排序方式： 共有29条查询结果，搜索用时 250 毫秒
1.
2.
A.D. Nozhkin A.A. Postnikov K.E. Nagovitsin A.V. Travin A.M. Stanevich D.S. Yudin 《Russian Geology and Geophysics》2007,48(12):1015-1025
Trachybasalt-alkali trachyte volcanism in the Yenisei Ridge was found out to be synchronous with deposition of coarse tilloids and flysch of the Chivida Formation of the Neoproterozoic Chingasan Group. New 703±4 Ma 40Ar/39Ar biotite and titan-augite ages of subalkaline basalts in the Chivida Formation indicated that they erupted in the Late Neoproterozoic. According to microfossil evidence, the Chingasan sediments correlate with Late Neoproterozoic strata in the type sections of the southern Siberian craton. The Chingasan deposition apparently lasted no longer than 30 Myr judging by the isotope ages obtained for the underlying Upper Vorogovka Group and subalkaline basalts in the Chivida Formation. The fault-parallel position of grabens and coarse grain sizes and variable thicknesses of their lithological complexes, as well as syndepositional trachybasalt-alkali trachyte volcanism provided evidence that the volcanosedimentary rocks of the Chingasan Group formed in an environment of active rifting. 相似文献
3.
Postnikov A. V. Postnikova O. V. Iz”yurova E. S. Poshibaev V. V. Kuznetsov A. S. Iz”yuraov A. D. Kozionov A. E. 《Lithology and Mineral Resources》2019,54(1):27-37
Lithology and Mineral Resources - Main regularities in the manifestation of epigenetic processes in Lower Vendian terrigenous rocks of the Nepa–Botuoba anteclise are established. Evolution of... 相似文献
4.
Watershed morphometric analysis of Wadi Baish Dam catchment area using integrated GIS-based approach
The integration of Remote Sensing (RS) and Geographic Information Systems (GIS) constitutes a powerful tool for the evaluation of watershed morphometric parameters. The benefits of this integration include saving time and effort as well as improving the accuracy of the analysis. Moreover, this technique is appropriate for describing the watershed and its streams. In this study, a detailed morphometric analysis of the Wadi Baish catchment area has been performed using the Shuttle Radar Topography Mission (SRTM). The performed morphometric analysis includes linear, areal, and relief aspects. The results of the morphometric analysis reveal that the catchment can be described as of eighth stream order and consists of an area of 4741.07 km2. Additionally, the basin is characterized by a relatively high mean value of bifurcation (4.012), indicative of the scarcity of permeable rocks with high slope in the area. This value of bifurcation ratio is consistent with the high drainage density value of 2.064 km/km2 and confirms the impermeability of the subsurface material and mountainous relief. The hypsometric integral of the catchment is 47.4%, and the erosion integral of the catchment is 52.6%, both were indications of a mature catchment area. 相似文献
5.
Corey A Cohn Christopher E Pedigo Shavonne N Hylton Sanford R Simon Martin AA Schoonen 《Geochemical transactions》2009,10(1):8-9
Background
Given the importance of highly reactive oxygen species (hROS) as reactants in a wide range of biological, photochemical, and environmental systems there is an interest in detection and quantification of these species. The extreme reactivity of the hROS, which includes hydroxyl radicals, presents an analytical challenge. 3'-(p-Aminophenyl) fluorescein (APF) is a relatively new probe used for measuring hROS. Here, we further evaluate the use of APF as a method for the detection of hydroxyl radicals in particle suspensions. 相似文献6.
7.
O. V. Postnikova A. V. Postnikov E. S. Konoval’tseva V. G. Toporkov S. I. Savchenko 《Lithology and Mineral Resources》2011,46(5):447-456
Basic regularities of secondary processes in reservoir rocks of the Yarakta Horizon are described with rocks in the Yarakta
field as example. To achieve the formulated goal, we elucidated rock types in the studied section, its structure and distribution
of reservoir rocks, as well as types of secondary alterations and their influence on filtration-capacity properties. The studies
revealed that reservoir rocks of the Yarakta Horizon were formed on an alluvial-deltaic plain on the southeastern slope of
the Nepa-Botuoba anteclise. The pore space of reservoir rocks is determined by conditions of their formation and peculiarities
of secondary alterations. Maximal filtration-capacity values are characteristic of gritstones, as well as coarse-grained and
inequigranular sandstones developed in the lower and middle parts of the Yarakta Horizon. The intergranular space of reservoir
rocks in the lower part of the reservoir is substantially “healed” by secondary processes (regeneration, dolomitization, sulfatization,
and salinization), probably, due to the gravitational seepage of stratal fluids, mineralization of which increased with time. 相似文献
8.
A.E. Kontorovich A.I. Varlamov D.V. Grazhdankin G.A. Karlova A.G. Klets V.A. Kontorovich S.V. Saraev A.A. Terleev S.Yu. Belyaev I.V. Varaksina A.S. Efimov B.B. Kochnev K.E. Nagovitsin A.A. Postnikov Yu.F. Filippov 《Russian Geology and Geophysics》2008,49(12):932-939
The Borehole Vostok 3 drilled in the east of the West Siberian Plate (Tomsk Region) revealed a Vendian section in the depth range 5002–3870 m, which was subdivided into the Poiga, Kotodzha, and Raiga Formations based on geological, geophysical, and paleontological data. In the Kotodzha and Raiga Formations, typical Upper Vendian fossils of Cloudina hartmanae and Namacalathus sp. were found along with diverse Platysolenites, which are commonly considered to be of zonal significance in Lower Cambrian strata. Hence, the stratigraphic interval with abundant diverse Platysolenites has a wider stratigraphic range than it was believed earlier and seems to cover the Upper Vendian and Lower Cambrian deposits. The Borehole Vostok 3 is the first Siberian occurrence of the fossils Namacalathus, the world's fourth occurrence of the Cloudina-Namacalathus association, and the first site where coexisting Platysolenites and typical Vendian organisms have been found. Therefore, the borehole provides one of the most informative (in paleontological context) Upper Vendian sections. 相似文献
9.
Alexander Smirnov Douglas Hausner Richard Laffers Daniel R Strongin Martin AA Schoonen 《Geochemical transactions》2008,9(1):1-20
Experiments with dinitrogen-, nitrite-, nitrate-containing solutions were conducted without headspace in Ti reactors (200°C), borosilicate septum bottles (70°C) and HDPE tubes (22°C) in the presence of Fe and Ni metal, awaruite (Ni80Fe20) and tetrataenite (Ni50Fe50). In general, metals used in this investigation were more reactive than alloys toward all investigated nitrogen species. Nitrite and nitrate were converted to ammonium more rapidly than dinitrogen, and the reduction process had a strong temperature dependence. We concluded from our experimental observations that Hadean submarine hydrothermal systems could have supplied significant quantities of ammonium for reactions that are generally associated with prebiotic synthesis, especially in localized environments. Several natural meteorites (octahedrites) were found to contain up to 22 ppm Ntot. While the oxidation state of N in the octahedrites was not determined, XPS analysis of metals and alloys used in the study shows that N is likely present as nitride (N3-). This observation may have implications toward the Hadean environment, since, terrestrial (e.g., oceanic) ammonium production may have been supplemented by reduced nitrogen delivered by metal-rich meteorites. This notion is based on the fact that nitrogen dissolves into metallic melts. 相似文献
10.
A. V. Kargin A. A. Nosova A. V. Postnikov A. V. Chugaev O. V. Postnikova L. P. Popova V. V. Poshibaev L. V. Sazonova A. Ya. Dokuchaev M. D. Smirnova 《Geology of Ore Deposits》2016,58(5):383-403
The results of geochronological, mineralogical, petrographical, and geochemical study of the Ilbokich ultramafic lamprophyre are reported. The specific features in the mineral and chemical compositions of the studied ultramafic lamprophyre indicate that it can be regarded as a variety similar to aillikite, while other differences dominated by K-feldspar can be referred to damtjernite. According to Rb–Sr analysis, ultramafic lamprophyre dikes intruded at the turn of the Early and Middle Devonian, about 392 Ma ago. This directly proves the existence of Early Paleozoic alkali–ultramafic magmatism in the northern part of the southwest Siberian Platform. A finding of Devonian alkali–ultramafic lamprophyre is of dual predictive importance. On the one hand, it is indicative of the low probability of finding large diamond-bearing deposits in close association with aillikite. On the other hand, it can be indicative of a possible large Devonian diamond province in the studied territory, where diamondiferous kimberlite is structurally separated from aillikite. 相似文献