Review of the Bulgarian Geological Society最新文献

{"title":"Mineralogical characteristics of coal seams Ia, I and IIa from Bobov Dol Basin, SW Bulgaria","authors":"A. Zdravkov, Danail Yovchev","doi":"10.52215/rev.bgs.2024.85.1.71","DOIUrl":"https://doi.org/10.52215/rev.bgs.2024.85.1.71","url":null,"abstract":"The mineralogical composition of Bobov Dol sub-bituminous coals from the lower part of the coal-bearing formation, was studied using optical microscopy, XRD and SEM-EDS analyses. Clay minerals (smectite, illite and kaolinite) and quartz, are the dominant minerals. Their characteristics indicate predominant terrigenous origin and argue for major detrital input from intermediate to mafic rocks. Accessory epigenetic barite-celestine mineralization, substituting almost completely oxidized siderite crystals and spheroidal aggregates, denotes circulation of meteoric aqueous solutions in the absence of other fracture-filing minerals. Finite glass spheres from the top of the coal seam I indicate synchronous volcanic activity, which did not influence peat formation.","PeriodicalId":509487,"journal":{"name":"Review of the Bulgarian Geological Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141691855","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":"Evaluation of geological sites in a park environment for the needs of the Bulgarian geoparks, nature parks, and national parks","authors":"D. Sinnyovsky","doi":"10.52215/rev.bgs.2024.85.1.11","DOIUrl":"https://doi.org/10.52215/rev.bgs.2024.85.1.11","url":null,"abstract":"The experience in the scientific evaluation of geological sites in the Bulgarian geoparks shows insufficient efficiency of the generalized criteria used for the evaluation of geotopes for the purposes of the Register and Cadastre of the Bulgarian geological phenomena. Here is proposes a new assessment methodology freed from some common criteria included in the expert card for national assessment of geosites. It includes the main evaluation criteria of the ‘scientific value’ category (representativeness, integrity, rarity), and ‘additional values’ – scenic/didactic potential, ecological, cultural, and geotourism impact. Due to the fundamentally different themes of the Bulgarian geoparks, the approach of ‘thematic geodiversity’ has been adopted, which defines one major theme expressing the identity of the geopark within its entire territory, and numerous secondary themes complementing the geodiversity of the area. One of the new criteria included in the expert card reflects the relation of a geosite with the main geopark theme and gives priority to outcrops representing key geological features for its understanding. At the same time, the possible identification of global cycles and events of special scientific interest, which can be presented to the general public in an attractive form, predetermines the high numerical indicator of the ‘scientific, research and educational value’. The main purpose of the expert card is to cover as wide a range of geological features as possible and to make the assessment less subjective by using a standard set of criteria against which specific examples can be compared. It is also important to minimize the possibility of interpretation of the explanatory text to the individual indicators. It includes 12 criteria of different weights with 4 to 7 indicators, the numerical expression of which starts from zero, corresponding to a complete lack of geoconservation value. The minimum number of 12 points (of total 48) required to pass the ‘threshold of significance’ is formed by the first six criteria. It provides the necessary rate of superiority over which the site must be considered geologically significant and deserves to be included in the geopark inventory. The scale of significance grades from local (12–20) to regional (21–30), national (31–40), and international (41–48). Geodiversity sites are of great importance for the geopark initiatives, so the weight of the ‘scenic (aesthetic) value’ corresponds to the weight of the ‘scientific, research and educational value’ (6) versus (3) or (4) of the other criteria to better reflect their geotourism significance. Geosites with high interpretive potential, especially where the relationship between geology and human history/culture/spirituality can be demonstrated, should also be prioritized for inclusion in the geopark list.","PeriodicalId":509487,"journal":{"name":"Review of the Bulgarian Geological Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141698717","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":"Preliminary petrographic assessment of the suitability of Bobov Dol coals, \u0000SW Bulgaria for fluidized-bed coal gasification","authors":"A. Zdravkov, Doris Groβ, D. Životić, Ivan Kojić, K. Stojanović, Achim Bechtel","doi":"10.52215/rev.bgs.2024.85.1.79","DOIUrl":"https://doi.org/10.52215/rev.bgs.2024.85.1.79","url":null,"abstract":"Coal samples from seams Ia, I, IIa+b, III, IV, and V from the Bobov Dol deposit in SW Bulgaria were studied using optical microscopy and proximate analysis in order to determine their suitability for fluidized-bed gasification. The moderate- to high seam averaged ash yields and the huminite reflectance values in the range 0.43–0.5 classify the studied coals as medium- to very low grade, low-rank A (sub-bituminous) according to the International classification of in-seam coals. Based on the organic composition and ash yields, the coals from seams IIa+b, III, IV, and V seem more suitable for fluidized-bed gasification, but their usefulness will depend largely on the coal pre-processing.","PeriodicalId":509487,"journal":{"name":"Review of the Bulgarian Geological Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141693611","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":"Insights into floral and climatic changes from biomarker and isotopic composition of land plant organic matter – A review","authors":"Achim Bechtel, Doris Groß","doi":"10.52215/rev.bgs.2024.85.1.67","DOIUrl":"https://doi.org/10.52215/rev.bgs.2024.85.1.67","url":null,"abstract":"Biomarkers and isotopic composition of coal and plant tissue enable insights into floral assemblage and paleoenvironment. Abundance, distribution, and d13C values of leaf wax lipids (i.e. n-alkanes) differ between angiosperm and gymnosperm plants. Terpenoid hydrocarbons are used to assess the contributions of gymnosperms versus angiosperms. The influence of varying contributions of angiosperms and gymnosperms on d13C of coal can be overcome by the analyses of fossil wood remains for their isotopic composition. Angiosperms and gymnosperms show similar H-isotope fractionation between n-alkanes and water. Diterpenoids yield lower d2H values compared to angiosperm-derived triterpenoids, due to different biosynthetic pathways. Differences in mean annual precipitation affect d13C of bulk leaf organic matter. Co-variations in d13C and d2H of lipids reflect changes in water availability to the plants. Temperature variations, based on branched glycerol dialkyl glycerol tetraethers (brGDGTs), and d2H values of n-C29 alkane from Lake Van sediments reveal warm-humid climate during interglacials and cooler and drier climate during glacials. Based on the methylation of brGDGTs, a calibrated paleothermometer is available for peats and lignites.","PeriodicalId":509487,"journal":{"name":"Review of the Bulgarian Geological Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141711064","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":"Organic petrography and biomarker proxies of subbituminous coal from the Dubrava field (Aleksinac Basin, Serbia)","authors":"Ivan Kojić, Željana Novković, K. Stojanović, D. Životić, Achim Bechtel, R. Sachsenhofer","doi":"10.52215/rev.bgs.2024.85.1.53","DOIUrl":"https://doi.org/10.52215/rev.bgs.2024.85.1.53","url":null,"abstract":"A comprehensive petrographic and biomarker study has been performed to evaluate sources, paleoenvironment and maturity of organic matter (OM) in coal samples taken from the borehole BD-4 in the Dubrava block (Aleksinac Basin, Serbia). Studied samples are dominated by vitrinite group macerals, with variable content of liptinite and very low amount of inertinite. The measured random vitrinite reflectance, Rock Eval data and biomarker assemblages confirmed subbituminous rank of coal. The OM is at the late diagenetic and early catagenetic stage. Contents of total organic carbon and mineral matter vary in wide range, indicating frequent changes of depositional settings. Content of sulphur is moderate to very high. The main sources of OM in Aleksinac coal were angiosperms, ferns and aquatic macrophytes, with subordinate contribution of conifer paleovegetation. Diagenetic alteration of OM was governed by methanotrophic bacteria and chemoautotrophic bacteria. Deposition of OM occurred in a low-lying mire environment, showing decreasing concentration of sulphate ions upward the borehole BD-4. The coal deposition was terminated by rise of water level, which led to drowning of the mire and transition to lacustrine environment.","PeriodicalId":509487,"journal":{"name":"Review of the Bulgarian Geological Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141689061","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":"Organic petrology as a tool for peat-forming environmental reconstructions: insights from Suhostrel and Bobov Dol coals, SW Bulgaria","authors":"A. Zdravkov, Doris Groβ, D. Životić, Ivan Kojić, K. Stojanović, Achim Bechtel","doi":"10.52215/rev.bgs.2024.85.1.41","DOIUrl":"https://doi.org/10.52215/rev.bgs.2024.85.1.41","url":null,"abstract":"The petrographic composition of samples from Suhostrel and Bobov Dol coal deposits was studied using optical micro­scopy. The maceral contents were further used to calculate maceral ratios which were interpreted in terms of environmental condition during peat deposition. Petrographic data of Suhostrel coal is compatible with its organic geochemical characteristics and indicate peat formation under inundated topogenous, meso- to rheotropic, sparsely forested marsh- or fen-type environment. Coal facies diagrams for Bobov Dol coal, however, provide contradictory depositional settings and therefore cannot be used alone for environmental reconstruction.","PeriodicalId":509487,"journal":{"name":"Review of the Bulgarian Geological Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141706571","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":"An Overview of Humus state in reclaimed lands, Bulgaria. Bulgarian experience in Wales, UK","authors":"Ekaterina Filcheva","doi":"10.52215/rev.bgs.2024.85.1.35","DOIUrl":"https://doi.org/10.52215/rev.bgs.2024.85.1.35","url":null,"abstract":"Soil forming process is accompanied by the accumulation of organic matter. Soil organic matter is an important component of soil physical characteristics, physico-chemical characteristics, formation of organo-mineral complexes for natural soils and determines soil fertility. All over the world large territories are disturbed after open-cast and underground coal mining processes demand biological land reclamation. Worldwide, forestation with different tree species and grasses are well known approaches and practices. Knowledge and experience on soil forming processes and humus formation in the initial stage clarify the direction and intensity of these important processes in land reclamation. Content of organic carbon and organic matter composition for different test plots of reclaimed lands in “Maritsa Iztok” JSCo and Pernik coal basin is discussed. Information on the land reclamation with zeolite materials in “Maritsa Iztok” JSCo is presented. Data on the Bulgarian experience of afforestation in Wales, UK is described.","PeriodicalId":509487,"journal":{"name":"Review of the Bulgarian Geological Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141708545","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":"Pyrolysis of Maritsa Iztok lignite lithotypes: geochemical implication","authors":"M. Stefanova, S. Marinov, Z. Milakovska, J. Czech, R. Carleer, J. Yperman","doi":"10.52215/rev.bgs.2024.85.1.47","DOIUrl":"https://doi.org/10.52215/rev.bgs.2024.85.1.47","url":null,"abstract":"Pyrolysis coupled “off-line” with thermal desorption gas chromatography–mass spectrometry (TD-GC/MS) instrument for flue gas analysis is used to specify qualitatively/quantitatively organic functionalities in “Maritsa-Iztok” lignite lithotypes thermal decomposed in the range 250–900 °C. The aim of the study is to specify organic volatiles and to assign identified components to the lignocellulose biomass building blocks of coal forming vegetation. In pyrolysates the total amounts of the analyzed organics, expressed in mg/g TOC, amount up to 58.14 for liptain, 21–37 for humoclarain and xylain, and the lowest values are determined for humovitrain, 12. The samples immaturity reflects in high diversity of phenols, methoxy phenols (only guaiacyl structures), furans, etc. maximizing at xylain lithotype, 68% of the total analyzed amount. Carbohydrate degradation products, i.e. furaldehydes, 2-cyclopenten-1-ones, etc. are identified as well. In lithotypes studied, coal biomarkers as n-alkene/n-alkanes, sesqui-, di-, polar diterpenoids and hopenes/hopanes, are present in different proportions.","PeriodicalId":509487,"journal":{"name":"Review of the Bulgarian Geological Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141693646","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":"Gemological study of faceted jewelry minerals from the Museum of Mineralogy, Petrography, and Resources at the University of Mining and Geology “St. Ivan Rilski” Sofia","authors":"Nikoleta Tzankova, Radostin Pazderov","doi":"10.52215/rev.bgs.2024.85.1.3","DOIUrl":"https://doi.org/10.52215/rev.bgs.2024.85.1.3","url":null,"abstract":"Selected samples from the main gemological exposition in the Museum of Mineralogy, Petrography, and Resources at the University of Mining and Geology “St. Iv. Rilski” were analyzed using standard gemological equipment such as a refractometer, polariscope with conoscopic lens, diffraction grating spectroscope, dichroscope, Hanneman gem filter set, and 10x triplet magnification loupe. This study aimed to identify and characterize mineral varieties for their gemological quality and processing. The identified mineral varieties include almandines, almandine-spessartine, aquamarines, rubellites, spinel-red, blue sapphires, olivines, and seventy-three corundums of different colors and sizes. These results aid in classifying the studied samples and contribute to the existing database for each of them.","PeriodicalId":509487,"journal":{"name":"Review of the Bulgarian Geological Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141057688","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":"Morphological and chemical characteristics of amphibole crystals in desilicated pegmatites, Rila Mountain, SW Bulgaria","authors":"Martin Dimitrov, B. Banushev, S. Pristavova","doi":"10.52215/rev.bgs.2023.84.3.19","DOIUrl":"https://doi.org/10.52215/rev.bgs.2023.84.3.19","url":null,"abstract":"The desilicated pegmatites from the area of the Urdini lakes, Northwest Rila Mountain intersect ultramafic bodies, occurring among high-grade metamorphic basement of the Rila-Rhodope batholith. The following rock-forming minerals are characteristic – plagioclase (mainly oligoclase), phlogopite, amphibole, actinolite, tremolite, anthophyllite, chlorite and others. Minerals from the amphibole supergroup are studied using optical, X-ray diffraction, X-ray spectral and chemical methods. Their morphology and crystal chemistry are characterized as well as their classification and nomenclature position are determined. Actinolite, tremolite, anthophyllite and Mg-hornblende from the amphibole supergroup are identified. The trends and variations in the chemical composition at their central and peripheral sections have been clarified.","PeriodicalId":509487,"journal":{"name":"Review of the Bulgarian Geological Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139191424","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}