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Fifty-four coal clast samples in the siliciclastic rocks (e.g., sandstone and conglomerate) were collected from cores of two-deep research wells (K20H and K20K) drilled at the Kozlu coalfield in Zonguldak Basin, and for the first time, they were evaluated using mineralogy by XRD and SEMEDX and random vitrinite reflectance (%Rr) measurements in order to find out their origin and timing. Petrographic observations on polish surfaces show that the coal clasts are either entirely xylitic/vitrinitic particles or coals including a broader range of macerals. The detected minerals in the samples are mostly derived from the parental coal seams and, to a lesser extent, precipitated from penetrated pore-water in the cleats/fractures of clasts. The %Rr values of coal clasts in Carboniferous sediments are generally relatively higher than those measured in the coal seams due to weak oxidation during transportation. Furthermore, similar mineralogical and maceral compositions between coal clasts and coal seams imply that these clasts were mainly eroded during the peatification and/or early coalification of parental seams and display similar coalification patterns. The close %Rr value of a coal clast sample in the Early Aptian Zonguldak Formation and Carboniferous coal seams could suggest that this coal clast sample is presumably derived from the coal seams eroded during Early Aptian. [ABSTRACT FROM AUTHOR]

The Bozburun coalfield hosts a late Miocene 1.1 m thick coal seam. This study aims to determine coal quality, mineralogy, petrography and geochemistry, and controlling factors of elemental enrichments. The coals are generally black and greyish black in colour, and the low part of the seam commonly includes fossil shell remains. The ash yield displays a decreasing trend towards the upper part of the seam; in turn, gross calorific and total C values increase upwards. The total S content being generally higher than 5% (on dry basis), displays an increasing trend towards the upper part. In the entire seam, huminite is the most common maceral group, while inertinite and liptinite display variable proportions. The identified minerals by XRD are mainly quartz, clay minerals, calcite, pyrite, and aragonite (in fossil shell remains-bearing samples), whereas feldspars and marcasite determined in a few samples. Furthermore, in the coal samples, celestine and barite were identified by SEM-EDX. This study indicates that precipitation of celestine and Sr-bearing barite grains during diagenetic stage and Sr-uptake by mollusc within the palaeomire caused Sr enrichment in the entire seam. Overall, the water influx and redox conditions controlled the mineralogical and the elemental compositions of the coal seam. [ABSTRACT FROM AUTHOR]

This study reveals the hydrocarbon production potential and thermal maturity of Çilhoroz coals, which is the most important local coal field around Erzincan in the Eastern Anatolia Region. This area is one of the best examples of the continental collision zone in the world and is located in a north-south convergent collision zone between the Eurasian and Arabian Plates. The average thickness of the coal seam is about 4 m and these coals are currently mined by open pit mining methods. Coal is predominated by combined xylitic/attrital lithotypes and by huminite macerals with inertinite and minor liptinite macerals. The content of mineral matter is variable but generally low, it consists mostly of quartz, calcite, clay minerals, and pyrite. Although the Rock-Eval pyrolysis data show that the investigated coal bearing unit is represented by a significant hydrocarbon (oil and gas) potential, hydrocarbon species did not develop due to low maturation. [ABSTRACT FROM AUTHOR]

With this study, the hydrocarbon generation potential of Miocene aged coals around Arguvan-Parçikan in the northern district of Malatya province was evaluated with the aid of petrological and organic geochemical data. According to organic petrography, coal quality data, and low thermal maturity, the Arguvan-Parçikan coals are of high-ash, high-sulfur subbituminous B/C rank. The organic fraction of the coals is mostly comprised of humic group macerals, with small percentages derived from the inertinite and liptinite groups. The mineral matter of the coals is comprised mainly of calcite and clay minerals. The total organic carbon (TOC, wt%) values of the shale and coal samples are between 2.61 wt% and 43.02 wt%, and the hydrogen index values are between 73 and 229 mg HC/g TOC. Pyrolysis (Tmax, PI), huminite/vitrinite reflectance (Ro, %), and biomarker ratios (CPI, Pr/Ph ratio, Ts/(Ts + Tm) ratio, C32 homohopane ratio (22S/22S + 22R) and C29ββ/(ββ + αα sterane ratio) indicate that the organic matter of the studied coals is thermally immature. When all these data are taken together, Miocene aged coals around Arguvan are suitable for hydrocarbon generation, especially gas, in terms of organic matter type (Type III and Type II/III mixed), organic matter amount (> 10 wt% TOC), however, low liptinitic macerals (< 15%–20%), low hydrogen index (< 200 mg HC/g TOC) and low thermal maturity values inhibit the hyrocarbon generation. [ABSTRACT FROM AUTHOR]

Coal channel samples of Middle Miocene age are collected from the first (Tv) and second (Tb) seams from underground mines and from exploration boreholes within the Çayirhan coal field in the Beypazari Basin (Turkey). They are investigated in order to detect spatial and temporal changes in maceral and molecular composition of coal and to relate them to changes in vegetation and depositional environment. The mean random reflectance values of ulminite (0.40% Rr) indicate a lignite to subbituminous-C coal in rank. Maceral composition and biomarker ratios of the samples from both seams at the Çayirhan deposit argue for coal formation in a limno-telmatic environment under dysoxic to anoxic conditions. Alkaline surface waters of changing pH-values and a high and unstable water level at the palaeomire are evidenced by moderate to high gelification index (GI) and ground water influence (GWI) values, as well as high sulphur contents. Variations in tissue preservation index (TPI) and vegetation index (VI) values point to minor variations in the palaeovegetation during peat formation. Herbaceous plants dominated in both Tb and Tv palaeomires (low TPI and VI values), whereas in the surroundings arboreal vegetation were predominant. The decreasing trends in pristane/phytane ratios and carbon preference index (CPI) values towards the NE are suggested to reflect oxygen deficient conditions during peat formation due to a higher (ground)water level in this part of the basin. The occurrence of C 29 diasterenes in low abundances provides evidence for periods of lower pH in the mire. The borehole samples from the NE show slightly enhanced contributions of n -alkanes from algal and microbial sources. The terpenoid hydrocarbons present in the lignite argue for a major contribution of angiosperms to peat formation and slightly enhanced proportions of gymnosperms in the Tv palaeomire in the NE. Based on the high concentrations of lupane-type triterpenoids in the coal seams from the underground mine, a higher density of Betulaceae in the arboreal vegetation in the SW is indicated. [ABSTRACT FROM AUTHOR]

Abstract: In this study, petrographic examinations along with proximate, calorific value, ultimate, sulphur form and XRD analyses were performed in order to determine the coal characteristics and the depositional environment of the Miocene Çan coals. Seventy coal samples were taken from cores and open pit mines. The investigated Çan coals are humic coals and classified as lignite to sub-bituminous coal based on the random huminite reflectance (0.38–0.54% Rr), volatile matter (45.50–62.25wt.%, daf) and calorific value (3419–6479kcal/kg, maf). The sulphur content of the Çan coals changes from 0.30 up to 12.23wt.%, and a broad range of ash contents was observed varying between 2.46wt.% and 41.19wt.%. Huminite is the most abundant maceral group (74–95vol.% mmf) consisting of mostly humocollinite (gelinite) which is followed by relatively low liptinite (2–18vol.% mmf) and inertinite content (2–13vol.% mmf). In general, major mineral contents of coal samples are clay minerals, quartz, mica, pyrite and feldspar. The Çan–Etili lignite basin consists of mainly volcano-clastics, fluviatile and lacustrine clastic sediments and contains only one lignite seam with 17m average thickness. In order to assess the development of paleo-mires, coal facies diagrams were obtained from maceral composition. According to the Vegetation Index (VI) and Ground Water Index (GWI), the Çan coal accumulated in inundated marsh, limnic and swamp environments under a rheotrophic hydrological regime. In general, the facies interpretations are in accordance with the observed sedimentalogical data. [ABSTRACT FROM AUTHOR]

The coal-bearing Soma basin is one of the most productive lacustrine coal basins of western Anatolia-Turkey. This study mainly focuses on petrography of the feed coals (FCs) in the Soma power plant. A total of 16 feed coal samples were systematically collected once a week over an eight-week period from both group boiler units, B1–4 with 660 MW and B5–6 with 330 MW capacity. The most abundant maceral group of FCs is huminite, in which texto-ulminite, eu-ulminite, attrinite, densinite are rich. Liptinite group macerals in FCs include mainly sporinite, resinite, and liptodetrinite, which are considerably higher than the other identified liptinite macerals. In the inertinite group, fusinite and inertodetrinite are more abundant. Identifiable minerals with petrographical studies are pyrite, siderite, other minerals (e.g., carbonates, clay minerals, quartz, feldspar, etc.), and fossil shells. This study shows that FCs used are subbituminous in rank with mean random ulminite reflectance of 0.43%Rr oil from B1–4 units and 0.39%Rr oil from B5–6 units. This indicates that coal rank is slightly higher in the central mines (southern Soma) than in the Denis mines (northern Soma). [ABSTRACT FROM AUTHOR]

The Seyitomer basin, which is one of the most productive coal basins of western Anatolia-Turkey, contains two seams, lower and upper, in the Lower-Middle Miocene lacustrine Seyitomer Formation. The lower seam in this basin is only extensively exploited by open-cast methods and produced lignites are mainly consumed in coal-fired power plants. A total of thirty-six lignite samples, of which thirty-one are from the lower seam and five from the upper seam, were collected from the two locations (DK and S30), and have been subjected to chemical and petrographic analyses. The chemical analyses of the coal ash samples with XRF show that the lignite samples on a whole-coal basis are enriched for Cr and especially Ni, and Bi, Co, Cu, Mo, Sc and V, and also exceed the range values of the most world coals. The most abundant maceral group of all the samples is huminite, in which textinite, ulminite and especially densinite are rich. Liptinite group macerals in all the samples, which are considerably higher than the inertinite group macerals, include mainly sporinite and liptodetrinite. The mean values of maximum reflectance (av. 0.29%) in oil of ulminite from the lignite samples in the Seyitomer Basin show a lignite stage (soft brown coal) in rank. In addition, vertical variations of some results in the two lignite seams have been also considered in this study. [ABSTRACT FROM AUTHOR]

The present study describes the sedimentology, coal petrology, and geochemistry of a Miocene coal- and oil shale-bearing succession in the Ilısılık region in central Anatolia, Turkey. Vertical sequence analysis within the 50–150 m thick coarse-grained succession of the Ilısılık oil shale field has allowed 4 sedimentary associations to be distinguished. The facies associations in the Ilısılık oil shale field are dominated by fluvial deposits, which document abrupt facies transitions along the axis of the basin. Fluvial poorly-sorted cobble conglomerates of facies association 1, located along the basin margin grade basinward into well-sorted conglomerates of facies association 2. These deposits grade basinward into the laterally continuous sheets of trough cross-bedded fine-grained sandstone and massive siltstone of facies association 3. Further basinward the fine clastics, oil shale, and coal of facies association 4 are common. Reflectances measured on vitrinite are between 0.54 and 0.67% Rmax. This indicates a coalification equivalent to low volatile subbituminous coal rank of the American Society for Testing and Materials classification for the Ilısılık coals. The maceral composition makes the Ilısılık oil shales of the lamosite type. [ABSTRACT FROM AUTHOR]

The Akalin seam in medium bituminous coal rank is located near the bottom level of the coal-bearing Kozlu Formation of Westphalian A age in the Zonguldak Basin of Turkey. Ten whole-seam channel coal samples were collected from the Gelik mine in this basin. The mineable coal thickness is between 50 and 120 cm (average 80 cm). The samples were characterized by low ash (average 5.3%) and low total sulphur contents (0.77%). The identifiable minerals by x-ray diffraction in whole-coal samples include clays (kaolinite, illite, and chlorite), quartz, calcite, dolomite, and pyrite. Accessory mineralogy, which was determined with a scanning electron microscopy (SEM) with an energy dispersive (EDX) on five coal samples, forms nearly pure barite, barite with Sr traces, chalcopyrite, apatite, REE-phosphate, Ti-oxide, galena, and Fe-oxide. All the samples were analyzed for trace elements using ICP-MS. Trace element contents of the coal samples studied are relatively low, except for Ba (31-432 μ g/g, average 130 μ g/g) and Mn (52-579 μ g/g, average 129 μ g/g). The former can be related to the barite and the later to mainly clays in the samples. [ABSTRACT FROM AUTHOR]

This study focuses on ascertaining controlling factors and differences on mineralogical and elemental contents for reconstructing palaeoenvironmental conditions of both seams applying standard coal characteristics, mineralogical, coal-petrologic, and elemental data of the Orhaneli coalfield. The studied coalfield, one of the important coalfields in NW Turkey, includes two workable coal seams, the lower with 0.5–2 m and the upper with 5–6 m in thickness, which are separated by 2–5 m thick, grayish-green limnic claystone. The floor rocks of the both seams are limnic claystones, whereas the roof rock of the upper seam is the tuffite layers-bearing lacustrine marls. Matrix and xylite-rich lithotypes are common in the upper seam, while alternations of xylite-clayey bands (detro-xylite and xylo-detritic) are common in the lower seam. The lower seam is also characterized with the presence of altered tuff layers, while freshwater gastropod shell-bearing bands were identified from the upper seam. Even though the banding character and maceral composition of the coals were invariant between the seams, there are distinct differences in mineralogy and elemental composition, that can be related to the nature of the clastic sediment influx and contemporary volcanic inputs into freshwater forested mires. The lower seam is characterized by high ash yields (%44.2–64.3, d) and relatively high concentrations of aluminosilicate-affiliated elements and REY (rare earth elements and Y). In contrast, the upper seam has relatively low ash yield, and is slightly enriched B concentration. The B enrichment in the upper seam is presumably controlled by the presence of clay mineral (e.g., illite) and clastic volcanogenic accessory minerals (e.g., apatite). Arsenic is the only enriched element in both seams due to development of anoxic conditions. Although no traceable As was detected from syngenetic framboidal pyrite grains, the contemporary volcanic inputs (e.g., air-fall ash/tephra) along with leached surface waters into palaeomires might be source for As, while the development of anoxic conditions palaeomires could cause formation of syngenetic pyrite grains. Thus, the As concentrations of the studied samples are elevated. Nevertheless, the difference on ash yields and mineralogical compositions between studied seams might be related with different clastic influx ratios and contemporary volcanic inputs, in turn, aluminosilicate affiliated elements display different concentration coefficients (CC) values in the studied seams, and high B concentrations that are not expectable for a limnic coal Besides, enrichment of Cr, V and Ni in the upper seam are controlled by clastic V-bearing chromite grains from Orhaneli chromite deposit in the adjacent area. Furthermore, the contemporary volcanic inputs into the palaeomire of the lower seam, and their alteration under anoxic conditions caused REY enrichment and the formation of kaolinite and smectite matrices of clay aggregates in coal and altered tuff layers in this seam. • Mineralogical and elemental compositions of Orhaneli coal are controlled by clastic influx and synchronous volcanic input. • Enrichments of REY in the lower seam are mainly controlled by synchronous volcanic inputs. • Cr and V enrichments in both seams are related with V-bearing chromite detrital grains from Orhaneli chromitite. [ABSTRACT FROM AUTHOR]

Three Miocene-age coal seams - a lower seam (kM2, subbituminous), a middle seam (kM3, subbituminous), and an upper seam (kP1, lignite) - in the Kınık coalfield, located in the southwesternmost part of the Soma Basin in western Turkey, and factors controlling mesoporosity and microporosity characteristics, were investigated using low-pressure N 2 and CO 2 adsorption techniques, respectively. In addition, this study is also aimed to compare controlling factors on meso- and microporosity characteristics of Soma Basin and Late Carboniferous Zonguldak, and Late Miocene-Pliocene Dombayova Basins. It is found that distinct differences with regard to meso- and microporosity exist among the three seams (kM2, kM3 and kP1) investigated in the Kınık coalfield. Specifically, samples from kP1 have greater mesopore surface areas and volumes than those from kM3. In addition, samples from the upper part of kM2 have significantly lower mesopore surface area and volume than from the lower part of this seam and from kM3 and kP1. Samples from the lower part of kM2 have higher meso- and micropore surface area and volume values than kM3 and kP1 samples. The increase in mesopore surface area and volume, along with the increase in ash yield toward the lower part of kM2, suggests that mesoporosity characteristics in this seam appear to be controlled mainly by mineral matter content. The results of this study show that meso- and micropore surface area and volume of Miocene subbituminous coal (kM2) in Kınık and Eynez coalfields of the Soma Basin have higher values than lignite from the Dombayova Basin and bituminous coal from the Zonguldak Basin. The differences in mesopore characteristics between the Soma and the Zonguldak Basins could be related to differences in rank. In addition, the mesoporosity of coal seams in the Dombayova Basin is more similar to seams in the Zonguldak Basin. These conflicting data suggest that rank might not be a controlling factor on the meso- and micropore characteristics of the basins investigated in this paper. Nevertheless, the common presence of structured huminite macerals in the Soma Basin seems to have caused relatively higher microporosity surface area and volume values, whereas the common presence of illite, particularly in the lower parts of kM2, resulted in higher values of mesopore surface area and volume in the Soma Basin samples. Consequently, maceral and mineralogical compositions of the studied Turkish coals seem to exert major controls on meso- and micropore characteristics. • Meso- and microporosity of selected Turkish lignite, subbituminous and bituminous coals have been studied. • Mesopore size of low-rank (subbituminous A) kM2 seam in Kınık coalfield controlled by structured huminite macerals. • Mesoporosity characteristics are mainly related to mineralogy of the studied Turkish coals. • Microporosity of the studied Turkish coals is mainly controlled by structured (e.g. telohuminite/telovitrinite) macerals. [ABSTRACT FROM AUTHOR]

The objective of this study is to identify and evaluate the organic geochemical properties, paleo vegetation, and paleo depositional environment of coals in Denizli (SW Turkey). Organic geochemical and petrographic investigations, scanning electron microscopy, X-ray diffractometry, and palynological and stable isotope (δ2H, δ13C, δ15N, δ18O and δ34S) investigations have been performed. Coal, clayey coal, and coaly claystone samples from the study area have gas and oil production potential according to their total organic carbon (0.59–48.30 wt%), hydrogen index (56–286 mg HC/g TOC), oxygen index (30–121 mg CO 2 /g TOC) and S 2 /S 3 (0.47–9.59) values. Dominant maceral assemblages included huminites and low amounts of liptinite group macerals. Tissue preservation index (0.39–5.13), gelification index (4.11–96.83), groundwater index (0.40–8.77) and vegetation index (0.49–42.67) parameters indicate a limno-telmatic environment and increased woody tissue. Mean random huminite/vitrinite reflectance values (ranging from 0.23 to 0.41 %Ro) denote lignite and sub-bituminous C and B ranked coals. Carpinus , Alnus , Zelkova , Platanus-Salix , Carya , and Ostrya were found through palynologic investigations. In addition, freshwater algae B otryococcus was detected in coal samples from Denizli. δ13C, δ15N values and C/N ratios indicated a terrestrial C3 ecosystem. Some sterane and tricyclic terpane ratios and aromatic biomarkers have shown that high plant input, immature organic matter and oxic-suboxic conditions are predominant in the depositional environment. [ABSTRACT FROM AUTHOR]

Pliocene coal, clayey coal, and coaly claystone sediments from the Yatağan Formation (Denizli Basin, southwestern Turkey) have been investigated with respect to maceral association, mineralogical composition, n -alkane, isoprenoid and saturated-aromatic biomarker characteristics, and stable isotopes (2H, 13C, 15N, 18O, and 34S). The main purpose of the present study was to determine the hydrocarbon potential and paleodepositional conditions of coals in the Denizli Basin. The abundances of huminite, liptinite, and inertinite macerals were 46.14%, 8.06%, and 1.57%, respectively. The huminite/vitrinite reflectances (%Ro) of the coal, clayey coal, and coaly claystone samples ranged between 0.26 and 0.37 %Ro, implying sub-bituminous B and C coal ranks. The total organic C (TOC, wt.%) content and the T max values of the investigated samples ranged between 0.74 and 43.80 wt% and 390–440 °C, respectively. In addition, the coaly horizons were characterized by very low H index (HI), O index (OI), production index (PI), and T max values. Moreover, a high waxiness degree, C preference index (CPI), odd-to-even predominance (OEP), terrigenous/aquatic ratio (TAR), and high C 19 tricyclic terpane/C 23 tricyclic terpane (C 19 /C 23 TT) and C 24 tetracyclic terpane/C 26 tricyclic terpane (C 24 */C 26 TT) biomarker ratios indicated a terrestrial plant input. These results were supported by stable isotope (2H, 13C, and 15N) investigations. Although the Pliocene coals have source rock potential according to the TOC content and pyrolysis analyses, they have been determined to be at the diagenesis and immature stages as a result of organic petrographic, and saturated-aromatic biomarker investigations. • Coals from Denizli have gas potential and can not reach adequate thermal maturity. • δ13C and δ15N values indicate the woody plants in terrestrial C3 ecosystem. • Coal samples are deposited at the oxic-suboxic conditions. • Huminite macerals are dominant in the coal samples. [ABSTRACT FROM AUTHOR]