The work studies mineralogical and geochemical features of the Jurassic coals of the Shubarkol deposit. The samples were examined using the method of scanning electron microscopy (SEM-EDX) Hitachi S-3400N, which was carried out at the Uranium Geology Research and Development Center at the Department of Geoecology and Geochemistry of TPU. Coal geochemistry was studied by instrumental neutron activation analysis (INAA) at the nuclear geochemical laboratory of the Department of Geoecology and Geochemistry of National Research Tomsk Polytechnic University (TPU). The choice of this object of study was determined by the tasks of research including the study of the patterns of accumulation of abnormal concentrations of REE, the effect of various factors of the geological environment on the levels of their accumulation in coals, as well as the conditions of its concentration and forms of occurrence in coals to expand the mineral resource base of Kazakhstan for rare earth elements. According to the results of scanning microscopic analysis, aluminosilicates, sulfides and sulfates with inclusions of microparticles of rare and rare earth elements were found in the composition of the Shubarkol deposit coals. According to the INNA results, abnormal concentrations of Sc, Ta, Nb, Hf, Zr, Ba, Sr, Ce and REE were found. Weathering processes led mainly to the loss and redistribution of REE in the coal seams of the Shubarkol deposit, which in turn led to increasing the content of rare earth elements from the bottom up the section. As a result of the action of multiple processes, increased concentrations of rare earth metals, mainly of the yttrium group, were formed. The absence of negative europium anomaly was determined, which confirms the original rocks composition peculiarity. The maximum contents of rare-earth metals are confined to weathered coals; for the medium-heavy group (Nd, PM, Sm, Eu), they are almost a hundredfold higher than the clarke in the upper continental crust. The tenfold excess of the clarke for elements from Gd to Lu was found in clayey sandstones and siltstones; for the rest of the rocks of the deposit the excess over the clarke is significantly lower. It was found that the coals of the deposit belong to the H-type and L-type of REE distribution. During the formation of oxidized H-type coals, clayey matter of terrigenous ash predominated as a carrier of REE, while unoxidized L-type coals were formed with the introduction of REE into the coal accumulation basin mainly in the composition of clay minerals and LREE-phosphates. Here the main source of REE was apparently the weathering crust over acidic rocks.
The article presents the results of studying the mineralogical and geochemical features of coals and clay interlayers of the Shubarkol deposit. There were analyzed 71 samples of clay layers and 49 samples of coal using the instrumental neutron activation analysis (INAA), powder X-ray diffractometry, and scanning electron microscopy. A comprehensive analysis of the geochemical and mineralogical characteristics of coals and their enclosing clay interlayers was carried out. A variety of geochemical criteria made it possible to establish the facts of the rare earth elements (REE) migration, and the latest data of mineralogy made it possible to establish the ways of their transportation to the paleobasin in the syn- and epigenetic periods of the Shubarkol deposit formation. The data of the paleoclimate and water composition of the paleobasin of peat formation are presented for the first time. Among other things, the analysis made it possible to identify a number of independent sources and various mechanisms of REE accumulation in the sediments of the Shubarkol deposit. The main patterns of the REE distribution that are expressed in the predominance of light lanthanides over heavy lanthanides, were established, and the role and composition of the rocks surrounding coal deposits in the concentration of REE were considered. Aluminosilicates, sulfides, and sulfates with inclusions of microparticles of rare and rare-earth REE elements were found in coals and clay interlayers.
E d i t o r i n c h i e f ZHURINOV MuratZhurinovich, doctor of chemistry, professor, academician of NAS RK, president of the National Academy of Sciences of the Republic of Kazakhstan, general director of JSC "Institute of fuel, catalysis and electrochemistry named after D.V. Sokolsky» (Almaty, Kazakhstan) H = 4 E d i t o r i a l b o a r d: ABSAMETOV Malis Kudysovich, (deputy editor-in-chief), doctor of geological and mineralogical sciences, professor, academician of NAS RK, director of the Akhmedsafin Institute of hydrogeology and hydrophysics (Almaty, Kazakhstan) H = 2 ZHOLTAEV Geroy Zholtaevich, (deputy editor-in-chief), doctor of geological and mineralogical sciences, professor, director of the institute of geological sciences named after K.I. Satpayev (Almaty, Kazakhstan) Н=2 SNOW Daniel, Ph.D, associate professor, director of the labotatory of water sciences, Nebraska University (Nebraska, USA) H = 32 Zeltman Reymar, Ph.D, head of research department in petrology and mineral deposits in the Earth sciences section of the museum of natural history (London, England) H = 37 PANFILOV Mikhail Borisovich, doctor of technical sciences, professor at the Nancy University (Nancy, France) Н=15 SHEN Ping, Ph.D, deputy director of the Committee for Mining geology of the China geological Society, Fellow of the American association of economic geologists (Beijing, China) H = 25 FISCHER Axel, Ph.D, associate professor, Dresden University of technology (Dresden, Germany) H = 6 KONTOROVICH Aleksey Emilievich, doctor of geological and mineralogical sciences, professor, academician of RAS, Trofimuk Institute of petroleum geology and geophysics SB RAS (Novosibirsk, Russia) H = 19 ABSADYKOV Bakhyt Narikbaevich, doctor of technical sciences, professor, corresponding member of NAS RK, Bekturov Institute of chemical sciences (Almaty, Kazakhstan) H = 5 AGABEKOV Vladimir Enokovich, doctor of chemistry, academician of NAS of Belarus, honorary director of the Institute of chemistry of new materials (Minsk, Belarus) H = 13 KATALIN Stephan, Ph.D, associate professor, Technical university (Dresden, Berlin) H = 20 SEITMURATOVA Eleonora Yusupovna, doctor of geological and mineralogical sciences, professor, corresponding member of NAS RK, head of the laboratory of the Institute of geological sciences named after K.I. Satpayev (Almaty, Kazakhstan) Н=11 SAGINTAYEV Zhanay, Ph.D, associate professor, Nazarbayev University (Nursultan, Kazakhstan) H = 11 FRATTINI Paolo, Ph.D, associate professor, university of Milano-Bicocca (Milan, Italy) H = 28 News of the National Academy of Sciences of the Republic of Kazakhstan. Series of geology and technology sciences.
Purpose. To study the features of the paleotectonic development of the area and to construct paleotectonic reconstruction of the deposit formation to establish the nature of impurity elements accumulation in the coals and enclosing rocks of the Shubarkol deposit, as well as to increase the mineral resource potential of coals. Methodology. 25 samples of coal and mudstone from the Shubarkol deposit were analyzed. The samples were studied by instrumental neutron- activation analysis (INAA) at the Nuclear Geochemical Laboratory of National Research Tomsk Polytechnic University. Findings. An analysis of geological-structural and paleotectonic formation conditions of the Jurassic coal deposit was carried. The factors of formation of coal and carbon-containing rocks enriched with impurity elements and the conditions needed for its leaching and transportation to the coal seam were analyzed. It was found that the coals in individual samples have average concentrations of Ce, Ba, Sr, Sc, Zn that are higher than the clarke, and Sm, Ce, U, Cr, Yb, Ba, Sr, Nd, As, Sc, Zn, Eu, La in the composition of mudstone have average values that are higher than in coals, and higher than the clarke. It was established that one of the sources of rare-metal mineralization of coals (peat) in the Mesozoic and Cenozoic times were the rock massifs of the Kokchetau uplift in the north and northwest, the Kaptyadyr, Arganatinsk and Ulutau mountains in the west. They form the chain of the Kokchetau-North Tien Shan ancient folded structure and the Central Kazakhstan (Devonian) volcanic-plutonic belt in the east. They surround the sedimentation basin and serve as suppliers of clastic material during the coal-bearing strata formation due to tectonic processes of the Mesozoic-Cenozoic time. Originality. The paleotectonic development of the Shubarkol deposit area during the coal-bearing formation has been reconstructed. It has been established that the Sarysu-Teniz uplift in the Permian-Triassic is separated into an independent block, to which the studied deposit is spatially and genetically related. It has been established that the distribution of elements in the coals of the Shubarkol deposit is determined by the peculiarities of metallogeny, geochemistry of the framing area and the mechanisms of the elements entering the coal seams. Practical value. A purposeful analysis of materials for the peculiarities of high concentrations of impurity elements accumulation in coal in connection with deep fault zones at the Shubarkol deposit serves as an objective justification of the possibility of their integrated use, ensuring the development of the countrys coal industry.
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