hopanoid hydrocarbons and perylene in lake biwa japan sediments environmental control on their abundance and molecular composition abstract we examined the vertical distribution of hopanoid hydrocarbons and perylene in sedimentary sections from lake biwa japan and discuss the results with respect to paleoenvironmental information from around the lake region over the last 120 kyr moretene concentration was high above the sections where fall out events of tephra tephra at occurred ca 30 kyr before present bp this feature suggests that the tephra fall out events created o 2 deficient conditions resulting in high activity of methane producing bacteria and of methanotrophic moretene producing bacteria becoming active above the tephra layer five sections at 10 20 kyr ca 35 kyr ca 70 kyr ca 90 kyr and ca 110 kyr bp exhibited peaks in the ratio of 17 21 22r homohopane to 17 21 22r homohopane hopc 31 the n c 23 n c 31 alkane ratio in these sections was 0 6 0 1 n 49 very low if compared with typical characteristics of n alkanes for a sphagnum peat environment n c 23 n c 31 ca 3 6 bingham et al 2010 we conclude that sphagnum peat may not have been an important contributor of n alkanes over the past 120 kyr comparison with previous pollen records for the lake region suggests that high hopc 31 values may be caused by production of acidic soil from expansion of temperate conifer e g cryptomeria forest under cold and wet climate conditions the abundance of perylene relative to sediment or total organic carbon toc was high in the sections at ca 20 kyr ca 70 kyr and ca 90 kyr bp these sections were approximately in accord with those having a maximum in hopc 31 this concordance indicates that the climatic conditions suitable for the production of perylene quinone in soil surrounding the lake coincided with those for a high hopc 31 ratio thus hopc 31 and perylene toc might be useful as proxies of soil acidity temperature and humidity

compositions sources and depositional environments of organic matter from the middle jurassic clays of poland abstract the comprehensive biomarker characteristics from previously undescribed middle jurassic clays of poland are presented the molecular composition of the organic matter om derived from clays of aalenian to callovian age has not changed significantly through time high relative concentrations of many biomarkers typical for terrestrial material suggest a distinct dominance of om derived from land plants increasing concentrations of c29 diaster 13 17 enes towards the northern part of the basin indicate an increase in terrestrial input this terrestrial material would have originated from the enhanced transport of organic matter from land situated at the northern bank of the basin i e the fennoscandian shield the organic matter was deposited in an oxic to suboxic environment as indicated by relatively low concentrations of c33 c35 homohopanes moderate to high pr ph ratio values an absence of compounds characteristic for anoxia and water column stratification such as isorenieratane aryl isoprenoids and gammacerane as well as common benthic fauna and burrows 18o measurements from calcitic rostra of belemnites suggest that the mean value of the middle jurassic sea water temperature of the polish basin was 13 1 c it is suggested that this mirrored the temperature of the lower water column because belemnites are considered here to be necto benthic the organic matter from the middle jurassic basin of poland is immature this is clearly indicated by a large concentration of biomarkers with the biogenic configurations such as hopanes hop 13 18 enes hop 17 21 enes diasterenes and sterenes the identification of preserved unaltered biomolecules like ferruginol 6 7 dehydroferruginol and sugiol in protopodocarpoxylon wood samples from these sediments present particularly strong evidence for the presence of immature om in the middle jurassic sediments moreover the occurrence of these polar diterpenoids is important due to the fact that they are definitely the oldest known natural products detected in geological samples

a hypothesis for the origin of perylene based on its low abundance in sediments of green bay wisconsin abstract perylene a polycyclic aromatic hydrocarbon pah that is common in sediments is believed to originate principally from anaerobic diagenesis of organic matter but its precursor material remains enigmatic we have investigated the formation of perylene in a dated sediment core from green bay wi comparisons of sedimentary profiles of perylene anthropogenic pahs land plant derived hydrocarbons and aquatic contributions of organic matter rule out a specific industrial terrigenous or aquatic precursor for perylene instead perylene seems to be formed from any kind of organic matter as a consequence of a specific type of microbial activity in sub bottom sediments despite an abundance of organic matter the amount of perylene is low in green bay and in other organic carbon rich lake sediments the abundant availability of organic matter that stimulates microbial activity in green bay sediments would seem to favor perylene formation in such sediments we therefore hypothesize that the microorganisms responsible for perylene formation do not compete successfully with those that flourish in sediments rich in organic matter perylene formation consequently does not become significant until deeper in sediments after the more reactive types of organic matter have been consumed

dynamic modelling of stress accumulation in central italy role of structural heterogeneities and rheology summary recent efforts to relate the style of seismicity in the central apennines to the stress build up induced by active geodynamic processes by means of simple viscoelastic dynamic models have shown that seismicity in this region is likely to be controlled by two major processes the westward underthrusting of the adriatic plate under the apennines and the asthenospheric upwelling underneath tuscany in this work using these results as a starting point we evaluate by means of 2 d dynamic models the effects of structural heterogeneities major crustal scale faults this improvement is made possible by the recent publication of the results of the crop 03 seismic line and of temperature dependent rheologies within the crust and the lithospheric mantle on the stress field induced by the two processes mentioned above modelling results are compared with detailed seismicity data we show that for all models the predicted stress fields are controlled at large wavelengths by an upward state of flexure in tuscany and a downward state of flexure in the apenninic foredeep in agreement with previous studies when activating crustal scale discontinuities however strong local rotations of the major axes of the stress tensor occur in the proximity of the faults generating complex local stress fields characterized by the coexistence of compressive and tensional styles this could explain the coexistence as observed within certain regions of central italy of compressive and extensional events when detailing the rheology using plastic behaviour for the lithospheric portions of the models a complex profile of yield stresses is considered the materials characterized by higher strength being the sedimentary cover and the lithospheric mantle model predicted stress concentrates in these materials the lateral variability of the thickness of the sedimentary cover induces strong local rotations at shallow depths of the stress eigenvectors all of the models predict a stress field roughly compatible with the distribution and style of seismicity of the region the use of progressively more realistic rheologies and geometries however gives slightly better results when compared to seismicity data this paper shows that sensible results may be obtained by combining active and natural source seismicity with finite element modelling

molecular stable carbon isotope compositions of alkylphenanthrenes in coals and marine shales related to source and maturity abstract phenanthrene phe and methylphenanthrenes mps extracted from coaly shale and coal samples containing terrestrial organic matter are compared with the same compounds from marine shales in terms of yields and 13 c values at marginally to fully mature stages of thermal evolution the shales derived from four boreholes in the hils half graben area northwestern germany were shown to be representative of a greater number of samples from the same sites the 13 c values of extractable phe and mps are less negative in the terrestrial 24 3 to 26 0 than in the marine 28 8 to 30 5 samples since these values are unrelated to mean vitrinite reflectance r r values in the range of 0 5 0 9 it appears that the stable carbon isotope composition of phe and mps is controlled by organic matter type rather than maturity

distribution of lipid class compounds in bottom sediments of freshwater lakes with different trophic status in japan abstract unbound and bound lipid class compounds mono and di carboxylic acids and hydroxy acids n alkanes n alcohols and perylene were studied in bottom sediments collected from four freshwater lakes in japan with different trophic status lakes motosu biwa haruna and suwa concentrations of some lipid components relative to total organic carbon toc showed positive or negative correlations with the primary productivity of the lakes n saturated c12 c19 fatty acids fa s branched chain fa s unsaturated fa s and c14 c19 fatty alcohols which are probably of autochthonous origin appear to increase with an increase in primary productivity whereas n saturated c20 c32 fa s c20 c30 fatty alcohols dicarboxylic acids n alkanes and perylene which are probably of terrestrial origin appear to decrease with an increase in primary productivity these results indicate that primary productivity of lakes is an important factor controlling the distributions of organic molecules in the bottom sediments on the other hand concentrations of hydroxy acids relative to toc did not show a correlation with primary productivity because these acids are derived from bacterial activity their distributions may be controlled by sedimentary environments such as oxic or anoxic rather than primary productivity

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

alkane and pah depositional history sources and fluxes in sediments from the fraser river basin and strait of georgia canada hydrocarbon data for dated sediment cores from fraser basin lakes and the strait of georgia in canada reveal a pristine pre industrial background that remains unaltered in modern sediments far from human activities these pristine sediments contain polycyclic aromatic hydrocarbons pahs from combustion natural forest and prairie fires and alkanes and pahs from weathering of soils containing vascular plant remains and natural petroleum hydrocarbons and algal production at other locations examined however these natural loadings have been augmented over the past century by hydrocarbons from petroleum the combustion of liquid oil gasoline and solid coal wood fuels and from processing of wood either directly from disturbed land and slash burning or indirectly through pulp mill effluent although contamination is clearest where there are nearby human activities alkane profiles pah distributions and alkane unresolved complex mixtures suggest a widespread contamination from petroleum combustion products from human activities can also be identified although with less source specificity than with the petroleum products regional emissions from anthropogenic combustion processes appear to support modern pah increases within the fraser river basin and there is little evidence of inputs from global emissions principal components analysis using the new centred log ratio normalisation procedure to normalise data discriminates well between pahs entering lakes from runoff or the atmosphere and pah formed diagenetically within lake sediments as well as between combustion and petroleum pahs

perylene degradation during gradual onset of organic matter maturation abstract perylene and benzo a pyrene concentration changes during the gradual increase of thermal maturity have been analyzed for the palaeogene podhale flysh deposits and other palaeozoic to cenozoic sedimentary rock samples perylene is present in high relative concentration in the samples of maturation below 0 6 of the vitrinite reflectance rr while in the range of 0 6 0 7 rr its abundance rapidly decreased in the case of samples with vitrinite reflectance higher than 0 7 rr perylene compound disappeared completely benzo a pyrene is also thermally unstable at elevated temperatures and its relative concentration is very low above vitrinite reflectance values of ca 0 9 such results could have important palaeoenvironmental implications if these five ring polycyclic aromatic hydrocarbon compounds are characterized by low to moderate thermal stability then their use as a wood degrading fungi tracer in the case of perylene and palaeo wildfire indicator in the case of benzo a pyrene is limited only to samples of maturation below the oil window range and below the major phase of oil generation respectively these results explain the scarcity of perylene in palaeozoic sedimentary rocks which are generally of higher maturation than the younger deposits

probable fungal origin of perylene in late cretaceous to paleogene terrestrial sedimentary rocks of northeastern japan as indicated from stable carbon isotopes abstract perylene is present in high concentration in paleogene sediments from the sanriku oki borehole of the ministry of international trade and industry miti northeastern japan the borehole penetrates a thick sequence of late cretaceous to neogene sediments deposited under a range of conditions including fluvial deltaic and shallow marine organic petrological and geochemical data show the sediments to be rich in organic matter om derived from higher plants biomarker analysis of aliphatic and aromatic hydrocarbons confirms a significant input from higher plants with extracts dominated by numerous gymnosperm and angiosperm derived biomarkers such as diterpanes oleanenes des a triterpanes and their aromatized counterparts the highest concentration of perylene occurs in middle eocene sediments deposited in a relatively reducing environment stable carbon isotope compositions show 13 c enrichment in perylene compared to gymnosperm and angiosperm biomarkers consistent with a fungal origin this elevated abundance of sedimentary perylene could relate to a paleogene continental climate where fungi probably flourished

new insights into the origin of perylene in geological samples abstract the origin of the polycyclic aromatic hydrocarbon pah perylene in sediments and petroleum has been a matter of continued debate reported to occur in phanerozoic organic matter om fossil crinoids and tropical termite mounds its mechanism of formation remains unclear while a combustion source can be excluded structural similarities to perylene quinone like components present in e g fungi plants crinoids and insects potentially suggest a product precursor relationship here we report perylene concentrations 13c 12c and d h ratios from a holocene sediment profile from the qingpu trench yangtze delta region china perylene concentrations differ from those of pyrogenic pahs and rise to prominence in a stratigraphic interval that was dominated by woody vegetation as determined by palynology including fungal spores in this zone perylene concentrations exhibit an inverse relationship to the lignin marker guaiacol d h ratios between 284 and 317 similar to the methoxy groups in lignin as well as co variation with spores from wood degrading fungi 13c 12c of perylene differs from that of land plant wax alkanes and falls in the fractionation range expected for saprophytic fungi that utilise lignin which is isotopically lighter than cellulose and whole wood during progressive lignin degradation the relative carbon isotopic ratio of the perylene decreases we therefore hypothesise a relationship of perylene to the activity of wood degrading fungi to support our hypothesis we analysed a wide range of phanerozoic sediments and oils and found perylene to generally be present in subordinate amounts before the evolutionary rise of vascular plants and to be generally absent from marine sourced oils few exceptions being attributed perhaps to a contribution of marine and or terrestrial derived fungi anoxia especially under marine conditions and or contamination of core material by fungi a series of low molecular weight aromatic quinones bearing the perylene backbone were detected in devonian and cretaceous sediments potentially representing precursor components to perylene

polycyclic aromatic hydrocarbons pahs in late eocene to early pleistocene mudstones of the sylhet succession ne bengal basin bangladesh implications for source and paleoclimate conditions during himalayan uplift abstract distribution and possible sources of polycyclic aromatic hydrocarbons pahs have been investigated in 23 late eocene to early pleistocene mudstones from the sylhet succession of the northeastern bengal basin bangladesh paleoclimatic conditions in the southern himalaya region throughout the himalayan uplift were reconstructed based on combustion derived pahs and aromatic land plant derived biomarkers phenanthrene fluoranthene fla pyrene py benz a anthracene baan chrysene triphenylene chry tpn benzofluoranthenes bflas benzo e pyrene bepy benzo a pyrene bapy perylene pery indeno 1 2 3 cd pyrene inpy benzo ghi perylene bghip coronene cor and retene ret were the identified pahs fla fla py ratios 0 5 and inpy inpy bghip 0 2 from almost all sylhet samples suggest occurrence of natural wildfires low contents of baan and bapy indicate decomposition by long exposure to sunlight before sedimentation or early diagenetic weathering increased cor inpy and bghip contents suggest occurrence of larger high temperature wildfires correlation coefficients of the pahs and p values for statistical hypothesis testing showed that the positive and negative correlations within the pahs may be indicative of high or low temperatures in wildfires fungi derived pery showed negative correlations with py r 0 67 p 4 6 10 4 and fla r 0 56 p 5 0 10 3 but not with cor bflas inpy and bghip based on the correlation coefficients for all pahs and their p values five statistical groups py fla cor bflas inpy bghip baan chry tpn bapy pery and ret were recognized these groups are probably correlated with origins and depositional processes according to the results the sylhet succession was deposited in three differing paleoclimatic regimes 1 first phase late eocene to early miocene early to middle stage of himalayan uplift high contents of combustion derived pahs fla py and bepy significant gymnosperm derived ret and low pery abundances in the jaintia and barail groups indicate arid climatic conditions although wildfires could often occur 5 or 6 ring combustion pahs cor inpy and bghip contents are low suggesting that the wildfires were relatively low temperature 2 second phase middle to late miocene middle to late stage of himalayan uplift combustion derived pahs and fungi derived pery were dominant in the surma group the climate was arid to humid and seasonal with a dry season giving conditions suitable for combustion abundant fla bflas bepy cor inpy and bghip imply high temperatures in large wildfires however frequency of the wildfires decreased because of wet climate 3 third phase late miocene to pleistocene late stage of himalayan uplift moderate to high pery contents and low fla py and bepy abundances in the tipam and dupitila groups indicate establishment of more humid climate inpy bghip cor bflas and bapy were predominant intensified humid and seasonal climate arising from the himalayan monsoon decreased the incidence and frequency of general wildfires but increased the ratio of large to small wildfires

perylene an indicator of alteration processes or precursor materials abstract perylene is a polycyclic aromatic hydrocarbon pah that is found pervasively in both marine and freshwater sediments yet its origin remains obscure we have explored relationships between perylene and possible precursor materials in two 210 pb dated sediment cores from lake ontario in which contributions of aquatic and land plant organic matter and concentrations of anthropogenic pahs have been measured no significant correlations were identified between perylene occurrence and indicators of terrigenous or aquatic sources of organic matter distinct differences between perylene and anthropogenic pah sedimentary profiles rule out an industrial source for perylene at these locations the general pattern of low to absent perylene concentrations in upper oxic sediments and increasing concentrations with depth indicates that in situ diagenesis under anoxic conditions produces perylene and that its formation is kinetically controlled the results of our study suggest that perylene is formed from non specific precursor materials by biotic or abiotic transformation processes if this scenario accurately describes its formation then perylene is an indicator of depositional conditions rather than the source of organic matter

sources and chronology of combustion derived pollution to shilianghe reservoir eastern china evidences from pahs profiles as hg pb and pb isotopes abstract the sedimentary records of polycyclic aromatic hydrocarbons pahs mercury hg arsenic as lead pb and stable pb isotopic ratios were studied in a sediment core collected from shilianghe reservoir in eastern china accumulations and distributions of these pollutants were measured in terms of pahs concentrations pahs fluxes and enrichment factor ef of hg as pb and pb isotopic ratios the accumulations showed a synchronous trend throughout the core due to close correlation with rapid economic and industrial development of the catchment linyi city in eastern china the results from pah isomer ratios reveal that pahs in sediments are dominantly from anthropogenic pyrogenic sources mainly from the combustion of coal and biomass furthermore the pb isotopic composition clearly indicates that coal combustion dust mainly contributed to the pb burden in the reservoir sediments based on mixing end member model of pb isotopic ratios contributions of coal combustion dust are ranged from 31 to 62 mainly from anthropogenic pb sources the contribution of leaded gasoline was lower than average at 25 in addition a steady increase in the contribution from coal combustion sources was found in the sediment core while the contribution of leaded gasoline showed a decline in recent decades due to the phase out of leaded gasoline in china capsule abstract pahs hg as and pb burden in a reservoir of china were chronicled increasing coal combustion dust is responsible for contamination of lake by end member model of pb isotopic ratios

preservation of elemental and isotopic source identification of sedimentary organic matter the amount and type of organic matter in the sediments of lakes and oceans contribute to their paleoenvironmental and paleoclimatological records only a small fraction of the initial aquatic organic matter survives destruction and alteration during sinking and sedimentation selective degradation modifies the character of the surviving small fraction of organic matter which becomes incorporated in bottom sediments organic matter alterations can continue to sub bottom depths of hundreds of meters corresponding to millions of years source and paleoenvironmental information nonetheless remains preserved in the molecular elemental and isotopic compositions of organic matter c n and 13c values of total organic matter in particular appear to retain paleoenvironmental information for multi myr time periods

perylene dominance in sediments from a subtropical high mountain lake perylene formation in sediments of water bodies has been a topic of continual discussion and debate we report the concentration and age ca 660 yr profiles of perylene and other polycyclic aromatic hydrocarbons pahs in a sediment core from emerald peak lake the largest high mountain lake in taiwan perylene is dominant at all depths of the sediment ranging from 60 to 98 of total pahs a feature not commonly found in other sediments the concentration profile of perylene with sediment age fits a first order kinetic model which might be an indication of a steady sedimentary environment

the biogeochemistry of ellesmere lake u k i source correlation of leaf wax inputs to the sedimentary lipid record abstract analyses of the free lipid distributions from ellesmere lake sediments taken from two depths and comparison with leaf wax lipid distributions from six deciduous tree species around the lake were made in order to assess lipid sources close correlations of aliphatic lipid distributions in the carbon number range c 20 c 50 were seen c 28 and c 29 sterols were observed in both sediment and leaf waxes but c 27 sterols were only present in the sediments and were thus assigned a nonleaf wax source unsaturated steroidal ketones were observed both in the sediment and in certain leaf waxes and were assigned specific sources alkan 2 ones were not present in the leaf waxes but were present in the sediment samples with an almost identical distribution to the sediment n alkanes indicating a microbially mediated source c 20 c 30 n aldehydes which have not previously been widely reported in free lipid distributions of freshwater lacustrine sediments were prominent in the surface sediment and in the leaf waxes examined

geochemical discrimination of hydrothermal and igneous zircon in the iberian pyrite belt spain intensely altered felsic volcanic subvolcanic rocks located at vhms footwalls in the aznalcollar mining district iberian pyrite belt spain contain both igneous and hydrothermal zircon grains according to textural evidence in order to discriminate their respective features we present a detailed description showing that these contrasting textural characteristics can be correlated with distinctly different chemical compositions in comparison with igneous zircons emp study shows that hydrothermal zircon grains have lower sio2 and zro2 contents whereas they are enriched in p2o5 al2o3 y2o3 and cao on the other hand la icpms study shows that the ree patterns of hydrothermal zircons strongly differ from those of igneous ones in that a hydrothermal zircons are highly enriched in ree b they display patterns with maximum values for intermediate ree often showing tbn ybn ratios 1 and c hydrothermal zircon grains do not display ce or eu anomalies which are widespread in igneous zircons we conclude that these chemical differences are consistent with zircon xenotime solid solution having reached here values close to a 10 mol which represent the maximum possible degree of xenotime substitution according to the available experimental data the absence of ce and eu anomalies is explained according to the particular characteristics of the hydrothermal environment during intense footwall alteration involving temperatures up to 350 c and destruction of plagioclase or other eu 2 hosting minerals we suggest that discrimination of hydrothermal zircons may open new ways in dating hydrothermal zircons in vhms and other mineralized areas related to intense hydrothermal alteration

perylene as an indicator of conifer fossil wood degradation by wood degrading fungi the occurrence of perylene in middle jurassic fossil wood and miocene xylites from poland is described along with its correlation with unsubstituted polycyclic aromatic hydrocarbons pahs as well as cellulose content both middle jurassic and miocene wood remnants were of relatively low maturity ca 0 2 0 3 vitrinite reflectance rr had excellent preservation of biomarkers and biomolecules and in the case of the middle jurassic fossil wood samples generally good preservation of anatomical structures due to early diagenetic mineralisation the results from 42 middle jurassic and 8 miocene most taxonomically defined fossil wood fragments demonstrated a negative correlation between the concentration of perylene and those of generally typical conifer biomarkers e g cadalene dehydroabietane simonellite and retene in addition good correlation r2 0 81 was observed between the ratio of perylene to the above conifer biomarkers and the ratio of pahs phenanthrene and fluoranthene and pyrene to the conifer biomarkers this implies that the high concentration of perylene in fossil wood indicate its extensive degradation during decay transport and early diagenesis we defined a conifer wood degradation index as cwdi perylene perylene cadalene retene simonellite dehydroabietane cwdi perylene perylene cadalene retene simonellite dehydroabietane and observed a wide range of values 0 001 for less degraded wood to 0 95 for highly degraded samples anatomical wood preservation was associated with cwdi values in most of the samples characterised by poorly preserved anatomy high cwdi values were observed while anatomically well preserved samples generally had lower cwdi values we determined similar 13c values for perylene from the fossil wood samples 26 4 to 27 8 whereas the values for the conifer biomarkers were slightly higher and varied from 25 6 to 26 6 in contrast pyrene was depleted in 13c 27 5 to 28 2 the carbon isotope values of perylene are consistent with an origin from wood degrading fungi

unusual carbon isotope compositions of biomarker hydrocarbons in a permian tasmanite abstract the permian oil shale sample of this study is from a deposit in tasmania in which the only recognizable structures are large thick walled unicellular specimens of the green alga tasmanites the fossils are so densely packed that this shale is termed tasmanite the carbon isotopic composition of bulk kerogen carbon c 13 c org 16 6 vs pdb is unusually enriched in 13 c compared to marine permian organic carbon 25 to 30 this 13 c enrichment suggests specific environmental conditions co 2 draw down and or physiological specialties cell size and growth rate of tasmanites which in modern environments are known to cause 13 c enrichment in marine phytoplankton isotope signatures of extractable organic species unlike in normal immature oil shales are considerably enriched in 13 c compared to the kerogen the bitumen 10 9 is composed predominantly of extended saturated c 18 c 25 tricyclic terpane hydrocarbons 9 9 to 12 2 total range with an average of 10 8 these tricyclics are not only found as free lipids in the extract but also in pyrolysates with similar isotopic signatures and are therefore likely biosynthesis products of tasmanites the monoaromatic and diaromatic tricyclic terpane hydrocarbons c 17 c 19 have similar isotopic signatures 9 3 to 12 8 total range with an average of 10 6 two monoaromatic tetracyclic hydrocarbons c 23 and c 24 a quantitatively minor but biogenetically interesting group average at 10 2 in contrast pristane and phytane as well as n alkanes 18 to 22 are depleted in 13 c compared to kerogen carbon the isotopic similarity of all the cyclic terpanes in this sample together with their occurrence in the free lipids and kerogen suggests that they have a common origin and are biosynthesis products of the marine unicellular green algae tasmanites the tetracyclic terpanes therefore are not des a oleananes derived from land plants but are possibly monoaromatic des a gammaceranes or other des a triterpenoids derived from marine sources the unusual enrichment in 13 c in the cyclic hydrocarbons is hypothesized to result from the special growth conditions of the algae isoprenoids and n alkanes are also likely biosynthesis products of tasmanites possibly during the spore formation stage when physiological and environmental conditions were different than during planktonic biosynthesis

significance of polycyclic aromatic hydrocarbons pahs in permian triassic boundary sections abstract in this study the abundances of several polycyclic aromatic hydrocarbons pahs table 1 i xxi have been measured throughout three permian triassic p tr sections from meishan south china kap stosch area east greenland and peace river basin western canada dibenzothiophene i and dibenzofuran ii were found to decrease in abundance just before or shortly after the p tr transition in all three sections while perylene iii was observed to increase in abundance at the onset of the main extinction horizon bed 25 in meishan perylene has been attributed to a wood degrading fungal source and therefore it seems possible these phenomena are related to the demise of land plants further distinct patterns of various combustion derived pahs occurring in each section imply that forest fire events occurred within the late permian and early triassic in the meishan section high amounts of combustion derived pahs pyrene iv fluoranthene v benzo a anthracene vi benzofluoranthenes sum i e vii benzo a pyrene viii benzo e pyrene ix and coronene x occur within bed 25 also containing ash attributed to the fallout from massive volcanic eruptions in siberia and or china

insights into the origin of perylene from isotopic analyses of sediments from saanich inlet british columbia perylene is an abundant and common polycyclic aromatic hydrocarbon in sedimentary settings yet its origin remains puzzling we have investigated the relation of perylene to the amount and type of organic matter in the sediments of saanich inlet a coastal marine anoxic basin organic matter is predominantly marine in origin but the proportions of marine and land derived components have varied perylene concentrations generally increase with sediment depth relative to toc which indicates continued formation of this compound by microbially mediated diagenesis perylene 13c values range between 27 7 and 23 6 whereas toc 13c values vary narrowly from 21 7 to 21 2 over the same sediment depth interval the variation in isotopic difference suggests that perylene originates from more than one precursor material both aquatic and continental organic matter different microbial processes or some combination of these possibilities

lipids of aquatic organisms as potential contributors to lacustrine sediments ii abstract the relationship between the lipid composition of organisms in the water column of an eutrophic lake and the lipid composition of underlying sediments previously examined for n alkanols and steroids is now reported for hydrocarbons ketones and carboxylic acids the n c7 alkane and alkenoic acids from two primary sources are rapidly metabolized in the water column and surficial sediment bacterial biomarkers including hopenes and i ai branched fatty acids were detected in the photosynthetic bacterial layer occurring just above the sediment water interface within the sediment the apparent conversion of free n alkanes alkan 2 ones and hydroxy acids to the corresponding bound form is noted microbiological oxidation of n alkanes to alkan 2 ones is supported by the detection of the intermediate alkan 2 ols with a distribution similar to that of the ketones the geochemistry of sediment deposited c 1900 prior to biological study of the site was interpreted from stable biomarkers and the diagenetic changes recognised in the study of contemporary deposition a qualitative difference in algal input to the older sediment is inferred from the low 7 sterol content and presence of 2 6 10 trimethyl 7 3 methylbutyl dodecane however there was still significant dinoflagellate input as indicated by the presence of 4 methylsterols a difference in higher plant input to the older sediment indicated from the n alkane alkene and triterpenoid ketone distributions is consistent with the recent development of tree cover

rare earth elements in saanich inlet british columbia a seasonally anoxic basin rare earth element and manganese distributions have been investigated in saanich inlet british columbia a seasonally anoxic basin redox cycling of ce and mn takes place across an oxic suboxic boundary approximately 20 m shallower than the o2h2s interface the remaining strictly trivalent ree undergo scavenging above this oxic suboxic boundary and regeneration from dissolving host phases below it these processes result in pronounced removal of ce from solution above the oxic suboxic boundary due to oxidative precipitation along with preferential uptake of the lighter trivalent ree during scavenging below the oxic suboxic boundary regeneration of particulate ree into solution leads to a less pronounced ce depletion and a less pronounced hree enrichment in the anoxic bottom waters dissolved ree concentrations in the sediment pore waters exhibit an approximately ten fold increase across the seawater sediment interface but then decrease with increasing depth indicating removal from solution during later diagenesis calculated diffusive fluxes of the ree and mn from the sediments into the overlying anoxic water column are insufficient to account for the accumulated trace metal enrichments observed in the water column we propose an annual redox cycle for saanich inlet in which flushing causes extensive oxidative precipitation and scavenging of trace elements from the water column each autumn the same material is rapidly regenerated from the underlying near surface sediments when the basin next turns anoxic

saturated hydrocarbons in the sediments of lake apopka florida lake apopka sediments were analyzed for n alkanes and total organic carbon toc from which long chain hydrocarbon short chain hydrocarbon ratios lhc shc and lhc toc and shc toc ratios were calculated these ratios were used to distinguish the three types of organic sediments that originated historically mainly from byproducts of the primary producer community these types are phytoplankton derived sediments deposited during the hypereutrophic phase of the lake macrophyte derived sediments deposited during a low nutrient clear water phase and transitional sediments deposited as the primary producer community shifted rapidly in the late 1940s from macrophyte dominance to phytoplankton abundance the three ratios employed distinguish the three sediment types with exceptions that may result from a mixture of sediment types formed during the transition from macrophyte abundance to phytoplankton abundance this study supports the hypothesis that the rapid shift from macrophyte dominance to phytoplankton dominance was induced by anthropogenic phosphorus loading more detailed sampling and n alkane analysis of cores from lake apopka have the potential to define when changes in the primary producer community occurred and to infer the temporal dynamics of the well known shift in the primary producer community

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

organic geochemistry and coal petrology of tertiary brown coal in the zhoujing mine baise basin south china 4 biomarker sources inferred from stable carbon isotope compositions of individual compounds abstract carbon isotopic compositions of extractable compounds derived from higher land plants are within 2 0 00 of the bulk coal 13 c 27 0 0 00 from baise basin this data suggests that either similar species contributed these compounds or that the plants from which this coal was formed imposed similar biosynthetic fractionations the terpenoid hydrocarbons form two isotopically distinct groups the diterpenoids 13 c 25 0 1 4 0 00 and the sesquiterpenoids 13 c 25 9 1 5 0 00 are on 1 2 0 00 enriched in 13c compared to the bulk coal whereas the oleanane ursane lupane derivatives 13 c 29 0 0 8 0 00 are on average 1 2 0 00 depleted in 13c compared to the bulk coal the n alkanes ranging from c15 to c35 have a mean 13c value of 32 4 0 6 0 00 whereby averages for the c17 c22 and c23 c33n alkanes do not significantly differ from the overall average hopane derivatives in this coal extract are depleted in 13c compared to the bulk coal by 8 34 0 00 suggesting that bacterial cycling of methane played a role during formation of this coal

comparison of lipid character of sediments from the great lakes and the northwestern atlantic abstract geolipid compositions of surficial sediments from lake michigan lake huron and from three locations in the northwestern atlantic were determined to compare source inputs and alteration processes in different sedimentary environments fatty acids sterols fatty alcohols and alkanes were examined in both unbound and bound extracts of these samples significant amounts of long chain fatty acids alcohols and hydrocarbons are present in the deep ocean station yet this location contains a proportionally larger amount of short chain geolipids than do marine stations closer to shore larger proportions of long chain lipids present in the lake michigan lake huron and gulf of maine samples relative to the open ocean samples reflect larger inputs of land derived lipids to sediments closer to terrigenous sources marine samples contain a more complex mixture of sterols than is found in lake sediments suggesting that sterol inputs and alteration processes in the marine environment are more complex than in lacustrine settings ratios of 16 1 16 0 and 18 1 18 0 fatty acids decrease with increasing distance from land which suggests that fatty acid degradation before and during deposition becomes more extensive in the open deeper ocean stations

origin distribution and environmental significance of perylene in okinawa trough since last glaciation maximum perylene a five ring nuclear polycyclic aromatic hydrocarbon pah has a different distribution pattern from anthropogenic pahs its source however remains obscure limiting its application as an environ mental indicator here we examine perylene in the upper 85 m sediments of the odp hole 1202b from the southern okinawa trough over the past 20 000 years the mass accumulation rate of perylene is sub stantially higher in the last deglaciation than the holocene and last glacial maximum perylene presents a strong correlation with c31 n alkane r 0 55 p 0 001 a biomarker for terrigenous organic matter and a weak correlation with c37 2 alkenone r 0 04 p 0 23 a biomarker for marine organic matter the mean d 13 c value of perylene 22 8 0 6 is substantially higher than that of long chain n alkanes 30 7 0 4 but close to that of fluvial organic matter in adjacent areas 24 0 to 25 0 our results strongly suggest that the perylene is of a terrigenous origin likely from soil fungi and may be a useful tracer for soil organic carbon in marine environments

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