coal maceral ratios as indicators of environment of deposition do they work for ombrogenous mires an example from the miocene of new zealand abstract maceral indices were applied to sub bituminous coals of the maryville coal measures as a means of interpreting environment of deposition very low amounts of inertinite and ubiquitous bituminite lead to difficulties in interpretation of the maceral ratios comparison with modern analogues suggests the theoretical basis for discrimination of mire type by maceral ratios is not well founded on the following grounds absence of well structured wood tissues does not imply the absence of arborescent vegetation inertinite formation may be unrelated to vegetation gelification is used in a geochemical sense and does not indicate groundwater table level as supposed for biochemical gelification detrital macerals often result from in situ fragmentation and not transportation

very recent and wide spread basaltic volcanism on mars new spacecraft data provide increasing evidence for a dynamic environment on presenta day mars exogenic processes such as impact cratering mass wasting processes and active dune migration have all been observed to modify the surface no traces of current endogenic activity have been found yet but some studies point to very localized volcanism in the last few millions of years however no systematic study of young volcanic surfaces had been performed so far we present absolute model age determinations of plains volcanism on mars as derived from impact crater sizefrequency distributions extended areas in tharsis the largest volcanoa tectonic region on mars have been resurfaced by lava flows in the last few tens of millions of years we also present results on the rheologic properties of these lava flows inferred from morphometric measurements yield strengths are in the range of 100a 300 pa and viscosities reach values of 10 2 to 10 3 pa s indicating basaltic compositions the results imply that mars retained until recently and probably still retains enough internal heat to produce widea spread plaina style volcanism producing lowa viscosity lava flows throughout large parts of tharsis

the depositional conditions and the palaeoenvironment of the achlada xylite dominated lignite in western makedonia greece abstract the depositional palaeoenvironment of the neogene achlada lignite deposit western makedonia greece was deciphered with respect to the evaluation of the macro petrographic characteristics and the data resulted from coal petrographic analyses the total thickness of the studied lignite seam is 26 m and consists of organic and inorganic alternations the macro petrographic observations suggest extremely high contributions of woody originated tissue xylite from a single tree type among the lignite layers whereas numerous in situ stems and trunks were observed the results of the coal petrographic analysis indicate the dominance of huminite 88 3 vol whereas liptinite and inertinite show much lower values 11 0 vol and 0 7 vol respectively high contribution of mineral matter is also observed in many cases ulminite types a and b are the most abundant macerals whereas the content of ulminite b is followed by the xylite content facies modeling using maceral composition and maceral indices suggested the alternation of forest swamp and reed moor environments where peat accumulated under highly saturated and intensely anoxic conditions a terrestrial origin with wet forest to piedmont plain depositional conditions was suggested by the gelification index gi and tissue preservation index tpi plot a cross plot of the ground water index gwi vs the vegetation index vi suggested swamps under mesotrophic and rheotrophic hydrogeological conditions where the dominant source for the peat was woody vegetation and vegetation high in preservation potential the overall macro and micro characteristics of the achlada lignite suggest a depositional palaeoenvironment that includes three independent parts a the main channel of a meandering river system b the floodplain area and c the oxbow lake the establishment of telmatic limnotelmatic conditions in this palaeoenvironment resulted in the formation of the entire achlada lignite deposit whereas numerous flood episodes interrupted the peat accumulation and resulted in the deposition of clay rich sediments

paleoenvironments of lacustrine coals the occurrence of algae in humic coals abstract according to previous studies there is a significant difference in the thickness and number of coal seams from the foredeep and the intermontane coal basins or basins situated on platforms and cratons recent petrographic and geochemical investigations on selected coal samples from foredeep and intermontane basins of europe carboniferous and tertiary and south america permian show that the coal seams in each of these coal basins have significant differences in their petrographic and geochemical compositions many intermontane coals are characterized by more liptinite than foredeep coals fluorescence studies show that up to 75 of the liptinite macerals of these humic coals can be attributed to alginite and or degradation products of algae this indicates that generally subaquatic conditions occurred more often in the peats that formed within intermontane basins

the relationship between coal petrography and depositional environments from selected coal basins in canada abstract this paper reviews current research in canada relating to the sedimentology of coal bearing sequences and the petrographic character of contained seams from selected intermontane and foreland basin settings the intermontane cumberland and stellarton basins of nova scotia contain westphalian coal bearing strata of different character coal seams that formed in fluvial dominated depositional environments of the springhill coalfield cumberland basin commonly brighten upward and laterally display distinct areal zones a piedmont zone formed by interfingering of mire and distal fan sheetflow deposits an inner mire zone largely devoid of partings and a riverine zone with large scale seam splits about multistorey sandstone bodies maceral based groundwater influence and vegetation indices combined with miospore analyses indicate that the peat precursors of the no 3 seam of the inner mire zone accumulated from a groundwater influenced rheotrophic to mesotrophic forest mire swamp fen both the gelification of lignin derived maceral precursors and the domination of mire vegetation by lycopsid trees reflect this groundwater influence coal that formed from the frequently flooded paleomires of the stellarton basin is generally dull microbanded and mineral rich the location of mires within the basin was largely determined by basin subsidence rates when subsidence rates were high mires developed around the margin of a central basin lake coal seams that formed from these mires e g mcleod seam thicken toward basin margins and grade into sapropelic shale near the basin centre petrographic analyses of the mcleod seam suggest development from limnic to wet forest swamp conditions and a return to a limnic environment at the top of the seam thick coal e g foord seam developed near the basin centre during periods of lower subsidence rates and grades into red beds and paleosols toward the basin margin the foord seam of the basin centre is characterized by low mineral matter contents and a high proportion of degraded vitrinite macerals in the central parts of the seam interpreted to reflect prolonged peat accumulation with very limited clastic input the top and the base of the seam in contrast were subjected to significant clastic input as indicated by microbanding associated with significant amounts of detrital minerals and macerals coal seams of the lower cretaceous gates formation in the western canada basin formed in depositional settings ranging from coastal swamps strandplains to the upper delta plain strandplain coal is characterized by great lateral continuity and substantial thickness whereas coal of the upper delta plain is thin and discontinous the strandplain coal is characterized by variable lithotype sequences oscillatory brightening up dulling up maceral based facies parameters indicate a wide range of mire facies for these lithotype successions open moor forest moor herbaceous and or shrubby marshes and slightly raised mires results from megafossil and phyteral analyses suggest that the coastal plain mires were dominated by taxodiaceous conifers whereas ferns angiosperms and herbaceous lycopods are thought to have occupied the more marshy and or marginal stream lake side environments

observations on the nature and origin of fusain abstract evidence for a wildfire origin of fusain is examined charcoal produced by natural fires and artificial charring resembles fossil fusain both in physical size and shape and in optical reflectance artificially charred leaves and naturally burnt wood are illustrated using the sem reflectance studies on modern charcoals suggest that much semifusinite may be produced by pyrolysis the ecological implications of a wildfire origin of fusain are discussed and it is concluded that fires have been a feature of terrestrial ecosystems from at least the late devonian

the genesis of coal from the viewpoint of coal petrology abstract the genesis of the microscopic constituents of coal macerals and of maceral associations microlithotypes representing various coal facies is discussed in the light of recent advances that have been made in the study of coals and modern peats peat microscopy especially promoted the understanding of humification and biological gelification both of which are decisive for the genesis of huminites vitrinites in brown coals and hard coals respectively microbial activity during peatification has been documented by chemists microbiologists and petrologists and recently by electron microscopical observations in coals this activity leads to the incorporation of lipid substances into the humic matter and later influences the chemical physical and technological properties of vitrinites geochemical gelification transforms the huminites of brown coals into the vitrinites of bituminous coals and is probably caused by the onset of bitumen generation in coal in this process the hydrogel brown coal is transformed to the bitumogel bituminous coal coal as a source rock for oil has become an important research subject for coal petrologists and oil exploration the formation of more or less liquid bitumen and its later cracking to gaseous hydrocarbons leads to the coalification jumps of the macerals especially liptinites and vitrinites and to the generation of secondary macerals like exsudatinite bitumen and micrinite dead carbon bituminization in coal has been revealed by the use of fluorescence microscopy which also found the presence of new liptinite macerals bituminite fluorinite and exsudatinite and suggests a higher proportion of algal material in coals than was thought earlier the genesis of various types of inertinite macerals will probably become an increasingly important subject of research especially with regard to rank inertinites that seem to attain their high inertinitic reflectance initially during coalification besides the origin of macerals the origin of various coal facies in terms of maceral associations is considered in relation to the palaeogeographic depositional milieu the peat forming vegetation palaeoclimate water and nutrient supply acidity marine and calcareous influence and fire with examples from euramerican carboniferous coals gondwana coals and tertiary brown coals vegetation water and oxygen supply eh conditions are most important for the generation of coal facies vegetation has been reconstructed with the help of palaeobotany including palynology cuticular analysis and wood anatomy in brown coals and with the study of petrified permineralized peats preserved in coal balls the microscopical investigations of botanically recognizable plant remains isolated from coals or accompanying rocks has been especially informative however the results of palynological and cuticular analyses should be evaluated with caution considering the varying resistance of palynomorphs and cuticles and in the case of palynomorphs their possible extrapaludal origin microscopical studies of modern peats that were derived from different types of vegetation growing in different hydrological environments have been very helpful in interpreting coal facies especially in brown coals the much disputed origin of brown coal lithotypes is considered in detail for hard coals there seems to be agreement that coal layers rich in vitrites and liptinite poor clarite were deposited in wet forest swamps that microlayered liptinite rich clarites are sub aquatic humic muds and that inertinite rich durites represent oxidized peats the origin of liptinite rich durites is controversial either subaquatic muds or oxidized peats the latter perhaps from raised bogs a recent trend in the literature is the assumption that many if not all mineable coal seams have been deposited in raised bogs under ombrogenous oligotrophic conditions although raised bogs with a dense arborescent vegetation are known from borneo it seems not probable that most seams which were deposited in foredeeps or steadily sinking graben zones are of ombrogenous origin although a succession from relatively wet and eutrophic to relatively dry and oligotrophic conditions may be true for occasional seams but as in modern peats striking changes of coal facies are commonly caused by hydrological events e g inundations as a consequences of crevasses or of fires that burned the peat the origin of the inertinite rich gondwana coals is discussed in relation to their specific climatic conditions and a comparison with sub arctic peats is recommended coals influenced by marine and calcareous conditions are characterized by high contents of sulfur and pyrite as well as by hydrogen rich vitrinites with a relatively low reflectance and high fluorescence all due to a strong bacterial activity in peats of low acidity proposals for further research are made in the conclusions

coal petrological and xylotomical characterization of miocene lignites and in situ fossil tree stumps and trunks from lusatia region germany palaeoenvironment and taphonomy assessment abstract the present paper investigates rank and composition of coal as well as depositional and hydrogeological settings persisting during the stage of peat accumulation and evaluates taphonomy and conditions for the in situ preservation of outstanding fossilized stump and trunks using coal petrological and xylotomical analyses the obtained results are further interpreted and compared with existing literature records lignite samples and fossil wood specimens were collected from the 2nd mfh 2nd miocene seam horizon or its equivalent present at meuro piskowitz and welzow sud open cast mines located in lusatia germany the examined lignite samples indicate low rank coals at lignite or subbituminous rank stage and are characterised by slight dominance of attrinite over textinite ulminite suberinite cutinite porigelinite resinite and corpohuminite macerals waterlogged conditions prevailing in the mire are associated with peat accumulation under anoxic conditions accompanied by low decomposition rates the determined facies indicators suggest a moderate to high as well as low gelification of the organic matter for the meuro and piskowitz open cast mines respectively in meuro open cast mine the prevalence of herbaceous plant in a mire or a bacterial fungal degradation of woody plant tissues can be envisaged whereas in the piskowitz open cast mine it is suggested that peat formed in a wet forest mire environment with a limited oxygen supply and a relatively low bacterial fungal degradation the studied fossil wood specimens revealed the presence of quasisequoioxylon piskowitzense preserved as an in situ fossilized stump as well as taxodioxylon cryptomerioides and sciadopityoxylon wettsteinii species preserved as fossilized trunks the examined species belong to the families of cupressacea sciadopityaceae and cupressaceae li sensu lato the taphonomy of the in situ fossilized stump and trunks can be explained by nutrient and oxygen poor oligotrophic mires distinguished as raised bogs and suggesting generally anoxic conditions during middle to late miocene climate transition

petrological and geochemical characterization of candiota coal seams brazil implication for coal facies interpretations and coal rank abstract seven coal seams from cores of the borehole m iv c 101 candiota coalfield located in rio grande do sul state southern part of the parana basin were analyzed by coal petrographical and organic geochemical methods the seams occur in the rio bonito formation guata group tubarao supergroup of the parana basin and are of permian artinskian kungurian age the composition rank coal facies and depositional environment characterization were made based on lithotype maceral and microlithotype analyses the data were then used in the definition of different types of facies critical petrographical indices and were displayed in diagrams of coal facies in addition coal seams samples from candiota mine were analyzed by proximate total moisture and gross calorific values and were classified using the united nations economic commission for europe un ece classification in addition rock eval pyrolysis liquid chromatography gc and gc ms analyses were made to obtain independent parameters on coal rank and organic matter composition and environment of deposition the results suggest deposition in open mires with elevated contents of detrital macerals and clay minerals and also limno telmatic coal facies coal bearing sequence of coal seams represent a back barrier setting according to the international classification un ece candiota coals are in the subbituminous or low rank coal a stage results from geochemical analyses showed that terrestrial organic matter is predominant as indicated by hydrogen and oxygen indices carbon preference indices and the sterane distribution geochemical maturity parameters such as the 20 s 20 s 20 r and ratios for c 29 regular steranes support the low level of rank maturity as indicated by the vitrinite reflectance measurements 0 41 0 45 and gross calorific values

organic geochemical characteristics and depositional environment of the tertiary tanjong formation coals in the pinangah area onshore sabah malaysia article i nfo article history the tertiary tanjong formation coals exposed in the west middle block of the pinangah coalfield central part of southern sabah were analyzed and their depositional environments were interpreted the tertiary tanjong coals are humic and generally dominated by vitrinite with significant amounts of liptinite and low amounts of inertinite macerals total organic carbon contents toc of the coals range from 51 2 to 77 7 wt and yield of bitumen values ranging from 57 300 to 140 000 ppm which meet the standard as a source rock with good hydrocarbon generative potential in support good liquid hydrocarbons generation potential can be expected from the tanjong coals based on significant liptinitic content 15 this is supported by their high hydrogen index up to 300 mg hc g toc consistent with type ii and mixed type ii iii kerogens and py gc s2 pyrograms with n alkane alkene doublets extending beyond c30 the coal samples have vitrinite reflectance values in the range of 0 42 0 66 ro indicating immature to early mature stage for hydrocarbon generation these vitrinite reflectance values also indicated that the tanjong coals are with sub bituminous b a and high volatile bituminous c rank tmax values ranging from 419 to 451 c are good agreement with the vitrinite reflectance data this is supported by biomarker maturity parameters as suggested by the c32 homohopane the saturated fraction of the tanjong coals are characterized by dominant odd carbon numbered n alkanes n c23 to n c33 high pr ph ratios 8 18 high tm ts ratios 6 28 and pre dominant of regular sterane c29 all biomarker parameters clearly indicate that the organic matter was de rived from terrestrial inputs and deposited under oxic condition

the formation of inertinite rich peats in the mid cretaceous gates formation implications for the interpretation of mid albian history of paleowildfire abstract image analysis and standard point count petrographic data are used to interpret the amount source and variation of inertinite in coal seams of the mid cretaceous gates formation rocky mountain foothills northeastern british columbia inertinite on average is abundant between 40 60 by seam by volume and higher in some zones and within seams fluctuates cyclically the inertinite is interpreted to be almost exclusively fire derived suggesting that fire was a relatively common occurrence in the original peat forming wetlands inertinite enrichment in the gates coals appears to have resulted from preferential destruction of vitrinite precursors by either low temperature decomposition processes or burning rather than by formation of inertinite by a microbial process the position of the gates formation depositional setting east of the rising canadian cordillera is interpreted to have resulted in overall drier conditions in the region and periodic drought in the wetland settings cyclic variation in inertinite vitrinite composition within some of the seams is primarily attributed to climatic variations although variation in subsidence rates could also have been responsible

sedimentological and petrographical characteristics of cretaceous strandplain coals a model for coal accumulation from the north american western interior seaway abstract coal seams formed on many cretaceous wave dominated strandplain sediments in north america are characterized by great lateral continuity tens to hundreds of kilometres substantial thicknesses up to 12 m relatively low ash and sulphur contents the coals formed behind an active shoreline in areas undergoing subsidence due to shale compaction and dewatering the zone of peat accumulation was remote from the shoreline and storm tidal inundations and generally protected from fluvial flooding if the rate of subsidence was too great lakes formed and peat did not accumulate statistical evaluation of petrographic properties by correspondence analysis of the lower cretaceous coals show that the strandplain coals form distinctive petrographic groups that are characterized by relatively low vitrinite contents and high inertinite contents semifusinite and inertodetrinite dominate in the inertinite maceral group liptinite contents are negligible tissue preservation indices and gelification indices indicate for the strandplain coals a forest type paleodepositional environment in which a relatively low water table allowed the accumulation of oxidized and partly oxidized components fusinite and semifusinite significant amounts of detrital components such as inertodetrinite and vitrinite b are diagnostic that some transportation of the organic material took place prior to deposition comparison of coal facies and depositional environments from permian coals of australian show that the lower cretaceous strandplain coals have petrographic similarities to coals that were formed under regressive back barrier conditions in the permian due to differences in nomenclature previously interpreted regressive back barrier environments may be similar to the strandplain environments discussed here

the age palaeoclimate palaeovegetation coal seam architecture mire types paleodepositional environments and thermal maturity of syn collision paralic coal from mukah sarawak malaysia abstract the mukah coal accumulated in the balingian formation where the time stratigraphic position is poorly defined by fauna though a probable late miocene age has always been assigned to this formation samples collected in the present study that yielded an abundance of casuarina pollen associated with occurrences of dacrydium stenochlaena palustris florschuetzia levipoli and also stenochlaena areolaris spores compare closely to zone pr9 of the palynological zonation of the malay basin and can be tied to depositional sequences of malay basin seismic sequences i2000 i3000 indicating an early miocene age for the studied coal the early miocene age shows that the mukah coal was formed during the collision between luconia block dangerous grounds with the borneo that lasted from late eocene to late early miocene the rapid increase of deposition base level caused by the collision is clearly reflected by the architecture of the mukah coal seams that were generally thin and also by the reverse order of the paleo peat bodies the studied coal samples contained large amounts of detrohuminite without the enrichment of liptinite group macerals usually explained by the dominance of herbaceous plants in the paleomires however the pollen assemblages recovered in the present study provide no support for a herbaceous swamp instead the peats were likely formed mainly from forest vegetation based on the recovery of dominant arboreal pollen assemblages in the present study palynomorph assemblages recovered in the present study with abundance of casuarina pollen associated with common occurrences of dacrydium strongly suggest kerangas vegetation and kerapah type peat swamps indicating a very wet climate the occurrence of rattan and pandanus pollens shows that the kerapah type peat swamps were locally bordered by rattan and pandanus swamps this shows that the prevailing use of coal petrography to discern the type of vegetation that was present in the peat forming mires may lead to wrong conclusions therefore a multi disciplinary approach must be applied for a more accurate and reliable spatial interpretation of the type of vegetation that was present in the peat forming mires consistent with the low sulphur content evidence from the palynomorph assemblages recovered from the coal seams shows that the coal forming peat was deposited in freshwater mires with little or no marine influence despite the fact that the accumulation of the mukah coal forming peat took place within a coastal plain setting moreover the fauna present in the host rock formation also suggested a brackish water environment of deposition

relationships between coal quality and organic geochemical parameters a case study of the hafik coal deposits sivas basin turkey abstract this study provides coal quality organic petrographic and organic geochemical data on tertiary subbituminous coal of the hafik area northwestern part of the sivas basin turkey coal petrological studies along with proximate and ultimate analyses were undertaken to determine the organic petrographic characteristics of the hafik coals huminite reflectances were found to be between 0 38 and 0 48 corresponding to an organic material rich and coal layers values characteristic of low maturity this parameter shows a good correlation with calorific values average 21 060 kj kg and average t max 422 c mineral matter diagenesis indicating immaturity the studied coals and organic material underwent only low grade transformation a consequence of low lithostatic pressure therefore the hafik coals are actually subbituminous in rank rock eval analysis results show types ii iii and iii kerogens the organic fraction of the coals is mostly comprised of humic group macerals gelinites with small percentages derived from the inertinite and liptinite groups in this study organic petrographic organic geochemical and coal quality data were compared the hafik deposit is a high ash high sulfur coal the mineral matter of the coals is comprised mainly of calcite and clay minerals

characterization of mangrol lignite gujarat india petrography palynology and palynofacies a multidisciplinary approach petrographical palynological and palynofacies has been adopted to characterize and assess the depositional conditions of eocene mangrol lignite deposit from western india the petrographic study reveals that the lignite is composed predominantly of huminite macerals produced from a woody forest the reflectance values range from 0 27 to 0 32 indicating a lignite rank the variable values of tissue preservation index tpi and gelification index gi as well as the maceral composition indicate fluctuating ground water conditions and difference in the type of vegetation during peat accumulation the palynofloral spectrum suggests the presence of angiosperms including mangrove and pteridophytes belonging to families of bombacaceae annonaceae alangiaceae ctenolophonaceae liliaceae osmundaceae schizaeaceae matoniaceae cyatheaceae among others as the peat biomass source materials for the origin of these lignites the palynomorphs indicate that a tropical to sub tropical climatic condition was present during deposition of the peat biomass and that the original mire likely occurred in a coastal setting this interpretation is strongly supported by palynomorphs with affinity to brackish water taxa palynofacies studies suggest peat deposition under dysoxic conditions in a marginal marine setting high amount of amorphous matter kerogen type i in the shale bed above the lignite and very high content of liptinite in lignite mainly comprised of resinite and liptodetrinite suggest the potential of both shale and lignite for the generation of hydrocarbon

storm and tide dominated shorelines in cretaceous moosebar lower gates interval outcrop equivalents of deep basin gas trap in western canada the moosebar and gates formations crop out in the deformed foothills belt south of fort st john british columbia they permit examination of the depositional environments of sandstones and conglomerates that are gas bearing in the equivalent wilrich falher interval of the deep basin of alberta and british columbia the moosebar gates interval consists of several upward coarsening and marine to nonmarine sequences moosebar bioturbated shales pass upward into turbidites and offshore storm deposits flow directions indicate a north dipping paleoslope a second coarsening upward sequence at the top of the moosebar and base of the gates terminates in a lenticular fluvial conglomerate up to 30 m thick which is overlain by coals carbonaceous mudstones and sandstones above the carbonaceous zone a major lateral facies change is observed fluvial conglomerates in the south grade into beach conglomerates northward the upper part of the beach conglomerate consists of exposed three dimensional storm berms at least 500 m long up to 1 5 m high with wavelengths of 12 to 24 m the berms trend east west seaward of the conglomerate beach are herringbone cross bedded tidal sandstones with a marine trace fauna graded sharp based conglomerates also are present probably washed out to sea by storms farther north at the same stratigraphic level is a series of partly overlapping conglomerate bars up to 5 m thick and 40 to 50 m across the tops of these bars are covered with storm formed symmetric conglomeratic dunes details of the orientation and geometry of these conglomerate bodies along with their internal structure and pebble fabrics suggest that four major environments fluvial beach offshore conglomerate bars and offshore graded storm conglomerates should be identifiable and predictable in the subsurface

lithotype maceral composition and variation as correlated with paleo wetland environments gates formation northeastern british columbia canada abstract lithotype samples collected from mid albian gates formation coal seams in northeastern british columbia were analysed in order to gain a better understanding of coal facies variation compositional boundaries between lithotypes are gradational from bright to dull coals there is a progressive decrease in vitrinite and increase in inertinite liptinite is negligible

sedimentology of fraser river delta peat deposits a modern analogue for some deltaic coals abstract on the recent lobe of the fraser river delta peat accumulation has actively occurred on the distal lower dilta plain the transition between upper and lower delta plains and the alluvial plain distal lower delta plain peats developed from widespread salt and brackish marshes and were not influenced appreciably by fluvial activity lateral development of the marsh facies were controlled by compaction and eustatic sea level rise the resulting thin discontinuous peat network contains numerous silty clay partings and high concentrations of sulphur freshwater marsh facies formed but were later in part eroded and altered by transgressing marine waters the peats overlie a thin fluvial fining upward sequence which in turn overlies a thick coarsening upward prodelta delta front succession lower delta plain upper delta plain peats initially developed from interdistributary brackish marshes and were later fluvially influenced as the delta prograded the thickest peats occur in areas where distributary channels were abandoned earliest sphagnum biofacies replace sedge grass dominated communities except along active channel margins where the sedge grass facies is intercalated with overbank and splay deposits the peats are underlain by a relatively thin sequence of fluvial deposits which in turn is underlain by a major coarsening upward delta front and pro delta sequence alluvial plain peats accumulated in back swamp environments of the flood plain earliest sedge clay and gyttjae peats developed over thin fining upward fluvial cycles or are interlaminated with fine grained flood deposits thickest accumulations occur where peat fills small avulsed flood channels overlying sedge grass and sphagnum biofacies are horizontally stratified and commonly have sharp boundaries with fine grained flood sediments at active channel margins however sedge grass peats are intercalated with natural levee deposits consisting of silty clay these levees reduce both the number and size of crevasse splay deposits coal originating from peats of the different environments of the fraser delta would vary markedly in character peats of the lower delta plain will form thin lenticular coal seams with numerous splits and have a high ash and sulphur content peats from the lower to upper delta plain will be laterally extensive and of variable thickness and quality basal portions of the seams will contain numerous splits and have a high sulphur content whereas upper portions will be of higher quality peats from the upper delta plain alluvial plain will form thick isolated and laterally restricted coal seams characterized by low ash and sulphur contents

petrographic characteristics of coal from the lati formation tarakan basin east kalimantan indonesia the present paper entails the petrographic characterization on limited coal samples drawn from the tarakan basin eastern kalimantan indonesia these coals contain a high concentration of huminite which in turn is dominated by telohuminite as a result of telohuminite content they have high gi and tpi values they contain low concentrations of liptinite and inertinite macerals the dominant microlithotype is vitrite based on the macerals and microlithotypes of these coals their paleodepositional environment has been reconstructed accordingly it is deciphered that these coals have originated under telmatic condition there was predominance of wood derived tissues and increased subsidence rate prevailed in the basin moreover during the time of their evolution there were alternate phases of oxic and anoxic moor conditions with intermittent moderate to high flooding in the basin

rates controls and sand body geometries of transgressive regressive cycles cretaceous moosebar and gates formations british columbia the moosebar and gates formations lower cretaceous in northeastern british columbia consist of seven transgressive regressive sequence nonmarine sediments are thickest in the south and pinch out northward the sequences are laterally persistent extending east from the foothills for 240 km 150 mi the orientation of maximum transgressive and regressive limits in five cycles occurs within an east west trending zone 30 40 km 19 25 mi wide a recurring northward bulging sediment depocenter near the alberta british columbia border was fed by a series of stacked northerly flowing rivers the rivers were a major source of sediment for gravel beaches to the north and east isopach maps of marine sandstone and conglomerate show a series of west northwest east southeast o iented sand bodies 60 70 km 37 43 mi wide parallel with the shorelines each coastline prograded northward as a shoreline attached strand plain and a series of arcuate or cuspate deltas gates formation marine nonmarine cyclicity is a series of fourth order cycles superimposed on a major third order cycle the cyclicity and lateral extent of the sequences can be explained as a result of tectonic thrusting and loading superimposed on the trend of the peace river arch the influence of eustatic sea level variations and sedimentologic switching of point sources had minimal effect coastal retreat ranged from 437 to 875 m 1 000 years 1 433 to 2 780 ft 1 000 years coastal progradation ranged from 218 to 437 m 1 000 years 175 to 1 433 ft 1 000 years the duration of several transgressive regressive cycles was 103 000 275 000 years

a short term establishment of forest fen habitat during pliocene lignite formation in the ptolemais basin nw macedonia greece the intermontane basin of ptolemais is part of a major tectonic trench located in nw greece and includes around 65 of greek coal reserves the upper xylite layer uxl is a distinct lignite layer being 3 6 m thick and outcropping in the upper part of the pliocene lignite bearing sequence at the notio field and tomeas eksi mines of ptolemais compared with the xylite rich lithotypes the matrix lithotypes within uxl contain more ash micropetrographic studies suggest that the upper xylite layer is rich in huminite 90 textinite dominates in the xylite rich lithotypes while attrinite dominates in the matrix lithotypes the liptinite content is 10 while inertinite rarely occurs palaeobotanical determination revealed that the xylite rich coal originated from coniferous vegetation specifically from glyptostrobus europaeus the occurrence of g europaeus as a coal forming element is significant because though this kind of vegetation was common in many greek coals of miocene age this is the first time it has been recorded from the pliocene this study suggests that the upper xylite layer is autochthonous according to coal facies diagrammes peat accumulated under pure telmatic conditions in a relatively wet forest fen both herbaceous and arboreal vegetation contributed to peat formation

a comparison of temperate and boreal peats from ontario canada possible modern analogues for permian coals abstract peat profiles were sampled from a raised bog and an interior fen located in the boreal james bay lowlands northern ontario and a cold temperate swamp and a cold temperate bog in the great lakes st lawrence lowlands southern ontario an examination of the micromorphology and maceral compositions of the peats indicates that considerable differences exist between environments the boreal bog and fen both consist predominantly of relatively unaltered textinite commonly sphagnum derived with higher liptinite contents in the fen profile attributable to the more diverse vegetation both the cold temperate swamp and bog show high levels of humification at the surface possibly partially attributable to recent climatic warming trends causing a decline in water table elevation in all profiles funginite was persistent ranging from 2 to 10 of the total maceral content indicating that aerobic conditions generally prevailed at the surface at the time of deposition the influence of depositional environment and vegetation type on the resulting peat was born out in plots of tissue preservation index vs gelification index the petrographic study also demonstrated that none of the profiles contained high inertodetrinite semifusinite contents comparable to those within cold climate cratonic permian gondwana coals since the oxidation processes leading to the formation of inertinite are considered to take place at the peat stage if the peats studied were to contain a similar maceral assemblage upon coalification inertinite precursors may be present in the peat the lack of petrographic similarity between the holocene peats and the permian coals may be related to a number of factors the decrease in water table elevation possibly responsible for the inertinization of the permian coals may have occurred following the cessation of peat formation not concurrently with accumulation and is potentially attributable to long term factors such as climatic warming the change in the peat forming vegetation from permian glossopteris and gangamopteris dominated communities to holocene sphagnum and coniferous vegetation alters the characteristics of the initial botanical starting materials and some aspects of the ecology particularly trophic and ph conditions which control the post depositional alteration of the plant materials and the resulting maceral assemblages

variability in coal facies as reflected by organic petrological and geochemical data in cenozoic coal beds offshore shimokita japan iodp exp 337 abstract this study reports on cenozoic coal seams recovered at integrated ocean drilling program iodp site c0020 during expedition 337 iodp site c0020 is located in a forearc basin formed by the subduction of the pacific plate off shimokita peninsula japan hole c0020a penetrated 14 coal layers between 1825 and 2466 mbsf eleven of them were investigated within the frame of this paper investigated seams show a slight maturity increase with depth from lignite to sub bituminous coal in order to detect temporal changes in maceral and molecular composition and to relate them to changes in vegetation and depositional environment macro and micropetrographic data bulk geochemical parameters biomarker analysis stable isotope geochemistry and vitrinite reflectance measurements were performed results were also compared with palynological data obtained from 9 coal samples elevated sulfur contents and high ash yields occur in the upper seams cores 14r to 18r whereas low sulfur contents and varying ash yields were determined for the lower coal seams 24r to 30r the maceral composition and biomarker ratios of the uppermost seams argue for coal formation in a paralic environment and brackish alkaline water conditions in contrast lignite samples from the lower part of unit iii point to a limnic fluviatile deposition conifers contributed significantly to peat formation in the uppermost seams from cores 15r to 22r and in the lowermost lignite seam in all other samples angiosperms are considered as the major peat forming plants the pollen and spore floras indicate rich angiosperm vegetation however significant contributions from pinaceae and taxodiaceae are evident for all coals sporophytes have no dominant influence on the coal flora microbial activity in the peat is suggested for instance by higher concentrations of hop 17 21 ene with increasing contents of hopanes or by low 13 c values of hop 17 21 ene the revealed changes in the environment during coal deposition highlight the importance of combined organic petrography organic geochemistry and palynology to reconstruct palaeoenvironmental conditions

organic geochemical palynofacies and petrographic analyses examining the hydrocarbon potential of the kharita formation albian in the matruh basin northwestern egypt abstract a recent study of selected samples from the cretaceous albian kharita formation of egypt revealed very good to excellent source rock sr potential for six intraformational organic rich intervals this work investigates the sr potential of the entire kharita formation across the matruh basin using samples from two wells the abu tunis 1x well from the central part of the basin and the siqeifa 1x well drilled on the eastern margin of the basin more strongly reducing conditions were developed in the centre of the basin and resulted in the deposition of more organic rich shales by comparison to the less reducing conditions that prevailed on the eastern basin margin where the shales contain less organic matter deltaic intraformational shales and carbonates in the kharita formation of abu tunis 1x constitute a significant 120 m net of the potential sr the lower kharita formation contains 34 m net shale sr of good to very good excellent organic richness yielding values of 1 14 11 59 wt total organic carbon toc the organic matter has low hydrogen index hi values 184 389 mg hc g toc and amorphous organic matter aom and relatively high non opaque phytoclast frequencies indicating mainly gas oil prone organofacies kerogen types iii ii the upper kharita is rather important containing 86 m net shale carbonate sr that has fair to good organic richness 0 8 1 8 wt toc and lower hi 126 250 mg hc g toc a dominance of non opaque phytoclasts and subordinate aom frequencies which together indicate gas oil prone organofacies kerogen iii ii in the siqeifa 1x well kharita deltaic intraformational shales and shaley dolostones comprise 80 m net sr which has mainly fair to good to less very good organic richness 0 8 2 1 wt toc whilst low hi 93 220 mg hc g toc dominance of non opaque phytoclasts and subordinate aom indicate gas prone organofacies kerogen type iii a relative upward increase in deposition of lignite and coaly carbonaceous material supports a gas prone organofacies whilst thermal maturity indices only point to immature to early mature pre to early oil window srs in both the abu tunis 1x and siqeifa 1x wells hydrocarbon exploration focussing on this potential source rock may be justified in areas to the southeast of the matruh basin where modelling indicates this unit may have reached the late mature oil to main gas generation windows

coalbed methane characteristics of gates formation coals northeastern british columbia effect of maceral composition the majority of research reported on methane adsorption characteristics of coal seams has focused on vitrinite rich coals however western canadian coals are more inertinite rich than those of the western united states and are shown to differ in gas adsorption characteristics the influence of maceral composition upon gas adsorption characteristics of medium volatile coal samples from the middle cretaceous gates formation of northeastern british columbia was investigated lithotype coal facies samples were analyzed for surface area maceral and mineral composition and methane adsorption standard coal analyses were also performed proximate low temperature ash and equilibrium moisture the vitrinite content of the samples analyzed ranges from 18 to 95 vol min ral matter free the ash yield varies from 4 4 to 33 7 wt both maceral composition and mineral matter content have an important influence on adsorption characteristics as indicated by carbon dioxide surface areas and methane adsorption isotherms on a mineral matter free basis the amount of methane adsorbed generally increases with vitrinite enrichment the lowest methane adsorption occurs in the sample with the highest inertinite content carbon dioxide surface areas of the lithotypes range from 87 to 176 m2 g on a raw coal basis and from 99 to 184 m2 g on a mineral matter free basis surface area generally decreases with increased mineral matter content and increases with increased vitrinite content the increase in adsorption of both methane and carbon dioxide with increased vitrinite concentration is interpreted a resulting from differences in the pore size distribution of vitrinite and inertinite vitrinite is predominantly microporous whereas inertinite is meso to macroporous the monolayer volumes of carbon dioxide as calculated from the dubininradushkevich equation are higher than those of methane as determined from the langmuir equation but are correlated the methane adsorption isotherms and surface area data indicate that the maceral compositional variations in coal are at least as significant as coal rank in determining the potential volume of adsorbed methane and thus the coalbed methane potential of a deposit

the changuinola peat deposit of northwestern panama a tropical back barrier peat coal forming environment abstract a large 82 km 2 thick 8 m low ash low sulfur peat deposit has formed on the northwestern coast of panama its low ash and low sulfur contents can be attributed partly to 1 doming 2 the occurrence of a relatively continuous marine blocking beach barrier shoreline feature and 3 leaching of the mineral matter this deposit is roughly rectangular in shape and oriented with its longest axis parallel to the beach barrier shoreline it would produce an economic coal bed that is bright and finely banded in its thickest central region and more coarsely banded at its margins its northwestern margin would be characterized by interfingering of coal with sandstone and siltstone of the changuinola river flood plain whereas its southeastern boundary would be characterized by truncation of the upper part of the seam by marine to brackish shales siltstones and carbonates that were derived from almirante bay total sulfur was found to be very low less than 0 2 dry wt except in a few places in these rare cases nearly all of the sulfur was pyritic and the total sulfur content was anomalously high 14 although the general tendency was for total sulfur to increase wherever the deposit was influenced by marine conditions one case was found where sulfur was high at the base of an inland freshwater peat core which suggests either a hidden marine influence or the need for some new mechanism to explain sulfur enrichment in such an anomalous case differences in inherent fixed carbon contents and calorific values due to changes in peat type and analytical uncertainties tended to mask seamwide trends in these parameters however fixed carbon contents and calorific values showed a slight tendency to increase with depth especially if plotted for single peat types vitrinite reflectance within the hypothetical changuinola coal bed would be expected to increase as follows 1 toward the margins of the deposit 2 toward the bottom and top of the bed and 3 toward stream channels or tidal inlets

petrographyof some fraser river delta peat deposits coal maceral and microlithotype precursors in temperate climate peats abstract peat deposits on the recent lobe of the fraser river delta british columbia have accumulated in a variety of depositional settings the study of the decomposition of the plant components associated with each depositional area has enabled prediction of the occurrence and distribution of the precursors of the loal macerals and microlithotypes on inactive portions of the distal lower delta plain thin sedge grass peats ave developed these peats were influenced by marine conditions near the base and freshwater conditions higher in the section a high ratio of cellulose to lignin in marsh plants and limited exposure of these tissues to desiccation and oxidation prodcue primarily desmocollinite smaller amounts of cernite cutinite and alganite origginate from algal and sedge lipids in the transition to freshwater peats oxyfusinite pyrofusinite and micrinite partially replace former exinite and vitrinite group maceral precursors subsequent transgression by marine waters has further promoted decomposition of the peat laterally extensive but thin and discontinouus coal seams which would develop from such peat will contain vitrite bands near the base and grade upsection into interlamlaminated durite and vitrinertite peats deposited between the upper and lowerdelta plain originate from brackish water as such earliest peat horizons contain similar maceral compositions to thoce encountered in distal delta plain deposits crevasse and fire splays disrupt gradational changes in fabric upsection and along channel margins flooding by oxygenated neutral ph waters followed by extended periods of desicaation result in increases of inertodetrinite macrinite sclerotinite and oxyfusinite interlaminated durites and vitrinertites will form common microlithotypes interbedded bands of telinite cutinite and cerinite are produced by later freshwater sedge grass peat accumulations in this biofacies clarite replaces durite after colonization by sphagnum lignin rich tissues from ericaceous shrubs and pinus contorta provide precurssors for subernnite telocollinite and telinite stumps of massive telinite interrupt these banded macerals coal seams originating from such peats would be thick laterally extensive and characterized by vitrite with laminae of liptite and lenses of clarite in the upper part

inertinite rich tertiary coals from the zeya bureya basin far eastern russia selected tertiary coals from the zeya buryea basin far eastern russia were investigated for aspects of their coal type rank depositional environment and post depositional history the coals have been examined in outcrop lithotype logging microscopically maceral reflectance and fluorescence and geochemically proximate analysis two laterally extensive coal bearing horizons occur one of palaeocene age and the other of early miocene age the palaeocene coals were investigated in active open cut mines at raichikhinsk and yerkovtsi and the early miocene deposit in an abandoned open cut mine at cergeyevka palaeocene coals at raichikhinsk and yerkovtsi were indistinguishable from each other macroscopically microscopically and geochemically the deposits were sufficiently coalified that brightness logging could be undertaken dull coals with numerous fusainous wisps were dominant four dulling up sequences which represent stacked peat deposits were observed at raichikhinsk at yerkovtsi only a small section of the middle of the seam which was mostly dull and muddy coal was investigated petrographically these coals were dominated by inertinite group macerals which is unusual in non gondwanan coals and rare in the tertiary rank classification was problematic with volatile matter vm content of vitrain daf macroscopic appearance and microscopic textures suggesting subbituminous b rank but carbon content moisture content and specific energy indicating a lignite rank notwithstanding complications of rank estimates of the maximum range burial depths were calculated taking the vm daf content of vitrain as 48 burial depth estimates range from 900 m for a high geothermal gradient and long heating time to a maximum of 3300 m for a low geothermal gradient and short heating time these estimates are maxima as the coal rank may be lower than implied by the vm the cergeyevka deposit is a soft brown coal limited sampling of the upper most portion indicated a high moisture content 75 daf and an unusual hydrogen rich geochemistry lack of identifiable liptinites using either reflected light or fluorescence microscopy suggested a significant bituminite component otherwise the coals appear to be typical for the tertiary an estimate of 125 m maximum burial depth was obtained using the bed moisture content of the coal which is around the present burial depth comparison of present day thicknesses with inferred burial depths suggests that at least 500 m of section is missing between the palaeocene coals and the early miocene coals palaeoenvironmental considerations suggest that fire played a significant role in the accumulation of the peats at raichikhinsk and yerkovtsi at cergeyevka peat accumulation ended by drowning of the mire two tuff beds were recognised within the seam at raichikhinsk and one in the seam at yerkovtsi correlation of the tuff beds is uncertain but they should prove useful in regional coal seam correlation and interpreting coal depositional environments geochemical analysis by xrf was complicated by high loss on ignition loi values despite extensive alteration an acid igneous source is implied from the presence of free quartz and tio2 al2o3 ratios of 0 02 to 0 05

evolution of pennsylvanian late carboniferous peat swamps of the ruhr basin germany comparison of palynological coal petrographical and organic geochemical data abstract this study focuses on the reconstruction of the environment during peat swamp development eight coal and sedimentary organic rock bearing seam successions were examined all belonging to the duckmantian pennsylvanian late carboniferous 410 samples were analysed with coal petrographical methods 155 of these also by palynological methods in addition on 55 samples organic geochemical investigations were carried out with respect to n alkanes and iso alkanes the established coal petrographical parameters gelification index gi tissue preservation index tpi groundwater index gwi and vegetation index vi were used to characterize different periods of peat swamp development furthermore the new index wci water cover index was introduced to reflect water level conditions by using the ratio between hydrophilous hygrophilous and mesophilous plants in this study the index is based on palynological data but can be equally applied when quantitative macrofloral counts are available gi versus tpi values show two general trends of peat swamp evolution low gi and tpi values as indicator for drier swamp conditions like ombrogenous mires and high gi and tpi values which show a trend to water covered environments like topogenous mires in addition ash yields and gwi versus vi data also emphasize a general trend from topogenous to ombrogenous mires a decrease in water level towards the top of the seams and thus resulting in the development of domed mires is reflected by the newly introduced wci hence these parameters show recurrent peat swamp successions characterized by mineral and vitrinite rich coals typical for topogenous swamps and an evolution towards inertinite liptinite rich coals with low ash yield typical for ombrogenous swamps n alkane ratios like the carbon preference index cpi pristane n c17 phytane n c18 pristane phytane and the n c17 n c27 relationship indicate a strong correlation of these parameters with thermal maturity e g cpi values correlate with vitrinite reflectance sulphur organic carbon s toc ratios are quite uniform in clastic rocks with low to moderate toc contents but highly variable in coals probably reflecting variable sulphate availability during deposition of peats sphenophyll rich floral assemblages are restricted to low sulphur environments