discrepancies between different organic maturity indicators in a coal series affected by an abnormal thermal event visean niger abstract classical petrographical and geochemical approaches have been used to study visean coal seams sampled in two areas 50 km apart in northern niger t max values given by rock eval pyrolysis and individual molecular ratios determined on hopanes and steranes are in agreement with the burial history of the two sets of samples studied the difference of maturity of the two sample sets revealed by these various parameters is consistent with their current difference in burial depth 400 m only small changes of these parameters with depth were observed owing to the small depth interval sampled at both sites 15 and 40 m these variations also appear to be related to normal burial diagenesis no maturity differences between the two sample sets are revealed by vitrinite reflectance data and atomic h c ratios which are in the same range at both sites but display very large variations with depth r v 0 60 1 40 and h c at 0 80 0 90 to 0 55 these data indicate rapid entrance into the oil window this conclusion also being supported by microspectrofluorimetric observations showing oil production and expulsion and by the presence of pyrobitumens containing large devolatilization vacuoles in the deepest samples the abnormally high maturity gradient could have been caused by a hydrothermal event the present observations on coals confirm and supplement previous conclusions drawn from the study of organic materials disseminated in zn pb sulfide ore bearing sedimentary rocks the difference in sensitivity shown by the various maturity indicators is considered very likely to be due to differences in the kinetics of the transformations on which they each depend

holocene climate variability archived in the puruogangri ice cap on the central tibetan plateau two ice cores 118 4 and 214 7 m in length were collected in 2000 from the puruogangri ice cap in the center of the tibetan plateau tp in a joint us chinese collaborative project these cores yield paleoclimatic and environmental records extending through the middle holocene and complement previous ice core histories from the dunde and guliya ice caps in northeast and northwest tibet respectively and dasuopu glacier in the himalaya the high resolution puruogangri climate record since ad 1600 details regional temperature and moisture variability the post 1920 period is characterized by above average annual net balance contemporaneous with the greatest 18 o enrichment of the last 400 years consistent with the isotopically inferred warming observed in other tp ice core records on longer timescales the aerosol history reveals large and abrupt events one of which is dated 4 7 kyr bp and occurs close to the time of a drought that extended throughout the tropics and may have been associated with centuries long weakening of the asian indian african monsoon system the puruogangri climate history combined with the other tp ice core records has the potential to provide valuable information on variations in the strength of the monsoon across the tp during the holocene

organic geochemistry in a sequence stratigraphic framework the siliciclastic shelf environment of cretaceous series se france for a better understanding of siliciclastic shelf environments correlation between sequence stratigraphy and organic geochemistry is used our study is focused on the cretaceous deposits of marcoule gard france particularly on a close packed siltites layer 200 400 m thick which is well characterized as a marine flooding facies of a single trangressive regressive cycle during the uppermost albian and the lower cenomanian the stratigraphic data indicate a change in the depositional environment from offshore to shoreface organic geochemistry is used in order to characterize origin and variability of the organic matter in relation to the stratigraphic data the study is carried out on core samples from 2 drill holes mar 203 and mar 501 analyses of the aliphatic and aromatic hydrocarbons were performed using gc ms and focused on biomarker distributions the biomarkers indicate a contribution of mixed terrestrial and marine organic matter the changes in molecular signatures are related to variations in the source of organic matter marine versus terrestrial preservation conditions largely influenced by clay and early diagenesis environmental oxidation reduction and acidic conditions as well as bioturbation various environmental zones characterized by different molecular signatures can be distinguished resin derived biomarkers can be assigned to higher plant material input and may reflect the evolution and diversity of gymnospermae versus angiospermae during the transgressive regressive cycle the relative sea level variations are clearly correlated with the nature and the preservation of the organic matter for example the pr ph and pr n c 17 ratios as well as the regular steranes distributions underline the maximum flooding surface evidenced by other studies we observe a good correlation between the organic data and sequence stratigraphy changes in geochemical signatures reflect the 3rd order depositional cycles

organic geochemical indicators of biological sulphate reduction in early diagenetic znpb mineralization the bois madame deposit gard france abstract at bois madame gard france zn pb s mineralization zn pb 4 occurs in dolomitized kimmeridgian carbonates very near layers which are rich in organic matter of planktonic origin previous geological and geochemical studies have suggested early syn or diagenetic ore deposition controlled by sulphate reducing bacteria the metals probably having originated from regionally mineralized triassic or liassic formations rock eval pyrolysis data complemented by biomarkers show that the organic matter reached only the organic diagenesis catagenesis transition owing to burial pb deposit as in many pb zn s deposits the hydrocarbons almost certainly autochthonous show no indication of relatively late alteration by biodegradation or water washing the presence of hopanes c 27 35 with high abundance in the c 27 32 range indicate that intense bacterial activity occurred during early diagenesis under su ic anoxic conditions this interpretation is reinforced by the presence of n alkanes in the range n c 22 to n c 28 dominated by compounds with an even number of carbon atoms which may have derived from the reduction of bacterial fatty acids except for these even number n alkanes the organic geochemical evidence for sulphate reducing bacteria during early diagenesis must remain equivocal

inferences for sources of oils from the norwegian barents sea using statistical analysis of biomarkers abstract conventional biomarker age indicators may not always give conclusive inferences for the age of an oil s source rock particularly with regard to condensates in which most of the key biomarkers are often too sparse to determine it is possible that other compounds reflecting changes in primary producer assemblages or depositional environment can provide age indications in basins that have experienced a progressive change in conditions the norwegian barents sea provides an opportunity to evaluate this approach although the gradual changes are punctuated by intervals of stratification oaes and extinctions partial least squares analysis was used to identify a number of apparently suitable parameters to establish an age calibration from source rock extracts and then to apply it to a variety of oils and condensates from the barents sea the resulting source age inferences are consistent with conventional age parameters for the normal oils providing a degree of confidence in their applicability to the problematic condensates in the main part of the hammerfest basin oils of jurassic origin dominate whereas contributions from triassic sources are suggested towards the margins particularly in pre jurassic reservoirs to the east on the norsel high and in the nordkapp basin the main oil sources are suggested to be early triassic although a palaeozoic possibly permian source is likely on the margin of the finnmark platform in well 7128 4 1 among the novel parameters the relative abundances of phytanyl arenes and diadrimanes appear to be controlled by diagenetic conditions

biological origin of tetracyclic diterpanes n alkanes and other biomarkers found in lower carboniferous gondwana coals niger abstract the saturated hydrocarbons of coal samples of the anou araren mine tim mersoi basin niger republic have been studied by gc and gc ms chromatograms revealed rather unusual n alkane distributions dominated by compounds in the c 20 c 23 range and showing a rapid and irregular decrease towards higher molecular weights these signatures appear to be typical of the paleozoic gondwana swamps flora unlike typical low maturity terrestrial organic matter characterized by a dominance of odd carbon number n alkanes in the c 27 c 33 range which could be attributed to angiosperms the presence of large amounts of polycyclic diterpanes ent beyerane phyllocladanes and kauranes is unexpected in samples of that age since these compounds are usually thought to be derived from conifers which supposedly had not yet evolved at the time a more likely explanation is that these diterpanes could be derived from biological precursors of the conifers

the transformation of amphibolite facies gneiss to charnockite in southern karnataka and northern tamil nadu india amphibolite facies metamorphic grade gives way southward to the granulite grade in southern karnataka as acid gneisses develop charnockite patches and streaks and basic enclaves develop pyroxenes petrologic investigations in the transitional zone south of mysore have established the following points 1 the transition is prograde amphibole bearing gneisses intimately associated with charnockite at kabbal and several similar localities are not retrogressive after charnockite as proved by patchy obliteration of their foliation by transgressive very coarse grained charnockite high fluorine content of biotite and amphibole in gneisses and high large ion lithophile element contents in gneisses and charnockites these features are in contrast to very low fluorine in retrogressive amphiboles and biotites very low large ion lithophile element contents and zonal bleaching of charnockite in clearly retrogressive areas as at bhavani sagar tamil nadu 2 metamorphic temperatures in the transitional areas were 700 800 c pressures were 5 7 kbar and h2o pressures were 0 1 0 3 times total pressures based on thermodynamic calculations using mineral analyses dense co2 rich fluid inclusions in the kabbal rocks confirm the low h2o pressures at the first appearance of orthopyroxene farther to the south in the nilgiri hills and adjacent granulite massif areas peak metamorphic temperatures were 800 900 c pressures were 7 9 kbar and water pressures were very low so that primary biotites and amphiboles those with high f contents are rare 3 the incipient granulite grade metamorphism of the transitional areas was introduced by a wave of anatexis and k metasomatism this process was arrested by drying out under heavy co2 influx charnockites so formed are hybrids of anatectic granite and metabasite of metabasite and immediately adjacent gneiss or are virtually isochemical with pre existing gneiss despite gross recrystallization to granulite mineralogy these features show that partial melting and metasomatism are attendant rather than causative in charnockite development copious co2 from a deep crustal or mantle source pushed ahead of it a wave of more aqueous solutions which promoted anatexis granulite metamorphism of both neosome and paleosome followed the process is very similar to that deduced for the madras granulites by weaver 1980 the massif charnockites for the most part extremely depleted in lithophile minor elements show many evidences of having gone through the same process

a high resolution atmospheric dust record for 1810 2004 a d derived from an ice core in eastern tien shan central asia centennial scale high resolution records of atmospheric dust conditions are rare in the arid and semiarid regions of central asia limiting our understanding of the regional climate and environmental changes and their potential driving forces in this paper we present an annually resolved atmospheric dust record covering the period of 1810 2004 a d reconstructed from an ice core retrieved at 4512 m above sea level from the miaoergou glacier in the eastern tien shan the time series of dust flux for the past 195 years shows three periods of relatively low values i e 1810 1829 a d 1863 1940 a d and 1979 2004 a d and two periods of relatively high values i e 1830 1862 a d and 1941 1978 a d spatial correlation analysis suggests possible regional factors controlling the dust flux including antecedent summer precipitation spring soil moisture and near surface wind speed in addition the miaoergou dust flux is closely associated with the winter index of the north atlantic oscillation nao over the past two centuries with high low dust periods coinciding with the negative positive phases of the nao the persistent relationship suggests that the nao may have been a key driver on dust flux change over the arid regions between the tien shan and kunlun mountains

characterisation of non extractable macromolecular organic matter in palaeozoic coals abstract comprehensive organic geochemical investigations were applied to permian carboniferous and devonian coals the major goal of the investigation was to quantify differences in organic matter composition of the coals on a molecular level and to associate these differences with either i primary composition of the precursor plant material or ii diagenetic processes related to burial and temperature increase or iii evolutionary time trends the pre extracted samples were analysed by means of pyrolytic and chemical degradation techniques as well as ftir spectroscopy additionally rock eval pyrolysis and organic petrography were used to obtain information on the bulk of the coal samples the degradation analysis revealed a wide variety of individual compounds including n alkanes isoprenoids polycylic aromatic compounds fatty acids alkylbenzenes aromatic carboxylic acids and phenols relative concentrations of substances or compound groups were correlated with bulk parameters and age of the samples significant correlations of the chemical data were found out mainly for maturity parameters and maceral composition time depending changes in chemical composition were observed only to a minor extent thus the rapid morphologic evolution of higher land plants in the late palaeozoic is not reflected in a significant way by the chemical composition of the non extractable matter in the coal samples investigated

co 2 melts and granulite metamorphism the discovery that granulites contain co2 rich fluid inclusions while amphibolites in the same terrane contain h2o rich or mixed co2 h2o inclusions1 has led to a debate over the processes that produce granulite metamorphism one theory2 4 maintains that granulites form as the result of a massive influx of co2 from lower crustal or mantle sources such an influx could be responsible for the marked depletion many granulite terranes show in large ion lithophile elements2 5 others however maintain that granulite facies metamorphism is a necessary complement of crustal melt ing6 9 recently lamb and valley10 11 have argued that granulite metamorphism may be a product of any one of three processes co2 streaming partial melting or recrystallization of originally dry rocks here we suggest that these processes need not be independent and that they all may be related to the passage of melts through the crust

the size distribution of microparticles from selected segments of the greenland ice core project ice core representing different climatic periods the size distribution of insoluble microparticles dust in the particle size interval 0 4 6 0 m radius has been measured in more than 1400 samples from the greenland ice core project grip deep ice core from summit greenland the samples were taken from ice core segments representing 32 climatic periods including ice from the eem interglacial and ice from below the eemian ice the mean dust volume distributions from the climatic periods are compared and the relationship of total dust mass to the concentration of ca2 and to the stable isotopic composition 18o is investigated the dust volume distributions are found to be lognormal in the size interval 0 4 2 0 m with nearly identical shapes changes of the lognormal part of the volume distributions are found to be connected to the total dust mass in a systematic way the total dust mass is correlated to the ca2 concentration and data do not show any enrichment in ca2 from exposed continental shelves due to lower sea levels during the last glacial maximum the total dust mass is strongly connected to 18o the volume distribution of the particles in the size interval 2 0 6 0 m is found to be almost the same in most periods the exceptions are the cold periods in the last part of the last glacial period where the volume of these particles is higher than in most periods and the periods from the eemian and just above the eemian where the volume of these particles is lower the volume distributions of both the eemian warm periods and the cold eemian events are different from the distributions in ice from both below and above the eemian ice climate changes appear to have modified the processes of production transport modification and deposition of the dust aerosol in the same way over the last 120 000 years or more

atmospheric soluble dust records from a tibetan ice core possible climate proxies and teleconnection with the pacific decadal oscillation record 1935 2005 statistical analysis of major ion time series suggests that atmospheric soluble dust species dominate the chemical signature and that background dust levels conceal marine ion species deposition the soluble dust time series have interspecies relations and common structure empirical orthogonal function eof 1 suggesting a similar soluble dust source or transport route annual and seasonal correlations between the eof 1 time series and national centers for environmental prediction national center for atmospheric research reanalysis climate variables 1948 2004 suggest that the mt geladaindong ice core record provides a proxy for local and regional surface pressure an approximately threefold decrease of soluble dust concentrations in the middle to late 1970s accompanied by regional increases in pressure and temperature and decreases in wind velocity coincides with the major 1976 1977 shift of the pacific decadal oscillation pdo from a negative to a positive state this is the first ice core evidence of a potential teleconnection between central asian atmospheric soluble dust loading and the pdo analysis of temporally longer ice cores from mt geladaindong may enhance understanding of the relationship between the pdo and central asian atmospheric circulation and subsequent atmospheric soluble dust loading

dust storm activity over the tibetan plateau recorded by a shallow ice core from the north slope of mt qomolangma everest tibet himal region 1 based on a 39 8 m ice core drilled at the east rongbuk glacier 27 59 n 86 55 e 6518 m a s l north slope of mt qomolangma everest central himalaya the changes of dust storm over the tibetan plateau tp recorded by insoluble particle and its possible connection with the winter jfm north atlantic oscillation nao are investigated the results show that the level of dust storm activity exhibits a significant decreasing trend during the past 50 years this may be attributed at least partly to a decrease in wind speed over the tp and its surrounding regions the normalized time series of the winter nao index shows a significant inverse correlation with the mass concentration of insoluble particle implying a possible connection between the winter nao and the dust storm activity over the tp

evidence for fluid pathways through archaean crust and the generation of the closepet granite karnataka south india abstract in the archaean amphibolite granulite facies transition zone of southern karnataka anatexis of amphibolite facies peninsular gneiss occurred based on cross cutting relationships this melting event which produced the closepet granite was contemporaneous with the formation of charnockitic rocks this formation of charnockite took place initially due to channelized co 2 rich volatiles moving along an anastamosing network of shears and micro fissures these fluid pathways are now represented by brown veins of charnockite later the fluid became more pervasive and resulted in areas of total inversion to charnockite a lateral change along the fluid pathways from charnockite through incipient charnockite to either a thin granitic vein or a vein of reddening can be traced through the country rocks these different effects along the same laterally continuous vein are interpreted to represent the lateral change of volatile composition which in front of the co 2 rich fluids were increasingly h 2 o dominated

palaeoenvironmental assessment of westphalian fluvio lacustrine deposits of lorraine france using a combination of organic geochemistry and sedimentology abstract the quality and the quantity of organic carbon preserved in modern and ancient terrestrial sediments is the result of a complex interactions of sedimentological factors such as in situ productivity allochtonous supply of organic matter oxidation processes biodegradation and sediment accumulation rates the study aims at utilizing multidisciplinary information in order to characterize the palaeoenvironment in westphalian fluvio lacustrine deposits of the lorraine coal basin ne france in this basin the lack of outcrops is the major difficulty to compensate for this problem sedimentology and molecular geochemistry are combined in order to significantly improve the palaeoenvironmental assessment of the area geochemical analyses and sedimentology have been carried out on several core samples of the saulcy drill hole to evaluate local palaeoenvironmental variability the lithofacies associations in the upper carboniferous of the lorraine basin suggest an alluvial plain environment without marine incursions sedimentological interpretations of the core as well as comparison with sedimentological models suggests the recognition of different depositional environments from braided and or meandering rivers to swamp and lakes the organic geochemistry is focussed on the recognition of aliphatic hydrocarbons and especially on molecular biomarkers which provide valuable information about the original organic matter and the transformations that took place during sedimentation and diagenesis in the lorraine basin the botanical variability is high and clearly related to the position of the vegetation communities in the fluvial system the biomarkers e g diterpanes steranes show variations which can be related to the diversity of this ecosystem in this study a reinterpretation of the environmental zonation in the sterane ternary diagram adapted to a fluvio lacustrine sedimentology is proposed the correlation between sedimentological and geochemical interpretation permits characterization of various depositional environments a palaeoenvironment model relating sediment deposition conditions and organic matter characteristics is proposed

origin of granulite terranes and the formation of the lowermost continental crust differences in composition and pressures of equilibration between exposed regional granulite terranes and suites of granulite xenoliths of crustal origin indicate that granulite terranes do not represent exhumed lowermost crust as had been thought but rather middle and lower middle crustal levels application of well calibrated barometers indicate that exposed granulites record equilibration pressures of 0 6 to 0 8 gigapascal 20 to 30 kilometers depth of burial whereas granulite xenoliths which also tend to be more mafic record pressures of at least 1 0 to 1 5 gigapascals 35 to 50 kilometers depth of burial thickening of the crust by the crystallization of mafic magmas at the crust mantle boundary may account for both the formation of regional granulite terranes at shallower depths and the formation of deep seated mafic crust represented by many xenolith suites

co2transfer between the upper mantle and the atmosphere temporary storage in the lower continental crust the co2 atmospheric content has shown large variations over geological times high contents up to one order of magnitude more than present day values ultimately correspond to discrete episodes of mantle degassing either juvenile or subduction related carbon recycling a number of arguments e g the continuous volume increase of carbonate bearing sediments with time suggest that throughout the earth s history juvenile co2 has formed a major contribution to the global carbon budget of the earth the absence of a direct relationship between major volcanic episodes and the average co2 atmospheric content suggests that volcanoes might not be the only way by which mantle co2 is transported to the surface it is proposed that large quantities of juvenile co2 could temporarily be stored in the lower continental crust during major episodes of granulite formation these are primarily caused by magmatic underplating and they result in a vertical accretion of the crust by accumulation of co2 bearing mantle derived magmas most of the co2 migrates through the crust during post metamorphic evolution and isostatic restoration of the normal continental thickness however large quantities of co2 can still be present in some areas notably as high density fluids enclosed in minerals

the timescale and mechanism of granulite formation at kurunegala sri lanka incipient charnockite formation at kurunegala in sri lanka is characterized by the growth of orthopyroxene at the expense of amphibole and biotite in an originally homogeneous gneiss mineral equilibria in the charnockite assemblage record pressure temperature p t conditions of 738 60 c and 6 9 1 2 kbar at 17 0 1 2 log fo2 and ah2o 0 18 0 16 wholerock trace element and isotopic measurements show that charnockite formation was accompanied by a systematic depletion of sm rb pb u sr nd with a fractionation of rb sr sm nd and th u ratios and crystallization of the charnockite assemblage at 535 5 ma major element fe mg ca and sm nd equilibration between minerals occurred at 524 9 ma whereas pb and rb sr underwent continued exchange to 501 5 ma and 486 1 ma respectively trace element data for both amphibolite and charnockite minerals show that depletion on a whole rock scale can be accounted for either by changes in mineral modes or trace element abundances within the immediate area of dehydration the fractionation of sm nd on a whole rock scale is controlled by the breakdown of amphibole without the growth of a major new host phase for sm in the charnockite rubidium and sr are dependent on the relative behaviour of biotite plagioclase and alkali feldspar modelling of dehydration melting involving the breakdown of amphibole biotite and alkali feldspar reproduces the observed sm nd and rb sr fractionation and indicates the loss of small melt fractions on a cm scale from the charnockite these observations suggest that partial melting is the most plausible means of effecting both the dehydration and depletion that accompanies charnockite formation

palaeoenvironmental implications of coal formation in dobrudzha basin bulgaria insights from organic petrological and geochemical properties abstract the dobrudzha basin in northeast bulgaria contains 86 coal seams distributed within three coal bearing formations of late carboniferous age this study presents the organic petrological and geochemical characteristics of coals from the makedonka and krupen formations containing some of the most prominent coal seams these were characterized by means of proximate and rock eval analyses vitrinite reflectance measurements organic petrography and gcms analysis in order to establish variations in vegetation and depositional settings based on random vitrinite reflectance avg 0 7 r r and toc contents avg 80 daf the coals can be classified as low rank bituminous high volatile b c low tmax values avg 430 c further indicate a low degree of organic matter maturity the low to moderately high ash yields together with the presence of shaly partings and generally low sulfur contents are consistent with peat formation in a fluviatile sedimentary environment petrographic analysis reveals complex maceral composition with abundant liptinite and inertinite the predominance of detrovitrinite and the almost complete lack of strongly gelified macerals argue for enhanced humification of the plant tissues and peat formation in relatively dry environments above water table the distributions of n alkanes diterpenoids and steranes indicate that the organic matter originated from terrestrial vascular plants the high pristane phytane ratios point to peat deposition under oxic conditions low concentrations of hopanes argue for limited bacterial degradation of the organic matter possibly due to low ph conditions during peatification the presence of tetracyclic diterpanes and their aromatic counterparts is attributed to pre gymnosperm cordaitean input the existence of cordaiteans although as minor component of the palaeovegetational communities is further evidenced by the presence of trace amounts of aromatic arborane fernane derivatives in almost all studied samples the occurrence of combustion derived pahs in all studied samples is consistent with the abundant inertinite and indicates frequent forest fires during peat formation

geochemical characteristics of early carboniferous petroleum systems in western australia abstract a geochemical study was conducted to establish oil oil correlations and evaluate potential source rocks within the latest devonian earliest carboniferous succession of the onshore canning basin western australia aromatic hydrocarbons together with the routinely used saturated biomarker ratios and stable carbon isotopes demonstrate that the recently discovered ungani oilfield located on the southern margin of the fitzroy trough are similar but not identical to the early carboniferous larapintine 4 l4 oil family present to the north of the fitzroy trough on the lennard shelf the l4 oil family has been correlated to a lower carboniferous tournaisian source rock core sample from the laurel formation at blackstone 1 although its bulk geochemical properties signify that it could generate substantially more gas than liquid hydrocarbons the ungani oils can be distinguished from the l4 oils by their higher concentrations of paleorenieratane and isorenieratane coupled with more depleted 13c values for n alkanes pristane and phytane compared with other components hopane isomerisation ratios show distinct grouping of the two oil families that reflect both source and maturity variations the oil from wattle 1 st1 on the lennard shelf has an unusual composition exhibiting some molecular and isotopic features similar to both the l4 and ungani oils source rocks for the ungani and wattle 1 st1 oils are unknown since their geochemical signature does not match that of the tournaisian laurel formation or the middle upper givetian frasnian devonian gogo formation which sourced the devonian reservoired larapintine 3 oils at blina and janpam north 1 it is postulated that such potential oil prone source rocks could occur within the famennian tournaisian succession

aliphatic and aromatic hydrocarbons in candiota coal samples novel series of bicyclic compounds abstract aliphatic and aromatic fractions obtained from nine samples taken from two different seams of five boreholes in the candiota coalfield lower permian were analysed by gas chromatography mass spectrometry the occurrence of the tetracyclic diterpenoids 16 h phyllocladane and ent 16 h kaurane among the aliphatic hydrocarbons and the tricyclic diterpenoids simonellite and retene in the aromatic hydrocarbon concentrates suggest an important input from conifers to the sedimentary biomass this may explain the origin of a novel series of saturated and aromatic bicyclic compounds detected in the extracts which may be structurally related to the same precursor possibly a conifer resin derived tricyclic diterpenoid

biomarkers and aromatic hydrocarbons in bituminous coals of upper silesian coal basin example from 405 coal seam of the zaleskie beds poland abstract this paper presents the geochemical characteristics of hard coals from the 405 coal seam found in several mines in the upper silesian coal basin poland the coals classifying as of medial coalification types d and c and as para and orthobituminous coals show variable technical chemical and petrographic properties vitrinite reflectance values range from 0 65 to 1 24 cdaf from 79 2 to 88 3 wt and vdaf from 23 7 to 37 4 wt maceral composition in all of the coals studied is dominated by vitrinite macerals 43 5 74 0 gas chromatography mass spectrometry was applied to assess organic matter sources and ranks using several biomarker and aromatic hydrocarbon parameters distributions of n alkanes acyclic isoprenoids diterpenoids steranes and triaromatic steroids indicate that the organic matter in the coals analysed is derived mostly from terrestrial vascular plants the biogenic organic matter was deposited mostly in an estuarine deltaic environment with a normal to low water level in a few cases a marine lagoonal or paludal environment is possible tetracyclic diterpanes such as phyllocladanes and kauranes indicators of the podocarpaceae and araucariceae families are explained by proposing input of organic matter deriving from voltziales plants which may have been able to synthesise these compounds biomarker and aromatic hydrocarbon parameters of thermal maturity in the coals show a clear correlation to vitrinite reflectance values and carbon content indicating degrees of thermal maturity in the range from early to advanced catagenesis frictional heat related to the klodnica fault movement caused aberrations in values of aromatic hydrocarbon maturity parameters in coals sampled

fluid inclusions in charnockites from the bjerkreim sokndal massif rogaland southwestern norway fluid origin and in situ evolution fluid inclusions and mineral associations were studied in late stage charnockitic granites from the bjerkreim sokndal lopolith rogaland anorthosite province because the magmatic and tectonic evolutions of this complex appear to be relatively simple these rocks are a suitable case for investigation of the origin and evolution of granulitic fluids fluid inclusions primarily contained in quartz can be divided into four types carbonic type i n2 bearing type ii co2 h2o type iii and aqueous inclusions type iv for each type the role of leakage and fluid mixing are discussed from microthermometric and raman spectrometric data the most striking features of co2 rich inclusions the predominant fluid is the presence of graphite in numerous trail bound inclusions ib and its absence in a few isolated very dense d 1 16 pure co2 inclusions ia and in the late carbonic inclusions ic fluid chronology and mineral assemblages suggest that carbonic ia inclusions represent the first fluid pure co2 trapped at or close to magmatic conditions t 780 830 c fo2 10 15 atm and p 7 4 1 kb outside the graphite stability field in contrast type ib inclusions enclosed graphite particles from a channelized fluid during retrograde rock evolution p 3 4 kb and t 600 c decreases in t fo2 could explain a progressive evolution from a co2 rich fluid to an h2o rich fluid in a closed c o h system however graphite destabilization observed in type ic inclusions implies some late introduction of external water during the last stage of retrogression the main results of this study are the following 1 a carbonic fluid was present in an early stage of rock evolution probably in the charnockitic magma and 2 this granulite occurrence offers good evidence of crossing the graphite stability field during post magmatic evolution

tibetan plateau summer monsoon northward extent revealed by measurements of water stable isotopes a program of individual precipitation events and river water sampling and of water isotopic measurements d 18o was carried out during summer 1996 along a northeast southwest transect of the tibetan plateau the spatial distribution of both 18o and deuterium excess d d 8 18o of the precipitation reveals three distinct regions simulations with a simple isotopic model and seasonal isotopic variations measured at two extreme south and north locations support our interpretation in terms of different summer moisture origins 1 south of the himalayan mountains the moisture provided by the indian monsoon has been recycled over the indian peninsula 2 between the himalayas and the tanggula mountains the oceanic moisture is directly transported from the bay of bengal along the brahmaptra river valley 3 north of the tanggula mountains the moisture is not provided by the monsoon anymore but by continental water recycling

effects of thermal maturity on biomarker distributions in gondwana coals from the satpura and damodar valley basins india abstract organic geochemistry of gondwana coals especially the distribution of molecular fossils or biomarkers is not well constrained throughout the world in this study we have therefore evaluated biomarker signatures along with bulk organic matter and petrographic characteristics in coal samples collected from two gondwana basins in india satpura basin kanhan coalfield and damodar valley basin jharia coalfield from both coalfields the samples were collected from the lower permian barakar formation which is one of the major coal bearing strata in india a significant variation in thermal maturity levels in the samples is indicated by rock eval pyrolysis and petrographic analysis with the kanhan samples generally belonging to immature to early mature stage while the jharia samples display characteristics of overmature coals this variation in the thermal maturity strongly affects the biomarker distributions especially the terpenoids hopanes and steranes were considerably degraded due to thermal maturation and were below detection limit in the overmature samples presence of aliphatic diterpanes ent 16 h kaurane 16 h phyllocladane as well as aromatic diterpanes retene methylretenes tetrahydroretene simonellite and bisnorsimonellite in low maturity samples indicate terrestrial input possibly from the primitive conifers however the aliphatic and aromatic diterpanes were below detection limit in overmature samples making it difficult to infer their source distributions of polycyclic aromatic hydrocarbons pahs are also controlled by thermal maturity levels as evident from difference in pah ratios in the low and high maturity samples

geochemical characteristics of tertiary coal bearing source rocks in xihu depression east china sea basin abstract this study aims at investigating hydrocarbon generation potential and biological organic source for the tertiary coal bearing source rocks of pinghu formation middle upper eocene in xihu depression east china sea shelf basin another goal is to differentiate coal and mudstone with respect to their geochemical properties the coal bearing sequence has a variable organofacies and is mainly gas prone the coals and carbonaceous mudstones in comparison with mudstones have a higher liquid hydrocarbon generation potential as reflected by evidently higher hi values averaging 286 mg hc g c and h c atomic ratios round 0 9 the molecular composition in the coal bearing sequence is commonly characterized by unusually abundant diterpenoid alkanes dominant c29 sterane over c27 and c28 homologues and high amount of terrigenous related aromatic biomarkers such as retene cadalene and 1 7 dimethylphenanthrene indicating a predominantly terrigenous organic source the source rocks show high pr ph ratios ranging mostly from 3 5 to 8 5 and low mdbts mdbfs ratios

biomarker signatures of permian gondwana coals from india and their palaeobotanical significance abstract coal samples belonging to the lower permian barakar formation and the upper permian raniganj formation collected from damodar valley basin of eastern india have been analysed for understanding their organic geochemical characteristics using rock eval pyrolysis gas chromatography mass spectrometry gc ms and comprehensive two dimensional gas chromatography coupled with time of flight mass spectrometry gc gc tofms the rock eval pyrolysis parameters suggest that the coals from both the formations contain a mixture of type ii and type iii kerogen the rock eval tmax values of the analysed coals vary from 417 to 451 c n alkanes ranging from c12 to c31 predominate the aliphatic hydrocarbons present in the coal extracts the carbon preference indices cpi as well as the odd to even preference oep values of the n alkanes are 1 suggesting input from higher vascular land plants c29 steranes predominate over c27 and c28 steranes which corroborates contribution from terrestrial higher plants aliphatic diterpanes like ent beyerane isopimarane abietane phyllocladanes and ent kaurane as well as aromatic diterpanes like simonellite bisnorsimonellite retene methylretenes and tetrahydroretene which are mainly known to originate from conifers are detected in the studied coals the lower gondwana floral assemblage of peninsular india is mainly represented by glossopteris flora pteridospermatophyta however some primitive conifers have also been reported from this succession we propose that the diterpanes detected in the studied coals were possibly derived from the primitive conifers this implies that the biosynthetic pathways to produce these diterpanes had evolved in the gondwana flora during the permian period

aromatic hydrocarbon biomarkers in terrestrial organic matter of devonian to permian age abstract this paper presents the results of a detailed study on the occurrence and distribution of alkylnaphthalenes and alkylphenanthrenes in 39 coal and sediment samples from the late palaeozoic containing predominantly terrestrial organic matter most of the samples represent the euramerian flora realm and originate from locations beyond the variscan front in eastern northern and central europe i e especially england and the moscow basin the samples are of relatively low maturity 0 32 to 1 80 rr and consist mainly of mixtures of type iii and ii kerogen quantification of the c0 to c4 naphthalenes and the c0 to c4 phenanthrenes showed that these compound classes were highly abundant in all samples aromatic hydrocarbon maturity parameters in general are in good agreement with measured vitrinite reflectance values 1 2 7 trimethylnaphthalene an assumed diagenetic product of oleanane type biomarkers was present in all investigated samples this observation provides evidence that oleanane type lipids were biosynthesised by organisms predating the evolution of angiosperms or that assumed formation pathways for 1 2 7 trimethylnaphthalene are insecure 1 2 8 trimethylphenanthrene was significantly enriched in samples from the permian and the one sample from the devonian investigated in this study the precursor s of 1 2 8 trimethylphenanthrene therefore may have been produced by organisms which were least abundant in the carboniferous depositional environments represented by our samples

stable isotopic variations in west china a consideration of moisture sources 1 in this study individual precipitation samples collected over 2 years at stations in different climatic regions of west china tibetan plateau region tianshan region and altay were analyzed for the stable isotopes of precipitation to improve our understanding of how vapor transport impacts the modern stable isotopic distribution our results identify regional patterns in both 18o and deuterium excess d excess defined as d 8 18o and in particular we have identified the northward maximum extent of the southwest monsoon over the tibetan plateau this demarcation is also the boundary for the fractionation effect of temperature on stable isotopes in precipitation the patterns we have identified are as follows 1 in the southern tibetan plateau along the southern slope of the himalayas our results show a distinct seasonality for both 18o and d excess as a result of the shift of summer monsoon moisture and winter westerly moisture transport the signals of 18o in the western tibetan plateau reveal that the region receives southwest monsoonal moisture in the east of the plateau stable isotopic variation shows alternation between monsoon intrusion and recycling of northern moisture 2 in contrast in tianshan there is an apparent temperature effect in 18o with enriched values occurring in summer and depleted values occurring in winter seasonal d excess values opposite to those observed in the southern tibetan plateau are controlled by differing seasonal evaporation conditions 3 in altay the most northern mountain region the seasonal 18o shows the same variation with that in tianshan region however d excess shows no apparent seasonal variation

the effects of varying tissue preservation on the aliphatic hydrocarbons within a high volatile bituminous coal detailed petrographic analyses of the barrett coal an upper permian high volatile bituminous coal in the hunter coalfield australia reveal cycles of peat formation defined by the tissue preservation index these cycles correspond to coal plies that are separated by dirtbands the petrographic cyclicity is also manifested by a corresponding stratigraphic cyclicity in the biomarker composition of the extracted aliphatic hydrocarbons higher amounts of hopanes and lower carbon preference index values n c22 to n c30 show greater bacterial contribution in samples characterised by low values of tissue preservation index the inherited biodegradation signal from the diagenetic stage has now been partially diluted by the generation of new hydrocarbons from the macromolecule the c31 22s22s 22r hopane and c29 20s20s 20r sterane ratios show least variation through the seam the homohopane epimer ratios have attained equilibrium whilst the hopane moretane ratios are typical of coals with unsupressed vitrinite reflectance of 0 65 however other hopane and sterane maturity ratios appear slightly affected by the degree of preservation of organic matter the c29 and c29 20s20s 20r sterane ratios were not found to be useful for maturity comparisons with other coals because of the low values average 0 18 and 0 43 respectively due to heating rate effects these and other biomarker distributions are syndepositional features of the coal precursor and therefore are controlled by the environmental conditions during the stage of peat accumulation and its subsequent coalification all these changes are evident in a coal member only 2 2 m in thickness the petrographic and geochemical evidence suggest that the environmental affinity of the barrett coal is that of a delta plain depositional setting

the origins of granulites a metamorphic perspective although many recent reviews emphasize a uniformity in granulite pressure temperature p t conditions and paths granulites in reality preserve a spectrum of important petrogenetic features which indicate diversity in their modes of formation a thorough survey of over 90 granulite terranes or occurrences reveals that over 50 of them record p t conditions outside the 7 5 1 kbar and 800 50 c average granulite regime preferred by many authors in particular an increasing number of very high temperature 900 1000 c terranes are being recognized both on the basis of distinctive mineral assemblages and geothermobarometry petrogenetic grid and geothermobarometric approaches to the determination and interpretation of p t histories are both evaluated within the context of reaction textures to demonstrate that the large range in p t conditions is indeed real and that both near isothermal decompression itd and near isobaric cooling ibc p t paths are important amphibolite granulite transitions promoted by the passage of co 2 rich fluids as observed in southern india and sri lanka are exceptional and not representative of fluid related processes in the majority of terranes it is considered on the contrary that fluid absent conditions are typical of most granulites at or near the time of their recorded thermal maxima itd granulites are interpreted to have formed in crust thickened by collision with magmatic additions being an important extra heat source erosion alone is not however considered to be the dominant post collisional thinning process instead the itd paths are generated during more rapid thinning 1 2 mm yr exposure related to tectonic exhumation during moderate rate or waning extension ibc granulites may have formed in a variety of settings those which show anticlockwise p t histories are interpreted to have formed in and beneath areas of voluminous magmatic accretion with or without additional crustal extension ibc granulites at shallow levels very rapid 5 mm yr extensional thinning subsequent to collision it is suggested that the preservation of ibc paths rather than itd paths in many granulites is primarily related to the rate and timescale of extensional thinning of thickened crust and that hybrid itd to ibc paths should also be observed most ibc granulites and probably many itd granulites have not been exposed at the earth s surface as a result of the tectonic episodes which produced them but have resided in the middle and lower crust for long periods of time 100 2000 ma following these events the eventual exhumation of most granulite terranes only occur through their incorporation in later tectonic and magmatic events unrelated to their formation

tropical climate instability the last glacial cycle from a qinghai tibetan ice core an ice core record from the guliya ice cap on the qinghai tibetan plateau provides evidence of regional climatic conditions over the last glacial cycle 36 cl data suggest that the deepest 20 meters of the core may be more than 500 000 years old the 18 o change across termination i is 5 4 per mil similar to that in the huascaran peru and polar ice cores three guliya interstadials stages 3 5a and 5c are marked by increases in 18 o values similar to that of the holocene and eemian 124 000 years ago the similarity of this pattern to that of ch 4 records from polar ice cores indicates that global ch 4 levels and the tropical hydrological cycle are linked the late glacial stage record contains numerous 200 year oscillations in 18 o values and in dust nh 4 and no 3 levels

aliphatic and aromatic biomarkers from carboniferous coal deposits at dunbar east lothian scotland palaeobotanical and palaeoenvironmental significance carboniferous visean coals from dunbar east lothian scotland contain well preserved miospore and megaspore assemblages suggesting a lycopod dominated forest ecosystem with some ferns sphenopsids and pteridosperms the low rank of the coals and the well defined microflora permit assessment of the palaeoenvironmental significance of lipid biomarkers during the early carboniferous rock eval petrographic and lipid analyses indicate a fully terrestrial depositional environment although we also present and discuss a wide diversity of other lipid biomarkers alkanes hopanoids steroids we focus on the terrestrial derived biomarkers combustion derived pahs pyrene fluoranthene benzo a anthracene chrysene and triphenylene indicate the occurrence of forest fires in the study areas during early carboniferous times alkyldibenzofurans are considered to derive from lichen biomass retene cadalene simonellite tetrahydroretene and kaurane are poorly specific and can derive from a variety of early palaeozoic land plants abietane phyllocladane ent beyerane and 4 h eudesmane as well as bisnorsimonellite diaromatic totarane diaromatic sempervirane and 2 methylretene however as yet had only been reported from conifers which do not appear in the fossil record until the late carboniferous within the lower carboniferous forest ecosystem arborescent lycopsids and pteridosperms are proposed as alternative sources for these compounds

geochemical and petrographic properties of some spitsbergen coals and dispersed organic matter abstract this paper presents the characteristics of selected parameters of organic matter of the tertiary coal samples and organic matter of carboniferous rock samples from the spitsbergen the coal samples were taken from central coal basin the longyearbyen region and from the forlandsundet basin oscar ii land the kaffioyra region samples of dispersed organic matter were collected from suffolk pynten and sergeijevfjellet area in sorkapp land the optical properties of coal samples are different from properties of dispersed organic matter macerals of vitrinite group dominate in all of the samples the average content of vitrinite group macerals is much lower in dipersed organic matter samples than it is in coals the average content of liptinite group macerals is a little lower and inertinite group macerals is much higher the average content of mineral matter is higher in organic matter samples than in coal samples the average value of vitrinite reflectance and standard deviation of organic matter is higher in comparison with coals the coal samples are generally classified as orthobituminous medium rank type c there are samples from very low to middle grade coal the values of vitrinite reflectance and standard deviation of coals investigated are similar and are lower than they are in dispersed organic matter gas chromatography mass spectrometry gc ms was applied to assess organic matter source and rank with use of several biomarker parameters primary organic matter of the tertiary coals contained predominantly material from conifers among them cupressaceae and or taxodiaceae and podocarpaceae families were identified by their characteristic biomarkers dispersed organic matter of rocks does not show features indicating input of vascular plants into its primary material and its origin is assumed to be algal bacterial samples with calamites fossils contained organic matter with only low terrestrial input results of rank assessment by thermal maturity parameters based on biomarkers agree with vitrinite reflectance data the kaffioyra and the longyearbyen coals are in the range of high volatile bituminous coals the dispersed organic matter samples seems to be more mature than that of both coals and can be assessed as late catagenetic the organic matter of the sergeijevfjellet formation was formed in basins with higher fluctuation of water level lower amount of water caused oxidation of organic matter in a basin the mire plants contained less of resins and essential oils than hornsundneset formation mire plants the deposits of organic matter in a tertiary basin were formed with faster subsidence and higher water level the plants of oligocene age kaffioyra region contain more resins and essential oils than plants of paleocene age longyearbyen region while coalification degree is similar however technological parameters of paleocene coals are better the organic matter of kaffioyra region was formed in basins with higher fluctuation of water level than from the longyearbyen region

organic geochemical characterisation of sediments from the sakoa coalfield madagascar abstract eleven coals and five mudstones of the sakoa coalfield southwest madagascar have been characterised by microscopy rock eval pyrolysis and detailed analysis of c 12 aromatic and c 15 saturated hydrocarbon fractions of the organic extracts average vitrinite reflectance of 0 77 r r and t max of 439 c indicate moderate thermal evolution of the organic matter corresponding to the beginning of catagenesis which is confirmed by molecular indicators based on aromatic hydrocarbons and saturated biological markers the average methylphenanthrene index mpi 1 of 0 69 corresponding to a calculated vitrinite reflectance r c of 0 81 is in agreement with an isomerisation of selected steranes and triterpanes having not yet reached equilibrium maceral compositions and molecular distributions of saturated and aromatic hydrocarbons are typical of organic matter mainly derived from terrestrial higher plants with significant contributions of bacteria and a minor input of algae the hydrocarbon potential in terms of hydrogen index hi values of the coal samples varies between 83 and 284 mg hydrocarbons hc g c org i e in approximately the same range as that commonly observed for high volatile bituminous coals carbon normalised concentrations of c 12 aromatic and c 15 saturated hydrocarbons generally are higher in the coals than in the mudstones thus suggesting expulsion of heavier hydrocarbons was relatively ineffective in sakoa coals

degradation et lessivage des hydrocarbures de la formation ordovicienne de thumb mountain encaissant le gite zn pb de polaris territoires du nord ouest canada carbonate rocks of the ordovician thumb mountain formation host to the zn pb polaris deposit contain hydrocarbons that show types of alteration classically attributed to biodegradation and water washing the hydrocarbons of the upper part of this formation and of the overlying irene bay formation indicate alterations due to water washing only the hydrocarbons of the impermeable shales of the overlying cape phillips formation display indices of only higher thermal maturity than the underlying units contrary to classical concepts of hydrocarbon biodegradation n alkanes cyclohexylalkanes even isoprenoids and perhaps also steranes seem to have been degraded simultaneously and not successively in this sequence this alteration process is mainly responsible for a log linear decrease of the amounts of n alkanes and cyclohexylalkanes with increasing depth the severe and uniform alteration of aromatic hydrocarbons throughout the interval which is opposite to the progressive alteration of associated n alkanes can be attributed solely to water washing this conclusion necessitates a reconsideration of previous interpretations attributing the loss of short side chain substituted polyaromatic compounds to microbial activity hopanes tri and tetra cyclic terpanes as well as aromatic steroids and hopanoids seem to have been unaffected by the alteration phenomena the increase in the degree of alteration of the hydrocarbons with increasing depth implies that the responsible migrating fluid circulated per ascensum

photochemical sulfurization of sedimentary organic matter a widespread process occurring at early diagenesis in natural environments abstract the possibility of light induced formation of sedimentary organo sulfur compounds has been investigated with simulation experiments these experiments using mono and diunsaturated hydrocarbons and reduced sulfur species in particular h 2 s and elemental sulfur were conducted under mild conditions sunlight low temperature likely to occur in the photic zone of anoxic environments these experiments showed an efficient sulphurization of the organic matter under sunlight conditions leading to the formation of organo sulfur compounds such as thiophenes and sulfur cross linked macromolecules very similar to those occurring in sediments deposited in anoxic environments these results show the potential for photochemically induced sulfurization of organic matter in environments with photic zone anoxia such a process would be especially favored in evaporitic environments with a shallow anoxic boundary extending well into the photic zone

the pliensbachian toarcian paleoclimate transition new insights from organic geochemistry and c h n isotopes in a continental section from central asia the taskomirsay section south kazakhstan is a unique pliensbachian toarcian sequence of lignites clayey layers and silty sandstones deposited in a fluvial lacustrine environment with nearby swampy areas this period characterized by a drastic climate change has been particularly studied in western tethyan marine environments whereas very few studies focused on continental settings paleoflora analyses associated with a multi isotope approach based on well preserved type iii bulk organic nitrogen isotopes a15norg and hydrogen isotopic composition a2h of n alkanes were developed to document paleoclimatic changes in the area sporomorph associations and fossil woods revealed a globally warm to cool temperate climate characterized by xenoxylon a conifer morphogenus biogeographically related to cool humid settings apart from slightly less humid and warmer conditions in the early toarcian warmer conditions are supported by reconstructed mean annual air temperatures maats based on the first branched glycerol dialkyl glycerol tetraethers brgdgts ever recorded in the early jurassic nevertheless no drastic changes were recorded in the a15norg values its signal being attributed to tenuous equilibrium between water and nutrient availability via intense n recycling based on n alkane distributions sources of organic matter were separated in two pools i a purely terrestrial n c27 and ii an aquatic pool n c23 constituted of vegetation that thrived under almost permanent water supply the n alkane a 2h values 248 to 151 as well as their amounts and average chain lengths acl are in agreement with cool temperate conditions in the pliensbachian and less humid warmer conditions in the early toarcian the isotopic difference between a2h values of n c27 and n c23 2hter aq suggests enhanced seasonality during the pliensbachian toarcian transition and low seasonality in the early toarcian in agreement with temperate climate regime finally contrasted response to paleoclimate changes between markers suggests different spatial integration of those proxies the role of sea level variations for a2h values might also resolve this contrasted response

an organic geochemical perspective on terrestrialization the colonization of land required new strategies for safe gamete diaspore dispersal and to cope with desiccation harmful radiation fire and gravity accordingly the morphology behaviour and physiology of the organisms changed here we explore to what extent physiological adaptations reflected in the molecular content of the sediments add to our understanding of the terrestrialization many compounds considered characteristic of land organisms do not provide valuable information from the fossil record since 1 they were not preserved 2 they occur or correspond to substances that evolved prior to the terrestrialization e g cutan vs algaenan cellulose or 3 they have been changed diagenetically and or catagenetically the latter leads to geo macro molecules without a chemical fingerprint relating them to their original bio macro molecules despite sometimes excellent morphological preservation of the organic remains nevertheless some molecular markers and their stable isotopes provide independent information on the terrestrialization process the odd predominance of n alkane surface waxes is a feature already apparent in early land plants and could with caution be used as such furthermore fossil terpenoids and their derivatives are valuable for reconstructing the evolution of major plant groups the radiation of the phenylpropanoid pathway with for example sporopollenin and lignin seems to be closely related to the evolution of land plants as for other disciplines occupied with unravelling past life and environment organic geochemistry relies heavily on the paradigm that the present provides a key to the past for organic geochemistry the biosynthetic pathways of living organisms provide such a key the biosynthetic differences between organisms provide insight into the evolution of biosynthetic pathways and this can be applied to and calibrated against the fossil record evolution also implies adaptation and by linking species ecology to their biochemistry the adaptive value of the biosynthetic pathways and the biomolecules produced may be resolved this biosynthetic link to environment can also be applied to the past for instance the notion that oxygen is required in steroid and non hopanoid triterpenoid synthesis implies that analysis of steroids in ancient sediments may help to unravel the early evolution of the atmosphere summons et al 2006 analogous to the oxygenation of the earth s atmosphere terrestrialization also required major adaptations of the terrestrializing organisms to the living conditions on land the conquest of land required the development or strengthening of supportive structures such as skeletons stems and roots to withstand earth s gravity without the support of water and to resist wind it also demanded water saving strategies such as arthropod and plant cuticles vertebrate skin and cork to survive low humidity environments and sometimes fire as well as the development of water conducting tissues in plants roots tracheids finally the higher exposure to harmful radiation required sunscreens such as pigments aromatic and other substances as uv filters whereas the endoand exoskeletal adaptations are intrinsically based on the formation of large biopolymers water saving and uv protection may be also realized by means of smaller molecules our working hypothesis is that the major changes in biosynthetic pathways which accompanied the terrestrialization of organisms are reflected in the molecular composition of the organic matter present in palaeozoic sedimentary rocks for instance a minor change in the biosynthesis of sporopollenin may have led to lignin in return we can expect the changes in composition of the organic matter om in palaeozoic rocks to help determine following evolutionary trends the question being asked is to what extent is our working hypothesis valid and what does this provide us with to understand terrestrialization we restrict ourselves to primary producers and arthropods since they have a rich fossil record both organic geochemically and as microand macroscopic remains we exclude other terrestrial heterotrophic life forms worms snails vertebrates etc since they do not usually leave a chemically characteristic signature in the sediments from vecoli m clement g meyer berthaud b eds the terrestrialization process modelling complex interactions at the biosphere geosphere interface geological society london special publications 339 11 36 doi 10 1144 sp339 3 0305 8719 10 15 00 the geological society of london 2010 organic matter analysis lipids and

a 108 83 m ice core record of atmospheric dust deposition at mt qomolangma everest central himalaya abstract the central himalaya can be regarded as an ideal site for developing a long term ice core dust record to reflect the environmental signals from regional to semi hemispheric scales here we present a dust record from segments of a 108 83 m ice core recovered from the east rongbuk er glacier 27 59 n 86 55 e 6518 m a s l on the northeast slope of mt qomolangma everest in the central himalaya covering the period ad 600 1960 due to rapidly layer thinning and coarse sampling we primarily discuss the changes in the dust record since ad 1500 in this paper results show a significant positive relationship between the dust concentration and reconstructed air temperatures during this period suggesting a likely cold humid and warm dry climatic pattern in the dust source regions namely central asia this is associated with the variability in the strength of the westerlies and its corresponding precipitation

high resolution trace element records of an ice core from the eastern tien shan central asia since 1953 ad 1 high resolution records of trace elements ba v cr mn co ni cu as rb sr mo cd sn sb tl pb bi th and u quantified in an ice core recovered from the miaoergou glacier in the eastern tien shan central asia spanning the period 1953 2004 ad provide the first comprehensive time series on characterizing the relative contributions from natural and anthropogenic sources to the deposition of trace elements in central asia it is suggested that rock and soil dust is the most important natural source for most of elements investigated slight decreases in concentrations or fallout fluxes of crustal elements such as ba mn rb th u and sr are observed during recent decades which may be due to decreases in dust emissions from source regions and a decrease of accumulation rate since 1980s the increasing trends of median concentrations and crustal enrichment factors efc of v cr co ni cu and mo during the period 1953 2004 ad are insignificant in comparison to their respective levels prior to 1953 ad however slight enhancements of both concentrations and efc are observed for cd sb pb bi tl and sn since 1950s such recent increases are likely to be attributed to enhanced anthropogenic emissions such as metal smelting mining stationary fossil fuel combustion and combustion of gasoline due to human activities in eurasia particularly xinjiang in northwestern china russia and kazakhstan our study supports evidence that environmental contamination has become a global problem for pb and bi and a large scale phenomenon for cd sb tl and sn

time marker of 137cs fallout maximum in lake sediments of northwest china abstract caesium 137 137cs has no natural source and is commonly employed in establishing the chronology of recent lake sediments in the anthropocene epoch because of their location in the northern mid latitude westerlies circulation region downwind of the chernobyl accident and their proximity to the lop nur chinese nuclear testing cnt site lake sediments in nw china record a137cs fallout maximum of global atmospheric thermonuclear weapon tests gtwt in 1963 1964 common era ce with probably local fallout subpeaks due to the chernobyl accident in 1986 ce and cnt in 1976 ce this complexity means that the use of 137cs fallout maximum in lake sediments as a time marker in nw china is thus far not well constrained impeding assessment of recent and future changes in paleoclimate and human activities to identify the 137cs time marker and provide a reliable chronology of surface lake sediments for investigating paleoclimatic changes and for defining the anthropocene epoch in nw china during the last 50 100 years here we describe chronologies of 6 near surface sediment cores from nw china based on 137cs and 210pb activities and review the chronology of 23 lake sediments and 10 ice cores from nw china and central asia based on 137cs 210pb 239 240pu 3h 241am and beta activity dating methods and annual layer counting as well as 240pu 239pu isotopic ratios based on the potential influence of radioactivity transport from the chernobyl accident and cnt and the comparison with deposition records of 26 european lake sediments and 5 alpine ice cores we propose that the 137cs fallout maximum of lake sediments in nw china and central asia is primarily attributable to gtwt and that there is no unambiguous evidence to confirm the chernobyl and cnt derived 137cs local fallout subpeaks taking into account the approximately one year delay between injection of 137cs into the atmosphere and its incorporation in lake sediment records we conclude that the 137cs fallout maximum in lake sediments of nw china provides a reliable gtwt time marker for 1964 ce

continuous record of microparticle concentration and size distribution in the central greenland ngrip ice core during the last glacial period 1 a novel laser microparticle detector used in conjunction with continuous sample melting has provided a more than 1500 m long record of particle concentration and size distribution of the ngrip ice core covering continuously the period approximately from 9 5 100 kyr before present measurements were at 1 65 m depth resolution corresponding to approximately 35 200 yr particle concentration increased by a factor of 100 in the last glacial maximum lgm compared to the preboreal and sharp variations of concentration occurred synchronously with rapid changes in the 18o temperature proxy the lognormal mode of the volume distribution shows clear systematic variations with smaller modes during warmer climates and coarser modes during colder periods we find 1 7 m diameter during lgm and 1 3 m during the preboreal on timescales below several 100 years and the particle concentration exhibit a certain degree of independence present especially during warm periods when generally is more variable using highly simplifying considerations for atmospheric transport and deposition of particles we infer that 1 the observed changes of in the ice largely reflect changes in the size of airborne particles above the ice sheet and 2 changes of are indicative of changes in long range atmospheric transport time from the observed size changes we estimate shorter transit times by roughly 25 during lgm compared to the preboreal the associated particle concentration increase from more efficient long range transport is estimated to less than one order of magnitude

the arctic oscillation signature in the wintertime geopotential height and temperature fields the leading empirical orthogonal function of the wintertime sea level pressure field is more strongly coupled to surface air temperature fluctuations over the eurasian continent than the north atlantic oscillation nao it resembles the nao in many respects but its primary center of action covers more of the arctic giving it a more zonally symmetric appearance coupled to strong fluctuations at the 50 hpa level on the intraseasonal interannual and interdecadal time scales this arctic oscillation ao can be interpreted as the surface signature of modulations in the strength of the polar vortex aloft it is proposed that the zonally asymmetric surface air temperature and mid tropospheric circulation anomalies observed in association with the ao may be secondary baroclinic features induced by the land sea contrasts the same modal structure is mirrored in the pronounced trends in winter and springtime surface air temperature sea level pressure and 50 hpa height over the past 30 years parts of eurasia have warmed by as much as several k sea level pressure over parts of the arctic has fallen by 4 hpa and the core of the lower stratospheric polar vortex has cooled by several k these trends can be interpreted as the development of a systematic bias in one of the atmosphere s dominant naturally occurring modes of variability

effect of water washing on c15 hydrocarbon fraction of crude oils from northwest palawan philippines recognition and subsequent correlation of biodegraded and or water washed oils with their unaltered counterparts has been a long recognized problem in petroleum geochemistry because water washing and biodegradation can occur concurrently it is difficult to delineate the individual effects of these two oil altering processes especially on the c15 hydrocarbon fraction both processes can cause an oil to become enriched in sulfur and to have a lower api gravity owing to loss of the more volatile components thus the altered oil may appear to be a high sulfur crude of low maturity altered and unaltered oil fractions extracted from cores of a water washed carbonate reservoir offshore northwest palawan were studied to observe the effect of alteration on correla ion parameters water washing resulted in the following changes 1 depletion of 13c in the c15 branched cyclic alkane fraction whereas virtually no change occurred in isotope composition of the aromatic fraction 2 selective loss of dibenzothiophenes followed by loss of aromatic hydrocarbons and 3 virtually no change in steranes or tricyclic and pentacyclic terpanes with the exception of enhancement of 17 agr h norhopane and decrease of 18 agr h trisnorhopane in situations of severe water washing mild biodegradation also occurred as indicated by the loss of n alkanes and possible selective loss of n alkanes having less than 25 carbon atoms relative to branched alkanes cycloalkanes and aromatic components because cycloalkanes and aromatic hydrocarbons are not generally preferentially utilized by bacteria as long as n alkanes are present the changes observed in these two fractions most likely result from water washing because of the potential for extreme compositional changes in the n alkane and aromatic fractions the most useful correlation parameters between the altered and unaltered oils are sterane and terpane distributions stable carbon isotope ratios are also useful however more studies of oils in which water washing is known to have occurred need to be made to explain the general response or various responses of the isotopic composition of oils to water washing

dehydration and incipient charnockite formation a phase equilibria and fluid inclusion study from south india a 3 m traverse across a charnockite lens in a biotite garnet graphite gneiss quarry from southern india has provided mineral equilibria that indicate charnockite formation occurred under fluid conditions of x h 2 o 0 2 to 0 3 at p 5 5 pm 1 9 kb and t 700 to 750 c dehydration of biotite loss of garnet and growth of orthopyroxene are related to a decrease in x h 2 o in the fluid phase within the charnockite lens isotopic analysis of the fluid entrapped in quartz from the charnockite indicates delta 13 c 8 2 0 3 0 heavier than delta 13 c values from smaller volumes of co 2 entrapped in quartz from the gneiss although the increase in fluid inclusion abundance in the charnockite can be related to oxidation of graphite without influx of co 2 an external source of co 2 is required in order to account for the shift to heavier carbon isotope values observed in both graphite and entrapped co 2 within the charnockite carbon isotope data across the gne

significance of organic matter in recording paleoenvironmental conditions of the safa formation coal sequence maghara area north sinai egypt abstract five coal and shale core samples of the middle jurassic safa formation were taken from a newly drilled water well at the depth interval from 191 to 208 m and have been investigated in this study detailed organic and inorganic geochemical analyses of the safa formation reveal no significant differences between the upper seams and the main seam the extracts of the coal samples have an unusual n alkane distribution the gc traces are dominated by unusual compounds eluting between n c19 and n c21 these compounds are thought to be diterpanes which suggest significant conifer contributions to the coals higher amounts of hopanes and higher carbon preference index cpi values n c22 to n c30 show significant bacterial contributions in samples characterized by high values of tissue preservation index tpi the c31 22s 22s 22r hopane and c29 20s 20s 20r sterane ratios show least variation through the shale coal sequence shale and coal samples from the upper and main seams are characterized by high relative abundance of 17 h hopanes which could be derived from non microbial organisms such as ferns the petrographic and geochemical evidences suggest that the maghara coal was formed in a wet forest swamp environment situated in a marine influenced lower delta plain

the pristane n heptadecane ratio as an indicator for recognition of hydrocarbon migration effects a simple scheme is proposed for type iii kerogen source rocks which uses pristane n heptadecane concentration ratios for recognition of hydrocarbon expulsion effects within the maturity interval 0 82 1 03 rm this scheme can be applied from gas chromatography data routinely obtained by most petroleum geochemistry studies in exploration exploration of this scheme to oil prone type ii source rocks appears very promising

processus d alteration thermique physico chimique et biologique de constituants organiques et genese d une mineralisation sulfuree le gite zn pb de la florida cantabria espagne the la florida lead zinc deposit cantabria spain which is hosted by urgonian carbonates is located on the border of the basco cantabric lower cretaceous basin the stratiform orebody which is composed of sphalerite galena and barite in iron dolostones occurs in an envelope of dolostone organic matter studies have been carried out on samples from this deposit to understand its genesis and later evolution the results of this work reveal the immatury of the autochthonous organic matter despite a slight paleothermal anomaly centred on the deposit various alteration processes have affected the hydrocarbons associated with autochthonous organic matter and or allochthonous bitumens namely geochromatographic fractionation water washing and biodegradation together with previous geological work the results of this study are consistent with epigenetic and or diagenetic emplacement of the mineralization the proposed genetic scheme involves hydrothermal fluids that would have acquired at least so

carbonic fluid inclusions in south indian granulites evidence for entrapment during charnockite formation field evidence and fluid inclusion studies on south indian incipient charnockites suggest that charnockite formation occurred during a decompressional brittle regime following the peak of metamorphism and regional deformation the most abundant type of inclusions in quartz and garnet grains in these charnockites contain high density carbonic fluids although lower density fluids occur in younger arrays of inclusions discrete fluid inclusion generations optically are observed to decrepitate over well defined temperature intervals and quantitative measurements of co2 abundance released from these inclusions by stepped thermal decrepitation show up to a four fold increase by volume in the incipient charnockites relative to the adjacent gneisses from which they are derived studies based on optical thermometry visual decrepitation and stepped heating inclusion release together indicate that entrapment of carbonic fluids coincided with charnockite formation we confirm that an influx of carbon dioxide rich fluids is associated with the amphibolite granulite transition as recorded by the incipient charnockites the remnants of which are commonly preserved as the earliest generation of high density fluid inclusions