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1.
Two thermal parameters, initial volatilization temperature (IVT) and average volatilization rate (AVR), have been determined by thermogravimetric analysis in argon for 38 coal samples ranging in rank from lignite to low-volatile bituminous. Both IVT and AVR are correlated with percent volatile matter and vitrinite reflectance.The IVT values increase gradually from about 250 to 445°C with increasing rank; however, a change in slope is observed in the region of high-volatile bituminous coals (from about 340°C to about 380°C) when IVT's are plotted against percent volatile matter or percent fixed carbon. The changes in slope near 340°C and near 380°C occur at “coalification jumps” recognized on the basis of changes in the optical and chemical character of the macerals. In general, AVR values decrease gradually with increasing rank for the lignite and sub-bituminous coals and for the medium- and low-volatile bituminous coals; however, a sharp increase in AVR occurs in high-volatile bituminous coals. The change in slope of the IVT curves and sharp increase in the AVR values for high-volatile bituminous coals reflect the development of new, higher vapor pressure organic compounds produced during this stage of the coalification process.A plot of AVR vs IVT reveals three regions which correspond to: (1) lignite and sub-bituminous coals; (2) high-volatile bituminous coals; and (3) medium- to low-volatile bituminous coals.  相似文献   

2.
This paper presents geological settings, stratigraphy, coal quality, petrography, reserves and the tectonic history of the Mongolian coal-bearing basins. This is based on a synthesis of the data from nearly 50 coal deposits. The results of ultimate and proximate analyses, and calorific value, maceral composition and vitrinite reflectance data is given.The coal deposits of Mongolia tend to become younger from west to east and can be subdivided into two provinces, twelve basins, and three areas. Main controlling factor of coal rank is the age of the coal bearing sequences. Western Mongolian coal-bearing province contains mostly high rank bituminous coal in strata from Late Carboniferous. The basins in southern Mongolia and the western part of central Mongolia have low rank bituminous coal in strata from the Permian. The northern and central Mongolian basins contain mainly Jurassic subbituminous coal, whereas the Eastern Mongolian province has Lower Cretaceous lignite. The Carboniferous, Permian and Jurassic coal-bearing sequences were mainly deposited in foreland basins by compressional tectonic event, whereas Cretaceous coal measures were deposited in rift valleys caused by extensional tectonic event. Petrographically, Mongolian coals are classified as humic type. Vitrinite/huminite groups of Carboniferous, Permian, and Cretaceous coal range from 44.9% to 82.9%. Inertinite group varies between 15.0% and 53.3%, but liptinite group does not exceed more than 7%. Jurassic coals are characterized by high percentages of vitrinite (87.3% to 96.6%) and liptinite groups (up to 11.7%). This might be explained by paleoclimatic conditions. Mongolian coal reserves have been estimated to be 10.2 billion tons, of which a predominant portion is lignite in the Eastern Mongolian province and coking coal in the South Gobi basin.  相似文献   

3.
This paper presents reviews of studies on properties of coal pertinent to carbon dioxide (CO2) sequestration in coal with specific reference to Victorian brown coals. The coal basins in Victoria, Australia have been identified as one of the largest brown coal resources in the world and so far few studies have been conducted on CO2 sequestration in this particular type of coals. The feasibility of CO2 sequestration depends on three main factors: (1) coal mass properties (chemical, physical and microscopic properties), (2) seam permeability, and (3) gas sorption properties of the coal. Firstly, the coal mass properties of Victorian brown coal are presented, and then the general variations of the coal mass properties with rank, for all types of coal, are discussed. Subsequently, coal gas permeability and gas sorption are considered, and the physical factors which affect them are examined. In addition, existing models for coal gas permeability and gas sorption in coal are reviewed and the possibilities of further development of these models are discussed. According to the previous studies, coal mass properties and permeability and gas sorption characteristics of coals are different for different ranks: lignite to medium volatile bituminous coals and medium volatile bituminous to anthracite coals. This is important for the development of mathematical models for gas permeability and sorption behavior. Furthermore, the models have to take into account volume effect which can be significant under high pressure and temperature conditions. Also, the viscosity and density of supercritical CO2 close to the critical point can undergo large and rapid changes. To date, few studies have been conducted on CO2 sequestration in Victorian brown coal, and for all types of coal, very few studies have been conducted on CO2 sequestration under high pressure and temperature conditions.  相似文献   

4.
The coal fields of the Unites States can be divided into six major provinces. The Appalachian and Interior Provinces contain dominantly bituminous coal in strata of Pennsylvanian age. The coal seams are relatively thin and are mined both by surface and underground methods. Sulfyur content is low to moderate in the Appalachian Province, generally high in the Interior province. The Gulf Coastal Plain Province, in Texas and neighboring states, contains lignite of Eocene age. The seams are 3–25 ft (0.9–7.5 m) thick and are minded in large open pits. The Northern Great Plains Province has lignite and subbituminous coal of Cretaceous, Paleocene and Eocene age. The coal, largely very low in sulfur, occurs in beds up to 100 ft (30 m) thick and is strip-mined. The Rocky Mountain Province contains a great variety of coal deposits in numerous separate intermontane basins. Most of it is low-sulfur subbituminous to bituminous coal iof Creatceous and early Tertiary age. The seams range from a few feet to over 100 ft (30 m) thick. Strip-mining dominates but underground mines are important in Utah and Colorado. The Pacific Coast Province, which includes Alaska, contains enormous cola resources but has seen little mining. The coal is highly diverse in physical character and geologic setting.  相似文献   

5.
The Cantabrian Mountains, containing about 70% of the total coals of the country and 95% of the anthracitic and bituminous resources, is the most important coal-mining district of Spain. Coal-bearing successions are Late Carboniferous in age and their deposition took place in a syn-orogenic context during the Hercynian activity, mainly in three different time-successive locations: foreland basins, intrathrust basins and intramontane fault-controlled basins. Foreland deposition occurred in strongly asymmetrical basins located ahead of thrust sheets units. Intrathrust basins resulted from folding and tightening of these units during or after their emplacement. Intramontane and fault-controlled basins were developed along lineaments with strike-slip movements and as a result of fold and fault reactivation. Peat mires in foreland and intrathrust coal basins mainly occupied broad areas on abandoned delta and fan delta lobes. Coals in intramontane and fault-controlled basins were related with alluvial fan and lacustrine environments. Coal ranks vary from high volatile bituminous coals to anthracite, depending on the structural location of the coalfields. Hydrothermal activity seems to be the most important factor in coal evolution.  相似文献   

6.
Thirteen coal areas of the Maritime Provinces in Atlantic Canada are estimated to contain some 2.23 trillion m3 (78.8 TCF) [TCF, BCF, MCF: trillion, billion, million cubic feet]) of coalbed methane resources. This compares with 510 billion m3 (18 TCF) of natural gas calculated for the Sable offshore resources in eastern Canada. In the United States, where coalbed methane resource evaluations and production have increased substantially over the past 20 years, 7% (1.34 TCF) of total domestic gas production is derived from coalbed methane. In this period, the cumulative US production of coalbed methane has exceeded 198 billion m3 (7 TCF) and more than 8000 coalbed methane wells have been drilled.In Maritime Canada, the largest coalbed methane resources occur in the offshore areas of the Gulf of St. Lawrence and Sydney Basins where 196 and 26 billion m3 (69 and 9.3 TCF) of gas, respectively, have been projected. In the old mines, the greatest resources are present in the Prince and Phalen mines of the Sydney coalfield, which together contain 1.70 billion m3 (60 BCF) of gas, and in the Westville mine of the Pictou coalfield with 198 million m3 (70 BCF).Vitrinite is the dominant constituent in 27 of the 42 coals examined. Vitrinite/inertinite ratios for these 27 coals range from 4.0 to 8.4. These high values may indicate the presence of highly fractured coals with corresponding high permeability and flow efficiency, favourable for the storage and flow of methane gas. Coal rank has a pronounced effect on coalbed methane generation, and the prime gas zone often lies between 1.2% and 1.6% Ro max. (medium to low volatile bituminous). The prime zone in the Maritimes Basin underlies much of the central and eastern Gulf of St. Lawrence, and extends for significant distances seaward into the offshore Sydney Basin.Coalbed methane production from the very large resources available in Atlantic Canada may provide a valuable and long-lasting energy resource, largely free of polluting components.  相似文献   

7.
More than 130 Mt of Pennsylvanian coal is produced annually from two coal fields in Kentucky. The Western Kentucky Coal Field occurs in part of the Illinois Basin, an intercratonic basin, and the Eastern Kentucky Coal Field occurs in the Central Appalachian Basin, a foreland basin. The basins are only separated by 140 km, but mined western Kentucky coal beds exhibit significantly higher sulfur values than eastern Kentucky coals. Higher-sulfur coal beds in western Kentucky have generally been inferred to be caused by more marine influences than for eastern Kentucky coals.Comparison of strata in the two coal fields shows that more strata and more coal beds accumulated in the Eastern than Western Kentucky Coal Field in the Early and Middle Pennsylvanian, inferred to represent greater generation of tectonic accommodation in the foreland basin. Eastern Kentucky coal beds exhibit a greater tendency toward splitting and occurring in zones than time-equivalent western Kentucky coal beds, which is also inferred to represent foreland accommodation influences, overprinted by autogenic sedimentation effects. Western Kentucky coal beds exhibit higher sulfur values than their eastern counterparts, but western Kentucky coals occurring in Langsettian through Bolsovian strata can be low in sulfur content. Eastern Kentucky coal beds may increase in sulfur content beneath marine zones, but generally are still lower in sulfur than mined Western Kentucky coal beds, indicating that controls other than purely marine influences must have influenced coal quality.The bulk of production in the Eastern Kentucky Coal Field is from Duckmantian and Bolsovian coal beds, whereas production in the Western Kentucky Coal Field is from Westphalian D coals. Langsettian through Bolsovian paleoclimates in eastern Kentucky were favorable for peat doming, so numerous low-sulfur coals accumulated. These coals tend to occur in zones and are prone to lateral splitting because of foreland tectonic and sedimentation influences. In contrast, Westphalian D coal beds of western Kentucky accumulated during low differential tectonic accommodation, and therefore tend to be widespread and uniform in characteristics, but exhibit higher sulfur values because they accumulated in seasonally drier paleoclimates that were unfavorable for peat doming. Hence, basin analyses indicate that many differences between the mined coals of Kentucky's two coal fields are related to temporal changes in paleoclimate and tectonic accommodation, rather than solely being a function of marine influences.  相似文献   

8.
The coal deposits of southern Africa (Botswana, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Zambia and Zimbabwe) are reviewed. The coal seams formed during two periods, the Early Permian (Artinskian–Kungurian) and the Late Permian (Ufimian–Kazanian). The coals are associated with non-marine terrestrial clastic sedimentary sequences, most commonly mudrock and sandstones, assigned to the Karoo Supergroup. The Early Permian coals are most commonly sandstone-hosted while the younger coals typically occur interbedded with mudstones. The sediments were deposited in varying tectono-sedimentary basins such as foreland, intracratonic rifts and intercratonic grabens and half-grabens. The depositional environments that produced the coal-bearing successions were primarily deltaic and fluvial, with some minor shoreline and lacustrine settings. Coals vary in rank from high-volatile bituminous to anthracite and characteristically have a relatively high inertinite component, and medium- to high-ash content. In countries where coal is mined, it is used for power generation, coking coal, synfuel generation, gasification and for (local) domestic household consumption.  相似文献   

9.
The effect of petrographic composition on the methane sorption capacity has been determined for a suite of coals and organic-rich shales. Subbituminous and bituminous coals were separated into bright and dull lithotypes by hand-picking. The methane sorption capacities range between 0.5 and 23.9 cm3/g at a pressure of 6 MPa. The low volatile bituminous Canmore coal and the anthracite sample have the highest capacities with the “natural coke” having the lowest. For low-rank coals there is no significant difference between bright and dull samples except for one coal with the dull sample having a greater sorption capacity than its bright equivalent. For higher-rank coals, the bright samples have a greater methane capacity than the dull samples and the difference between sample pairs increases with rank. The boghead coal samples have the highest sorption capacities in the liptinite-rich coals suite and are higher than subbituminous to medium volatile bituminous samples. Pore size distribution indicates that methane is held as solution gas in liptinite-rich coals and by physical sorption in micropores in liptinite-poor coals. These contrasting processes illustrate that liptinite-rich samples need to be independently assessed. The positive relationship between reactive inertinite content and methane sorption capacity occurs within the subbituminous to medium volatile bituminous coals because the reactive inertinite is structurally similar to vitrinite and have a higher microporosity than non-reactive inertinite. Reactivity of inertinite should be assessed in CBM studies of dull coals to provide a better understanding of petrographic composition effects on methane capacity.  相似文献   

10.
潮水盆地位于内蒙古西南部和甘肃省东部地区,是我国中新生代含煤断陷盆地.采用粉晶X衍射、ICP-MS、ICP-AES 方法,从煤的岩石学、煤化学及煤地球化学的理论出发,对潮水盆地西部煤样进行了煤化学、显微组分、矿物学及地球化学分析.其研究结果表明潮水盆地西部煤以中等水分、低一中灰分和硫质量分数、高挥发分产率为特征,煤级为烟煤—亚烟煤;煤中有机显微组分以镜质组为主,惰性组次之,煤相类型以潮湿森林沼泽相为主,其次为较浅覆水森林沼泽相;煤中的常量矿物以石英和高岭石为主,部分样品中含有黄铁矿、方解石、菱铁矿和少量的微斜长石;煤中除Sr、B和Cs质量分数相对较高外,其他微量元素质量分数普遍较低.Cr、Ga、Pb、Li、Cu、Ge、V、Sc、Be、W、Th和As,以及Ti和Nb主要与硅铝酸盐矿物有好的亲和性;B和Sr可能主要以碳酸盐矿物的形式存在;S和Mo可能主要以硫化物矿物的形式存在;另外,Ti、Zr、Nb和Ta有好的相关性,可能与重矿物有关.  相似文献   

11.
A detailed macro- and micro-petrological investigation of 8 coal seam profiles of Eocene age from the sub-Himalayan zone of Jammu was undertaken in order to characterize them petrographically and to focus on their evolution. The quantitative data suggest that these coals are vitrinite rich, with low concentrations of inertinite and rare occurrences of liptinite. According to microlithotype concentration these coals may be characterized as vitrinite rich, with minor amounts of clarite, vitrinertite and trimacerite. The dominant minerals are clays, siderite and pyrite (occurring mostly as disseminations, cavity filling and in framboidal state). These coals are vitric in type, low volatile bituminous in rank and ashy in grade.The petrographic character and the presence of teleutospores suggest that, similar to other Tertiary coal deposits in the world, the angiosperm flora contributed chiefly to the development of coal facies in the area. The maceral and microlithotype composition shows that these coals originated from the low forest and undisturbed (in situ) peat in foreland basins under limno-telmatic depositional conditions. The water was brackish with regular influxes of fresh water.  相似文献   

12.
Most types of coal in Turkey are generally low in rank: lignite, and subbituminous. Most of the coal was formed during the Miocene, Eocene, and Pliocene ages. There are only a few thin Jurassic-age coal occurrences in Turkey. Pennsylvanian age bituminous coal is found on the Black Sea coast. General implications of the petrographic properties of Turkey's coal seams and coal deposits have not yet been taken into consideration comparatively or as a whole.For this study, about 190 channel samples were collected from different locales. The composite profile samples of the seams were taken into considerations. The content and depositional properties as well as some chemical and physical properties of the main coal seams are compared. All coal samples tend to have similar coal petrographic properties and were deposited in intermontane lacustrine basins. Later, they were affected by faulting and post-depositional volcanic activity. As a result, there are variations in the properties and rank of the coal samples. The most abundant coal maceral group is huminite and the most abundant maceral is gelinite. The liptinite and inertinite contents of the coal are low and the maceral contents of the coals show great similarity. The depositional environments of the all coals are lacustrine dominated.  相似文献   

13.
The Rocky Mountain basins of western North America contain vast deposits of coal of Cretaceous through early Tertiary age. Coalbed methane is produced in Rocky Mountain basins at depths ranging from 45 m (150 ft) to 1,981 m (6,500 ft) from coal of lignite to low-volatile bituminous rank. Although some production has been established in almost all Rocky Mountain basins, commercial production occurs in only a few. Despite more than two decades of exploration for coalbed methane in the Rocky Mountain region, it is still difficult to predict production characteristics of coalbed methane wells prior to drilling. Commonly cited problems include low permeabilities, high water production, and coals that are significantly undersaturated with respect to methane. Sources of coalbed gases can be early biogenic, formed during the early stages of coalification, thermogenic, formed during the main stages of coalification, or late stage biogenic, formed as a result of the reintroduction of methane-generating bacteria by groundwater after uplift and erosion. Examples of all three types of coalbed gases, and combinations of more than one type, can be found in the Rocky Mountain region. Coals in the Rocky Mountain region achieved their present ranks largely as a result of burial beneath sediments that accumulated during the Laramide orogeny (Late Cretaceous through the end of the Eocene) or shortly after. Thermal events since the end of the orogeny have also locally elevated coal ranks. Coal beds in the upper part of high-volatile A bituminous rank or greater commonly occur within much more extensive basin-centered gas deposits which cover large areas of the deeper parts of most Rocky Mountain basins. Within these basin-centered deposits all lithologies, including coals, sandstones, and shales, are gas saturated, and very little water is produced. The interbedded coals and carbonaceous shales are probably the source of much of this gas. Basin-centered gas deposits become overpressured from hydrocarbon generation as they form, and this overpressuring is probably responsible for driving out most of the water. Sandstone permeabilities are low, in part because of diagenesis caused by highly reactive water given off during the early stages of coalification. Coals within these basin-centered deposits commonly have high gas contents and produce little water, but they generally occur at depths greater than 5,000 ft and have low permeabilities. Significant uplift and removal of overburden has occurred throughout the Rocky Mountain region since the end of the Eocene, and much of this erosion occurred after regional uplift began about 10 Ma. The removal of overburden generally causes methane saturation levels in coals to decrease, and thus a significant drop in pressure is required to initiate methane production. The most successful coalbed methane production in the Rocky Mountain region occurs in areas where gas contents were increased by post-Eocene thermal events and/or the generation of late-stage biogenic gas. Methane-generating bacteria were apparently reintroduced into the coals in some areas after uplift and erosion, and subsequent changes in pressure and temperature, allowed surface waters to rewater the coals. Groundwater may also help open up cleat systems making coals more permeable to methane. If water production is excessive, however, the economics of producing methane are impacted by the cost of water disposal.  相似文献   

14.
The effect of coal composition, particularly the organic fraction, upon gas sorption has been investigated for Bowen Basin and Sydney Basin, Australia coals. Maceral composition influences on gas retention and release were investigated using isorank pairs of hand-picked bright and dull coal in the rank range of high volatile bituminous (0.78% Ro max) to anthracite (3.01% Ro max). Adsorption isotherm results of dry coals indicated that Langmuir volume (VL) for bright and dull coal types followed discrete, second-order polynomial trends with increasing rank. Bright coals had a minimum VL at 1.72% Ro max and dull coals had a minimum VL at 1.17% Ro max. At low rank, VL was greater in bright coal by about 10 cm3/g, but as rank increased, the bright and dull trends converged and crossed at 1.65% Ro max. At ranks higher than 1.65% Ro max, both bright and dull coals followed similar trends. These competing trends mean that the importance of maceral composition on VL varies according to rank. In high volatile bituminous coals, increases in vitrinite content are associated with increases in adsorption capacity. At ranks higher than medium to low volatile bituminous, changes in maceral composition may exert relatively little influence on adsorption capacity. The Langmuir pressure (PL) showed a strong relationship of decreasing PL with increasing rank, which was not related to coal type. It is suggested that the observed trend is related to a decrease in the heterogeneity of the pore surfaces, and subsequent increased coverage by the adsorbate, as coal rank increases. Desorption rate studies on crushed samples show that dull coals desorb more rapidly than bright coals and that desorption rate is also a function of rank. Coals of lower rank have higher effective diffusivities. Mineral matter was found to have no influence on desorption rate of these finely crushed samples. The evolution of the coal pore structure with changing rank is implicated in diffusion rate differences.  相似文献   

15.
A quantitative 13C-NMR technique was applied to humic acids, isolated from total solvent extracts obtained from coals, varying in rank from lignite to medium volatile bituminous. The results from elemental analysis and 13C-NMR structural ratios are interpreted in the form of three distinct structural phases in the maturation of coal humic acids. These phases reflect the rank of the parent coals. A decrease in polar functional group content and corresponding increase in aromaticity is observed with increasing maturation of humic acid chemical structure. Limits are postulated for the oxygen content and level of aromaticity for humic acids derived from higher rank coals.  相似文献   

16.
The gravity of Ethiopian energy problem has initiated studies to explore various energy resources in Ethiopia, one among this is the exploration for coal resources. Studies confirmed the presence of coal deposits in the country. The coal-bearing sediments are distributed in the Inter-Trappean and Pre-Trap volcanic geological settings, and deposited in fluvio-lacustrine and paludal environments in grabens and half-grabens formed by a NNE–SSW and NNW–SSE fault systems. Most significant coal deposits are found in the Inter-Trappean geological setting. The coal and coal-bearing sediments reach a maximum thickness of 4 m and 300 m, respectively. The best coal deposits were hosted in sandstone–coal–shale and mudstone–coal–shale facies. The coal formations of Ethiopia are quite unique in that they are neither comparable to the coal measures of the Permo-Carboniferous Karroo Formation nor to the Late Devonian–Carboniferous of North America or Northwestern Europe. Proximate analysis and calorific value data indicated that the Ethiopian coals fall under lignite to high volatile bituminous coal, and genetically are classified under humic, sapropelic and mixed coal. Vitrinite reflectance studies confirmed 0.3–0.64% Ro values for the studied coals. Palynology studies confirmed that the Ethiopian coal-bearing sediments range in age from Eocene to Miocene. A total of about 297 Mt of coal reserve registered in the country. The coal reserve of the country can be considered as an important alternative source of energy.  相似文献   

17.
老挝的煤炭资源以褐煤为主,烟煤次之。烟煤的含煤地层为石炭系乍奎组（Cz）、中二叠统南康尚组（P2nk）、上三叠统。褐煤产于新近系中。煤炭资源主要分布在沙拉湾（Samvane）石炭系烟煤成矿远景区,万荣（Vang Vieng）中二叠统烟煤成矿远景区,丰沙里（Phong Saly）-孟赛（Muang Xay）上三叠统烟煤成矿远景区,南塔（Nam Tha）新近系褐煤成矿远景区,桑怒（Xam Nua）-孟佩（Muang Pek）中新统褐煤成矿远景区。  相似文献   

18.
The only significant deposits of anthracite and meta-anthracite in Canada occur in Upper Jurassic-Lower Cretaceous strata of the Groundhog coalfield in northcentral British Columbia. The coal rank in the coalfield varies from low volatile bituminous (1.70% R0 max) to meta-anthracite (5.8% R0 max). The main coal bearing unit, the Currier, includes up to 17 seams of anthracite and meta-anthracite most of which are less than 1 m thick. In the McEvoy unit, which overlies the Currier, up to 9 coal seams, mainly of semi-anthracite, occur that are up to 0.8 m thick. The coals are variably argillaceous, locally sheared and cut by quartz and less commonly, by carbonate veins. Coalification gradients in the coalfield vary from 0.8% to 3.0% R0 max km?1. The rank of coal within both the McEvoy and Currier units appears to increase towards the eastern edge of the coalfield.The level of coalification and the coalification gradients in the coalfield are anomalously high considering an indicated maximum depth of burial of 3500 m. From comparison with coalification models it appears that geothermal gradients in the order of 50° to 70°C/km must have existed for a period of time measured in millions of years. Studies to date suggest the coalification is pre-tectonic and thus pre-Late Cretaceous although there is some evidence for high heat flow in the Tertiary. The origin of the high heat flow may be related to intrusion accompanying collision of the Stikine terrain with the early Mesozoic margin of North America and/or high heat flux over an easterly dipping subduction zone below the Coastal volcanic-plutonic arc to the west.  相似文献   

19.
Petrographic investigations of serial ply samples from five high- to medium-volatile bituminous coal seams from Australia (4) and Canada (1) reveal substantial in-seam variations in the reflectance and monochromatic microfluorescence intensities of the maceral subgroup telovitrinite. The variations consist of one case of reflectance enhancement and fluorescence suppression, and four cases of reflectance suppression and fluorescence enhancement. The single case of reflectance enhancement and fluorescence suppression is due to the oxidation of the vitrinite nuclei at the sequence boundary between the Bayswater and Upper Wynn seams in New South Wales. The four cases of reflectance suppression and fluorescence enhancement result from the syn- and epigenetic absorption by the vitrinite nuclei of hydrogen donated by, presumably, anaerobic bacteria-generated lipids. Two of the coals are marine-influenced: the Liskeard Seam from the Bowen Basin by combined syngenetic and epigenetic effects, and the Greta Seam from the Sydney Basin mainly by epigenetic contact with sea water. For both coals, the results are strong vitrinite reflectance suppression and fluorescence enhancement. The remaining two coals, the Bulli Seam from the Sydney Basin and a coal seam from the Gates Formation in British Columbia, show moderate epigenetic effects on the optical properties of telovitrinite by fresh-water. In the Bulli Seam which was studied in two adjacent localities, the reflectance suppression and fluorescence enhancement of telovitrinite are stronger under sandstone roof than under shale roof. In some cases, the epigenetic effects are superimposed on syngenetic telovitrinite reflectance and fluorescence variations resulting from the cogeneration and mixing of different telovitrinite precursors, for example, autochthonous roots and hypautochthonous or allochthonous shoots. A measure of the degree of dispersal and mixing is the coefficient of variation of telovitrinite reflectance and/or fluorescence. This coefficient correlates well with detrital minerals and dispersed macerals, e.g., inertodetrinite and, to a lesser extent, sporinite. Some comments are made on slitted so-called pseudovitrinite which is regarded as a telovitrinite that was subjected to very weak post-coalification desiccation and possibly oxidation without losing much of its thermoplastic properties.  相似文献   

20.
选取煤与油页岩共生典型盆地山东黄县盆地、辽宁抚顺盆地、黑龙江依兰盆地和内蒙古金宝屯盆地,综合分析了其成矿物质特点,认为共生背景下煤岩中的低等动植物和油页岩中的高等植物均比单一矿种下含量高。这一规律可用于勘探、开发煤或油页岩单一矿种时预测其共生矿种存在的可能性。对古气候的分析表明,气候变换在一定程度上制约着煤与油页岩的共生模式,这种共生模式可为古气候研究提供一定依据,反之,通过古气候的变迁也可帮助勘探、开发共生背景下的煤与油页岩。  相似文献   

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