Geology and Geochemistry of Combustible Minerals最新文献

{"title":"Clay minerals from rock salt of Bahadur Khel Formation, Eocene, Pakistan","authors":"Y. Yaremchuk, S. Vovnyuk, M. Tariq","doi":"10.15407/GGCM2020.01.087","DOIUrl":"https://doi.org/10.15407/GGCM2020.01.087","url":null,"abstract":"According to studies of the pelitic fraction of the water-insoluble residue of 10 samples of Eocene rock salt of the Bahadur Khel Formation (Pakistan), it was determined that the clay minerals association contains swelling chlorite, chlorite-smectite, illite and kaolinite; chlorite was identified in three samples. Non-clay minerals are represented by quartz, dolomite, less often – magnesite; one sample contains impurities of both carbonates. Swelling chlorite, chlorite and mixed-layer minerals are trioctahedral, and illite and kaolinite are dioctahedral. All identified clay minerals, with the exception of kaolinite, are authigenic. The presence of swelling chlorite in Eocene rock salt is probably caused by changes in the concentration of brines in the basin against the background of complex geological processes of this era (climate change from thermal maximum to global cooling, changes in water circulation in oceans, changes in isotopic composition of carbonates). The association of clay minerals of Eocene rock salt, taking into account the peculiarities of its composition and the presence of swelling chlorite in it, we attributed to that formed during the SO4-rich seawater chemical type. This is also confirmed by two finds of swelling chlorite in the Triassic evaporites (rock salt of the Western Moroccan Basin, Midland marl) described in the literature, which are known to have been deposited from SO4-rich seawater. The presence of kaolinite in almost all samples is caused by its largest accumulation in sediments of this time period – terrigenous kaolinite came in large quantities from dry land and did not transform even at the stage halite precipitation. Full Text Keywords clay minerals, swelling chlorite, rock salt, Eocene, Bahadur Khel Salt, Pakistan.","PeriodicalId":176324,"journal":{"name":"Geology and Geochemistry of Combustible Minerals","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125165723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithological-geochemical types of deposits of Cretaceous-Paleogene flysch of the Ukrainian Carpathians and conditions of their formaition","authors":"I. Popp, Petro Moroz, M. Shapovalov","doi":"10.15407/ggcm2019.04.116","DOIUrl":"https://doi.org/10.15407/ggcm2019.04.116","url":null,"abstract":"The results of lithological, mineralogical and geochemical investigation of Cretaceous-Paleogene flysch deposits of the Ukrainian Carpathians are cited here. There are three main lithological-geochemical types of these deposits which differ in the composition of rock-forming ingredients of biogenic origin (SiO2 biog, CaCO3, Corg): grey limestone-clayey-terrigenous (type-I), non-carbonate or low-carbonate-clayey-terrigenous (type-II), and black carbonate-silica-terrigenous-clayey (type-III). The deposits of the first type are attributed to alkaline-oxic (oxic-calcitic), the second – to acid and low-alcaline oxic (oxic with redeposited glauconite), the third – to reducing (siderite, dolomite or ferrodolomite and low-reducing calcitic) and strong by reducing (primary-sulfidic or hydrogen sulfidic) mineralogical-geochemical facies. The forming of the Barremian-Albian (Shypot suite; Spas suite) and Oligocene (Menilite suite; Dusynska suite) organic-rich sediments in the Ukrainian Carpathians we associate with the phase of oceanic anoxic events OAE-1 and OAE-4 in the Carpathian segment of the Tethys, where anoxic reducing environments favoured to fossilization of huge amount of the dispersed organic matter. The structural-fabric features and composition of separate lithological types of silicites and diagenetic concretions of the Lower Cretaceous and Oligocene of the Ukrainian Carpathians show that their sedimentogenesis and diagenesis took place in conditions of strong oxygen deficit. The studied siliceous rocks can be considered as indicators of the anoxic events in the Carpathian segment of Tethys ocean. It is shown, that alcaline-reducting environments which was the most favourable for the diagenetic transformation of sedimentary organic matter in to petroleum hydrocarbons, prevailed in the organic-rich deposits of Oligocene age.","PeriodicalId":176324,"journal":{"name":"Geology and Geochemistry of Combustible Minerals","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133368695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PROSPECTS FOR OIL AND GAS PRESENCE IN THE SOUTH-EASTERN PART OF THE INNER FLYSCH COVERS OF THE UKRAINIAN CARPATHIANS","authors":"M. Pavlyuk, V.Ye. Shlapinsky, O. Savchak, Myroslav Ternavsky, Lyubov Huzarska, Nazar Triska, Nataliia Ohrenda","doi":"10.15407/ggcm2019.04.005","DOIUrl":"https://doi.org/10.15407/ggcm2019.04.005","url":null,"abstract":"We have studied the Cretaceous and Paleogene flysch of the Duklya-Chornohora, Burkut, Rakhiv, Marmarosh and Pieniny covers that in the south-eastern sector of the Ukrainian Carpathians near the Romanian border (Hutsulian segment) distinguish themselves by very inclined overthrust. Spatially the given tectonic units are in so-called hydrothermal fluid, unfavourable on the whole as to the presence of hydrocarbons in it on a large scale. But, within its limits the plots, small in area, with hydrocarbon prevalence in the gas composition are distinguished. Prospects for gas presence in the region should be connected with those of them that spatially are drown to the Transcarpathian trough. One such section is the Velikobychkovk sector of the Monastyretsky sub-cover, where it is proposed to lay a parametric well 1-Velikiy Bychkov, in order to reveal the possible para-autochthon of the Vezhany sub-cover and the Paleogene of the Dilovetsky sub-cover. In addition, according to seismic data, a significant rise in the pre-flysch base is forecast in this section of the Carpathians under the Marmarosh cover. The roof of this foundation at the location of the recommended well 1-Velikiy Bychkov may be at a depth of 5000–5500 m. It may be represented by the youngest deposits of the pre-Alpine complex – the Triassic strata, industrially oil and gas saturated in the neighboring countries.","PeriodicalId":176324,"journal":{"name":"Geology and Geochemistry of Combustible Minerals","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134413803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geological-petrophysical characteristic of Silurian deposits of the Volyn-Podillya edge of the East-European Platform","authors":"I. Kurovets, Y. Lysak, P. Chepusenko, Stepan Mykhalchuk, Roman-Danylo Kucher","doi":"10.15407/ggcm2019.04.017","DOIUrl":"https://doi.org/10.15407/ggcm2019.04.017","url":null,"abstract":"Taking into consideration well logging of the Silurian deposits of the Volyn-Podillya plate, the materials of laboratory investigations of petrophysical parameters of reservoir rocks were analyzed and systematized. Studied were capacity-filtration properties of reservoir rocks as well as their lithological-petrographical and structural-textural features. An analysis of the distribution of petrophysical parameters of the Silurian deposits of the Volyn-Podillya plate was executed by the methods of mathematic statistics. Main statistics and correlation coefficients between individual parameters were calculated, histograms of the distribution of the porosity factor Kpor and the permeability factor Kper, volumetric weight δ and carbonation C in rocks were compiled, regression equations between parameters and their alteration with depth were formed. Petrophysical parameters of the samples available for carbonate and terrigenous rocks of Silurian were analyzed separately. Executed investigations of petrophysical properties of rocks testify that in the Silurian deposits the carbonate reservoirs with the complex structure of the porous space were distributed. A visible alteration of capacity-filtration parameters of rocks of Silurian deposits is observed with depth. Porosity of rocks decreases with depth, but permeability increases that is a confirmation of the formation of the secondary fractured-covernous porosity. Increase in the permeability factor with depth is characteristic of carbonate rocks. According to geological-geophysical data available, the reservoir rocks with better capacity-filtration properties are distributed in the zone of the barrier reef. The best reservoir parameters are characteristic of cavernous dolomites and limestones at the Lokachy area and in the region of Lutsk. Reservoir rocks of porous type are practically absent at depths over 2500 m. Here a significant role in improving of collecting properties of rocks belongs to their fracturing. Microfractures are observed in clayed limestones, marls and clay rocks. Under favourable geodynamic conditions the subvertical zones of disconsolidation occur in which composite reservoir rocks with fracture porosity may be formed.","PeriodicalId":176324,"journal":{"name":"Geology and Geochemistry of Combustible Minerals","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128952202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Equilibrium temperatures of hydrocarbon gas formation in sedimentary strata of the Western oil and gas region of Ukraine (according to thermodynamic modelling)","authors":"Y. Khokha, M. Yakovenko, O. Lyubchak, Dmytro Bryk","doi":"10.15407/ggcm2019.04.066","DOIUrl":"https://doi.org/10.15407/ggcm2019.04.066","url":null,"abstract":"The article reviews the question of interpretation of natural gases component composition from the aspect of their evolution. The parameters available for study, which show a strong correlation with the conditions of formation, migration and accumulation of natural hydrocarbon gases, are selected. Among these parameters, the ratio of the butanes isomeric form (i-C4/n-C4) was selected for thermodynamic analysis as a dependable indicator of the kerogen degradations temperature regime. It is shown that the dependence of the i-C4/n-C4 ratio on the normalized methane content shows the trend of increasing kerogen maturity, and deviations from this trend indicate a distant migration of hydrocarbon fluid from the formation zone to the current deposit. Analysis of the residence and thermodynamic conditions of hydrocarbons in the deposits of the Western oil and gas region showed that kerogen/gas systems are in a state close to equilibrium, in terms of thermodynamics. The composition of the gas/kerogen equilibrium system in the conditions of sedimentary thickness for two heat fluxes – 75 and 100 mW/m2 was calculated by the method based on Jaynes’s formalism. Among hydrocarbons in gases, the content of isomeric forms of butane and pentane, as well as methane, ethane and propane was calculated. The results of the calculations revealed a monotonic dependence of the equilibrium temperature and depth of formation on the ratio of isobutane to n-butane. It was found that the results of thermodynamic calculations coincide with experiments on kerosene pyrolysis and correlate with studies of the composition and residence of natural gases. Equilibrium formation temperatures were determined for 59 gas, oil and gas condensate fields of the Western oil and gas region, the information on which contained data on the i-C4/n-C4 ratio. Based on the results of calculations, maps of these temperatures distribution within the region were constructed. The analysis of the maps showed the presence of two distinct temperature maxima, which are concentrated in the Boryslav-Pokuttya oil and gas region and are located at the intersection of regional faults. It has been suggested that the hydrocarbon source is significantly distant from modern deposits for the study region. The results of the calculation are compared with the data obtained using the model of fossil hydrocarbons inorganic origin.","PeriodicalId":176324,"journal":{"name":"Geology and Geochemistry of Combustible Minerals","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115013526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Technogenic carbonaceous objects of the Chervonohrad mining and industrial district and some technical solutions for their using","authors":"Dmytro Bryk, Oleg Gvozdevych, Lesya KULCHYTSKA-ZHYHAYLO, Myroslav Podolskyy","doi":"10.15407/ggcm2019.04.045","DOIUrl":"https://doi.org/10.15407/ggcm2019.04.045","url":null,"abstract":"Ukraine has significant coal resources. Chervonohrad Mining and Industrial District is the main coal complex in the west of Ukraine. In recent years, the average annual coal production in the mines of Chervonohrad Mining and Industrial District has amounted to 1.5 bn t, coal ash varies over a wide range of 25 to 53 %, average coal ash content of about 40 %. Coal mining has produced millions of tons of coal waste every year. Concentration of technogeneous coal objects (mines, mining infrastructure, coal-mining waste dumps and wastes of coal enrichment) in a relatively small area has caused environmental degradation. Therefore, technological and environmental aspects of carbon-containing technogenic objects are particularly important and actual. Coal-waste dumps in the territory of Chervonohrad Mining and Industrial District are characterized in detail. The dumps cover different areas – from 9–10 to 29–30 ha, the height of the dumps reaches 62 m at the mostly heights of 25–40 m. The total waste deposit in the dumps of existing mines has a volume of more than 20 million m3. The coal wastes from Mezhyrichanskaya mine coal-waste dump was investigated to determine the suitability for thermochemical processing. Technical characteristics of taken coal-waster samples is presented. The technogenic carbonaceous objects and the impact to the environment are evaluated. The developed and patented technical and technological solutions for the technogenic carbonaceous objects using are considered. It is shown that the concept of industrial development of coal wastes dumps is based on two aspects – extraction of valuable mineral components and energy utilization of carbonaceous wastes of coal production. Its patented as Patents of Ukraine technological schemes for terrestrial process in of solid carbonaceous raw material from dumps and sludges with the production of coal tar and synthesis gas CO + H2 are presented, as well as the scheme of a system for utilization of heat from coal dump. Recommendations for the implementation of innovative technologies are based on the results of the laboratory research. The purpose of the resolution is to obtain valuable components and energy from coal wasters while improving the environment.","PeriodicalId":176324,"journal":{"name":"Geology and Geochemistry of Combustible Minerals","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114387217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bowels of the earth – natural physical-chemical reactor: is the search for natural methane a fundamental science or a technical problem?","authors":"Yo.M. Svoren","doi":"10.15407/ggcm2019.04.104","DOIUrl":"https://doi.org/10.15407/ggcm2019.04.104","url":null,"abstract":"It is shown that the hypothesis of organic origin of hydrocarbons doesn’t respond to the presence of a dominant concentration of methane in sediments, deposits, “shale’ series and so on, hence prospecting and exploration for hydrocarbon deposits in them are conducted in most cases intuitively, but not on the fundamental scientific basis. Experimental studies based on the heating of slightly modified organic matter (peat) show that up to 200 °C in the process of its decomposition the following gases were delivered (vol. %): CO2 = 49.5; H2O = 49.3; CH4, C2H6, C3H8, N2, H2, SO2, H2S within 1.2 % in total. It is confirmed that there is no coal methane, there is no shale gas-methane, but there is methane of one genesis with slightly different isotope composition of carbon, but synthesized according to the same mechanism in the high-thermobaric processes that after migration into the earth’s crust accumulated in the form of deposits in cavities of coal seams, terrigenous units, sandstones and so on. Prospecting for pool-deposits of hydrocarbons should be carried out in conformity with developed “new technology of determination of prospects for oil and gas presence in the local area”, “physical-chemical model of synthesis of hydrocarbons and the way of geochemical searching for their occurrences”, “new theory of hydrocarbon synthesis and genesis in the earth’s lithosphere: abiogenic-biogenic dualism”.","PeriodicalId":176324,"journal":{"name":"Geology and Geochemistry of Combustible Minerals","volume":"854 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126965198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Сollision deformations of the Dnieper-Donets Depression. Article 2. Kinematic mechanisms of tectonic inversion","authors":"Оleksiy Bartashchuk","doi":"10.15407/ggcm2019.04.032","DOIUrl":"https://doi.org/10.15407/ggcm2019.04.032","url":null,"abstract":"The second article is devoted to the investigation of the natural mechanisms of tectonic inversion of the Dnieper-Donets depression. Using the materials of geological mapping of the territory of the West-Donetsk graben, structural proofs of the destruction of the riftogenic structure by collision tectonic movements of Hercinian and Alpic tectogenesis were obtained. The consequence of the inversion deformations is the formation of the West Donets cover-folding tectonic region within the Lugansk-Komyshuvasky tectonic area of the uplift-folding and the Kalmius-Toretsky region of the scalloped thrust covers, which are divided by the Main anticline. For the diagnosis of kinematic mechanisms of tectonic inversion, the data of reconstruction of tectonic stress fields and quantitative modeling of deformations of the southern outskirts of the Eastern European Platform were used. It is assumed that the tectonic inversion of the Dnieper-Donets basin began in the Zaal and Pfalz phases of orogenesis due to the collision motions of the compression orogen at the outskirts of Paleotetis. The formation of linear folding occurred in the uplifting-thrust mode in the field of stresses of the oblique left-hand compression of the sub-meridional directions. The kinematic mechanism of the folded deformations determined the longitudinal bending of the layers due to the extrusion of sedimentary geomas from the zone of maximum compression in the axial part to the zones of “geodynamic shadow” – in the direction of the sides of the depression. In the late Mesozoic and Cenozoic, uplifting-thrust and strike-slip stresses formed echeloned cover-thrust and coulisse-jointed uplift-folded structural paragenesis. According to the results of tectonophysical diagnostics of deformation structures, it was found that under geodynamic conditions of clustering of compression axes in the central part of the West-Donets graben against the reduction of the geological space horizontally and extension of the section due to the formation of the cover-folded allochthon, there were flexural deformations of the primary linear Hercinian folded forms. Such data can be considered as a kinematic mechanism of tectonic inversion of the invasion of the “tectonic stamp” by the Donets folded structure. Under its influence, the wedge-shaped segment of the tectonic thrust, which was diagnosed by the orcline of the transverse extension of the shallow type, was formed by the repeatedly deposited folds of sedimentary geomas in the articulation zone between the depression and the folded structure. In the front of the thrusted were formed folded zones of extrusion of geomas, which consist of coulisse-jointed uplift-anticlines and folded plates-coverings of tectonic thrusted. At the apex of the orocline, at the end of the dynamically coupled main thrusts, an advanced tectonic fan of compression is formed. In the rearward of the oraclline formed sutures – the roots of folded cover.","PeriodicalId":176324,"journal":{"name":"Geology and Geochemistry of Combustible Minerals","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132421009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On content, migration and concentration of heavy metals in oils (by the example of the Dnieper-Donets Depression)","authors":"A. Yerofieiev, I. Berezovsky","doi":"10.15407/ggcm2019.04.096","DOIUrl":"https://doi.org/10.15407/ggcm2019.04.096","url":null,"abstract":"Literature review and analysis of previous studies of the problem was carried. The main scientific works on the research topic, as well as the main directions and stages of the study are indicated. Similar studies that were conducted on the territory of Ukraine are considered. The results of the study of heavy metals in oil samples taken from a large oil and gas region from more than thirty deposits of Ukraine are presented. All current and non-working fields are considered. The geological structure of the oil and gas province, as well as the main geochemical features of the formation of mineral deposits are considered. The main forms of finding target metals, as well as possible ways of transferring these elements in the earth’s crust are given. Samples were investigated using x-ray fluorescence and neutron activation analysis. The obtained research data in the framework of two selected methods are combined for analysis. The results obtained within the same geological structure are compared with each other to determine the effect of the physical conditions of sediment formation on the microcomponent composition of crude oil. They also compared the effect of physical conditions on the properties of oil and their ability to accumulate heavy metals. Possible causes of the abnormal accumulation of heavy metals due to the close occurrence of oil and formation water are noted. According to the results obtained, a graph is constructed of the dependence of the mineralization of oil on its depth. An exponential graphical approximation is presented to display the general trend of dependence. Possible sources and ways of migration and accumulation of heavy metals in hydrocarbons are analyzed. The concept of the migration of heavy metals in oil is proposed in conjunction with the ore mineralization of adjacent and adjacent deposits. Possible causes of differences in the concentrations of heavy metals in oil of various geological structures are indicated, as well as the main possible causes of measurement errors and complications in the selection of each of the analysis methods are specified.","PeriodicalId":176324,"journal":{"name":"Geology and Geochemistry of Combustible Minerals","volume":"366 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124593730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Peculiarities of chemical composition of Early Paleozoic seawater (study of fluid inclusions in halite of Ordovician Ordos salt basin, China)","authors":"A. Galamay, F. Meng, D. Sydor, Yongsheng Zhang","doi":"10.15407/ggcm2019.04.078","DOIUrl":"https://doi.org/10.15407/ggcm2019.04.078","url":null,"abstract":"The fluid inclusions in the marine Middle Ordovician halite of the Majiagou Salt Formation of the Ordos Basin (China) have been investigated. In addition to the primary inclusions the secondary ones of several generations were also detected. The fluid inclusions brine chemistry of halite was studied using an ultramicrochemical (UMCA) method, and the homogenization temperature of fluid inclusions was determined in a special thermal chamber designed by V. A. Kalyuzhny At the post-sedimentation stage, the studied salt strata were exposed to high temperature (58–72 °C) and high (up to several tens of MPa) pressure. Although there are opinions of the inability of primary inclusions in such halite to determine the physical and chemical conditions of sedimentation, however, the informative value of primary inclusions in halite of the Majiagou Formation has remained. The preservation of the integrity (and thus the informative value) of primary inclusions in halite is evidenced by the same chemistry of their brines, which differs from that of secondary inclusions The sedimentation brines of the basin were concentrated to the middle of halite stage and points to the Na-K-Mg-Ca-Cl seawater. The physical and chemical conditions of evaporites formation are not known enough. Currently, the results of the brine chemistry of primary fluid inclusions in marine halite are the best indicators of seawater composition in the Phanerozoic. It is established that the magnesium content in the brines of the Lower Paleozoic basins is lower comparing to modern seawater of the corresponding concentration, and the potassium ion concentration is higher. The chemical composition of the concentrated seawater from which the halite was crystallized in the Ordovician salt basin of Ordos, with the exception of the calcium ion content, is similar to the seawater chemistry of the Cambrian and Silurian basins, which indicates the relative constancy of Early Paleozoic seawater chemistry. Age-related changes in the chemical composition of seawater are always consistent with many quantitatively or qualitatively characterized processes of the Earth’s crust evolution. So we believe that the causes that led to more than twice the potassium content of Riphean-Devonian clays, unlike the younger ones, it were also the reason for the increase in potassium content in the Lower Paleozoic marine brines. The studies conducted also clarify the limits of oscillation of calcium ion content, which determines the type of seawater. Its content in the sedimentary brines of the Ordos basin of the Middle Ordovician reaches 66 g/l at the middle of halite stage. Therefore, at the beginning of the stage of halite precipitation, its content should be approximately 20 g/l (considering its theoretical content of 10 g/l with the modern composition of the atmosphere). Apparently, the cause of the abnormally high calcium content in the early Paleozoic Ocean was the direct flow of it with hydrothermal solutions into t","PeriodicalId":176324,"journal":{"name":"Geology and Geochemistry of Combustible Minerals","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121497165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}