structure of chlorella fusca algaenan relationships with ultralaminae in lacustrine kerogens species and environment dependent variations in the composition of fossil ultralaminae numerous kerogens from marine and lacustrine source rocks and oils shales previously considered as amorphous were recently shown to comprise very thin 10 30 nm thick lamellar structures termed ultralaminae comparative morphological and chemical studies of a lacustrine ultralaminae rich kerogen and of the non hydrolysable biopolymer algaenan isolated from the thin resistant outer walls of a freshwater microalga scenedesmus quadricauda established a close relationship between these two materials chemical correlation was mainly based on the production upon pyrolysis of a series of n alkylnitriles with a bimodal distribution the non hydrolysable biopolymer isolated from the outer walls of the ubiquitous freshwater microalga chlorella fusca exhibits the same morphologicalfeatures as those observed in s quadricauda and in fossil ultralaminae the investigation of c fusca algaenan by solid state 13c nmr and analysis of pyrolysis products revealed that the correlation previously established between s quadricauda and lacustrine ultralaminae also holds for c fusca since the same series of n alkylnitriles with the same distribution is formed upon pyrolysis probably via cleavage of amide functions this confirms that fossil ultralaminae in lacustrine kerogens derive from the algaenans building up the thin outer walls of freshwater microalgae via the selective preservation pathway in addition the analysis of the 2 n alkanones generated on pyrolysis indicates that their distribution depends on the algal species considered accordingly variations in ketone distributions in the pyrolysates of lacustrine ultralaminae rich kerogens may reflect differences in populations of the source microalgae on the contrary changes in n alkylnitrile distribution would not be species dependent but would reflect the lacustrine or marine origin of the considered material

classification of huminite iccp system 1994 abstract in the new classification iccp system 1994 the maceral group huminite has been revised from the previous classification iccp 1971 int handbook coal petr suppl to 2nd ed to accommodate the nomenclature to changes in the other maceral groups especially the changes in the vitrinite classification iccp 1998 the new vitrinite classification iccp system 1994 fuel 77 349 358 the vitrinite and huminite systems have been correlated so that down to the level of sub maceral groups the two systems can be used in parallel at the level of macerals and for finer classifications the analyst now has according to the nature of the coal and the purpose of the analysis a choice of using either of the two classification systems for huminite and vitrinite this is in accordance with the new iso coal classification that covers low rank coals as well and allows for the simultaneous use of the huminite and vitrinite nomenclature for low rank coals

assessing δ13c and c n ratios from organic material in archived cores as holocene sea level and palaeoenvironmental indicators in the humber estuary uk organic 13c and c n analyses of estuarine deposits provide proxies for changes in the source of organic matter which can be driven by fluctuations in relative sea level river discharge and catchment disturbance here we present the results of a comprehensive vegetation and sediment 13c and c n survey of welwich marsh outer humber estuary uk together with high resolution 13c and c n analyses of holocene cores collected nine years previously from the humber estuary and the lincolnshire marshes eastern england uk the contemporary intertidal 13c and c n dataset shows a gradual increase in surface sediment 13c with decreasing marsh height and suggests that 13c is controlled by the degree of tidal inundation and thus reflects organic matter source however sediment c n ratios are less sensitive to tidal changes and the recent introduction of c4 salt marsh species complicates the contemporary analogue the holocene 13c and c n records are in general agreement with existing microfossil data and provide additional palaeoenvironmental information this includes support for an estuary wide expansion of marine conditions from c 3 3 ka cal yr bp followed by a contraction of marine conditions after c 2 7 ka cal yr bp and evidence for an increase in delivery of terrigenous organic matter to the inner estuary in the late holocene bulk organic 13c and c n analysis is shown to be a reliable and independent indicator of coastal environmental change and is therefore a complementary technique to the more commonly used microfossil approach however this study also shows that in some circumstances the technique may be compromised when applied to sediments from cores that have been stored for a period of time

radiation and self ignition induced alterations of permian uraniferous coal from the abandoned novator mine waste dump czech republic abstract the effects of uranium mineralization and self burning processes on inorganic and organic components of coal have been studied at a waste pile of the former novator coal and uranium mine at beckov intrasudetic basin czech republic in order to characterize physical and chemical properties of wastes as a basis for further environmental studies unaltered bituminous coal was composed predominantly of vitrinite with random reflectance values between 0 72 and 0 86 and inertinite less common liptinite macerals and a low level of organic solvent extractable material 0 01 1 33 wt uranium minerals caused local radioactive alterations in the uranium enriched coal matrix the diameter of rounded radiation induced haloes ranged from 0 35 to 100 m with higher reflectance 0 84 3 44 compared with bulk coal structural changes in radiation induced altered organic coal matter were characterized by low values of raman band disorder fewer aliphatic c h bonds and higher levels of oxygenated functional groups in micro infrared spectra zones of higher reflectance were also confined to veinlets of epigenetic chalcopyrite galena and sphalerite mineralization oriented perpendicularly to the coal bedding the methylnaphthalene ratios mnr of extracted organic matter correlated with uranium concentrations in individual samples in self ignition affected samples the higher reflectance 1 31 1 71 and values of raman band disorder mirrored the intensity of burning processes organic matter samples located at unburnt and burnt coal interfaces were composed of a mixture of coal macerals char and solid bitumens in the waste heap burning zone coal and claystone were transformed to clinkers composed of plagioclase pyroxenes tremolite hematite magnetite anatase and aluminosilicate glass or to paralava formed by porous cordierite and hematite organic components in the burnt out zone were represented by small dense and massive coke particles with reflectance of 4 48 fusinite with reflectance of 3 05 and rare coke droplets of solid bitumen r 1 90 only traces of phenanthrene and alkanes were identified in organic extracts of burnt out rock

13c and 15n nmr spectroscopic investigation on the formation of fossil algal residues 13c and 15n nmr spectroscopy was applied to modern a mixed algal culture its algaenan and its compost ancient algal derived sediments from mangrove lake bermuda and fossilized algal residues torbanite green river shale for the purpose of establishing the forms of nitrogen algal remains and evaluating their long term stabilities the results indicate that proteinaceous material can resist microbial degradation in sediments as old as 4000 yr possibly in refractory biopolymers by encapsulation into their macromolecular network the 15n nmr spectra of the torbanite and the green river shale show a relative enrichment of heterocyclic n which may derive from selective preservation of biogenic heterocyclic compounds or by rearrangement of peptide chains during diagenesis

a reappraisal of kerogen formation abstract comparative microscopical and chemical studies of recognizable entities in kerogen and their extant counterparts suggest a new and simple mechanism of kerogen formation which clarifies the interrelationships between extant biomass kerogen and fossil fuels

paleoenvironmental settings of the sofia lignite basin insights from coal petrography and molecular indicators abstract compositions of balsha lignite sofia coal bearing basin bulgaria and carbonaceous shales are studied by petrological and geochemical proxies the macropetrographic characteristic of profiles is relatively constant the lignite is generally composed of dull matrix coal containing significant amounts of xylite fragments the typical microscopic constituents of the lignite are the ulminite and less frequently textinite lenses scattered within attrinitic groundmass the maceral composition of the organic matter in carbonaceous shales does not differ significantly from that of the lignite samples biomarker assemblages of the extractable portions are determined by gas chromatography mass spectrometry additional information for the compositions of residues after extractions is obtained by tmah thermally assisted hydrolysis methylation petrographic contents lipid assemblage and tmah thermally assisted hydrolysis methylation data imply that the original peat bog is formed in fresh water forest swamp preferably composed by gymnosperms polar diterpenoids argue for cupressaceae s l taxodiaceae as the most probable vegetation for one of the profiles appreciable angiosperm rich herbaceous type flora contribution is assumed polar oleanane triterepenoids and their aromatized derivatives argue for angiosperm input the relevance of a norfriedel 8 en 10 one friedelin ratio for groundwater level appraisal is discussed it admits long period of high water level in the paleomire high content of vanillyl structures and subordinated presence of syringyl units in products of tmah thermally assisted hydrolysis methylation are hint for gymnospermae input in the paleoswamp and angiospermae contribution to one of the profiles cinnamyl phenolic units indicating non woody angiosperm vegetation presence are registered as well flavonoids in products are considered as taxonomic markers of cupressaceae plants in the paleoswamp

fossil wood in coal forming environments of the late paleocene early eocene chickaloon formation the early cenozoic chickaloon formation is the main coal bearing sequence in south central alaska coal and associated plant macrofossils are well exposed in the eska premier and jonesville coal groups in the wishbone hill district there is a striking variation in the degree and mode of preservation of fossil trees in a vertical sequence through these coal groups we examined the wood taxonomy mineralogy and geochemistry to elucidate potential cause s for these differences the wood anatomy indicates that the wood is all assignable to the cupressaceae taxodiaceae s str and assignable to the form genus taxodioxylon hartig emend gothan however we found no significant variation in the taxonomy of the wood between stratigraphic layers the wood generally becomes better preserved in the jonesville coal group wood from the stratigraphically lower premier coal group exhibits greater plastic deformation and contains less well preserved wood anatomical features the wood from the overlying jonesville coal group retains most of its original morphology but has suffered from brittle fracture the geochemistry and mineralogy of the wood follow a pattern that corresponds to the degree of preservation the less well preserved wood tends to have a higher concentration of iron carbonate minerals e g siderite and ankerite whereas the better preserved wood contains more calcium carbonate or silica all evidence points to rapid permineralization of the original wood although the least well preserved wood shows evidence of greater organic matter decomposition than the better preserved wood the wood taxonomy and mode of preservation of wood from the upper part of the chickaloon formation is similar to wood from coeval fossil forests that developed at higher polar paleolatitudes

occurrence and origin of ultralaminar structures in amorphous kerogens of various source rocks and oil shales abstract forty low maturity type i ii kerogens from source rocks and oil shales ranging in age from infra cambrian to miocene were examined by transmission electron microscopy tem when previously observed by light microscopy and or uv fluorescence microscopy the above samples like a very large number of kerogens seemed homogeneous and amorphous in fact tem revealed the presence of ultralaminar structures in 22 of these amorphous kerogens the abundance of ultralaminae depends on the considered sample and some of the tested kerogens are nearly exclusively composed of ultralamina accumulations based on thickness three main groups of ultralaminae can be identified parallel studies on extant algae indicated that some of the above ultralaminae likely derived from the resistant outer walls of microalgae the fossilization of such outer walls should occur via the selective preservation pathway and result in the formation of highly aliphatic ultralaminar kerogens the lack of ultralaminae in infra cambrian kerogens is consistent with a cyanobacterial origin

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

the nature and fate of natural resins in the geosphere iv middle and upper cretaceous amber from the taimyr peninsula siberia evidence for a new form of polylabdanoid of resinite and revision of the classification of class i resinites abstract analysis of three amber resinite samples collected from middle and upper cretaceous sediments in the taimyr peninsula siberia indicates that these materials are based on copolymers of biformene i and communol ii these resinites represent a previously undescribed form of class i polylabdanoid resinite definitions of the sub classes of class i resinites have been revised generalized to recognize the general relation between these samples and other class ib resinites and to facilitate classification of polylabdanoid resinites which do not necessarily incorporate communic or ozic acids

relationships between environmental conditions and the diagenetic evolution of organic matter derived from higher plants in a modern mangrove swamp system guadeloupe french west indies abstract the sedimentary organic matter content of a series of 2 m deep cores was investigated along a sea land transect at five sites representing five species of mangrove and salt marsh vegetation the vegetation was settled at the same place for at least 1000 years and therefore sedimentary organic matter deriving from the decay of higher plants has accumulated in large amounts the global morphological and chemical preservation of the organic matter attested by various sedimentary parameters including the proportions of cellulose bearing tissues the toc contents the c n ratios the total sulphur contents and the 13 c compositions reveals that the sedimentary organic matter is less degraded when it has been under the influence of the marine water table for a long time this is indicated by a good correlation between the salinities of interstitial waters the redox potentials measured in the wet sediments and the chemical composition of the organic matter moreover the concentration of organic sulphur shows a positive correlation with the hydrogen index hi only under the marine water table influence suggesting the very local presence of sulphur hc compounds

biogeochemical controls on mercury stable isotope compositions of world coal deposits a review abstract coal deposits were important natural hg sinks in the late paleozoic and middle late mesozoic coal combustion since the industrial revolution has emitted more than 35 000 t of hg into the atmosphere environmental geochemistry research on hg in coal is essential to understand the natural hg cycle throughout earth history and the present day hg cycle under human perturbation in this review we summarize the methods of hg isotope measurement in coals and compile recently published hg isotope data of 200 world coal samples according to their locations formation periods carboniferous permian jurassic cretaceous early middle cenozoic and ranks anthracite bituminous coal subbituminous coal lignite and illustrate the controls of sources and biogeochemical processes on hg isotope compositions in coal deposits up to 4 7 variation 3 90 to 0 77 in mass dependent fractionation mdf represented by 202 hg and 1 0 variation 0 63 to 0 34 in mass independent fractionation mif represented by 199 hg are observed in world coal deposit with an average value of 1 16 0 79 1sd and 0 11 0 18 1sd for 202 hg and 199 hg respectively we find that coal 202 hg and 199 hg are broadly controlled by two source materials terrestrial plants biogenic hg and crustal rocks geogenic hg accounting for 37 46 and 54 63 of hg in coals no clear trends are seen in neither 202 hg vs coal forming periods nor 202 hg vs coal ranks which we attribute to important overlapping of 202 hg in the source materials of different coal forming periods and the multidirectional hg mdf during coalification interestingly a step wise increase in total hg and a disappearance of 199 hg are observed along with increasing coal rank suggesting the addition of hydrothermal hg into high rank coals the hydrothermal fluids not only upgraded the coal ranks but also increased the hg concentrations and 199 hg of coals in addition the addition of hydrothermal hg into coal deposits was also partly responsible for the comparatively higher total hg and 199 hg in the late paleozoic coals relative to the mesozoic and cenozoic coals the co variation of atmospheric oxygen levels and 199 hg of coals at different coal forming time widows suggests that the removal of biogenic hg in response to widespread swamp fires may have increased the 199 hg in late paleozoic coals as well our study indicates that coal hg isotopes provide new insights into the biogeochemical cycle of hg in coal deposits and that 199 hg is a robust indicator to trace hg addition removal in coal deposits and biogeochemical processes magmatic intrusion hydrothermal fluids penetration burning of coal swamp occurring during coal deposition

biomarkers aromatic hydrocarbons and polar compounds in the neogene lignites and gangue sediments of the konin and turoszow brown coal basins poland abstract this paper presents geochemical characteristics of 35 samples of miocene lignites and gangue sediments clays sampled in the konin and turoszow brown coal basins poland lignites belonged to xylitic detro xylitic detritic and fusitic lithotypes organic geochemistry of them were investigated using such methods as rock eval pyrolysis gas chromatography mass spectrometry of separated aliphatic hydrocarbons compounds of medium polarity and methyl esters of fatty acids flash pyrolysis gc ms was applied for investigation of macromolecular organic matter of the samples reflected light microscopy was used to find maceral composition and huminite reflectance all samples organic matter show immature features well corresponding to its values of huminite reflectance 0 17 0 35 rock eval t max values were exceptionally low in all cases on average 387 c and they show high differentiation according to the lignite lithotypes with lowest values for xylites also other geochemical features of organic matter are lithotype dependant such as n alkanes and fatty acids distributions many biomarkers presence and distribution types and chemical composition of lignite macromolecular fraction it was possible to asses dominating sources of organic matter using relative concentrations of three groups of compounds with diterpene hopane and oleanane molecular structures most of miocene detritic lignites come from monocotyledonic material with some of them containing coniferal detritus like needle leaves xylitic lignites come from podocarpaceae pinaceae cupressaceae and taxodiaceae families what is indicated by diterpenoids and sesquitenoids distribution detro xylitic lignites show intermediate geochemical features between detritic and xylitic lignites

occurrence of polycadinene in fossil and recent resins abstract dammars produced by dipterocarpaceae growing in southeast asia are partly composed of a macromolecule with a polycadinene structure this polymer is the precursor of many specific compounds encountered in crude oils and sediment extracts from south asia until recently there was no evidence for a more widespread geographical occurrence of this resinous polymer using different pyrolysis methods it is shown that the polymers present in a resinite from utah usa and in resins contained in resin canals of eocene fossil fruits from germany and england are also polycadinenes the fossil fruits were undoubtedly produced by ancient representatives of mastixioid cornaceae a group of plants which was widespread in the tertiary of europe and north america and which is not related to dipterocarpaceae these findings extend the known occurrence and origin of the sesquiterpenoid type resin polymer it is to be expected that catagenetic products of these resin polymers should be present in oils coals and sediment extracts from areas outside southeast asia

the organic geochemistry of coal from plant materials to coal coalification is a process that transforms plant remains under the influence of time temperature and possibly pressure to a black generally lustrous solid organic fossil fuel having a very complex chemistry although much has been learned in the past two centuries on coal chemistry we still have little knowledge of the way plant materials undergo these transformations the problem has been the existence of adequate characterization tools the advent of some new tools for structural elucidation of macromolecules has led to some revised thinking on coalification originally thought to be a process involving the full degradation of plant remains and subsequent reconstitution of these remains the general consensus today is that the process involves a selective preservation of certain resistant plant components followed by some minor reorganization of the biopolymers that survive the major components of plants do degrade and the resistant ones often constitute only a small fraction of the original mass of the plant materials this paper examines the most recent literature concerning coalification and focuses on the chemistry associated with coalification of certain recognizable plant remains that have been at the center of research activity for the past two decades thus we examine the recent knowledge of the chemistry of resistant biopolymers in extant and fossil wood cuticles resins spores and algae knowledge that has been assembled to establish the reaction pathways towards coal macromolecules

non destructive multiple approaches to interpret the preservation of plant fossils implications for calcium rich permineralizations permineralized fossil coniferous woods from the pliocene of dunarobba umbria italy and the jurassic of swindon wiltshire england were studied using non destructive techniques on uncoated polished thin sections to elucidate their preservational history specimens were observed using transmitted light polarized light reflected light under oil and cathodoluminescence selected areas were studied using a variable pressure sem in backscattered electron mode this allowed uncoated specimens to be examined and elemental distributions to be determined using an energy dispersive x ray microanalyser the data were used to interpret details of the permineralization history results reveal that anatomical interpretations based merely on observations of thin sections in transmitted light can be very misleading and could potentially affect the application of permineralized plant fossils for example in evolutionary biology palaeoclimate analysis and isotope geochemistry

effect of relative lake level changes in mire lake system on the petrographic and floristic compositions of a coal seam in the most basin miocene czech republic abstract exposures in the bilina opencast mine provide a direct evidence that the 3 5 m thick upper bench of the main seam in the most basin passes over a distance of about a kilometre into a hundred metres thick equivalent of clastic deltaic sediments with gilbert type mouth bars and thus clearly corroborates the co existence of lacustrine delta mire system deposition of the delta and the upper bench of the main seam were affected by five short term lacustrine incursions possibly related to tectonic subsidence before final lacustrine transgression took place between the temporary lacustrine incursions delta mouth bars prograded into an extensive mire being separated only by a shallow compaction lake along mouth bars foreland however most clastics introduced from delta were caught by dense vegetation in a narrow proximal zone of mire and did not affect more distal parts of relatively dry woodland mire with water table fluctuating around the surface it is therefore characterised by low ash yield and increased resinite fusinite and inertodetrinite contents palynological data indicate that the peat forming vegetation of the upper bench of the main seam was dominated by taxodiaceae glyptostrobus athrotaxis and calamus palm accompanied by paludal species of the family pinaceae and rich undergrowth of ferns and vaccinium type ericaceae progradation of delta mouth bars to the proximity of the study section is documented by increasing proportion of allochthonous elements produced by plants colonizing the flood plain and delta plain areas nyssa taxodium parrotia ulmus pyramidalis and comptonia pinus oviformis associations in contrast during periods of temporary lacustrine transgressions the mire was replaced by open water environment which favoured deposition of clay rich coals or partings 30 of ash yield of the flooding horizons in spite of fact that delta body retreated to the basin margin and the clastics were introduced from a larger distance rare palynomorphs indicate only sparse vegetation cover of aquatic plants during this time clay content seems to be the best indicator of the water level fluctuations facies indices e g tpi and gi show only poor correlation to hydrological and floristic changes detected in the mire lake system

the molecular composition of kerogen in pliocene mediterranean sapropels and associated homogeneous calcareous ooze abstract the organic matter of three time equivalent pliocene sapropels was characterized as being predominantly type ii kerogen using rockeval pyrolysis it is dominated by amorphous organic matter originating mainly from marine organisms as indicated by the relatively high abundances of algaenan and chlorophyll derived pyrolysis products in the curie point pyrolysates of the kerogen of the sapropels however a small amount of terrigenous organic matter was also observed in the form of pollen and spores that most probably yielded the oxygenated aromatic pyrolysis products known to derive from sporopollenin lignin pyrolysis products such as methoxyphenol and catechol 1 2 benzenediol commonly used as unequivocal evidence for a contribution of terrestrial higher plants in the form of woody material to the kerogen were absent from the kerogen pyrolysates no major spatial and temporal differences in the kerogen composition of the three time equivalent sapropels were observed palynological studies revealed that organic matter in the homogeneous intervals below and above the sapropels consisted of pollen spores and amorphous organic matter this was confirmed by curie point pyrolysis gc ms results showing a relatively high abundance of algaenan derived compounds and the presence of oxygenated aromatic pyrolysis products the differences observed between the kerogen pyrolysates of the sapropels and their homogeneous intervals are suggested to be governed primarily by enhanced preservation conditions resulting in increased preservation of marine organic matter in the sapropels

oxygen isotope ratios in fossil wood cellulose isotopic composition of eocene to holocene aged cellulose abstract we measured the 18 o of cellulose 18 o cel extracted from fossil wood collected at 9 sites in the northern and southern hemispheres as a potential source of information about precipitation 18 o 18 o ppt in the past and paleotemperatures the samples had been buried in fluvial sediments for periods of time ranging from ca 45 million to 250 years at the oldest localities high latitude eocene through pliocene age sites in canada and russia mean annual temperature mat estimates derived from the modern relationship between mat and 18 o cel are 6 16 c lower than the mat estimates derived from other biological proxies estimates of pleistocene and holocene mean annual temperatures are close to the modern values at those sites these results are consistent with other recent findings that the mat 18 o ppt relationship across north america was not constant throughout the cenozoic paleo 18 o ppt estimates derived from fossil cellulose and the modern north american relationship between 18 o cel and 18 o ppt are within the current annual range of 18 o ppt values at all locations the middle eocene 18 o ppt we determined from arctic cellulose samples 21 9 is consistent with river water 18 o determined in two other studies 19 1 to 22 these findings provide some evidence that a precipitation 18 o signal may be retained in wood cellulose during millions of years of burial and that latitudinal patterns in 18 o ppt may not have changed much during the past 45 ma these interpretations depend of course on the assumption that the isotopic composition of the cellulose has not changed during burial an assumption for which it is difficult to gather direct evidence xrd analysis shows that the crystalline form of the fossil cellulose we used to estimate paleoprecipitation 18 o and paleo mat is the same as that of modern cellulose and that the samples are free of quartz and iron oxide contaminants that result in negative errors in measured 18 o cel

characterization of peatified and coalified wood by tetramethylammonium hydroxide tmah thermochemolysis abstract seven samples of peatified and coalified wood varying in rank from peat to subbituminous coal have been analyzed using a new technique thermochemolysis with tetramethylammonium hydroxide tmah the preserved lignin in the coal undergoes thermochemolysis reactions when subjected to treatment with tmah at 300 c for 10 min yielding a series of methylated guaiacyl derivatives that originate from the cleavage of o 4 bonds from preserved lignin as rank increases from peat to subbituminous coal the yields of lignin derived monomers decreases and the ratio of methylated acids to methylated aldehydes increases systematically describing a general increase in the level of alteration of the lignin side chain this new technique of tmah thermochemolysis lends itself well to studies of structural changes that may occur in lignin as it is being altered during coalification data obtained in this study along with structural models proposed in the past have given insight to mechanistic changes that occur in the lignin biopolymer during early coalification we propose that the first reaction to occur is o 4 bond cleavage and subsequent re alkylation of the aromatic ring followed by demethylation of the methoxyl side chain functionalities to produce catechol like structures

chemical evidence of kerogen formation in source rocks and oil shales via selective preservation of thin resistant outer walls of microalgae origin of ultralaminae abstract new structures termed ultralaminae were recently observed by transmission electron microscopy usually in high amounts in a number of kerogens from oil shales and source rocks morphological similarities were noted between ultralaminae and the thin ca 15 nm resistant outer walls composed of non hydrolyzable macromolecules algaenans commonly occurring in extant chlorophyceae especially in the cosmopolitan genus scenedesmus identification of the pyrolysis products of s quadricauda algaenan showed i a highly aliphatic structure based on a macromolecular network of long up to c32 polymethylenic chains probably cross linked by ether bridges and ii a close correlation based on the formation of n alkylnitriles between this algaenan and two ultralaminar kerogens the rundle oil shale mainly composed of ultralamina accumulations and the green river shale ultralaminae dispersed within an amorphous matrix these fossil ultralaminae therefore likely originated from the selective preservation of the thin algaenan containing outer walls of scenedesmus and or of other chlorophyceae containing outer walls of a similar morphology and composition relative distributions of n alkylnitriles and of n alkanoic acids in the pyrolysates of s quadricauda algaenan and of the rundle oil shale indicated that nitriles are not derived from secondary reactions of carboxylic acids but originate from preexisting nitrogen functions likely amides previous evidence of kerogen formation via selective preservation of algaenans was restricted to rather uncommon kerogens the present results added to ultralamina common occurrence and abundance point to a wide involvement and to a large contribution of the selective preservation of algaenan containing thin outer walls of chlorophyceae in the formation of kerogens in a number of lacustrine source rocks and oil shales all the available information suggest that the three way correlation selective preservation of algaenans from thin resistant chlorophycean outer walls formation of fossil ultralaminae presence of n alkylnitriles with a typical distribution in the pyrolysates of ultralaminar kerogens observed in this study might be of a general character

computation of the palaeointensity of the geomagnetic field abstract a procedure for statistical analysis of data obtained by the thellier palaeointensity method is presented the procedure comprises multicomponent analysis of natural remanent magnetization nrm vectors the development of a statistical model of the nrm trm thermoremanent magnetization diagram computation of the regression line and of the confidence interval for its slope by use of the one way analysis of variance the criterion for testing the differences between results obtained from a set of samples is derived and the problem of accumulation of results is discussed the usefulness of the method is demonstrated on a few samples of tertiary porcellanites from northern bohemia

coal petrology and the origin of coal macerals a way ahead the development of coal petrology and the establishment of a nomenclatural system have proved of major use both for the industrial utilization of coal and for the development of a broad understanding of coal formation and diagenesis the development over the past 30 years however of nomenclature that includes aspects of plant origin and process is a retrograde step e g pyrofusinite degradofusinite and funginite equally problematic is the use of prescriptive formulae to indicate coal origins this paper reviews some of the problems involved with coal petrology as it is usually practiced in addition new advances in organic geochemical techniques have led to a fuller understanding of the relationship of plants and coal macerals recent research on the origin of coal macerals is presented and there is a discussion of the problems and challenges facing coal petrologists a holistic approach to studies of the origin of coal and coal macerals which includes not only petrographic but also chemical and biological studies is advocated d 2002 elsevier science b v all rights reserved

application of etching and sem in the identification of fossil plant tissues in coal abstract the masking effects of diagenesis and coalification on plant material in coal can be removed by chemical etching in addition identification of detailed botanical structure can be improved through scanning electron microscopy sem which provides greater resolution and clarity of image than conventional optical microscopy the combined techniques of etching and sem allow the original constituents of coal plant fossils as opposed to macerals to be characterized and compared in far greater detail than previously possible for example preserved woody tissue secondary xylem in some coals can be compared to extant plant material and identified as either gymnosperm or angiosperm based on anatomical characteristics such as type of ray tissue xylem tracheids and vessel elements observable in sem smaller structures such as types of fossil cork cells with suberized cell walls and inner cortex tissue are also described in submicron detail finally a feature discernable in the sem but not observed in optical microscopy are micron sized structures possibly mycorrhizal hyphae associated with secondarily thickened epidermal cell walls of probable primary roots in an eocene coal bed

x ray photoelectron emission spectromicroscopic analysis of arborescent lycopsid cell wall composition and carboniferous coal ball preservation abstract two alternative processes complicate understanding of the biochemical origins and geochemical alteration of organic matter over geologic time selective preservation of original biopolymers and in situ generation of new geopolymers one of the best constrained potential sources of bio and geochemical information about extinct fossil plants is frequently overlooked permineralized anatomically preserved plant fossils allow analysis of individual cell and tissue types that have an original biochemical composition already known from living plants the original composition of more enigmatic fossils can be constrained by geochemical comparisons to tissues of better understood fossils from the same locality this strategy is possible using synchrotron based techniques for submicron scale imaging with x rays over a range of frequencies in order to provide information concerning the relative abundance of different organic bonds with x ray absorption near edge spectroscopy in this study x ray photoelectron emission spectromicroscopy x peem was used to analyze the tissues of lepidodendron one of the lycopsid trees that were canopy dominants of many pennsylvanian coal swamp forests its periderm or bark the single greatest biomass contributor to many late paleozoic coals is found to have a greater aliphatic content and an overall greater density of organic matter than lignified wood because x peem allows simultaneous analysis of organic matter and matrix calcite in fully mineralized fossils this technique also has great potential for analysis of fossil preservation including documentation of significant traces of organic matter entrained in the calcite crystal fabric that fills the cell lumens

paleoenvironmental implications from biomarker and stable isotope investigations on the pliocene velenje lignite seam slovenia a pliocene lignite seam up to 160 m thick occurs in the velenje basin slovenia the seam originated in a topogenous mire and evolved within a non marine transgressive setting differences in soluble organic matter yield and hydrocarbon content of borehole samples from the lignite are related to differences in the composition of free lipids of microbial origin and or hydrocarbons derived from the biogeochemical degradation of plant tissue variations of the redox conditions within the mire are reflected by pristane phytane ratios the abundance of terpenoid biomarkers indicates the predominance of gymnosperms over angiosperms which is consistent with palynomorphic spectra dominated by pollen of the sequoia taxodium metasequoia plant community rather than by angiosperms evidence is also provided that the content of land plant derived biomarkers and the preservation of plant tissue is controlled by the input of resin rich decay resistant conifers sections of the seam characterized by a high degree of gelification of humotelinite gelification index show high contents of hop 17 21 ene but low hopane concentrations the results suggest that the gelification of plant tissue may be governed by the activity of anaerobic rather than aerobic bacteria despite the minor variation in the proportions of gymnosperms versus angiosperms in the peat forming vegetation a general influence of the floral assemblage on carbon isotopic composition of the coals 13c 25 3 to 27 0 is proposed carbon cycling during biogeochemical decomposition of plant tissue by bacteria is assumed to affect the 13c value of the lignite petrographic and geochemical data of gelified and ungelified fossil wood provide evidence that gelification may be governed by microorganisms e g anaerobic bacteria different from those responsible for decreasing cellulose contents during early diagenetic aerobic degradation of wood based on the molecular composition of terpenoid biomarkers the wood fragments are identified as derived from gymnosperms the relative proportions of saturated versus aromatic hydrocarbon fractions of fossil gymnosperms display a general tendency towards lower values in gelified wood remains this indicates that bacteria involved in gelification of plant tissue may also be involved in aromatisation of diterpenoid hydrocarbons the chemotaxonomical classification of the macrofossils as gymnosperms is corroborated by the mean carbon isotopic compositions of the macrofossils 13c 24 5 and the extracted cellulose 13c 22 0 the higher isotopic difference of about 2 5 between cellulose and fossil wood compared to that found in modern trees can most probably be explained by the smaller effect of 13c discrimination for cellulose when compared with wood during decomposition chem geol 158 1999 121 compared with the coals the 13c values of wood and extracted cellulose are affected to a minor extent by microbial activity

kerogen origin evolution and structure kerogen commonly defined as the insoluble macromolecular organic matter om dispersed in sedimentary rocks is by far the most abundant form of om on earth this fossil material is of prime importance as the source of oil and natural gas moreover kerogen can provide essential information on major topics such as past environments climates and biota this review reports the main advances in kerogen studies since the comprehensive synthesis edited by durand durand b ed kerogen insoluble organic matter from sedimentary rocks editions technip paris 1980 it is organized into eight sections the first two are concerned with the successive definitions of kerogen and the definition used here the different techniques used for kerogen isolation without loss or degradation and basic kerogen analysis the third and fourth focus on sedimentary om sources and preservation processes in relation to depositional environment including sedimentation conditions favourable for kerogen accumulation and extrapolation to past geological time great strides have been made in the latter topics over the last 25 years owing to a combination of classical studies in organic geochemistry and studies in other domains such as biogeochemistry oceanography hydrology and soil science along with the development of powerful analytical tools the next two sections deal with the different kerogen classifications by type and kerogen evolution and maturation upon burial in sediments structural modelling of coal and kerogen based on physical and or chemical structural analysis is described in the following section although only statistical the models thus derived provide a synthetic view of the main structural resemblances and differences among various samples in relation to source maturity or physicochemical properties finally the last section explores some of the advances in kerogen understanding expected for the near future the review includes a list containing about 500 references

a review of charcoal analysis as a tool for assessing quaternary and tertiary environments achievements and limits abstract identification of charcoal fragments 2 mm using reflected light microscopy is routinely carried out to study former natural ecosystems assess changes in vegetation communities over time and identify the influence and patterns of behaviour of human populations on vegetation material studied comes either from archaeological horizons or soil profiles despite undeniable limits informative results have been obtained in the last 25 years mostly in southwestern europe where charcoal analysis has been widely applied in quaternary studies examples of these achievements are provided focusing on the major vegetation trends since the upper palaeolithic to the middle ages the techniques used for charcoal analysis in the reconstruction of quaternary vegetation are now being used to study tertiary charcoal and lignites the study of fossil charcoal can be a highly informative method for interpreting ancient ecosystems as species easily degraded may be preserved by charcoalification some results from the lower rhine embayment germany are presented here

interrelationship of fluid venting and structural evolution alvin observations from the frontal accretionary prism oregon seismic reflection and sea beam bathymetric data plus submarine geological measurements define a ramp anticline at the deformatoin front of the central oregon subduction zone at its northern termination the ramp anticline is deeply incised by a large 500 m deep submarine canyon and cut by a probable backthrust to the south along the strike of the fold a smaller submarine canyon shallowly erodes the anticline and backthrusting is not apparent in the submersible observations two alvin dives along a transect through the southern canyon show active fluid vents demarked by biological communities at the frontal thrust and at the breached crest of the anticline along a northern transect encompassing the large submarine canyon 10 alvin dives indicated no venting on the formal thrust limited venting in the canyon but numerous biological communities along a scarp interpreted as the surface trace of the backthrust these observations suggest a scenario of vent and structural geomorphic development consisting of 1 frontal thrust faulting and associated venting facilitated by high fluid pressure 2 erosion of the oversteepened seaward flank of the ramp anticline assisted by seepage forces and leading to fluid flow out of stratigraphically controlled conduits in the limbs of the overthrust deposits 3 lockingmore of the frontal thrust due to dewatering or a local decrease in wedge taper associated with development of the large canyon leading to failure along the backthrust and 4 redirection of fluid flow by the backthrust thus within le 0 3 m y deformation of the relatively permeable sediments of the oregon margin results in stratigraphically controlled flow being partially captured by faults less

a paleoclimatic and paleoatmospheric record from peatlands accumulating during the cretaceous paleogene boundary event western interior basin canada petrological and 13 c analyses were undertaken on contiguous specimens of coal and intercalated minor organic rich clastic sediments collected from coal seams spanning the cretaceous paleogene boundary in the alberta and saskatchewan portions of the western interior basin the generally high smectite content of the coal suggests that the original mires were largely small disconnected and rheotrophic readily receiving abundant waterborne detrital clastic material of largely volcanic origin nevertheless using the distinctive claystone that marks the cretaceous paleogene boundary as a regional datum it is possible to correlate cycles in the vitrinite and inertinite composition of the coals over 500 km estimates of peat accumulation rates suggest that the cycles in vitrinite and inertinite composition represent regional cyclic fluctuations in wildfire and oxidation of the peatlands and overlying canopy at a frequency of hundreds to thousands of years the likely causes of these fluctuations were cyclic regional scale changes in temperature the cretaceous paleogene boundary event occurred early during a phase of gradually increasing temperature and or decreasing rainfall but peak wildfire and desiccation of peat occurred up to 14 000 yr later than the cretaceous paleogene boundary and the mires did not experience significant water stress in the immediate aftermath of the extinction event a persistent 1 5 3 0 negative 13 c excursion occurs across the cretaceous paleogene boundary but it cannot be readily separated from four further negative excursions later in the earliest danian the negative carbon isotope excursion linked to the cretaceous paleogene boundary began a few hundred years before the event itself and recovery occurred within 21 k y and possibly in as little as just a few thousand years consistent with recently calibrated shallow marine 13 c records hence the atmospheric and surface ocean carbon pools were coupled at this time the absence of evidence for catastrophic change in the climatic regime at the time of the cretaceous paleogene extinction in these mires supports the notion that the negative shift in atmospheric 13 c was brought about by changes in the 13 c composition of the surface ocean this is consistent with the greater magnitude of extinction experienced by marine fauna relative to the terrestrial realm

palaeoenvironment assessment of pliocene lom lignite bulgaria from bitumen analysis and preparative off line thermochemolysis abstract the dacian coal bearing province is located in nw bulgaria coal formation is thought to be connected with desiccation of the dacian basin during a prolonged regression in the late pontian and pliocene dacian romanian age a lom lignite sample was characterized via micropetrography bulk chemical analysis spectral methods and thermochemolysis the pollen record was poor suggesting coal formation under oxygen rich conditions during peatification straight chain alkanes alkan 2 ones alkanols des a triterpenoids aromatized triterpenoids aromatized hopane hopene hopanes and triterpenoids with a strong dominance of oleanane derived structures were present in the extracted bitumen the residue after extraction was subjected to preparative off line tetramethylammonium hydroxide tmah thermochemolysis the aliphatic products released were c22 c27 fatty acid fa methyl esters i e methoxymethyl esters c22 c28 even numbered diacids dimethyl esters with a smooth distribution and traces of i and ai c15 acid methyl esters trapped and bound fas were distinguished using tetraethylammonium acetate teaac treatment the main thermochemolysis products were phenols structurally related to lignin vanillyl and syringyl units were produced in similar amounts indicating nonwoody angiosperm vegetation as the main plant input to the palaeo swamp probably originating from marsh or grassland sources the bitumen provided unequivocal information for an angiosperm contribution to the mire while the results of the tmah pyrolysis revealed a concomitant angiosperm and gymnosperm input the biomarker assemblage makes the lom lignite unique in bulgaria all the other bulgarian neogene lignites being dominated by coniferous vegetation with only traces of angiosperm contributions

environmental history of the german lower rhine embayment during the middle miocene as reflected by carbon isotopes in brown coal stable carbon isotope investigations have been carried out on miocene brown coal from the garzweiler seam of the german lower rhine embayment material studied included fossil wood from seven different taxa and brown coal matrix isotope results from macrofossil analysis show variations of more than 6 within individual samples and reveal a general isotopic difference between angiosperm and gymnosperm wood specimens according to mean carbon isotope values found for gymnosperms angiosperms and brown coal matrix 23 3 26 0 and 25 8 the peat forming vegetation of the garzweiler seam was dominated by angiosperm taxa results from brown coal matrix establish a continuous high resolution depth profile of carbon isotope variations during the late middle miocene they show a significant and characteristic isotope pattern with distinct medium and short term cycles high frequency variations in the two main units of garzweiler seam locally split into three units the medium term 13c variations are most likely caused by varying proportions of gymnosperms within the peat forming vegetation while high frequency oscillations seem to be a direct signal of environmental changes a long term decline of carbon isotope values observed within the complete garzweiler seam from base to top is presumably due to a cooling trend in the miocene

formation of ultralaminae in marine kerogens via selective preservation of thin resistant outer walls of microalgae abstract transmission electron microscopy tem observations recently revealed the common occurrence of very thin lamellar structures termed ultralaminae in kerogens from source rocks and oil shales so far considered as amorphous ultralaminae in lacustrine kerogens were shown to derive from the selective preservation of the algaenans occurring in the very thin outer walls of various freshwater chlorophyceae the chemical correlation between such algaenans and fossil lacustrine ultralaminae was chiefly based on the production on pyrolysis of n alkylnitriles with a typical distribution bimodal maxima at c 28 and c 16 the origin of marine ultralaminae is investigated in this work to this end spectroscopic and pyrolytic studies were carried out on i the algaenan forming the very thin outer walls of nanochlorum eucaryotum an extant marine chlorophycea and ii two ultralaminae containing marine kerogens from the lower toarcian shales of paris basin fecocourt and bray a high contribution of polymethylenic chains probably linked via ehter bridges was observed in these bio and geopolymers furthermore on pyrolysis they afforded the same n alkylnitriles with the same distribution unimodal maximum at c 13 lack of c 17 compounds fossil ultralaminae in marine kerogens therefore derive from the selective preservation of the algaenan composed very thin outer walls of marine chlorophyceae such as n eucaryotum algaenans from marine and freshwater chlorophyceae and therefore marine and lacustrine ultralaminae should be characterized by sharply distinct n alkylnitrile distributions