Roslyakova ◽  
A. G. Kalmykov ◽  
G. A. Kalmykov ◽  
R. A. Khamidullin ◽  
N. I. Korobova ◽  
...  

The paper presents a study of the structure and reservoir properties of rocks of the Bazhenov formation in the sections of three wells located in different structural zones of the Priobskoye field. It is shown that the porosity of the samples varies from 0.02% to 6.95%, the absolute gas permeability of the rocks reaches 1.364 mD. It is established that the collectors in the Bazhenov formation are confined to silicite-radiolarites (possessing porosity associated with the leaching of radiolarian shells) and kerogen-clay-siliceous rock and kerogen-clay silicite (porosity is associated with the release of space between the clay-siliceous matrix and kerogen by ripening organic matter). The following secondary processes influenced the formation of voids in these lithotypes: recrystallization of radiolarians and local warming up.


Georesursy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 125-135
Author(s):  
Valery I. Isaev ◽  
Galina A. Lobova ◽  
Alexander N. Fomin ◽  
Valery I. Bulatov ◽  
Stanislav G. Kuzmenkov ◽  
...  

The possibilities of Geothermy as a geophysical method are studied to solve forecast and prospecting problems of Petroleum Geology of the Arctic regions and the Paleozoic of Western Siberia. Deep heat flow of Yamal fields, whose oil and gas potential is associated with the Jurassic-Cretaceous formations, and the fields of Tomsk Region, whose geological section contents deposits in the Paleozoic, is studied. The method of paleotemperature modeling was used to calculate the heat flow density from the base of a sedimentary section (by solving the inverse problem of Geothermy). The schematization and mapping of the heat flow were performed, taking into account experimental determinations of the parameter. Besides, the correlation of heat flow features with the localization of deposits was revealed. The conceptual and factual basis of research includes the tectonosedimentary history of sedimentary cover, the Mesozoic-Cenozoic climatic temperature course and the history of cryogenic processes, as well as lithologic and stratigraphic description of the section, results of well testing, thermometry and vitrinite reflectivity data of 20 deep wells of Yamal and 37 wells of Ostanino group of fields of Tomsk region. It was stated that 80 % of known Yamal deposits correlate with anomalous features of the heat flow. Bovanenkovskoe and Arkticheskoe fields are located in positive anomaly zones. 75 % of fields of Ostanino group relate to anomalous features of the heat flow. It is shown that the fields, which are characterized by existence of commercial deposits in the Paleozoic, are associated with the bright gradient zone of the heat flow. The forecast of commercial inflows in the Paleozoic for Pindzhinskoe, Mirnoe and Rybalnoe fields is given. The correlation between the intensity of naftidogenesis and the lateral inhomogeneity of the deep heat flow is characterized as a probable fundamental pattern for Western Siberia.


LITOSFERA ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 592-600
Author(s):  
G. H. Shaikhutdinova

Subject. This paper presents the results of studies of the mechanism of primary oil migration in the boundary sediments of the late Jurassic (Bazhenov formation)–early Cretaceous (Achimov pack) on the example of the well 431Р of the Imilor field. Materias and methods. Based on the working hypothesis of fluid fracturing as the main mechanism of primary oil migration, using optical-petrographic analysis, supplemented by geochemical research methods, systems of interconnected microcracks in the Tithonian-lower Berriasian and early Valanginian deposits were studied. Results. It is established that the investigated cracks occurred in three stages: 1) formation of primary sedimentary-lithogenetic fissures as a result of dehydration of clays in the stage of diagenesis and hydraulic fractures in the implementation of the Achimov of terrigenous rocks; 2) partial healing of cracks with secondary minerals in the catagenesis; 3) restoration of patency of the cracks in the generation of large amounts of free hydrocarbons of protopetroleum. It is shown that the migration of hydrocarbons generated by the formation occurred both within the Bazhenov formation itself and through a system of interconnected cracks in the contact zone of the Bazhenov formation with the Achimov formation. Conclusion. A detailed study of the mechanism of oil migration allows us to expand our understanding of the reservoir properties of the oil column, which in the future will allow us to forecast the reservoir properties of the Bazhenov formation including in the zones of anomalous sections (for example, in the Kogalym region).


The paragenesis of low-temperature metasomatic calcium-iron garnets or hydrogarnets in marine sediments is discussed. Oxygen isotope data indicate that the garnetiferous (micarb) chalk from DSDP site 251, southwest branch, Indian Ocean Ridge (gros 52 and 40 py 6 alm 1.5 sp 0.5 ), formed at about 170 °C from circulating seawater hydrothermal solutions passing through the underlying altered basalts. Other possible examples of the hydrothermal metasomatic formation of garnets are found on bleached coprolites in the basal Bone Bed at the junction of the Rhaetic and the underlying Triassic Tea Green Marls at Larne, Antrim, in association with montmorillonite, analcime, magnetite, fluorite, and calcite, near to Tertiary basalts (and 89.4 gros 6.1 sp 3.1 alm 1.0 py 0.4 ) ; in recrystallized chalk and glauconitic sandstones, associated with zeolites and other minerals, near a dolerite dyke, at Portmuck, Antrim (andraditic); and in a calcareous sedimentary lens in bedded trachytic tuffs, cut by dolerite dykes, at Fuerteventura, Canary Islands (gros 94.5 and 5.0 py 0.5 ). An extensive search through DSDP basal sediments has revealed no further examples.


2019 ◽  
Vol 2 (1) ◽  
pp. 217-224
Author(s):  
Kseniya Kanakova ◽  
Mikhail Kanakov

Despite the recent increased interest of researchers in the pre-Jurassic deposits of Western Siberia, this complex of rocks still remains relatively unexplored. In this paper, we consider fields that are in close proximity to each other, but have. fundamentally different geological structure and criteria for the oil and gas content of rocks that form the top of the pre-Jurassic complex.


2021 ◽  
Vol 7 ◽  
pp. 87-92
Author(s):  
Anna N. Nekratova ◽  
Nadezhda S. Zinner ◽  
Anastasia V. Shchukina

The genus Thalictrum species (Ranunculaceae) are of interest for study as medicinal plants that are promising for expanding the gene pool and treating socially significant diseases. The data of the analysis of more than 100 geobotanical descriptions obtained in 2010-2017 were used to study the coenotic complexes of Thalictrum minus and Thalictrum simplex growing in Tomsk region and to determine their ecological-coenotic confinement. The aim of our research was to study the species of the genus Thalictrum growing in Tomsk region, their distribution and use in medicine, to investigate the coenotic complex, and to determine the ecological-coenotic confinement of Thalictrum minus L. and Thalictrum simplex L. growing in Tomsk region. The coenotic complex of Thalictrum minus includes 146 species. Thalictrum minus is the reserve of raw materials of Category II, which are identified in species confined to coenoses of different synanthropic degree, where they grow abundantly. The coenotic complex of Thalictrum simplex in Tomsk region includes 62 species. Thalictrum simplex is the reserve of raw materials of Category II.


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