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Date submitted2024-04-10
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Date accepted2024-10-14
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Date published2024-11-12
The influence of ocean anoxia on conditions for the Domanik deposits formation
The article considers one of conditions for the Domanik facies formation on the example of Tatarstan and Bashkortostan. The main emphasis is on the influence of anoxic paleobasin conditions on the high-carbon strata formation. A detailed study of the hydrocarbon composition of Domanik deposits made it possible to find characteristic biomarkers in their composition. They are based on the composition and structure of diagenetic products of biological compounds composing the sulphur bacteria living in anoxic/euxinic paleobasin conditions. Such compounds include C40 diaryl isoprenoids – isorenieratane and paleorenieratane. C10 tetramethylbenzenes also occupy a special place in the Domanik deposits study. Their appearance in the composition of organic matter of these deposits results from the transformation of sulphur bacteria compounds. Diaryl isoprenoids and tetramethylbenzenes are a reliable indicator of anoxic conditions of the Domanik deposits formation. The thermodynamic state of the hydrocarbon environment can be determined from the ratio of tetramethylbenzene isomers.
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Date submitted2008-10-09
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Date accepted2008-12-12
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Date published2009-12-11
New source of noble corundum in Kenya
- Authors:
- L. V. Kulachkov
- K. Kamwathi
- V. L. Shterhun
The large-scale occurrence of ruby and sapphire in Kenya is represented by contemporary river-bed and valley alluvial placers. The first ones are characterized by a high content of ruby (up to 10,4 ct/m 3 ), the second type is interesting due to the amount of forecasted resources: up to 2,3 million ct of ruby and 1,2 million ct of sapphire. It turned out to trace the mechanism of corundum concentrations forming, the mineral crystallized in Archean high-alumina gneisses affected by Precambrian basites (ultrabasites), and then survived a complicated way: – ancient eluvium – ancient alluvium – transportation by basaltic Pleistocenic magma – Holocenic weathering crust of volcanites – talus – contemporary alluvium.
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Date submitted1958-03-23
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Date accepted1958-05-15
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Date published1958-05-09
СТРОЕНИЕ И ГЕНЕЗИС ПИСЬМЕННЫХ ГРАНИТОВ В ПЕГМАТИТОВЫХ ЖИЛАХ
- Authors:
- Unknown
Письменные граниты своеобразием своей структуры давно привлекали внимание исследователей. Известно, что эти породы по своему химическому и минеральному составу подобны обычным гранитам, но весь кварц в них заключен внутри кристаллов полевых шпатов в форме многочисленных правильно ориентированных включений. Последние часто напоминают рисунок древних письмен. Эта особенность структуры пород и определила их название: руниты, еврейский камень, графические пегматиты, пегматит и наиболее принятое в нашей литературе — письменные граниты. Письменные граниты входят в состав различных геологических образований. Они известны в дайках кислых магматических пород, в апикальных частях гранитных массивов, в составе толщ глубоко метаморфизованных пород типа гнейсов и других. Наиболее эффектные и крупнозернистые образцы письменных гранитов находятся в пегматитовых жилах. Именно здесь они изучались подробно, и их первые описания насчитывают уже более чем полуторавековую давность. С тех пор изучению письменных гранитов и особенно обсуждению генезиса этих пород было посвящено большое количество работ.
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Date submitted1951-08-23
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Date accepted1951-10-03
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Date published1952-11-20
Feldspars of ceramic pegmatites of the Southern Karelia
- Authors:
- S. A. Rudenko
Recently, a discussion has developed regarding the genesis of pegmatites. The beginning of this discussion was laid by D. S. Korzhinsky in 1937. In 1944, A. N. Zavaritsky demonstrated the inconsistency of the physicochemical substantiation of the pegmatite process proposed by Vogt and Niggli and accepted by A. E. Fersman. Later, in 1947, he put forward a new theory of the genesis of pegmatites, contradicting the idea that pegmatites are a product of direct crystallization of residual melt (A. E. Fersman's theory). According to A. N. Zavaritsky, the main structural features of pegmatites are created as a result of recrystallization of certain igneous rocks. Next, V. D. Nikitin, who studied ceramic and mica pegmatites (1946-1951), based on a detailed analysis of the relationships between individual minerals and structural components of pegmatites, developed ideas about the genesis of pegmatites of this specific type, which are basically consistent with the theory of A. N. Zavaritsky. However, much effort is still needed to more fully resolve issues related to establishing all the features of the transformations that both the deposits as a whole and the individual minerals that make them up undergo during the complex and lengthy process of pegmatite formation. This article highlights the main features of the evolution of feldspars in ceramic pegmatites of Southern Karelia.
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Date submitted1950-08-15
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Date accepted1950-10-13
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Date published1951-08-08
Conditions for squeezing water and oil from clays
- Authors:
- V. D. Lomtadze
Studying the conditions of squeezing water and oil from clays is of exceptional importance for understanding the genesis of oil, oil fields, the formation of the salt composition of groundwater and the properties of clay sediments. Squeezing water and oil from clays is associated with the issue of clay compactibility. Clay compactibility has been studied many times, and there is extensive literature devoted to this issue. However, all these studies, in most cases, were conducted for engineering and construction purposes. Therefore, clay compaction was studied, as a rule, under low loads (4-6 kg/cm2). In addition, these studies were usually carried out to obtain the physical and mechanical characteristics of the soil. Only a few works are devoted to studying clay compactibility under higher loads.