scholarly journals Comparison of source rocks from the Lower Silurian Longmaxi Formation in the Yangzi Platform and the Upper Devonian Semiluksk Formation in East European Platform

2021 ◽  
Vol 2 (1) ◽  
pp. 63-72
Author(s):  
V.P. Morozov ◽  
Zhijun Jin ◽  
Xinping Liang ◽  
E.A. Korolev ◽  
Quanyou Liu ◽  
...  
LITOSFERA ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 560-573
Author(s):  
A. G. Mizens ◽  
L. I. Mizens

Research subject. Brachiopods from the core of the Kurgan-Uspenskaya-1 parametric borehole. The borehole was drilled in the south of Western Siberia 80 km southeast of the Kurgan town. Brachiopods were collected at a depth of 1,525.4 m in the IV tectonic block (core interval 1,450–1,794 m) in the greenish-gray marls of the Famennian stage of the Upper Devonian.Materials and methods. The paleontological material is presented in the form of complete undamaged shells and individual valves of small- and medium-sized brachiopods. The safety of brachiopods makes it possible to determine their species and genera, sometimes in open nomenclature. The article provides a brief description of the available material.Results. 11 species of brachiopods of the subtype Rhynchonelliformea belonging to six orders and nine genera were identified. The following ten species were described: Orbinaria fallax (Pand.), Semiproductus amplus Bubl., Schuchertella sp., Dalejina? sp., Camarotoechia panderi (Sem.et Moell.), C. volucera Nal., Athyris tobolica Nal., Cleiothyridina tenuilineata (Row.), Cl. ex gr. pectinata (Sem. et Moell.), Retzia? sp. The presented information allows conclusions about the age of the sediments enclosing the brachiopods under study and expands the existing knowledge of both the composition of the Upper Famennian brachiopods of the basement of the south of Western Siberia and their geographical and stratigraphic distribution.Conclusion. An analysis of the stratigraphic distribution of the described brachiopods taking into account data on foraminifera allowed us to determine the age of the host rocks as the very top of the Famennian stage. The composition of the brachiopods allows these rocks to be correlated with coeval deposits of the East European Platform, Timan, the Urals, Kuzbass, the Gorny Altai, Kazakhstan and North America.


2014 ◽  
Vol 1014 ◽  
pp. 228-232 ◽  
Author(s):  
Chen Lin Hu ◽  
Yuan Fu Zhang ◽  
Zhi Feng Wang ◽  
Hai Bo Zhang

In order to understand the sedimentary characteristics of shale and prospects of shale gas exploration in the lower Silurian Longmaxi Formation northern of Guizhou Province, outcrop and core observations, thin sections, X-ray diffraction analysis and other means are used. Studies show that the thickness of Longmaxi formation shale is generally large, range from 20m to 200m, mainly develop in the water shelf. The mineral mainly compose of detrital quartz and clay minerals, and five lithofacies can be identified: black shale, silty shale, carbonaceous shale, calcareous shale and argillaceous siltstone. Longmaxi shale kerogen type is mainlyIand II, and Ro value is average of 1.87%, mainly in the mature - over mature stage. In addition, the TOC content and gas content of Longmaxi shale is high, what’s more, these two parameters have good positive correlation. Compared with the Barnett shale, both of them have some similarities in the development environment shale, shale thickness and type of organic matter and TOC content, while, Longmaxi shale is deeply buried and post-destruction more intense. Longmaxi shale sedimentary environment is stable, high shale thickness and stable distribution, good quality source rocks and high brittle mineral content, which has meet the basic parameters of shale gas exploration and development, and has a large shale gas exploration potential in study area.


2013 ◽  
Vol 868 ◽  
pp. 186-191 ◽  
Author(s):  
Sheng Ling Jiang ◽  
Chun Lin Zeng ◽  
Sheng Xiu Wang ◽  
Mei Li

In order to carry out a more comprehensive discussion on shale gas accumulation conditions of Lower Cambrian Shuijingtuo Formation and Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation, the distribution, source rock conditions and reservoir conditions of these two shales are comprehensively analyzed, these two shales are both have the characteristics of high organic carbon content, high maturity, appropriate thickness and mainly typeⅠkerogen as source rocks, and interbedded with siltstone and/or fine sandstone, rich in quartz and other detrital components, easy to break and form the cracks, micro cracks as reservoirs, these characteristics provide a favorable material basis and reservoir space for shale gas accumulating. On this basis, the effective distribution areas of these two shales are further determined and shale gas resources are preliminary evaluated, eventually come to the results of shale gas resources of Lower Cambrian Shuijingtuo Formation and Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation respectively are 0.409×1012m3and 0.389×1012m3.


LITOSFERA ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 32-54
Author(s):  
G. Yu. Shardakova ◽  
A. V. Korovko

Research subject. The composition and isotope systems of zircons and their host granites from the Krutorechensky complex (western part of the Main Uralian fault zone, Northern Urals) were investigated. Methods. The U-Pb age, trace element contents and Lu-Hf isotopes in the zircons under study were determined by LA-ICP-MS (Ulan-Ude, Ekaterinburg). TIMS was used to determine Sm-Nd isotopes in the rocks. Results and Discussion. It was shown that the morphology and composition of the main zircon group from granites confirm their magmatic origin and the absence of alteration. It means that the previously defined Vendian-Cambrian (542 Ma) age of the granites remains valid. The relics ancient (1043–122 Ma) cores were probably inherited from Isherim suite rocks. The source of such detrital grains could have been the rocks from the East-European platform basement. Young zircons (400 Ma) differing strongly from others in composition could have been formed around the already existing grains produced by a fluid generated under the action of plume activity. The source for granite melting was mainly of a crust nature: εNd(t) = –6, εHf(t) = –6…–9, initial ratio (87Sr/86Sr)i = 0.796943. In terms of lithology, the source rocks correspond to sandstones with a small admixture of clay components. The obtained information confirms the necessity to further investigate questions concerning the area of distribution and the age of the Sarankhapnorsk suite within the Krutorechensky complex, as well as the position of the eastern boundary of the Isherim block. Conclusion. The obtained results can be used in geological mapping.


Author(s):  
O. F. Kuzmenkova ◽  
A. G. Laptsevich ◽  
A. A. Nosova

For the first time, the authors determined lateral-temporal series of magmatic complexes of the Late Frasnian-Early Famennian Pripyat-Dnieper Magmatic Area according to the results of petrological and geochemical study of rocks of the Pripyat-Dnieper Magmatic Area (north-western part of the Pripyat-Dnieper-Donetsk Magmatic Province) in the southwest of the East European Platform using the principles of structural-material analysis and taking into account previous studies. The series consists of four complexes, formed during stages of magmatic activity, separated by time intervals: Zhlobin Complex (Rechitsa Time, the beginning of the Late Frasnian), Uvarovichi complex (Late Voronezh Time, the middle of the Late Frasnian), Pripyat Complex (Skolodin (Skolodin-Chernin?) Time, the end of the Late Frasnian) and Loev complex (Yelets (Yelets- Petrikov?) Time, Early Famennian). The rocks of the Zhlobin Complex belong to the alkaline-ultramafic (carbonatite-kimberlite-nephelinite) formation; Uvarovichi Complex - to the alkaline-mafic formation (basaltoids and phonolites); Pripyat Complex - to the alkaline-mafic-salic formation (trachyandesites); Loev Complex - to the alkaline-ultramafic (nepheline) formation.


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