early diagenetic transformation of higher plant triterpenoids in deep sea sediments from baffin bay abstract a sediment sequence of early miocene to holocene from ocean drilling program site 645 in central baffin bay was found to contain abundant triterpenoids of higher plant origin including monodesmethyl derivatives and other oxidative degradation products 24 nor triterpenoids of the oleanene ursene and lupane series were found in the nonaromatic hydrocarbon and alcohol fractions of the sediment extracts other diagenetic transformation products included 24 28 dinor olean 17 ene and 24 nor urs 12 en 1 1 one as well as their tentatively identified des a counterparts the identification of these novel degradation products was confirmed by synthesis of a suite of reference compounds the simple reaction sequence applied to obtain 24 nor urs 12 ene from 3 acetoxyurs 12 en 24 oic acid is likely to happen in a similar manner during early diagenesis of organic matter in nature these results have implications for the understanding of the diagenetic reaction sequence leading to the formation of other demethylated triterpenoids of terrigenous origin e g 24 28 dinor lupanes 28 30 dinor 17 hopane is sometimes the dominant hydrocarbon in the most deeply buried samples its co occurrence with higher plant triterpenoids and the low abundance of other regular hopanoids is not considered an indication however that 28 30 dinor 17 hopane is derived from a higher plant precursor molecule it is suggested that two independent sedimentary processes are responsible for the presence of the two types of demethylated triterpenoids observed in baffin bay sediments

recognition of 18β h oleanane in several crudes and tertiary upper cretaceous sediments definition of a new maturity parameter abstract ekweozor et al chem geol 27 11 28 and 29 37 first discovered an unknown compound with a gc retention time very close to that of the 18 h olenane peak in oils and tertiary sediments of the nigerian delta this compound was called j several authors wang et al advances in organic geochemistry 1981 pp 108 113 wiley chichester 1983 schoelle et al ibid pp 156 163 reported the occurrence of 18 h oleanane without underlying the presence of j because of their coelution in this study the presence of j has been confirmed in more than 150 rock extracts and 19 oils from different countries and is identified as the 18 h oleanane by comparison to retention time and mass spectrum and by its coelution with an authentic standard apart from tertiary sediments the 18 h and 18 h oleananes have also been found in upper cretaceous sediments which extends the occurrence of these compounds back in age a maturity correlation has been found between the relative concentration of 18 h oleanane and 18 h oleanane in fact an increase in the 18 h 18 h oleanane ratio has been observed with increasing depth in several wells the 18 h 18 h oleanane ratio has been correlated with other classical maturity parameters i e ts tm ro and tmax

early diagenesis of terrigenous triterpenoids and its implications for petroleum geochemistry abstract the distribution of triterpanes in sediments and crude oils is commonly used for oil oil and oil source rock correlation in petroleum geochemistry while isomer ratios of such compounds are applied as maturity parameters the triterpane pattern in terrestrially influenced geological samples is however remarkably less diverse than the triterpenoid skeletons occurring in the extant higher plant biosphere natural observations laboratory experiments and molecular mechanics calculations have revealed that acid catalysed double bond isomerization and skeletal rearrangement reactions of terrigenous triterpenoids during early diagenesis are the key to understanding the triterpane patterns in more matured geological materials examples studied in detail are the double bond isomerization of oleanenes and the subsequent hydrogenation of the products into oleanane and 18 oleanane and the transformation of taraxer 14 ene and lup 20 29 ene into oleanenes although the reactions are likely to be kinetically controlled the main products formed and ultimately preserved are the thermodynamically most stable ones the experimental results and natural observations have significant implications for the use of terrigenous triterpenoid compounds in petroleum geochemistry

the occurrence of norlupanes and bisnorlupanes in oils of tertiary deltaic basins lupanoid hydrocarbons are known to occur in several petroleum systems and lupane c30 has recently been confirmed to exist in several crude oils in contrast norlupanes c29 and bisnorlupanes c28 are rarely observed in oil all of these compounds are considered to derive from natural products of angiosperms and numerous examples of their functionalized analogs are known the occurrence of c28 and c29 lupanoids in biochemical and geochemical systems is reviewed here and the presence and origin of their hydrocarbon analogs in crude oils are examined in detail although direct biochemical precursors for the lupane of crude oil are evident such precursors for norlupane and bisnorlupane are not obvious nor is it clear if the c28 and c29 analogs are diagenetic descendants from the lupane structure adding additional confusion is the occurrence of these analogs in oils which show numerous indications of post source molecular addition during migration and entrapment making it unclear if they originate from a conventional source rock or from carrier or seal rock despite these uncertainties there is extensive potential some of which has already been realized to use these compounds in oil oil and oil source rock correlations particularly in instances where extensive biodegradation has occurred deconvolution of the time s of introduction of norlupane and bisnorlupane into the fluid as well as various other hydrocarbons including olefins also provides great potential as a tool for mapping the migration history of an oil

organic geochemical and stable carbon isotopic investigation of coals formed in low lying and raised mires within the eastern alps austria abstract up to 16 m thick coal seams formed in miocene pull apart basins within the eastern alps in low lying and raised mires despite similar rank sub bituminous stage coal quality differs significantly coals from low lying mires e g fohnsdorf are characterized by significantly higher ash yields and sulfur contents than coals from raised mires e g leoben organic geochemical and carbon isotope investigations were performed to assess the differences in facies the fohnsdorf coals are characterized by higher yields of soluble organic matter som slightly higher proportions of hydrocarbons in the som generally lower pristane phytane ratios and the occurrence of high corg normalized n alkane concentrations only n alkane patterns in the leoben samples show a marked odd over even predominance these differences are indicative of a more intensive dys to anaerobic biochemical degradation of plant material within the fohnsdorf mire terpenoid biomarkers characteristic of conifers and angiosperms were detected in the leoben coals whereas the latter are missing in the fohnsdorf samples in the leoben coals higher saturated to aromatic diterpenoid ratios were detected than in the fohnsdorf coals because of similar rank enhanced aromatisation in the fohnsdorf basin is probably related to microbial activity despite this the fohnsdorf coals are characterized by lower hopane concentrations the results imply that the aromatisation of terpenoid biomarkers is governed by the activity of anaerobic rather than aerobic bacteria an overall negative correlation between 13c of organic matter and the degree of aromatisation of diterpenoid biomarkers is observed it is suggested that the carbon isotopic composition results from different extents of microbial degradation of the biomass the fohnsdorf coals are rich in sulfur high contents of coalbed methane were encountered during mining suggesting high activities of anaerobic bacteria in a nearly neutral sulfate bearing brackish environment of the low lying mire and methanogenesis during or after coalification sulfate reduction and methanogenesis are known to increase 13c values of residual organic matter

novel tricyclic and tetracyclic terpanes in tertiary deltaic oils structural identification origin and application to petroleum correlation abstract tricyclic terpanes of the cheilanthane series in crude oils and sediments are routinely used for geochemical correlation the cheilanthanes are particularly useful to identify crude oils derived from marine clastic or carbonate source rock as well as input to the source rocks from marine algal or terrigenous organic matter however they sometimes have limitations for the correlation of oils expelled from different source rocks that received similar organic matter e g oils from source rocks dominated by terrigenous organic matter novel non cheilanthane tricyclic terpanes consisting of c21 and c25 compounds and a c27 tetracyclic terpane were identified in oils from the assam india beaufort mackenzie canada and the niger nigeria deltas nmr data reveal that all three compounds have an oleanane type structure with rings c d and e intact while rings a and b have been degraded leaving a side chain attached to ring c in the case of the tricyclics and only a degraded a ring in the tetracyclic on the basis of occurrence nmr structure and co variance with oleanane abundance these new tricyclic and tetracyclic compounds are believed to form from a ring functionalised oleanoid precursors in angiosperm flowering plants the distribution of these compounds in representative oils from the niger delta accumulations permits separation of the oils into at least three distinct source rock organofacies

biomarkers of oligocene lacustrine source rocks beibuwan song hong basin junction offshore northern vietnam abstract highly oil prone source rocks containing sapropelic type i and mixed types i and iii kerogen are found in 233 m of the 500 m deep fully cored enreca 3 well drilled on bach long vi island located at the junction between the beibuwan and the song hong basins offshore northern vietnam the cored succession is made up entirely by oligocene deep lacustrine deposits the origin of the organic matter om in 62 samples is evaluated on the basis of gas chromatography mass spectrometry gc ms and gc ms ms om in 55 samples is sourced primarily from lacustrine organisms and contains abundant 4 methylsteranes tetracyclic polyprenoids tpp and lycopane and no markers for marine organic matter the proportion of triterpanes derived from angiosperms is low in most saturated fractions and only traces of gymnosperm diterpanes are detected in contrast all aromatic fractions have a high proportion of compounds having an origin from both gymnosperms and angiosperms very high concentrations of hopanoids in both fractions suggest significant bacterial alteration of the original om most samples have a high concentration of rare c31 diaromatic 8 14 secohopanes with a fluorene moiety low pristane phytane pr ph ratios indicate that anoxic suboxic bottom water conditions existed during om accumulation the presence of carotane gammacerane and traces of arylisoprenoids could indicate a stratified water column om in a few samples with lower than average hydrogen index hi is mainly of terrestrial origin with a higher proportion of c29 steranes diterpanes and oleanoids and lower concentrations of both saturated and aromatic hopanes higher pr ph a higher c34 isohopane ratio ihr34 and a lower homohopane index hhi indicate that this low hi om was originally deposited under more oxic conditions and subsequently transported to deeper water low sterane and hopane isomerization ratios show that no samples have reached the oil window some novel maturity parameters for immature lacustrine samples are proposed

palaeoenvironment of the eocene eckfeld maar lake germany implications from geochemical analysis of the oil shale sequence abstract drill core samples from the depth interval between 19 4 and 32 0 m of the laminated central lake facies of the eocene eckfeld maar were investigated for biomarker and stable isotope composition bulk organic geochemical parameters c n hi and the molecular composition of the soluble organic matter indicate a dominance of particulate organic matter from land plants and microbially derived lipids in the lower part of the sedimentary succession an angiosperm dominated vegetation is indicated from the terpenoid biomarker composition abundant 4 methylsteroids in the 25 6 30 8 m section of the oil shale sequence reflect a contribution of algal derived biomass samples with high concentrations of methylsteroids are characterized by low amounts of triterpenoids related to the arborane skeleton and vice versa this pattern is interpreted as reflecting differences in autochthonous organic matter production vs microbial activity in the lowermost section 32 0 30 6 m a trend towards heavier 18 o and 13 c values indicates the evolution of permanently meromictic conditions in the lake and an increase in methanogenesis high 13 c values of siderites 10 throughout most of the sequence are consistent with permanently anoxic conditions at the sediment water interface the lighter 18 o values of siderites from turbidites relative to siderites from biogenic laminites are postulated to have been caused by temporary phases of increased precipitation followed by landslides and improved circulation within the lake depletion of the organic matter in 13 c average 13 c 29 4 in comparison with the fossil wood ranging from 23 1 to 26 6 is explained by the dominance of waxy lipid rich land plant material e g leaf waxes resins bark over wood supplied to the lake carbon cycling during anoxic decomposition of organic matter is assumed to further affect the 13 c values through the activity of anaerobic e g methanogenic bacteria resulting in a depletion of the biomass in 13 c the overall trend in the isotopic composition of organic carbon towards heavier values in the depth interval between 26 0 and 3 2 m is accompanied by decreasing c n ratios indicating an increase in aquatic organic matter production the geochemistry of the oil shale succession points towards a highly productive eutrophic ecosystem with intense microbial activity under meromictic conditions in the maar lake beside the high input of land plants to the biomass major contributions from bacteria and phytoplankton are indicated by the biomarker composition

triterpanes and ring a degraded triterpanes as biomarkers characteristic of tertiary oils derived from predominantly higher plant sources abstract a number of oils previously proposed to be derived from terrigenous source materials have been obtained from the taranaki basin new zealand niger delta beaufort mackenzie region taiwan and indonesia and their c24 tetracyclic and c30 pentacyclic terpenoid distributions examined by gc ms and gc ms ms the c24 tetracyclic terpanes are thought to be derived from their corresponding c30 hopane oleanane ursane and lupane counterparts as previously reported a mixture of at least nine c30 pentacyclic terpanes are found to be present with remarkably uniform distributions in oils from these widely separated provinces whilst definitive structures have not been proposed for these compounds information has been obtained as to whether these pentacyclic terpanes are all six membered rings or contain one or two five membered rings the presence of this mixture of tetracyclic and pentacyclic terpanes provides a good indicator for oils derived from terrigenous source materials and in the case of these basins of tertiary age

biomarker distributions in australian oils predominantly derived from terrigenous source material oils found in many australian sedimentary basins contain a relatively high input of terrigenous organic source material a study of a large number of these oils has permitted a number of biomarker distributions to be determined that appear to be characteristic for oils derived from terrigenous source material these features include the presence of sesquiterpanes absence of tricyclic terpanes relatively high concentrations of a c24 tetracyclic terpane predominance of c29 steranes presence of two unidentified c27 and c30 terpanes and virtual absence of 18 h oleanane the latter observation is significant since it appears that 18 h oleanane appears only in oils of tertiary age derived from terrigenous source material an attempt has also been made to compare the results for the australian oils with published results for oils derived from terrigenous source material in other parts of the world the number of reports in the literature for these oils is fairly limited but it appears that some of the observations for the australian oils can be extended to them this study is an initial attempt to devise a classification scheme that can be used to determine the origin of an oil unambiguously from biomarker parameters in order for this approach to be successful a relatively large number of biomarker parameters need to be assigned as characteristic of a particular type of source material

generation of gas and oil from coal and other terrestrial organic matter abstract late carboniferous permian sedimentary rocks contain the world s largest coal reserves which have generated and released gas but little if any oil in comparison organic matter deposited in lacustrine fluvial deltaic or brackish water sediments has sourced large quantities of waxy oils in countries such as china australia the u s a argentina venezuela and indonesia plus gas and condensate in deltas worldwide why is more oil coming from land derived organic matter disseminated in sediments than from the carboniferous permian coal beds which also are land deposits the answer appears to be in the hydrogen content and the ease of migration when organic matter and coals have high hydrogen contents relative to carbon they can form oil when the hydrogen is low mainly gas is formed most of the world s coal is low in hydrogen whereas much of the terrestrial organic matter disseminated in sediments is higher in hydrogen so it forms more oil also both gas and oil are adsorbed on coal more strongly than on the disseminated kerogen of sedimentary rocks this makes migration of oil out of the coal more difficult compared to migration from conventional shale source rocks

the diagenetic fate of taraxer 14 ene and oleanene isomers abstract the extractable organic matter in holocene to early miocene deep sea sediments from site 645 odp leg 105 in baffin bay contains almost exclusively biological markers of terrigenous origin pentacyclic triterpenoids of the ursene and amyrin oleanene type often occur as the most abundant compounds in the aliphatic hydrocarbon ketone and alcohol fractions of the sediment extract a specific diagenetic reaction involves the conversion of taraxer 14 ene into olean 12 ene in the upper 700 metres of the sedimentary sequence the taraxerene to oleanene conversion is complete before the onset of isomerisation of diasterenes at c 20 in the sediment as well as in laboratory simulation experiments olean 12 ene further isomerises to olean 13 18 ene and olean 18 ene the latter of which may be the direct precursor of 18 h and 18 h oleanane found in sediments containing more mature organic matter and in crude oils the subsurface interconversion of these triterpenoid skeletons indicate that oleanane does not necessarily start life as an oleanoid

the middle eocene markushegy subbituminous coal hungary paleoenvironmental implications from petrographical and geochemical studies abstract samples from two coal seams of the markushegy underground mine hungary were investigated for variations in maceral composition petrography based facies indicators and various geochemical parameters using three seam profiles both seams originate from a topogenous mire and evolved within a peneplaned coastal area covered with eutrophic swamps the presence of foraminifera and marine algae in the marly layers is indicative of marine ingressions coal facies characterisation from these parameters is combined with the results from biomarker analyses of soluble organic matter in order to reconstruct the depositional environment and to relate petrography based indicators to the molecular composition the contents of macerals of the liptinite group are positively correlated with soluble organic matter som yields and hydrogen index hi consistent with maceral composition and high hi values enhanced proportions of n alkanes of intermediate molecular weight n c21 25 which are predominantly found in macrophytes are obtained from samples of the marly shales the final drowning of the mire is reflected by decreasing pristane phytane ratios due to the rise of the ground water table and the establishment of anaerobic conditions the observed positive correlation between pristane phytane ratios and inertinite percentages suggests that at least in the markushegy deposit both parameters reflect variations in redox conditions of the mire the predominance of angiosperms in the peat forming vegetation of the markushegy coal is evidenced by the high relative proportions of angiosperm derived triterpenoids the influence of the relative proportion of fossil wood on tissue preservation tpi is indicated by the positive relationship of the concentration of land plant derived terpenoid hydrocarbons and tpi the degree of gelification of plant tissue gi is governed by the microbial activity in the mire as indicated by a negative relationship between gi and the steroids hopanoids concentration ratios the variation of the 13c values of coal is obviously governed by the relative contribution of plant lipids to the biomass the obtained negative relationship between 13c of the coal and gi is explained by the effect of cellulose decomposition and microbial activity on the isotopic composition of the organic matter

the oleananes origin maturation and limits of occurence in southern nigeria sedimentary basins oleananes occur within well defined age and paleogeographic boundaries in the sedimentary province of southern nigeria thus signifying that the biomarkers may be analogous to index fossils in anambra syncline lower benue trough the biomarkers are found in rocks which are as old as late upper cretaceous in tertiary niger delta the concentration composition and distribution of the oleananes in rocks and oils are determined mainly by palaeodepositional environment and thermal history and are independent of age and geographical location of specific samples oleanane content varies with increasing burial depth with peak concentration coinciding within rm range 0 4 0 6 implying early generation of hydrocarbons from the basin s typically resin rich kerogens it is evident that the oleanane content parameter is superior to the hopane and sterane isomerisation indices for monitoring thermal maturation in the delta and for differentiating paralic from paralic marine source facies as well as early from late generated oils

a review of the biogeochemical controls on the occurrence and distribution of polycyclic aromatic compounds pacs in coals abstract the organic matter in coal contains polycyclic aromatic compounds pacs of varying quantities in diverse soluble and insoluble forms pacs in coal are of special interest for organic geochemical studies because they have been successfully used as biological marker compounds biomarkers and indicators of thermal maturity in addition they could provide critical information to understand the structural and compositional evolution of the coal organic matters during coalification and to predict pac releasing characteristics during coal utilization the main purpose of this paper is to provide a critical review on the current state of knowledge on the potential use of pac composition to understand the underlying biogeochemical factors that control pac occurrence and distribution in coal the published pac data of world coal are first compiled according to their ranks natural coke anthracite semi anthracite bituminous coal low volatile bituminous coal medium volatile bituminous coal high volatile bituminous coal sub bituminous coal lignite countries brazil canada china france germany japan usa formation periods carboniferous permian jurassic cretaceous early middle cenozoic then the biogeochemical factors affecting the occurrence and distribution of pacs in coal including biogenic precursor materials coal rank maceral composition depositional environment and geological settings are comprehensively reviewed the results show that the geochemical parameters of pacs in coal are robust tools to trace the coalification processes from the molecular perspectives and to understand the corresponding biogeochemical process e g depositional environment geological settings igneous intrusion occurring during coal formation

δ2 triterpenes early intermediates in the diagenesis of terrigenous triterpenoids a series of 2 triterpenoids oleana 2 12 diene oleana 2 13 18 diene oleana 2 18 diene ursa 2 12 diene and taraxera 2 14 diene has been identified in holocene buried mangrove sediments florida usa by comparison of the mass spectra of and by co injections with authentic standards in the oligocene brandon lignite vermont usa oleana 2 12 diene and oleana 2 13 18 diene were also identified along with two a ring contracted amyrin derivatives by comparison with the sedimentary occurrence of related analogues of oxyallobetulin and betulin and the demonstrated diagenetic formation of lup 2 ene from lupan 3 one these novel terrigenous biological markers are considered diagenetic products formed by dehydration of precursor molecules such as and amyrin and taraxerol the identification of these early intermediates brings us one step closer to the full understanding of the diagenetic fate of terrigenous triterpenoids

triterpane and sterane biomarkers in the ya13 1 condensates from qiongdongnan basin south china sea triterpanes and steranes in condensates from the ya13 1 gas field qiongdongnan basin were monitored the ya13 1 condensates have unusual biomarker distributions dominated by terpanes and steranes derived from higher plants anomalously abundant 1 got oleanane and remarkably abundant bicadinanes are present in the ya13 1 condensates whereas the 17alpha hopane contents are extremely low taraxastane and significantly abundant 17alpha diahopanes occur in the condensates in addition a number of unknown c 29 and c 30 pentacyclic triterpanes including previously unreported compounds were detected in the condensates some of which are significantly abundant the unknown compounds may be terrestrial biomarkers c 29 homologues are relatively predominant among the regular and rearranged steranes the diasterane concentrations are markedly higher than those of regular steranes the maturity of the ya13 1 condensates is relatively high at the peak to late oil generation stage corresponding to 0 85 1 10 ro based on sterane and terpane and including bicadinane maturity parameters i e t t 1 r and 2t r bicadinane ratios the above maturity assessment result is different from that based on diamondoid maturity parameters ro 1 60 1 70 org geochem 25 1996 179 which can be explained by a contribution of hydrocarbons from two sources at different depths the ya13 1 condensates were probably generated from the yacheng and lingshui coal bearing source rocks buried both in the qiongdongnan basin 3400 5000 m and in the yinggehai basin 5000 m the possible contribution of lower maturity hydrocarbons from the yacheng and lingshui formations 3400 4100 m in the qiongdongnan basin to the ya13 1 gases and condensates should not be neglected c 2003 elsevier science b v all rights reserved

mineralogy petrography and organic geochemistry of miocene coal seams in the kinik coalfield soma basin western turkey insights into depositional environment and palaeovegetation abstract the kinik coalfield is located in the south westernmost part of the soma basin in western turkey and hosts all three miocene coal seams from bottom to top km2 km3 and kp1 this study presents the coal petrographical mineralogical and organic geochemical features of samples collected from two deep cores samples from seam km2 generally display low ash yields and high toc content whereas the km3 and kp1 seams are characterized by relatively high ash yields and low toc values furthermore total s content of the kp1 is very high up to 7 0 on dry basis the maceral composition the coal facies diagrams and the distributions of n alkanes and diterpenoids indicate changes of depositional conditions and vegetation in the palaeomires of the km2 seam during early miocene the precursor peat of km2 seam started accumulating under limnotelmatic conditions followed by pure telmatic ones consequently initial mixed vegetation was replaced by a conifer dominant assemblage in the palaeomires in the upper parts of the km2 seam the coal facies indices and high concentrations of n alkanes along with the relatively low di di tri terpenoid ratios are indicators of the higher contribution of herbaceous species and minor abundance of conifers in the palaeomires of km3 and kp1 seams nevertheless the mineralogical composition of the km3 and kp1 seams indicate increased clastic input and alkalinity in the palaeomires that could reduce preservation of organic matter thus high ash yields and low toc were obtained from these seams in addition sulphate rich water supply along with synchronous pyroclastic air borne input into the palaeomires caused elevated total s content of the kp1 seam

geochemical and biological marker assessment of depositional environments using brazilian offshore oils abstract a combined geochemical and molecular characterization of a wide selection of oils from the major brazilian offshore basins has been undertaken the elemental sulphur nickel and vanadium and bulk oapi and 13c properties of each sample been considered together with its molecular composition determined using liquid and gas chromatography and quantitative biological marker investigations using gas chromatography mass spectrometry for alkanes the results reveal significant differences in the chemical features of the various oils which enable them to be divided into five groups the distinction of the groups appears to reflect differences in the depositional environment of the source rocks of the oils each group is correlated tentatively with source rocks laid down in a specific depositional regime namely lacustrine freshwater lacustrine saline water marine evaporitic marine carbonate or marine deltaic the diagnostic features that allow this classification are the relative abundance and carbon number distributions of n alkanes pristane phytane ratios sulphur nickel and vanadium contents carbon isotope data the absolute concentrations of hopanes and steranes and their abundance relative to 4 methylsteranes and also the occurrence and abundance of several specific biological markers including 18 h oleanane gammacerane carotane tricyclic terpanes higher acyclic isoprenoids 28 30 bisnorhopane and 25 28 30 trisnorhopane this investigation shows the value of a combined geochemical and molecular approach in the assessment of the palaeoenvironment of deposition of the source rocks which gave rise to the oils

mixed marine and lacustrine input to an oil cemented sandstone breccia from brora scotland abstract a rounded cobble collected from a beach near brora scotland contains angular brecciated sandstone clasts cemented together by crude oil no oil occurs within the tight dolomite cemented clasts except along fractures provenance of the cobble is uncertain however the lithology and shape of the clasts suggests that they are fault gouge breccia composed of old red sandstone from the nearby helmsdale fault oil emplacement presumably along the fault cemented the breccia prior to transport and weathering of the cobble independent source and biodegradation parameters support mixing of two charges of oil like oil from the nearby beatrice field the oil cement contains 24 n propylcholestanes and carotane that indicate marine and lacustrine source rocks respectively the oil cement also contains pristane phytane residual n alkanes and a complete series of 25 norhopanes which indicate mild and heavy biodegradation respectively the first charge consisted of lacustrine devonian oil that was heavily biodegraded at shallow depth the origin of the second charge is unclear unlike beatrice oil the oil cement contains oleanane and shows a higher 24 24 27 nordiacholestane ratio suggesting input from a cretaceous or younger paralic marine shale source rock although cretaceous and paleocene source rocks are inferred to exist in various depocenters in the northeast atlantic margin subcrops of these rocks offshore brora are thermally immature alternately the second charge could originate from an effective middle jurassic source rock that contains oleanane this hypothesis is supported by mass spectrometric confirmation of oleanane in an extract from the marine equivalent of the middle jurassic brora coal in the nearby ukcs 11 30 2 well oleanane in crude oil is not positive proof of a cretaceous or younger source rock for the oil

the impact of stored solar heat on arctic sea ice growth high resolution measurements of ocean temperature and salinity in the arctic ocean s canada basin reveal the importance of the release of solar derived stored ocean heat on sea ice growth locally absorbed summer solar heat is stored in a near surface temperature maximum nstm layer underlying the mixed layer the heat content of the nstm layer was anomalously large following summer 2007 which saw considerable sea ice losses and intense solar absorption into the exposed surface ocean measurements provide evidence for the entrainment of nstm layer heat in fall winter 2007 2008 by shear driven mixing and convective mixing by the release of dense salty plumes during sea ice growth while at least a portion of the nstm layer was eroded deeper warm ocean layers remained unaffected it is shown that the release of solar heat stored following summer 2007 was sufficient to have reduced sea ice thickness at the end of the 2008 growth season by about 25

a long term high latitude record of eocene hydrological change in the greenland region abstract a range of proxy approaches have been used to reconstruct short term changes to earth s hydrological cycle during the early eocene hyperthermals however little is known about the response of earth s hydrological and biogeochemical systems to long term cenozoic cooling which began following the early eocene climatic optimum 53 3 49 4 million years ago ma here we use the molecular distribution and isotopic composition of terrestrial biomarkers preserved in marine sediments of odp site 913 east greenland to develop a long term record of high latitude hydrological change between 50 and 34 ma there is a marked decline in the concentration of conifer derived diterpenoids and angiosperm derived triterpenoids during the eocene as the input of wind blown conifer pollen remains stable during this interval this implies that decreasing di and triterpenoid concentrations reflect declining influence of fluvial inputs and perhaps terrestrial runoff throughout the eocene branched gdgts and bacterial derived hopanes indicate an increased input of soil and kerogen derived organic matter respectively after 38 ma this coincides with evidence for ice rafted debris and suggests input of organic matter via glacial processes this also implies some continental glaciation occurred on east greenland in the middle to late eocene leaf wax hydrogen isotopes extending throughout this section the first such long term record from the paleogene indicate that precipitation 2h was persistently higher than that of modern coastal greenland consistent with warmer ocean source waters and enhanced poleward moisture transport non intuitively however this effect appears to have been smallest during the warmest part of the record and higher 2h values occur in the middle eocene although interpretation of these hydrogen isotope trends is unclear they clearly indicate alongside the changes in biomarker abundances a perturbed hydrological cycle through the eocene in coastal greenland more long term records are required to ascertain if this represents regional or global hydrological reorganisation

organic geochemistry of the lower miocene oberdorf lignite styrian basin austria its relation to petrography palynology and the palaeoenvironment abstract in the oberdorf trough at the northwestern margin of the styrian basin austria an up to 36 m thick lower miocene ottnangian lignite seam occurs within the fluvial koflach voitsberg formation previous results indicate that the lignite originated in a topogenous mire within a wet forest swamp palaeoenvironment differences in soluble organic matter som yield of borehole samples from the lignite seam are related to free lipids present in plant waxes or resins and the presence of thermally labile polymers indicated by the contents of liptinite macerals i e resinite suberinite and liptodetrinite the n alkane distribution patterns are dominated by high molecular weight lipids with marked odd over even predominance originating from plant waxes a contribution of algae to the even numbered short chain lipids observed in considerable amounts in the footwall sediments is proposed terpenoid biomarkers characteristic for conifers and angiosperms were detected consistent with palynomorphic spectra which are dominated by forest swamp pollen taxodiaceae cupressaceae and pollen from plants living in a mixed mesophytic forest excellent relationships between higher plant biomarker composition and palynologic data indicate that the organic geochemical results reflect the varying inputs of coniferales vs angiosperms the data further imply that cuparene may be used for taxonomical differentiation of coniferales families organic geochemical data provide evidence that the content of land plant derived biomarkers is controlled by the input of resin rich conifers concentrations of hopanoids dominated by hop 17 21 ene generally increase towards the top of the lignite a section characterised by high extents of aromatisation of triterpenoid biomarkers the results suggest that the aromatisation of angiosperm derived biomarkers may be governed by the activity of anaerobic rather than by aerobic bacteria however changes in the depositional environment and palynologic facies during peat formation probably influenced the origin and fate of angiosperm derived triterpenoids the results indicate how biomarker composition may contribute to the evaluation of environmental changes cross correlations of organic geochemical parameters with palynological data and petrography based facies indicators will provide further insights in the peat forming vegetation and biogeochemical activities in the mire

biomarker and micropetrographic investigations of coal from the krepoljin brown coal basin serbia abstract we investigated early diagenetic processes of the extractable organic matter from the miocene freshwater sequence which consists of coal fragments in clays sandstones and shales alternating with continuous brown coal layers we examined eight coals thirteen sediments and three non coaly underground layers the molecular assemblages of the identified aliphatic hydrocarbons in the krepoljin basin reflect the abundance of plant taxa as precursors or participants in the early diagenetic stage the data provide insight into the conditions prevailing in the lakes and bogs during early diagenesis the dominance of diterpanes indicates that the prevalent of the organic matter was of gymnosperous origin the hopanoid contents are considered to reflect microbial activity that the organic matter in the miocene krepoljin coal basin is immature was confirmed by the presence of biolipids such as hopanes c 27 17 h trisnorhopan saturated and aromatized abietanes pimaranes and phyllocladanes the most abundant compounds in all samples indicate a predominantly higher plant input related to the coniferous group but identification of the individual plant families was not possible amyrin and other triterpenoid derived triaromatic and triaromatic c ring cleaved hydrocarbons with triterpenoid structures are thought to be characteristic for angiosperms unsaturated compounds 2 triterpanes early intermediaries in the diagenetic transformation of angiosperms also indicate a low degree of sediment maturity

the petroleum geochemistry of canadian beaufort tertiary non marine oils abstract molecular isotopic and elemental data for a set of 28 paleogene and 3 cretaceous oils from the mackenzie delta and offshore canadian beaufort sea have been evaluated the depositional environment and organic matter characteristics of the source units for these oils have been predicted the paleogene oils of the canadian beaufort are molecularly distinctive and clearly contain a major land plant component oleanane and the 17 h and 17 h 24 28 bisnorlupanes are present as well as the following compound types 24 norlupanes and possibly higher homologues de a lupane noroleanenes norursene dehydroabietane 28 30 bisnorhopanes several molecular and isotopic characteristics are useful in assessing and ordering the extent of biodegradation and thermal maturation of these oils the cretaceous oils are separately sourced from the paleogene oils the latter oils comprise two distinct land plant derived genetic families distinguished by the presence absence of 24 28 bisnorlupanes 24 norursene 24 norlupane and 24 noroleanenes the kugmallit richards family contains each of these compound types and is considered to originate from the eocene richards formation in contrast lupanoids and noroleanenes are absent in oils of the reindeer moose channel family the occurrence of 28 30 bisnorhopane and or oleanane in these oils suggests a paleocene origin although these source rock predictions are supported by the available data they must be considered speculative until detailed molecular isotopic and elemental compositional data are available regionally for potential source rocks of the eocene and paleocene source units in the canadian beaufort

organic geochemistry of freshwater and alkaline lacustrine sediments in the green river formation of the washakie basin wyoming u s a abstract two members of the green river formation in the washakie basin have been analysed by organic geochemical and organic petrographic techniques and the results placed in a sequence stratigraphic framework one of these members the laney shale was deposited in a hydrologically closed alkaline lake under an arid climate and was characterized by high concentrations of alginite rich organic matter whereas the other the luman tongue was deposited in a hydrologically open freshwater lake under a humid climate and consisted of organic poor profundal lake mudstones and coaly lake margin sediments potential source rocks in both lake types have the potential for generating high wax oil at high subsurface temperatures 150 175 c at a heating rate of 5 k ma but the alkaline system is clearly more prolific the most abundant biological marker hydrocarbons were the 4 methylsteranes in both lake types though dinosteranes were found only in the laney shale oleanane was absent from the luman tongue despite an abundance of angiosperm palynomorphs intraformational heterogeneities were best documented for the laney shale where molecular differences in kerogen type occur at the parasequence level with early transgression maximum transgression and rejuvenation stages of lake history having its own kerogen type and distinctive high wax oil fingerprint thermal lability was shown to be linked to kerogen structure in particular the presence of alicyclic and oxygen containing moieties and these in turn are correlated with total organic carbon content and thence productivity degree of preservation some kerogen components appear to have originated via selective preservation whereas others may have been formed by diagenetic condensation reactions

paleogeography and paleoecology of the upper miocene zillingdorf lignite deposit austria abstract the zillingdorf deposit formed during the late miocene filling of lake pannon and contains austria s largest lignite reserves two lignite seams are present and developed within frequently flooded low lying mires in near shore environments high sulphur contents are due to the influence of the brackish water body of lake pannon during peat accumulation a transgression forced the nw se trending shoreline northeastwards differences in soluble organic matter som yield and hydrocarbon content of borehole samples and woody macrofossils are related to differences in the content and composition of free lipids of microbial origin and or hydrocarbons derived from the biogeochemical degradation of plant tissue variations of pristane phytane ratios are interpreted to reflect differences in the redox conditions of the mire peatification in an acidic and aerobic environment is further reflected by the predominance of aromatic over saturated hydrocarbons the presence of an intense complex mixture in the gc traces due to biodegradation processes high ratios for diasterenes relative to sterenes and high concentration ratios of hopanes to hop 17 21 ene of the respective samples gelification of plant tissue is governed by microbial activity as indicated by the positive relationship between gelification index and hopanoids concentration the composition of terpenoid biomarkers indicates the predominance of gymnosperms over angiosperms and increasing proportions of angiosperms in the peat forming vegetation with decreasing depth in the upper seam from the sesqui and diterpenoids present in the lignite and fossil wood remnants a predominant role of species of the coniferales families cupressaceae taxodiaceae are concluded the preservation of plant tissue is governed by the presence absence of decay resistant gymnosperms a general influence of the floral assemblage on the isotopic composition of organic carbon of the lignite 13c 27 2 to 24 6 is proposed decomposition of plant tissue and biogeochemical carbon cycling is assumed to further affect the 13c values of the lignite carbon isotope data of fossil wood remnants are consistent with their chemotaxonomical classification as gymnosperms 13c between 22 5 and 24 9 and angiosperms 13c between 25 5 and 26 6 respectively the 13c data of the extracted cellulose reveal clear differences between fossil wood from gymnosperms average 13c 20 3 and angiosperms mean 13c 22 9 the higher isotopic difference of about 3 5 between cellulose and fossil wood compared to that found in modern trees is explained by the smaller effect of 13c discrimination for cellulose when compared with wood during decomposition

depositional palaeoenvironment and economic potential of khadsaliya lignite deposits saurashtra basin western india based on petrographic palynofacies and geochemical characteristics abstract the lignite and associated shale of the khadsaliya clays formation eocene of saurashtra basin india have been studied organic petrographic palynofacies and organic geochemical analyses have been carried out to deduce the depositional palaeoenvironment including the assessment of the hydrocarbon potential of this sequence petrographically the lignites constitute huminite macerals in dominance av 60 the organic facies as derived from maceral composition and biomarker data suggests that the peat biomass was formed from woody forest vegetation consists of angiosperms and pteridophytes microbial activity was also prominent over the peat biomass the peat biomass was deposited in tropical subtropical humid climatic conditions under deltaic control and brackish water influence further there are signatures of intermittent floods in the mire and is evident from the shift from mesotrophic to rheotrophic conditions the organic matter has been categorized into two palynofacies and is derived from degraded terrestrial biomass the extrapolation of tyson s app diagram and pr n c17 vs ph n c18 plot suggest that deposition took place in dysoxic to sub oxic conditions the huminite reflectance values 0 30 0 38 av 0 34 rr suggest that lignites are less mature and have reached up to lignitic stage low rank b of coalification the geochemical proximate ultimate analyses reveal that the lignites are characterized by high moisture content av 18 and relatively low ash yield av 27 the volatile matter yields and carbon contents are moderately high whereas fixed carbon sulphur and oxygen contents are average and hydrogen and nitrogen contents are relatively low rock eval pyrolysis data indicate that the hydrogen index values of the samples vary between 23 and 477 mg hc g toc av 188 mg hc g toc the tmax values of the lignites range between 377 and 433 c av 418 c along with the presence of hopanes suggesting the immature nature of the deposits hi vs tmax s2 vs toc hi vs oi and h c vs o c plots of the studied samples indicate that the organic matters are a mix of type ii iii kerogens the types of kerogen along with high toc contents av 33 wt indicate the ability of lignite bearing sequence of khadsaliya to generate mix of oil gaseous hydrocarbons upon maturation

the effect of river delta system on the formation of the source rocks in the baiyun sag pearl river mouth basin abstract source rock formation influenced by river delta system especially in continental margin basins is still poorly understood this article aimed to reveal the effect of river delta system on the formation of the source rock by taking the baiyun sag of the pearl river mouth basin for example paleo pearl river began to develop since the enping formation providing abundant organic matter beneficial for the formation of the source rocks in the baiyun sag the main controlling factor of source rock formation in the baiyun sag is terrestrial organic matter supply rather than the paleoproductivity or redox conditions low al ti and p ti ratios suggest low marine productivity which may be associated with a large number of terrigenous detritus input occupying about 43 04 94 91 there is a positive correlation between the oleanane c30hopane ratio and the toc value showing that terrigenous organic matter controls the source rock formation the size of the delta below pearl river estuary determines the extent of terrestrial organic matter supply source rocks with high organic matter abundance mainly formed in delta environment and those in neritic environment in enping and zhuhai formations also have high toc values as a result of adequate terrestrial organic matter supply

terpenoids in surface soils from different ecosystems on the tibetan plateau abstract realizing the potential of terpenoid biomarkers as an unequivocal land ecosystem and floral diversity indicator calls for work to establish a direct link between the terpenoids extracted from the plants and those found in the underlying soils to this end we have characterized the triterpenoid profile of soils and vegetation along two altitudinal transects representing very different ecosystems the first transect comprising 31 sample sites was on the eastern slopes of mt gongga eastern tibetan plateau rising from 1230 m to 4500 m above sea level an area with a temperate monsoonal climate the second transect sampling 29 sites was on the northern slopes of mt west kunlun a region characterized by montane desert meadow and alpine steppe located between 1300 m and 5050 m above sea level the dominant terpenoid biomarkers polycyclic triterpenoids of the taraxerane oleanane friedelane ursane lupane glutinane and lanostane series identified in the soils were found to be consistent with the overlying vegetation however the discovery of some unusual triterpenoids including the pentacyclic triterpene 3 methyl ethers ptmes d a friedo 2 3 secoolean 2 3 dioic acid methyl 3 acetoxylup 20 29 en 28 oate 24 methylenecycloartan 3 one 9 19 cyclolanostan 3 yl 24 methylene acetate 3 methoxy 9 lanosta 7 24 dien 26 23 olide and 3 methoxy 9 lanost 7 en 26 23 olide in the gongga soils does not match the current vegetation and may be indicative of a long vanished forest type vegetation thus soil biomarkers may be a useful tool in the reconstruction of palaeo vegetation

higher plant biomarkers reflect palaeovegetation changes during jurassic times abstract the relative abundances of three higher plant derived biomarkers retene cadalene and ip ihmn have been measured in marine sedimentary rocks from the northwest margin of australia it is thought that each biomarker represents input from a different plant type the distributions of these three compounds form a fingerprint representing higher plant input hpf variations in hpf in oxfordian sediments were nearly identical in all three locations with retene becoming very abundant relative to the other two compounds with decreasing age of the sediment this finding strongly suggests that the composition of terrestrial input during deposition largely determines hpf and that the possible effects of diagenesis and catagenesis on the distribution of the three biomarkers are relatively unimportant the marked increase in the abundance of retene relative to that of cadalene during the oxfordian is interpreted to reflect an increase in the contribution of plants that produced precursors for retene i e conifers brought about by a significant change in climate this was exemplified by measuring the distributions of retene and cadalene expressed in the higher plant parameter hpp for a suite of sediments from the carnarvon basin western australia covering the complete jurassic period the hpp profile displays three major cycles each covering a period of at least 10 million years this profile not only compared well with published palaeoclimate data but also showed a remarkable similarity with second order cycles in the global sea level curve thus strongly supporting the proposal that variations in hpf and hpp are indications of changes in palaeoclimate the relation with global sea level further suggests that global factors e g the atmospheric carbon dioxide concentration may play a major role in determining the observed variations in the distributions of these higher plant derived biomarkers

complex series of pentacyclic triterpanes in a lacustrine sourced oil from korea bay basin abstract gc ms analysis was undertaken of a waxy paraffinic low sulphur oil from korea bay basin apparently deriving mainly from bacterially reworked terrestrial organic matter deposited in a lacustrine environment in addition to the regular c27 35 hopanes a number of pentacyclic triterpanes was identified in the range c29 c32 these components appeared to be members of at least two homologous series one of which has been previously postulated to be 18 h neohopanes a further previously unreported series is characterized by a relatively intense molecular ion response during gc ms analysis a bacterial origin is suggested for these pentacyclic triterpane series the presence of which may reflect a particular set of sedimentological conditions

the paleogene vegetation and petroleum system in the tropics a biomarker approach abstract the present study investigates the biomarker signatures of sediments and crude oils to infer the paleovegetation from the two petroleum systems of assam basin eastern india they are classified as the paleocene middle eocene and the middle eocene oligocene petroleum systems the sediments are oil and gas prone with an early catagenetic stage of thermal evolution here we report tricyclic diterpanes such as rimuane pimarane rosane and isopimarane along with tetracyclic diterpanes ent beyerane phyllocladane kaurane from paleocene eocene coal bearing sediments and crude oils these diterpane biomarkers attest dominant contribution from conifers possibly from podocarpaceae and araucariaceae however diterpanes are not detected in oligocene sediments and oils crude oils from both paleocene eocene and oligocene reservoirs and organic rich sediments contain angiosperm biomarkers such oleanane and related triterpanes along with bicadinane a biomarker specific for the dipterocarpaceae family of angiosperms the equatorial position of india during early paleogene along with the presence of angiosperm signatures including dipterocarpaceae and gymnosperms reflect the emergence of tropical rainforest elements in eastern india absence of diterpenoids in oligocene samples and difference in angiosperm parameters from paleocene eocene samples suggests a change in source vegetation and organofacies

oleanane or lupane reappraisal of the presence of oleanane in cretaceous tertiary oils and sediments nonpolar gc columns are normally used for gc ms analysis of saturate fractions from crude oils under these conditions lupane coelutes with oleananes and some minor c30 compounds of non terrigenous origin having lupane like mass spectra because any peak eluting fractionally earlier than 17 21 h hopane in the m z 191 mass chromatogram is routinely assigned to oleanane the presence of lupane may sometimes have been overlooked lupane and oleananes are easily separated using reverse phase hplc triterpane concentrates from 10 crude oils known to contain oleananes were hplc separated lupane was unambiguously identified in six of the oils by full scan gc ms analysis of fractions having the hplc retention time of authentic lupane gc separation of lupane and oleananes is possible using polar gc columns having a polyethylene glycol stationary phase organic geochemistry 23 1995 21 allowing estimation of the lupane lupane oleanane ratio high ratios were measured in the marraat oil west greenland 0 8 and the amauligak oil from the beaufort mackenzie delta 0 26 the results suggest that lupane may be more frequently occurring than previously thought and that this compound is preferably associated with high latitude samples high concentrations of 28 nor and 24 28 bisnortriterpanes oleananes lupanes and taraxastanes were detected in the marraat oil

the spatial distribution of solar radiation under a melting arctic sea ice cover 1 the sea ice cover of the chukchi and beaufort seas is currently undergoing a fundamental shift from multiyear ice to first year ice field observations of sea ice physical and optical properties were collected in this region during june july 2010 revealing unexpectedly complex spatial distributions of solar radiation under the melt season ice cover based on our optical measurements of first year ice we found the under ice light field in the upper ocean to be spatially heterogeneous and dependent on wavelength ice thickness and the areal and geometric distribution of melt ponded and bare ice surfaces much of the observed complexity in radiation fields arose because the transmission of light through ponded ice was generally an order of magnitude greater than through bare unponded ice furthermore while many sites exhibited a consistent exponential decay in light transmission through both ponded and bare ice surfaces light transmission under bare ice was also observed to increase with depth reaching maximum values 5 10 m below the bottom of the ice a simple geometric model shows these transmission peaks are a result of scattering in the ice and the interspersion of bare and ponded sea ice surfaces these new observations of complex radiation fields beneath melt season first year sea ice have significant implications for biological production biogeochemical processes and the heat balance of sea ice and under ice ocean waters and should be carefully considered when modeling these sea ice related phenomena

molecular marker records of land use change abstract evidence of a changing environment in the catchment area of a small lake gormire yorkshire uk over the past 3000 years is provided by the mean carbon number of n alkanes and the ratio of lignin thermochemolysis products together with pollen analysis and bulk organic geochemistry periods of deforestation which commenced at 600 bc and ad 1200 display a significant decrease in organic carbon contents of the lake sediments which probably reflects dilution by enhanced influx of clastic material the mean carbon number of waxy c27 c31 n alkanes closely corresponds with the percentage of pollen derived from grass in the sediments a higher plant derived triterpenoid tentatively identified from its mass spectrum as 28 carboxyursen 12 enol appears exclusively in samples where tree and shrub derived pollen is dominant thermochemolysis of lignin confirms that there was a significant change in the nature of material deposited in the lake sediments from woody to grass dominated changes in both the sedimentary c n ratios and yields of lignin derived phenols suggest that deforestation events led to enhanced aquatic productivity initially through the development of reed swamp vegetation

southeastern tanzania depositional environments marine and terrestrial links and exceptional microfossil preservation in the warm turonian sediment cores from southeastern tanzania contain exceptionally well preserved calcareous and organic walled microfossils in numerous samples spanning from the aptian to the miocene the unusually high quality of preservation is commonly attributed to shallow burial and high clay content of the host sediments however such attributes apply to many deposits that are not characterized by exceptional preservation and thus invoking only grain size and burial depth is clearly an incomplete explanation for the exceptional microfossil preservation in an attempt to better characterize additional factors that were important in creating the tanzanian microfossil lagerstatte we integrated a wide range of paleontological geochemical and sedimentological observations to constrain the paleoenvironmental and early diagenetic conditions of a turonian interval where exceptional preservation is common planktic microfossil assemblages suggest that open ocean surface water conditions prevailed at the site but despite excellent organic matter preservation marine biomarkers are rare the sediments are dominantly composed of terrigenous silts and clays and terrestrially derived organic matter paleontological and geochemical observations record a remarkably stable interval dominated by excellent preservation through the lower middle turonian during the middle upper turonian though the preservation quality declines and this is associated with notable shifts in foraminiferal assemblages palynological species diversity carbon and sulfur isotope compositions and biomarker distributions the integrated data suggest that an increase in subsurface microbial activity and associated changes in pore water chemistry were important proximate variables that led to the decline in the quality of microfossil preservation up section within these shallowly buried turonian silty claystones from tanzania

geochemical application of sterane and triterpane biomarkers to a description of oils from the taranaki basin in new zealand abstract the distributions of sterane and terpane biomarkers in a suite of 25 oils from onshore and offshore regions of the taranaki basin of new zealand have been determined by gc ms features of these distributions include the presence of relatively high concentrations of a number of c 24 tetracyclic terpanes the virtual absence of tricyclic terpanes a predominance of c 29 normal iso and dia steranes and the presence of a number of non hopanoid triterpanes in one member of the suite urenui 18 h oleanane is the most abundant component m z 191 ion chromatogram of the terpane class of biomarkers based upon the distributions of 18 h oleanane the mckee and moturoa families of oils can be delineated these terpane distributions are qualitatively similar to those encountered in crude oils from a number of far eastern basins and from the handil field of the mahakam delta indonesia the taranaki oils are of approximately the same thermal maturity maturity parameters calculated from the distributions of c 29 steranes and of 17s h 21 h and 17 h 21s h hopanes confirm recent findings of incomplete nuclear isomerisation in oils derived from tertiary sediments an attempt has been made to correlate the mckee 1 and maui 4 crude oils with potential source rocks from depths of 3708 m and 3825 m respectively the rocks studied have attained insufficient maturity to have been the sources of these oils

bitumen in potsherds from two apulian bronze age settlements monopoli and torre santa sabina composition and origin abstract bitumen was found to occur on archaeological potsherds collected from two apulia middle bronze age sites monopoli and torre santa sabina italy bitumen from two different areas majella italy and selenice albania were analyzed as potential reference samples to assess the geographic origin of the archaeological bitumen using geochemical analytical techniques analysis of the archaeological samples from different layers at both sites showed that the bitumen possesses the same gross composition and biomarker distribution patterns sterane and terpane profiles from the archaeological samples were very similar to some of the geological samples collected from selenice in both archeological and selected selenice samples sterane distributions were dominated by the c 29 homologues 46 54 followed by the c 27 26 33 and c 28 homologues ca 21 other biomarkers such as gammacerane and oleanane as well as the stable carbon isotopic composition of the asphaltene fraction also suggest that the bitumen from the two archaeological sites was imported from albania during middle bronze age

bacterial methane in the atzbach schwanenstadt gas field upper austrian molasse basin part i geology abstract bacterial methane gas accumulations occur in upper oligocene to early miocene clastic deepwater sediments in the austrian molasse basin methane gas is produced from the upper puchkirchen fm aquitanian in the atzbach schwanenstadt gas field which is one of the largest gas fields in this basin the bacterial gas is composed of 97 vol methane 13 c 62 d 200 connate pore water below the gas water contact is characterized by low salinity ccl ca 0 25 mol kgw or 8900 mg kgw the top of the main reservoir zone a4 is approximately 1600 m subsurface thickness of reservoir intervals in the a4 sands the main reservoir is variable and ranges from 8 to 30 m with decreasing thickness to the north the porosity of the sand ranges from 13 to 20 permeability from 6 md to 70 md the reservoir temperature is 63 c reservoir rocks of this field wedge out to the north and represent dam break through splay sediment this reservoir architecture enabled early gas accumulation in a stratigraphic trap the source rocks and reservoir rocks are intimately connected claystone layers intercalate and seal the reservoir sediments these fine grained sediments with potential source rock characteristics contain immature organic matter of kerogen types ii iii the toc contents of these fine grained sediments vary from 0 34 to 0 94 wt the cement inventory of the source and reservoir rocks is characteristic for diagenetic pathways of organic rich sediments pyrite is preserved in the sediments as the first precipitation product due to rapidly developing anoxic pore water conditions a following dolomite precipitation dissolution phase was replaced by precipitation of calcite ankerite and siderite a last cement phase is chlorite the about 700 m thick upper puchkirchen fm was deposited during a time interval of about 2 6 ma aquitanian in a deep sea fan environment water depth 1000 m bottom water temperature of about 4 c free gas phases may have been trapped as gas hydrate due to basin subsidence and high sedimentation rates hydrates have been decomposed below the base of the gas hydrate stability zone 200 40 mbsf still during the aquitanian and thus still during or shortly after deposition of the upper puchkirchen fm

late pleistocene changes in terrestrial biomarkers in sediments from the central arctic ocean abstract biomarkers in late pleistocene sediments collected from the integrated ocean drilling program iodp arctic coring expedition acex hole m0004c central arctic ocean were investigated the major biomarkers are long chain n alkanes n fatty acids and n alkan 1 ols indicating fresh organic matter om derived predominantly from higher plants the dominance of terrestrial biomarkers is attributed to severe om degradation caused by slow sedimentation in oxygen rich benthic water and or low primary production due to permanent sea ice coverage hopanes representing thermally altered om tend to be abundant in samples with abundant ice rafted debris ird an om rich dark grey layer deposited during marine isotope stage mis 6 contains a significant amount of branched glycerol dialkyl glycerol tetraethers branched gdgts suggesting ice erosion of organic rich continental soil followed by transportation to the central arctic by drifting ice the labile refractory index i e the abundance ratio of long chain n alkan 1 ols to the sum of long chain n alkanes and long chain n alkan 1 ols decreases above the dark grey layer indicating that the om became more refractory this change suggests that coverage of the source region by om rich soil decreased because of extensive glacial erosion during mis 6

organic geochemistry of the lower suban coal seam south sumatra basin indonesia palaeoecological and thermal metamorphism implications abstract hydrocarbons extracted from the tertiary age coals from the lower suban seam south sumatra basin indonesia have been investigated using gas chromatography gc and combined gas chromatography mass spectrometry gc ms low rank vitrinite huminite reflectance 0 41 0 45 coals from the tambang air laya mine represent different maceral assemblages of an ideal succession of ombrogenous palaeo peat development in a vertical section high rank coals vitrinite reflectance 1 42 5 18 from the suban mine have been thermally metamorphosed by an andesitic intrusion variations in the distributions of n alkanes isoprenoids and saturated and aromatic biomarkers in the low rank coals reflect variations in local source input and palaeomire conditions terpenoid biomarkers such as cadinane and eudesmane type sesquiterpenoids and oleanane and ursane type triterpenoids indicate the predominance of angiosperm plants in the palaeomire particularly dipterocarpaceae the distribution of hopanoids is affected by the organic facies of the coal and their maturity and correlates with the palaeomire evolution as derived from petrological studies close to the igneous intrusion rapid thermal stress has destroyed most of the biomarkers but variations in n alkane distributions attributable to palaeomire conditions remain reversals in the trends for molecular parameters based on aliphatic hydrocarbons n alkane distribution and pristane phytane ratio and aromatic hydrocarbons methyl phenanthrenes with coal rank are observed

application of the change of sterane isomer ratios to the reconstruction of geothermal histories implications of the results of hydrous pyrolysis experiments abstract kinetic data for the change of the c 20 isomer ratio of 5 h 14 h 17 h steranes have been derived from a series of hydrous pyrolysis experiments on samples of the lower toarcian posidonia shale from northern germany the results are compared with other published kinetic data for the same apparent biological marker reaction it is shown that the sensitivity of these different sets of kinetic data varies drastically in the application to model calculations using predefined geothermal conditions the difference in sensitivity is hard to estimate from an inspection of the numerical values of activation energy and frequency factor alone a procedure for the selection of analytical sterane isomer ratios for kinetic assessment using a tti approach is demonstrated error calculations show what level of accuracy can be reached in the prediction of formation temperatures and burial depths when the kinetic data are applied to the reconstruction of geothermal histories of sedimentary basins

investigation of multifrequency multipolarization radar signatures of rain cells over the ocean using sir c x sar data radar signatures of rain cells are investigated using multifrequency multipolarization synthetic aperture radar sar images acquired from the space shuttle endeavour during the spaceborne imaging radar c x band sar sir c x sar missions in april and october 1994 in sir c x sar images radar signatures of rain cells over the ocean usually consist of irregularly shaped bright and dark patches that strongly depend on radar frequency and polarization the radar signatures of rain cells observed in sir c x sar imagery of the ocean originate from 1 the scattering and attenuation of the microwaves by raindrops and ice particles in the atmosphere and 2 the modification of the sea surface roughness induced by the impact of raindrops and by wind gusts associated with rain cells raindrops impinging on the sea surface generate ring waves which enhance the sea surface roughness but they also generate turbulence in the upper water layer which reduces the sea surface roughness depending on the radar wavelength ocean areas struck by rain can have higher or lower normalized radar cross section nrcs than the surrounding rain free area in ocean areas where heavy rain is impinging on the sea surface the x and c band nrcs is usually enhanced and the l band nrcs is reduced from the phase difference between the horizontally and vertically copolarized signals estimates of the rain rate are obtained the present analysis shows further that the presently used wind speed retrieval algorithms for the scatterometers aboard the ers and adeos satellites may yield biased wind fields if several rain cells lie within a scatterometer resolution cell

a new zealand record of sea level rise and environmental change during the paleocene eocene thermal maximum abstract the global warming associated with the paleocene eocene thermal maximum petm ca 55 5 myr ago is the most dramatic identified short term temperature increase of the cenozoic one direct consequence of a warming world is a rise in sea level due primarily to the thermal expansion of water as oceans warmed the kumara 2 core south island new zealand spans the paleocene eocene transition and provides a rare southern hemisphere continental margin record of the petm lithology palynology and compound specific stable isotope compositions of higher plant leaf wax n alkanes reveal a 4 85 m petm and a carbon isotope excursion cie of ca 4 5 larger than the 2 5 to 3 5 cies generally recorded by deep sea foraminifera there is a shift from a terrestrial to a marine potentially anoxic sedimentary depositional environment at the base of the petm interpreted as being the result of a local sea level rise coincident with the onset of the cie is the appearance of pollen associated with thermophilic conditions and the development of nypa mangrove swamps moreover there is a reorganisation of the angiosperm pollen assemblage during the petm and an initial increase in fern spores and decrease in gymnosperms crucially all of these changes occur below the horizon characterised by the most negative 13c values suggesting that 1 the recorded negative excursion of 4 5 may indeed reflect the shift in atmospheric co2 isotopic composition and 2 that the large input of 13c depleted carbon into the ocean atmosphere system was not geologically instantaneous with at least some of the added carbon lagging warming sea level rise and vegetation change furthermore compound specific hydrogen isotope analyses show a large degree of variability both directly before and during the cie suggesting that the petm in new zealand was characterised by complex and transient changes in the hydrological regime similar to those reported in north america the arctic and eastern africa thus the new petm record from kumara 2 reveals local climatic and biotic responses driven by a combination of global warming and the consequential change in local depositional environment induced by sea level rise

winter sea ice melt in the canada basin arctic ocean 1 recent warming and freshening of the canada basin has led to the year round storage of solar radiation as the near surface temperature maximum nstm using year round ocean from ice tethered profilers and autonomous ocean flux buoys sea ice from ice mass balance buoys and atmosphere from ncep ncar reanalysis data from 2005 2010 we find that heat from the nstm is entrained into the surface mixed layer sml during winter entrainment can only occur when the base of the sml reaches the top of the nstm if this condition is met the surface forcing and stratification together determine whether the sml deepens into the nstm heat transfer occurs by diffusion or by the erosion of the summer halocline the average temperature of the sml warmed by as much as 0 06 c during storm events solar radiation began warming the sml about 1 month early during the winter of 2007 2008 and this can be explained by thin sea ice

saturated and olefinic terrigenous triterpenoid hydrocarbons in a biodegraded tertiary oil of northeast alaska abstract dinorlupanes norlupanes olean 12 ene 18 olean 12 ene and urs 12 ene occur in a heavily biodegraded tertiary oil tested from the ocs y 0849 1 well drilled on the hammerhead prospect in the beaufort sea offshore northeast alaska these indicators and other source related characteristics of the hammerhead oil ring a degraded oleanoids ursanoids and lupanoids v and ni less than 2 0 ppm v v ni less than 0 5 indicate a land plant angiospermous character in the source facies the olefins in the hammerhead and canadian oils are considered to be contributed directly from the source rather than extracted from adjacent immature non source sediments during migration as indicated by a the accompanying presence in the oil of saturated angiosperm markers and b the absence of measurable amounts of other olefins characteristic of immature organic matter e g diasterenes and hopenes

sesquiterpanes diterpanes and other higher terpanes in oils from the taranaki basin of new zealand abstract the bi tri and tetracyclic terpenoids in crude oils from the taranaki basin of new zealand have been studied the distribution of c14 c15 and c16 bicyclanes was essentially invariant amongst the various fields a suggestion is made that the proportion of rearranged to total drimanes may be related to maturity and the ratio of homodrimane to drimane may be related to depositional environment mass spectra are reported for a number of unidentified sesquiterpanes including possibly norbisabolane and bisabolane the distribution of bi tri and tetracyclic diterpanes was very similar to that of crude oils from the gippsland basin of south east australia the occurrence of rimuane was confirmed 8 h labdane was identified and 4 h 18 norisopimarane was tentatively identified isopimarane dominated the diterpane distribution of oils from the maui field in the south west of the basin and its abundance gradually diminished in a north westerly direction until it became a minor component of oil from the new plymouth field this trend coincided with an increase in the complexity of the triterpane distribution and with the oleanane content of the oils these northwards trends also followed the evolution of coal deposits in the region the diterpanes in these oils had the same structure as those which occur in extant trees of the araucariaceae and podocarpaceae which flourish in new zealand today and did so even more extensively in the past coal measures formed from forests of such trees are probably the source of the diterpanes a situation analogous to that in the gippsland basin of south eastern australia tricyclanes of the cheilanthane series were not detected in any of the taranaki oils lending support to the view that these tricyclanes occur most abundantly in oils derived from marine sources c24 tetracyclanes secotriterpanes occurred abundantly in all the oils as they do in terrigenous oils from other parts of the world

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

composition of lipids from coal deposits of the far east relations to vegetation and climate change during the cenozoic abstract twenty one samples of sub bituminous coal and 1 sample of coaly shale have been collected from different coal seams representing the cenozoic coal basins widely distributed in the region of primorye and sakhalin russia and ne china hunchun deposit the seams belong to lower miocene upper oligocene sineutesovsky oligocene upper eocene pavlovsky upper eocene ust davydovsky lower eocene uglovsky and upper paleocene kivdinsky local chronostratigraphic units terpenoid biomarker compositions indicate the contribution of conifers and angiosperms to peat formation the results are in agreement with paleobotanical data from sedimentary successions closely associated with the seams highlighting abundant conifers of the taxodioid cupressaceae and pinaceae families as well as betula alnus fagus and ulmus during cenozoic in the far east in contrast to previous findings about changes in peat forming vegetation in central europe the terpenoid biomarker ratios revealed increased contributions of angiosperms during the oligocene and gymnosperm domination during eocene and miocene the different evolution may be related to differences in temperature and precipitation distribution as well as in geomorphology and landscape evolution a positive relationship between the di di tri terpenoid biomarker ratios and 13c of oligocene samples indicates the role of varying gymnosperm angiosperm influences on the 13c of coal differences in vegetation and climate are most probably responsible for the different trends in 13c of terpenoid biomarkers over the cenozoic beside their general variation coupled to the evolution in 13c of atmospheric co2 lower 2h values of plant derived lipids during the oligocene were most probably caused by lower temperatures during coal formation this conclusion is supported by the results of recent paleobotanical studies yielding lower mean annual temperatures mat during the oligocene but comparable values for mean annual precipitation map during the eocene and oligocene in the primorye region pimarane type diterpenoids are significantly depleted in 2h the results are in agreement with previous studies identifying different sources of hydrogen and or different biosynthetic pathways during their formation

depositional environment and hydrocarbon source potential of the oligocene ruslar formation kamchia depression western black sea abstract the oligocene ruslar formation is a hydrocarbon source rock in the kamchia depression located in the western black sea area depositional environment and source potential of the predominantly pelitic rocks were investigated using core and cuttings samples from four offshore wells in these wells the ruslar formation is up to 500 m thick based on lithology and well logs the ruslar formation is subdivided from base to top into units i vi dysoxic to anoxic conditions and mesohaline to euhaline salinities prevailed during deposition of the ruslar formation relatively high oxygen contents occurred during early solenovian times lower part of unit ii when brackish surface water favoured nannoplankton blooms and the deposition of bright marls solenovian event anoxic conditions with photic zone anoxia were established during late oligocene times units iii and iv and probably reflect a basin wide anoxic event in the eastern paratethys during kalmykian times organic carbon content in the ruslar formation is up to 3 autochthonous aquatic and allochthonous terrigenous biomass contribute to the organic matter relatively high amounts of aquatic organic matter occur in the lower part of the ruslar formation units i and ii and in its upper part unit vi diatoms are especially abundant in the lower part of unit vi the kerogen is of type iii and ii with hi values ranging from 50 to 400 mghc gtoc units i and ii pshekian lower solenovian are characterized by a fair to good potential to produce gas and oil but potential sources for gas and oil also occur in the upper oligocene units iv vi

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

biomarker characterisation of an oil and its possible source rock from offshore korea bay basin abstract comparison of biomarker distributions in an oil and in sedimentary rock samples from an offshore well in korea bay basin indicates that an upper jurassic 500 m thick mudstone zone could form the source rock for the oil the organic material in this zone appears to be h rich and of sufficient abundance from pyrolysis measurements to generate oil it seems to derive primarily from bacterial lipids as reflected in high levels of bacterial hopanoids and predominance of amorphous kerogen macerals a higher plant wax contribution to the organic matter is indicated by an oep in n akanes c 20 and there may also be an autochtonous algal contribution sedimentological and biomarker evidence is consistent with input from a river delta prograding into a deep freshwater lake biomarker distributions suggest that pronounced bacterial reworking of allochthonous higher plant material had occurred in probably anoxic conditions high heat flows in a rapidly subsiding extensional basin probably account for the observed extensive aromatisation of monoaromatic steroidal hydrocarbons at a relatively early stage of sterane isomerisation

relations of petrographical and geochemical parameters in the middle miocene lavanttal lignite austria abstract samples from two lignite seams lower seam upper seam of the lavanttal basin austria and additional xylite were investigated for variations in maceral composition petrography based facies indicators bulk geochemical parameters and molecular composition of hydrocarbons both seams originated in a topogenous mire and evolved within a transgressive setting the final drowning of the mire is indicated by sapropelic shales whereas the sapropelic shale overlying the lower seam was deposited in a freshwater lake the sapropelic shale above the upper seam represents a brackish lake numerous relationships are found between petrography based facies indicators and the geochemical composition of organic matter the contents of macerals of the liptinite group are positively correlated with soluble organic matter som yields and hydrogen index hi consistent with maceral composition and high hi values enhanced proportions of short chain n alkanes which are predominantly found in algae and microorganisms are obtained from samples of the sapropelic shales the final drowning of the mire is reflected by decreasing pristane phytane ratios due to the rise in ground water table and the establishment of anaerobic conditions as well as by decreasing ratios of diasterenes sterenes indicating increasing ph values in the mire the degree of gelification of plant tissue gelification index is governed by the microbial activity in the mire as indicated by the hopanes concentration the differences in floral assemblage during the formation of the lavanttal lignite seams are reflected by major differences in tissue preservation preservation of plant tissue tpi in the lavanttal lignite is obviously controlled by the presence absence of decay resistant gymnosperms in the peat forming vegetation and additionally influenced by the relative contribution of wood to coal formation the results provide evidence that valuable information for coal facies characterization could be obtained by petrography based and geochemical facies indicators an influence of the floral assemblage gymnosperms angiosperms ratio and of the contribution of algal biomass on carbon isotopic composition of the organic matter 13c 24 2 to 28 6 is proposed carbon cycling during biogeochemical decomposition of plant tissue by bacteria is suggested to affect the 13c values of the coal the chemotaxonomical classification of the xylites as gymnosperm remnants based on the molecular composition of terpenoid biomarkers is corroborated by the carbon isotopic composition of the xylites mean 13c 24 1 and the extracted cellulose mean 13c 20 2 the higher isotopic difference of about 3 9 between cellulose and total organic carbon of the xylites compared to the difference between cellulose and wood found in modern trees is explained by the smaller effect of decomposition on 13c of cellulose

characterization of eocene lacustrine source rocks and their oils in the beibuwan basin offshore south china sea two hundred twenty five rock samples and thirty seven oil samples from the beibuwan basin south china sea were analyzed with geochemical and organic petrological techniques to evaluate the eocene lacustrine source rocks and investigate controls on their properties and the distribution of different oil families in the basin two types of organic facies are recognized in the liushagang ls formation the first organic facies is algal dominated and mainly occurs in the organic rich laminated mudstones of the middle member of the ls ls 2 that were deposited in an anoxic stratified medium deep lake environment it is geochemically identified by its high abundance of c30 4 methylsteranes and heavy 13c values in the range of 22 4 to 27 5 the organic matter in this organic facies comprises type i and ii1 kerogens with its macerals dominated by fluorescent amorphous organic matter aom and exinites indicating a highly oil prone character the second organic facies is of terrestrial algal origin and is mainly identified in the non laminated mudstones of the upper ls 1 and lower ls 3 members of the liushagang formation that were deposited in shallow dysoxic weakly stratified fresh water environments source rocks of the second organic facies mainly contain type ii1 ii2 kerogens with mixed macerals of aom internites and vitrinites it is geochemically differentiated from the algal dominated organic facies by its relatively low abundance of c30 4 methylsteranes and lighter 13c values in the range of 27 20 to 28 67 three oil groups are identified by their biomarkers and stable carbon isotopes the first two groups a and b are probably end members of two major oil families a and b that correspond to the algal dominated organic facies and algal terrestrial organic facies respectively most of the discovered oils belong to group a oils that are characterized by a high abundance of c30 4 methylsteranes and heavy 13c values and show a good correlation with the algal dominated organic facies in ls 2 group b oils are found only within the ls 1 and ls 3 reservoirs and they are recognized by their relatively low content of c30 4 methylsteranes and lighter 13c values showing a close relation to the algal terrestrial source facies within the ls 1 and ls 3members respectively group c oils display intermediate biomarker features and stable carbon isotope values and are interpreted to be a mixture of group a and b oils the oil source correlation reveals a strong control of organic facies on the geographic distribution of oil groups or oil fields in the basin

biomarker distributions in crude oils and source rocks from different sedimentary environments abstract the saturated and aromatic hydrocarbons from a significant number of oils and source rocks derived from terrestrial and marine organic matter have been analysed by gc and gc ms results show that certain classes of biomarkers including bicyclic sesquiterpanes tricyclic terpanes pregnanes methylsteranes rearranged steranes hopane sulfides benzohopanes long chain alkylbenzenes and pentacyclic triterpanes can be used to distinguish differences in source input and or depositional environments variations in the distributions of the naphthalenes phenanthrenes fluorenes dibenzofurans dibenzothiophenes naphthobenzothiophenes and triaromatic steroid hydrocarbons may also reflect disparities in source input or sedimentary environments

biological marker composition of typical source rocks and related crude oils of terrestrial origin in the people s republic of china a review abstract typical source rocks and related crude oils of terrestrial origin in china come from five major environments a sedimentary formations in large lake basins in china s interior plate b lacustrine clastic rocks in fault subsidence basins c saline lake strata in fault subsidence basins d lagoonal lacustrine volcano clastic rocks in intermontane basins and e paralic coal bearing formations of the platform facies each has its specific biomarker characteristics as follows 1 environment a is poor in gammacerane and triterpane of higher plant origin 2 environment b contains abundant biomarkers especially hopanoid and steroid hydrocarbons with some triterpanes of higher plant origin 3 environment c has extremely high amounts of phytane and series of s compounds with high ratios of phytane pristane and gammacerane c30 hopane and sometimes high even carbon predominance of n alkanes 4 environment d contains abundant isoprenoid alkanes and carotanes carotane and carotane and 5 environment e is rich in biomarkers of high plants such as diterpenoid and aromatized terpenoid hydrocarbons

saturated and aromatic diterpenoids and triterpenoids in eocene coals and mudstones from china several series of saturated diaromatic triaromatic c ring cleaved and triaromatic diterpenoids and triterpenoids have been detected in 4 immature coal and mudstone samples a number of these compounds appear to represent intermediates in a series of postulated pathways for progressive aromatization of biogenic diterpenoids and triterpenoids diagenetic pathways for the formation of tricyclic aromatic hydrocarbons from abietane and pimarane type diterpenoid precursors and for the formation of diaromatic triaromatic c cleaved and triaromatic hydrocarbons from amyrin and other triterpenoid precursors are proposed saturated and aromatized abietanes pimaranes and phyllocladanes which are the most abundant compounds in all 4 samples indicate a predominant higher plant input which can be related to the coniferales group but not to individual plant families amyrin and other triterpenoid derived triaromatic and triaromatic c ring cleaved hydrocarbons with triterpenoid structures are thought to be characteristic for angiosperms the relative concentrations of the triaromatic and triaromatic c ring cleaved hydrocarbons are higher in samples 9602 mudstone and 9603 coal than samples 9601 coal and 9604 mudstone indicating samples 9602 mudstone and 9603 coal contain relatively more angiosperm derived organic matter than samples 9601 coal and 9604 mudstone the distribution patterns and the relative concentrations of saturated and aromatic diterpenoids and triterpenoids thus are valuable markers for the determination of the relative contents of biological sources of organic material in geological samples

paleoenvironment of the upper oligocene trbovlje coal seam slovenia abstract in the trbovlje region slovenia an upper oligocene coal seam up to 30 m thick developed in a topogenous mire and evolved within a transgressive setting the lower ash rich part of the seam unit i accumulated in a forest swamp strongly influenced by fluvial activity palynomorph spectra are dominated by taxodiaceae cupressaceae pollen ash yields decrease in the middle unit ii and upper part of the seam unit iii indicating decreasing fluvial activity an increase in cao contents reflects increasing amounts of inflowing water from an alkaline lake which progressively controlled peat hydrology in units ii and iii high sulfur contents in the nonmarine coal are a result of the carbonate rich water abundant pollen and spores from myricaceae and polypodiaceae indicate that unit ii represents a bush moor during deposition of unit iii this environment was replaced by a reed moor sapropelic coal unit iv and sapropelic shale unit v accumulated in a relatively large lake which was established by another water table rise the interpreted environmental changes are confirmed by biomarker data pristane phytane ratios reflect variations of the redox conditions within the mire and reach a minimum in the sapropelic unit iv the abundances of gymnosperm and angiosperm derived terpenoid hydrocarbons testify the predominance of gymnosperms over angiosperms during early peat stages unit i and increasing proportions of angiosperms during deposition of units ii and iii highest contents of diterpenoids coincide with maxima in the preservation of plant tissue tpi within unit i wet forest swamp suggesting that tpi is partly controlled by the input of resin rich decay resistant conifers sections of the seam characterized by advanced gelification show low steroids hopanoids ratios the results imply that gelification of plant tissue is related to increased microbial activity evidence is provided that the hopanes could be used as a measure for the activity of aerobic bacteria whereas for the hop 17 21 ene a microbial origin from anaerobic iron reducing bacteria is assumed a general influence of the floral assemblage and of varying contributions of algal biomass on carbon isotopic composition of the organic matter 13 c 24 0 to 28 1 is proposed carbon cycling during biogeochemical decomposition of plant tissue by bacteria is assumed to affect the 13 c values of the coal fossil wood collected from the seam is identified as derived from gymnosperms based on the molecular composition of terpenoid hydrocarbons this chemotaxonomical classification is corroborated by the mean carbon isotopic compositions of the fossil wood 13 c 24 0 and by the 13 c value 21 8 of the extracted cellulose from one macrofossil the low cellulose content of the sample 2 7 together with the slightly higher isotopic difference of 1 6 between cellulose and fossil wood compared to that found in modern trees can most probably be explained by the possible reversal in 13 c discrimination for cellulose when compared with wood in highly degraded samples

spatial and temporal variability in vegetation and coal facies as reflected by organic petrological and geochemical data in the middle miocene cayirhan coal field turkey abstract coal channel samples of middle miocene age are collected from the first tv and second tb seams from underground mines and from exploration boreholes within the cayirhan coal field in the beypazari basin turkey they are investigated in order to detect spatial and temporal changes in maceral and molecular composition of coal and to relate them to changes in vegetation and depositional environment the mean random reflectance values of ulminite 0 40 rr indicate a lignite to subbituminous c coal in rank maceral composition and biomarker ratios of the samples from both seams at the cayirhan deposit argue for coal formation in a limno telmatic environment under dysoxic to anoxic conditions alkaline surface waters of changing ph values and a high and unstable water level at the palaeomire are evidenced by moderate to high gelification index gi and ground water influence gwi values as well as high sulphur contents variations in tissue preservation index tpi and vegetation index vi values point to minor variations in the palaeovegetation during peat formation herbaceous plants dominated in both tb and tv palaeomires low tpi and vi values whereas in the surroundings arboreal vegetation were predominant the decreasing trends in pristane phytane ratios and carbon preference index cpi values towards the ne are suggested to reflect oxygen deficient conditions during peat formation due to a higher ground water level in this part of the basin the occurrence of c 29 diasterenes in low abundances provides evidence for periods of lower ph in the mire the borehole samples from the ne show slightly enhanced contributions of n alkanes from algal and microbial sources the terpenoid hydrocarbons present in the lignite argue for a major contribution of angiosperms to peat formation and slightly enhanced proportions of gymnosperms in the tv palaeomire in the ne based on the high concentrations of lupane type triterpenoids in the coal seams from the underground mine a higher density of betulaceae in the arboreal vegetation in the sw is indicated

contrasted distributions of triterpene derivatives in the sediments of lake caco reflect paleoenvironmental changes during the last 20 000 yrs in ne brazil lipid fractions extracted from sediment layers deposited in a small brazilian lake during the last 20 000 yrs were investigated by gas chromatography mass spectrometry considerable differences in the distribution and the amount of triterpene derivatives in the aliphatic as well as in the aromatic fractions were observed all along the series although no precise identification of these compounds was undertaken our interpretation of mass spectral data allowed us to discriminate between des a triterpenes mono and triaromatic derivatives of pentacyclic triterpenes and a series of compounds tentatively identified as diaromatic derivatives of tetracyclic triterpenes the largest compound diversity was found in the lowest levels of the series dated back to the end of the last glacial maximum when good preservation of terrestrial plant debris was ensured by rapid burial in a semi arid climate then except for a period corresponding to the younger dryas only des a lupane was detected in significant amounts the high predominance of des a lupane is interpreted to result from the development of a belt of eleocharis sp spike rush that filtered most of organic inputs from the catchment and was the site of des a lupane production and exportation towards the lake centre during the younger dryas a strong influx of des a lupane is attributed to the destruction of the spike rush belt consecutive to the lowering of the lake level under drier conditions the temporary destruction of this barrier allowed other triterpene derivatives to reach the lake the distinct dynamics of des a and aromatic triterpene derivatives under variable medium conditions led us to hypothesis that these two families of compounds derive from distinct pools that contributed differently to the sediment depending on environmental and climatic conditions des a lupane was most probably produced in sub aquatic conditions within the belt of spike rush conversely aromatic derivatives of triterpenes could have resulted from the degradation of their biological precursors within reducing micro environments in the catchment

depositional environment of the late miocene hausruck lignite alpine foreland basin insights from petrography organic geochemistry and stable carbon isotopes abstract lignites and fossil wood from two boreholes in the late miocene hausruck district alpine foreland basin austria were investigated with respect to organic carbon and total sulfur contents ash yields maceral composition organic geochemistry and stable carbon isotope ratios the lignites from the two sampled profiles differ in sulfur contents and petrography based facies indicators gelification index gi tissue preservation index tpi the results point to drier and more acidic conditions in the part of the mire sampled at drill site lukasberg whereas the lignites from kalletsberg formed under near neutral conditions due to a raised ground water table the different depositional environments are supported by the paleogeographic positions of the boreholes borehole lukasberg is located within a paleo valley whereas borehole kalletsberg is located at the deeper part of a basin situated south and southwest of the hausruck area environmental changes with time within the mire are confirmed by the molecular composition of the soluble organic matter som differences in pristane phytane ratio isomerisation of hopanes at position 17 concentrations of hopanes and in the ratio of hopanes to hop 17 21 enes are related to the extent of gelification of plant tissue sulfur content and ph values caused by differences in ground water table the variable contents of individual terpenoid hydrocarbons derived from land plants indicate that angiosperms and conifers contribute to peat formation in the hausruck district in variable proportions overall angiosperm biomarkers slightly predominate the tissue preservation index tpi within the kalletsberg profile is probably governed by the proportion of decay resistant conifers as indicated by the correlation between tpi and biomarker composition of the coals correlations between 13 c values of the lignites between 24 9 and 27 4 and their non hopanoid terpenoid composition indicate the major influence of changes in peat forming vegetation on the carbon isotopic composition of the coals in the hausruck district carbon isotope data of macrofossils are consistent with their taxonomical classification as conifers 13 c between 22 7 and 25 1 and angiosperms 13 c between 25 5 and 26 6 respectively the 13 c data of the extracted cellulose reveal clear differences between fossil wood from gymnosperms average 13 c 21 0 and angiosperms mean 13 c 23 4

coal characteristics and biomarker investigations of dombayova coals of late miocene pliocene age afyonkarahisar turkey abstract in dombayova graben dinar afyonkarahisar western turkey a 203 m thick coal bearing zone of late miocene to pliocene age was recently drilled the zone hosts several coal beds with a total thickness of 46 m coal samples from the dombayova field were studied by means of standard proximate ultimate petrological analyses micro ftir spectroscopy and rock eval pyrolysis and organic geochemical analyses coal proximate analyses and the presence of carbonate minerals and fossil shell fragments point to alkaline surface waters of changing ph values due to fluctuations of the water level in the paleomire and or ca rich water influx low sulfur contents argue for sulfate limitation of bacterial sulfate reduction petrographic observations reveal that the coal is dominantly composed of weakly altered wood fragments and roots the mean random reflectance values of ulminite 0 33 ro indicate lignite rank of the coal the micro ftir data of macerals of huminite group indicate higher contributions of aliphatic hydrogen in textinite compared to more aromatic levigelinite the semi quantitative differences in the ratios of selected functional groups suggest that aromaticity and the extent of oxidation are higher in levigelinite aliphatic chains are longest in textinite and ulminite and shortest in texto ulminite and levigelinite we interpret this difference to point to a different origin of levigelinite probably from colloidal humic solutions that were gelified during diagenesis the concentrations of n alkanes and their distribution patterns provide evidence for higher terrestrial plants as the dominant source of organic matter decreasing pristane phytane ratios with depth are interpreted to reflect more reducing conditions during peat formation due to higher ground water level the absence of diasterenes is most probably caused by low clay mineral contents and is consistent with the presence of alkaline waters in the paleomire the presence of terpenoid hydrocarbons in the lignite indicates a major contribution of angiosperms to peat formation the positive relationship between the concentrations of perylene and lupane type triterpenoids suggests an increasing abundances of wood degrading fungi in the peat forming vegetation characterized by a high density of betulaceae

biomarkers and geochemical indicators of holocene environmental changes in coastal lake sarbsko poland organic rich samples from the holocene sedimentary sequence of lake sarbsko were investigated to reconstruct variations in the aquatic system in response to environmental change the aims were to i identify organic matter om sources ii examine changes in soluble om composition in relation to fluctuations in limnological conditions and iii validate the sensitivity of organic geochemical indicators in tracing environmental changes diatom frustules are abundant in all samples alginite macerals and terrigenous organic matter further contribute to the sedimentary om organic petrography total organic carbon toc n ratio values and high content of biogenic silica sio2 biogenic argue for a predominant algal source of om in contrast the n alkane distributions high relative abundance of c29 steroid hydrocarbons and high content of detrital quartz in the sediments provide evidence for the input of terrigenous material as a major om source within the basin the terpenoid biomarker composition indicates a contribution from conifers and angiosperms from the diterpenoids in the samples a contribution from species of the coniferales family pinaceae is concluded toc s and mg ca values as well as steroid hopanoid concentration ratios reflect enhanced water salinity in this coastal lake due to ingression of brackish water from the baltic sea during the atlantic and sub atlantic periods as indicated by the positive relationship between d 13 c of toc and mg ca d 13 c values are influenced by changing contribution of marine vs freshwater phytoplankton additional isotopic heterogeneity in d 13 c may result from differences in terrigenous om supply vs autochthonous om production in the lake the isotopic composition of calcites supports the establishment of freshwater conditions in the lake during the sub boreal period pristane phytane and fe mn ratios are interpreted to reflect differences in the redox conditions oxygenation of bottom waters was temporarily variable with highest levels of oxygen availability during the sub boreal freshwater lake high contents of hopanoid hydrocarbons argue for enhanced microbial activity in the water column and sediment the occurrence of 2b methyl hopanes is related to the presence of cyanobacteria or methylotrophic bacteria

oleananes in oils and sediments evidence of marine influence during early diagenesis abstract the oleananes as markers for the angiosperms provide valuable source and age information when present in an oil nevertheless they are not quantitatively related to the land plant input and indeed their presence reflects only a small leak in diagenetic processes leading primarily to aromatic oleanoids because they are minor products the abundance of oleananes in terrigenous oils and sediments may be highly sensitive to changes in early diagenetic conditions here we present evidence that contact of plant matter with seawater during early diagenesis enhances the expression of oleananes in a mature sediment or oil oleananes are absent or present at very low concentrations in samples from the base of an eocene coal seam affected by postdepositional seawater intrusion however their abundance increases toward the top of the seam in correlation with organic sulphur dibenzothiophene phenanthrene and the homohopane index similarly in deltaic sediments from the south sumatra basin oleanane hopane is strongly correlated with indicators of marine influence such as c 27 c 29 steranes and the homohopane index in each case increasing oleanane abundance is accompanied by a reduction in the extent of aromatisation and for the south sumatra basin the proportion of a ring contracted oleananes an angiosperm derived miocene coal from the philippines deposited under freshwater conditions shows abundant aromatic oleanoids but no oleananes these results show that oleananes need to be used with caution as age and source markers in fluvio deltaic and lacustrine petroleum systems on the other hand their sensitivity to early diagenetic conditions may make them useful in locating effective source rocks in such systems

early eocene equatorial vegetation and depositional environment biomarker and palynological evidences from a lignite bearing sequence of cambay basin western india abstract an investigation of palaeofloral distribution with depositional environment and palaeoclimatic condition of western indian subcontinent during early eocene period has been carried out from a lignite bearing succession of cambay basin western india the study of biomarkers palynological remains and petrography is taken as proxies for providing supportive evidence for our inference the petrographic results reveal that the sediments are thermally immature and coalification was extended up to the lignitic stage low rank b the palynological results show the dominance of angiosperms mainly members belonging to the arecaceae family throughout the studied section triterpenoids with oleanane ursane and lupane structure in extractable organic matter are derived from angiosperm wax pollen grains spinizonocolpites proxapertites dipterocarpuspollenites albertipollenites retipollenites arengapollenites lakiapollis and longapertites with pteridophyte spores and fungal fruiting bodies confirm the prevalence of tropical to subtropical climate during the deposition of the sediments sesquiterpenoids like longifolene 12 methanoazulene cadinane and selinene together with amyrin derivatives are the indicator of dipterocarpaceae family that grows in the extant tropical rain forests in se asia appearance of dinoflagellate cysts and the predominance of lower molecular weight part in n alkane series with the signature of submerged floating vegetation in the shale horizon indicate marine influence in the younger part of the mine section the presence of mangrove pollen such as spinizonocolpites proxapertites and acanthotricolpites further suggests that the lignite bearing sequence was deposited in marshy marginal marine environment

a comparison of terpenoid and leaf fossil vegetation proxies in paleocene and eocene bighorn basin sediments abstract plant derived terpenoids long recognized as biomarkers can help reveal the major taxonomic groups of land plants present in ancient environments even if rocks and sediments do not preserve plant macro or microfossils previous studies have used simple di to triterpenoid ratios to reconstruct floral changes in the geologic past but few have compared terpenoid ratios with estimates of floral composition from fossils further reconstructions have not taken into account differences in biomarker production i e concentration relative to leaf biomass between different types of plants here we have examined terpenoids from early cenozoic fluvial rocks from the bighorn basin wyoming usa where fossil flora has been studied in detail we analyzed the distributions of diterpenoids triterpenoids and n alkanes from leaf wax in a total of 43 samples from 15 stratigraphic horizons of late paleocene 63 ma to early eocene 53 ma in age in nearly all samples triterpenoids derived from angiosperms were significantly lower in abundance than conifer specific diterpenoids a finding that contrasted with plant fossil evidence for the same rocks this suggests that di to triterpenoid ratios severely underestimate the abundance of angiosperms in paleovegetation angiosperms dominated n alkane production among modern plants and we propose a new paleovegetation proxy based on the ratio of diterpenoids conifers to n alkanes angiosperms corrected for lipid production estimated from extant vegetation using diterpenoids and alkanes we infer the composition of paleovegetation to be similar to that inferred from plant fossils although the approach works well for the bighorn basin we stress the new paleovegetation proxy will need to be evaluated for other time periods communities paleogeography and depositional environments with pollen or megafossil data available

hydrocarbon traces in the tertiary basalts of the faeroe islands abstract hydrocarbons in the form of gases oils and waxes have been observed in the basalts of the faeroe islands in the north atlantic gases and traces of oil were observed in the outflowing water of the deep lopra 1 well drilled in 1981 the hydrocarbon gas was fairly dry with stable isotopic ratios of 13c1 3 41 4 32 4 26 5 respectively typical of a thermogenic gas high temperature gas chromatography of the oil showed that it consisted mostly of c13 60 n alkanes biomarker distribution observed by gc ms indicates that the oil was derived from a mature source rock deposited in an anoxic environment this suggests that the source rock must lie beneath the known basalts waxes exhibiting bright yellow fluorescence under uv light were observed as coatings on zeolite minerals widely distributed on the faeroe islands the waxes consist predominantly of higher n alkanes shown by htgc the fluorescence indicates the presence of aromatic compounds biomarker distribution indicated that the waxes were derived at least in part from a source rock containing some terrestrial organic matter astestified by the low amounts of oleanane present the waxes were probably deposited from traces of oil present in deeply circulating waters in fractures within the basalts coals which had been suspected to generate some of the hydrocarbons observed in the faeroese basalts were also examined vitrinite values of ro 0 5 as well as gc ms analyses of the suduroy coal extracts showed that these coals are immature and have not generated significant hydrocarbons

the petrographical and organic geochemical composition of coal from the east field bogovina basin serbia abstract a petrological and organic geochemical study was performed on coal samples from the east field deposit bogovina basin serbia fourteen coal samples were collected from different parts of the main and upper coal seams from fresh working faces in the underground subbituminous coal mine the lower miocene coal of the east field is a typical humic coal with huminite liptinite and inertinite concentrations of up to 81 4 vol 16 1 vol and 13 5 vol respectively densinite is the most abundant maceral with variable amounts of ulminite and gelinite sporinite and liptodetrinite are the most common macerals of the liptinite group exsudatinite was detected in the lower part of the lower coal seam inertodetrinite is the most abundant maceral of the inertinite group the mineral matter consists mostly of clay minerals and carbonates the mean random huminite reflectance ulminite b for the main coal seam is 0 42 0 04 rr and 0 41 0 04 rr for the upper coal seam which are typical for an immature to early mature stage of the organic matter the distribution and abundance of n alkanes and steranes indicates a significant contribution of epicuticular waxes from higher plants high amount of phyllocladane type diterpenoids 16 h phyllocladane suggests that coal forming plants were conifer families taxodiaceae podocarpaceae cupressaceae araucariaceae sciadopityaceae and phyllocladaceae while a higher amount of pimarane and norpimarane suggests pinaceae taxodiaceae and cupressaceae the pristane phytane pr ph ratio implies variable anaerobic to oxic conditions during sedimentation the distribution of the hopanes detected in the bogovina east field coal indicates an immature to early mature stage of the organic matter which is in agreement with huminite reflectance the high coal sulphur contents from the east field are characteristic for slightly alkaline depositional environments generated by bentonite from the basement of the main coal seam the petrological observation and biomarker composition provide evidence for the generation of immature hydrocarbons which most probably originated from the resins and waxes of higher plants mostly gymnosperms

oleanane parameter verification by quantitative study of the biomarker occurrence in sediments of the niger delta abstract the variation of the absolute concentration of oleananes in three selevted sedimentary columns of the tertiary niger delta is paralleled by the corresponding oleanane parameter op profile thereby confirming that the latter can be utilized for estimating the relative contribution of terrigenous organic matter it is shown that op features a dynamic range especially at the oil generative window ogw and can precisely delimit the top of the ogw which for the niger delta is shown to coincide approximately with the 80 c isotherm and ro 0 55 this study provides the first direct evidence of the inadequacy of vitrinite reflectance as a maturity parameter for type iii kerogen furthermore based on the new findings an alternative model for oleanene oleanane interconversions in the geosphere is proposed

characterization of organic matter and depositional environment of tertiary mudstones from the sylhet basin bangladesh abstract the sylhet basin of bangladesh is a sub basin of the bengal basin it contains a very thick up to 22 km tertiary stratigraphic succession consisting mainly of sandstones and mudstones the sylhet succession is divided into the jaintia paleocene late eocene barail late eocene early miocene surma middle late miocene tipam late miocene pliocene and dupitila groups pliocene pleistocene in ascending order the origin of the organic matter om and paleoenvironment of deposition have been evaluated on the basis of c n s elemental analysis rock eval pyrolysis and gas chromatography mass spectrometry gc ms analysis of 60 mudstone samples collected from drill core and surface outcrops total organic carbon toc content ranges from 0 11 to 1 56 sulfur content is low in most samples toc content in the sylhet succession varies systematically with sedimentation rate with low toc caused by clastic dilution produced by high sedimentation rates arising from rapid uplift and erosion of the himalaya the om in the succession is characterized by systematic variations in pristane phytane pr ph oleanane c30 hopane n c29 n c19 alkane tm ts 17 h 22 29 30 trisnorhopane 18 h 22 29 30 trisnorhopane and sterane c29 c27 c28 c29 ratios during the middle eocene to pleistocene based on biomarker proxies the depositional environment of the sylhet succession can be divided into three phases in the first middle eocene to early miocene deposition occurred completely in seawater dominated oxic conditions with abundant input of terrestrial higher plants including angiosperms the second phase middle to late miocene consisted of mainly freshwater anoxic conditions along with a small seawater influence according to eustasic sea level change with diluted om derived from phytoplankton and a lesser influence from terrestrial higher plants oxygen poor freshwater conditions prevailed in the third phase post late miocene planktonic om was relatively abundant in this stage while a high angiosperm influx prevailed at times tmax values of ca 450 c vitrinite reflectance ro of ca 0 66 and methylphenanthrene index mpi 3 of ca 1 indicate the om to be mature the lower part middle eocene to early miocene of the succession with moderate toc content and predominantly terrestrial om could have generated some condensates and oils in and around the study area

influence of floral assemblage facies and diagenesis on petrography and organic geochemistry of the eocene bourgas coal and the miocene maritza east lignite bulgaria abstract numerous differences in the petrography and organic geochemistry of two tertiary low rank coal deposits of bulgaria formed within comparable depositional environments are outlined different floral assemblages are indicated as the main sources of organic matter for the eocene bourgas sub bituminous coals a warm climate plant community dominated by angiosperms is reflected in the biomarker composition whereas a coniferous flora was the main source of the resinous organic matter of the miocene maritza east lignite the results are in agreement with palaeobotanical data these differences in the peat forming vegetation of the paleogene compared to the neogene of bulgaria are attributed to decreasing temperature during the tertiary the abundance of resinous compounds relative to lipids from plant waxes long chain n alkanes as well as the preservation of plant tissue are mainly controlled by gymnosperm angiosperm ratios pristane phytane and diasterenes sterenes ratios reflect variations in redox conditions and the ph of the depositional environments caused by eustatic sea level changes freshwater inflow or varying ground water table changing eh and ph values are associated with differences in microbial activity controlling the extent of gelification of plant tissue bacteria most probably contributed to the aromatisation of triterpenoids in the mire enhanced thermal maturation of organic matter during diagenesis is reflected in higher contents of n alkanes and the presence of alkyl naphthalenes in the bourgas coals alkyl naphthalenes are thought to have been formed from pentacyclic triterpenoids rather than from resinous compounds

methoxy serratenes in a soil under conifers and their potential use as biomarkers of pinaceae abstract in the frame of a study aimed at defining new soil molecular biomarkers that could attest to former land use and that could also be screened in lake sediments for palaeoenvironmental reconstruction we analysed the 2 4 cm depth layer of a soil developed under a conifer forest in the lake aydat catchment french massif central the lipid fraction of the sample contained 12 serratenoids bearing at least a methoxyl ome group at c 3 or c 21 and various additional functional groups alcohol ketone or acetate a survey of the literature provided indubitable evidence that these compounds are typical for pinaceae species in agreement with the surrounding vegetation at the sampling site due to the economic and ecological importance of the taxa the presence of these highly specific compounds in soil sediments or peat could therefore help in unravelling the timing of forestry activity

diagenesis of higher plant triterpenes in evaporitic sediments abstract several samples from a tertiary carbonated evaporitic series sainte cecile camargue france were investigated their analysis revealed a high abundance of new or uncommon hydrocarbons and organic s compounds related to higher plant triterpenes several of them in particular 12 29 cyclolupa 12 18 20 29 triene 1 could be positively identified these triterpenoids are generally absent from non evaporitic sediments which contain essentially aromatic triterpenoids resulting from microbially mediated aromatization processes starting in ring a or in ring b when preceded by the loss of ring a the uncommon transformations undergone by higher plant triterpenes in the highly anoxic sediments from sainte cecile are specific for each series of triterpenes i e oleanane ursane lupane and are probably linked with the rapid disappearance of the functionality located in ring a by reduction or by the incorporation of the triterpenes in s rich macromolecules by reaction with inorganic s species these biological markers represent new source parameters which may be quite useful as indicators of terrestrial inputs in evaporitic deposits

geochemical composition and origin of tertiary oils in the yinggehai and qiongdongnan basins offshore south china sea abstract this study comprehensively characterizes the geochemical compositions of tertiary crude oils in the yinggehai and qiongdongnan basins offshore south china sea and differentiates their source properties using chemical and isotopic data the oils in the two basins have distinct source characteristics the majority of the oils from the yacheng yc field in the qiongdongnan basin are commonly marked by high pr ph ratios mostly from 4 5 to 7 0 unusually abundant angiosperm derived compounds and a domination of c29 in diasteranes suggesting a predominantly terrigenous organic source in contrast the oils from the dongfang df and ledong ld fields in the yinggehai basin have relatively lower pr ph values 2 5 5 5 and a low amount of bicadinanes moreover some oils in this basin contain abundant 4 methylsteranes and detectable c30 desmethyl steranes the difference in the molecular composition is also apparent with regard to the aromatic hydrocarbons the former oils contain more abundant biphenyls fluorenes and 2 phenylnaphthalene than the latter ones the oils from the qiongdongnan basin are relatively depleted in 13c and have 13c values of the whole oil in the range of 24 9 to 26 9 consistent with the great terrigenous input in contrast the yinggehai oils are isotopically heavier with 13c values from 21 6 to 23 6 typical of a marine isotope signature correspondingly their n alkane isotopes have different 13c ranges and exhibit distinct distribution profiles based on the oil source rock correlation the oils in the yc field were generated from the coastal plain swamp and shallow marine strata of the oligocene in the qiongdongnan basin while the yinggehai oils were sourced from the miocene shallow marine mudstones in the basin

facies evolution and stratigraphic correlation in the early oligocene tard clay of hungary as revealed by maceral biomarker and stable isotope composition abstract hydrocarbon source rocks i e tard clay formation containing type ii organic matter were deposited in the hungarian paleogene basin during lower oligocene a major contribution of aquatic organisms green algae dinoflagellates chrysophyte algae and minor inputs from macrophytes and land plants to organic matter accumulation is indicated by n alkane distribution patterns composition of steroids and 13c of hydrocarbon biomarkers microbial communities included heterotrophic bacteria cyanobacteria chemoautotrophic bacteria as well as green sulphur bacteria the presence of methanotrophic bacteria is indicated by 13c depleted hop 17 21 ene higher inputs of terrestrial organic matter occurred during deposition of the lower and uppermost units of the tard clay formation the terpenoid hydrocarbon composition argues for angiosperm dominated vegetation in the area of the hungarian paleogene basin diterpenoid hydrocarbons derived from the resins of conifers are about 2 3 enriched in 13c compared to the angiosperm biomarkers environmental conditions changed from marine to brackish accompanied by oxygen depletion in the lower parts of the water column organic carbon accumulation during this period was a consequence of stagnant bottom water conditions in the hungarian paleogene basin due to salinity stratification this is indicated by low pristane phytane ratios varying from 0 27 to 1 44 enhanced ratios of dimethylated versus trimethylated mttcs 0 14 0 59 and the presence of aryl isoprenoids from 0 4 to 14 1 g g toc a major marine incursion is evidenced by stable isotope ratios of organic matter and carbonates in the uppermost member of the tard clay a transition from brackish towards normal marine conditions is proposed up to 3 anoxic cycles are recognized in the drill core sections separated by minima in pristane phytane ratios and maxima in the depth trends of di tri methylated mttcs and aryl isoprenoid concentrations in combination with the position of maxima of 13c of carbonate and organic matter and an abrupt decrease in perylene concentrations the cycles can be used for intra formational correlation of the tard clay