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30th International Meeting on Organic Geochemistry (IMOG 2021)
- Conference date: September 12-17, 2021
- Location: Online
- Published: 12 September 2021
51 - 100 of 279 results
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ORGANIC POLLUTION OF SOIL CAUSED BY THE MINING INDUSTRY ON THE SOUTH OF POLAND – A CASE STUDY
Authors E.A. Szram, M.J. Fabiańska and M. KondrackaSummaryIn southern Poland, the mining industry caused diverse wastes to be produced and stored (post-mining waste, tailings from flotation, washing, and smelting). Perennial storage of industrial waste leads to pollutions of soil, surface, and underground water. Trace elements and toxic organic compounds in wastes are mobilised by surface runoff and the infiltration of rainwater into the ground. Thus the soil in the dump vicinity is contaminated. Such pollution can spread over a long distance.
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HYDROUS PYROLYSIS IN THE SIMULATION OF COAL WASTE SELF-HEATING
Authors M.J. Fabiańska, D. Więcław, M. Misz-Kennan, E.A. Szram, J. Ciesielczuk and K.J. JurekSummaryCoal wastes are produced in large amounts at various stages of coal exploitation. These rocks require special dump sites designed to store them for many years. If sufficiently large volumes of coal waste are accumulated, self-heating driven by their oxidation may occur. This process generates toxic compounds contaminating the atmosphere, water, and soil. Self-heating is a highly variable process since it depends on numerous factors. Hydropyrolysis experiments simulate well natural self-heating of coal wastes occurring in the presence of water. Pyrolysates show composition analogous to that of self-heating products what allow to predict types of contaminants formed in the process.
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Potential Water and Soil Contaminants from Coal Waste Dump Being at the Late Stage of Self-Heating (Rymer Cones, Poland)
Authors M. Lupanciuc, M.J. Fabiańska, E.A. Szram and D. WięcławSummaryCoal mining generates a great amount of wastes deposited in coal waste dumps, commonly adjacent to the mines. Its oxidation during storage in dumps often leads to self-heating or even self-ignition. This process produces large amounts of polar compounds that are relatively well water-soluble. They are leached by rainwater from permeable coal wastes, only loosely packed within a dump. The dissolving of better water-soluble compounds such as phenols, present in coal wastes, has led to their pre-concentration in leachates. Despite their relatively low stability, polar compounds were well preserved in pyrolysates formed during self-heating. Thus, even after self-heating ceasing, cold coal wastes surrounding overburnt zones can still be a source of water and soil contaminants. Phenols and aromatic acids can be considered as markers of coal waste contamination.
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Determination of Methane Cracking in Pyrolysis Experiment and its Geochemical Significance
More LessSummaryThe methane will be cracked in a certain thermal maturity stage, but it is uncertain if the methane of shale gas at high-over maturity has been cracked. In the present work, methane pyrolysis experiments were carried out in closed gold-tube system to investigate methane cracking and its carbon isotope fractionation.
From the pyrolysates, we detected the cracking of CH4 and the generation of bigger hydrocarbons like C2H4, C2H6, and C3H8 from the methane pyrolysis experiments within the shale gas maturity scope. CH4 cracking and recombined to C2H6 will cause the residual CH4 enriched whereas the produced C2H6 depleted in 13C, however, the secondary reaction of C2H6 will complicate the isotope distribution features of the pyrolysates in the methane pyrolysis experiments.
Based on our experimental results and the data of the shale gas reservoirs from different regions of the world, we suggested that CH4 will be cracked and combined into C2H6 in high-over matured shales. When the contribution from methane-derived C2H6 is sufficiently massive, the commonly found order of δ13Cmethane < δ13Cethane will change with increasing maturity (e.g. vitrinite reflectance, Ro > ∼2.0%) and a carbon isotope reversal will occur for the shale gas.
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POTENTIAL THERMAL MATURITY PARAMETERS ASSOCIATED WITH AROMATIC HYDROCARBONS IN LIGHT CRUDE OILS
More LessSummaryIn this work, we found that some conventional maturity parameters such as Ts/(Ts+Tm), C29-20S/(20S+20R), and C29-sterane-ββ/(αα+ββ) have reached an equilibrium value without changes after the high maturity stage (such as Ro%>1.3), or breakdown and no longer applicable, and thus cannot be used to properly evaluate the thermal evolution stage of crude oil reservoirs. But the results from this present work showed that toluene (Tol) and methy cyclohexane (MCH) maybe had an inherited relationship in the oil and then the ratio of Tol/(MCH+Tol) can be applied to evaluate the thermal stage of oil reservoirs( Cheng et al,.2018 ). Furthermore 2-methy naphthalene (2-MN) and 1-methy naphthalene (1-MN) have different thermal stability, the ratios of 2-MN/(1-MN+2-MN) were linearly changed with the Easy%Ro.
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FACTORS CONTROLLING THE ORGANIC MATTER ACCUMULATION OF CAMBRIAN STRATA IN THE WESTERN AND EASTERN TARIM BASIN, NW CHINA
More LessSummaryLower Cambrian black shales are widely distributed in the Tarim Basin, NW China, but those in the Keping area in the west have a high total organic carbon (TOC) content different from those in the Kuluketage area in the northeast of the basin. The Cambrian Yuertusi Formation in the Shiairike section (Keping) and the Xishanbulake Formation in the Yaerdangshan section (Kuluketage) are time-equivalent and can be correlated. Black shales of the Yuertusi Formation have lower δ13CKer values (<−34‰) than the Xishanbulake Formations (δ13CKer values >−34‰). These values suggest that black shales in the Yuertusi Formation were dominated by benthic algae, whereas rocks in the Xishanbulake Formation contain substantial amounts of planktonic algae. Analyses of trace elements demonstrate an anoxic depositional environment, with high productivity in both the Yuertusi and Xishanbulake Formations. The enhanced productivity was promoted by upwelling fluids and hydrothermal events, leading to the enrichment of nutrient elements such as barium, cadmium, copper, phosphorus, nickel, vanadium, and zinc. More terrigenous inorganic detritus input to the Xishanbulake Formation, which led to less amounts of organic matter and degradation of planktonic algae during sedimentation, resulted in a lower TOC content than the Yuertusi Formation.
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ENVIRONMENTAL CONTROLS ON BACTERIAL LIPID PRODUCTION BY A METHANOTROPH-METHYLOTROPH CO-CULTURE
Authors N. Richter, S. Van Grinsven, L. Villanueva, E.C. Hopmans, N. Bale and D. RushSummaryMethane-oxidizing bacteria regulate the natural release of methane, however, the role of aerobic methane oxidation in the geologic record is poorly constrained. Our study evaluates potential biomarkers for methane-oxidizing bacteria by assessing the environmental controls on bacteriohopanepolyol (BHP) production by a Type I methanotroph, Methylobacter sp. We also evaluate the partnership of Methylobacter sp. with a methylotroph, Methylotenera, sp., which is known to co-occur with methanotrophs and is thought to play a role in enhancing methane oxidation rates. We set up incubation experiments for an enrichment co-culture of Methylobacter sp. and Methylotenera sp. to evaluate how temperature, methane concentrations, and salinity influence (1) the culture’s lipidome (specifically BHPs), (2) the community composition, and (3) methane oxidation rates.
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Natural and Anthropogenic Biomarkers in Urban Speleothems
Authors J. Jacob, A. Diacre, T. Thiebault, L. Fougère, E. Destandau, C. Le Milbeau, P. Branchu, E. Dumont and E. Pons-BranchuSummaryWe analysed biomarkers enclosed in carbonate crusts deposited in urban surrounding as tracers of pollution
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Response Of Carbon Cycling To Hydroclimate Changes In The Subtropical Carbon-rich Wetland Ecosystem During The Late Pleistocene.
By Y. YangSummaryA borehole core (ZK7) was collected in the Dajiuhu Basin, in the middle reaches of the Yangtze River. Lipid and bulk geochemical analyses were conducted to exploit the responses of past geochemical processes to hydroclimate changes. These preliminary results clearly showed a drastic shift of paleoecological processes during the transition from a lacustrine phase to a peat accumulating condition. More work is conducting to infer how is the methane dynamic during this shift.
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ORIGIN AND FATE OF ISOPRENOID GLYCEROL DIALKANOL DIETHERS IN SEDIMENTS FROM LATE MIOCENE TO MID-EOCENE
Authors D. Mitrovic, E. Hopmans, N. Bale and S. SchoutenSummaryIn the past decade especially, more light has been shed on the high diversity in structures of isoprenoid glycerol dialkyl glycerol tetraethers, providing improved insight into both their origin and fate in different settings. A closely related set of isoprenoidal lipids, isoprenoid glycerol dialkanol diethers (isoGDDs), were reported by Liu at al. (2012a ; 2012b ) in marine subsurface sediments. In this study we investigated the occurrence and distribution of GDGTs and GDDs in sediment cores from 3 well-known organic rich sampling sites, Messel oil shale, Vena del Gesso evaporites and Monterey sediments. The strong correlation in abundance and isomer distributions between isoGDDs and isoGDGTs strongly suggest that isoGDDs predominantly have a diagenetic origin, forming by glycerol cleavage of isoGDGTs. The rate at which this happens likely depends upon many factors. Further work will be carried out in order to ascertain the link between these two lipid classes.
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The Benefit of Geochemistry and Basin Modeling Integration for Oil & Gas Exploration. The Case Study for Migration Analysis
Authors I. Campoli, D. Kalacheva, N. Morozov, O. Zakharova, A. Gulyaev and F. GaynetdinovSummaryPetroleum systems analysis has been carried out to better understand migration and filling processes in the eastern edge of the West Siberian basin (Yamalo-Nenets Autonomous District, Russia). Within an area of 37 793 km2 two main petroleum kitchens for Upper – Jurassic Bazhenov formation were distinguished which generated petroleum and guaranteed oil volumes to form fields in the Upper - Jurassic section of sedimentary cover. The migration processes are dominated by downward and lateral fluid flow with filled-to-spill mechanism.
The results of this research provided understanding of the lateral limit and maximum distance for migration, which were later supported by the results of drilling of the well. Allowed to evaluate geological risks, correct exploration plans and change priorities in the list of prospects. It also helped to better understand geological reasons for fluid properties in Upper - Jurassic section and plan research of deeper section to find additional source rocks in Lower - Jurassic section which was previously never taken into account in this zone. Later this statement was proved by the results of geochemical pyrolysis analysis. The upgraiding of the model is planned in 2021 to solve more local issues for production process.
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Utilization of Ancient Petrogenic Carbon in Svalbard Sediments, Derived from Glacial Meltwater Streams
Authors M. Ruben and S. DerenneSummaryThe Study addresses the subject of ancient carbon utilization in sediments of Hornsund Fjord, Svalbard. Using a combined approach of biomarker analysis, lipidology, and compound specific radiocarbon dating. We were able to show that the local sedimentary microbes utilize "presumably recalcitrant" petrogenic organic matter for their biosynthesis to a certain extend. Indicating its degradation in the subsurface and hence displaying a not yet accounted source of fissile carbon entering today's carbon cycle.
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δ13C Compositions of Bacteriohopanetrol Isomers Reveal Bacterial Processes Involved in the Carbon Cycle
SummaryBacteria play key roles in the carbon cycle. In many sediments and peatlands, methanotrophic bacteria consume a portion of released methane, reducing the emissions of this potent greenhouse gas. In marine oxygen minimum zones (OMZ) and other anoxic settings, anaerobic ammonium oxidizing (anammox) bacteria remove bioavailable nitrogen while performing chemoautotrophic carbon fixation. Methanotrophic and anammox bacteria synthesize a wide number of complex bacteriohopanepolyols (BHPs), comprising notably several stereoisomers of bacteriohopanetetrols (BHTs), which are used as biomarker lipids. We used a gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) method to measure the δ13C of BHTs of cultured bacteria. These δ13C values were combined with bulk isotopic measurements of the bacterial biomass and δ13C analyses of the bacterial growth substrates to establish carbon isotopic fractionation from substrate to biomass to BHT lipid. We demonstrated that bacteria using different metabolic pathways produced distinct fractionation factors between substrate and BHTs, which potentially allows for distinguishing BHTs produced by ‘Ca. Brocadia’ and methanotrophs from other freshwater producers (e.g. in peatlands). Measurement of BHT-specific fractionation factors allowed us to better constrain the contribution of anammox bacteria to fixed carbon in OMZ. This work expands the application of BHT isomers to isotopically identify carbon cycle processes.
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Terrestrial Temperatures Peak in the First Millenia After the Cretaceous-Paleogene Boundary
SummaryThe Cretaceous-Paleogene (K-Pg) boundary extinction represents one of the most severe, with approximately 75% of life on earth suffering extinction. An new terrestrial mean annual air temperature (MAAT) record based on branched tetraether data from southern Saskatchewan (Canada) permits, for the first time, the recognition of a distinct episode of rapid global warming in the first approximately 1 ka of the Paleogene, which is attributed to a rapid release of CO2 at or around the K-Pg boundary. Irrespective of the source(s) of CO2, the extinction on land may therefore have been partly driven by MAATs exceeding a threshold for ecosystem resilience. These data are the first in their kind at this resolution, providing new boundary conditions of absolute values, and rates of temperature change. Further studies of terrestrial MAAT at a similar resolution will be essential for demonstrating the unparalleled trends observed in our record to be a global phenomenon.
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Fuelling Earliest Life — Volatile Organic Compounds in 3.5 GA Old Fluid Inclusions
Authors H. Mißbach, J. Duda, A.M. Van den Kerkhof, V. Lüders, A. Pack, J. Reitner and V. ThielSummaryIt is widely accepted that small organic molecules played a central role in the emergence of life on Earth. As yet, however, there has been no conclusive evidence for the existence of the discussed relevant candidate molecules on early Earth. Here we report on indigenous, biologically-relevant organic molecules in 3.5 Ga old barite-hosted fluid inclusions from the Dresser Formation in Western Australia. We characterized the organic inventories by combining fluid inclusion petrography, stable isotope analysis and different GC-MS techniques. Our study establishes a primary origin of the fluid inclusions. They contain CO2, H2S and H2O, minor amounts of COS, CS2, N2, and CH4 as well as various oxygen and/or sulfur containing organic molecules. Notably, most of the identified compounds could have served as substrate for purported ancestral sulphur and methanogenic metabolisms. Perhaps most remarkably, the fluid inclusions also contain the stable building blocks of methyl thioacetate which is a potential key-agent in the emergence of life. Thus, our study provides the first robust evidence for the existence of such organic compounds on the early Earth and strongly supports the idea that microbial life in the 3.5 Ga old Dresser Formation was linked to hydrothermal seepage.
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Long-Term Anoxia Driven by High Temperature of Equatorial Atlantic During Cenomanian Leading up to OAE 2
Authors M.A.F. Abraham, D. Naafs and R. PancostAbstractOceanic Anoxic Event (OAE) 2 occurred during the Cenomanian/Turonian and marks one of the most significant perturbations of Earth’s system of the last 250 million years. Although the burial of black shales in the marine environment under depleted (bottom) water column oxygen conditions was widespread during OAE 2, the state of anoxia in the million years leading up to OAE 2 and the correlation between anoxia and temperature are poorly constrained. Here, we report long-term biomarkers records of (a) water column anoxia, (b) water column and photic zone euxinia (PZE), and c) TEX86-based sea surface temperature (SST) from Demerara Rise (ODP Site 1258) that span the Albian to Turonian, including OAE 2. Our data suggest a depositional environment under long-term anoxic condition at Demerara Rise during the Cenomanian as indicated by elevated total organic carbon content (up to 10 wt.%) and episodic occurrence of the biomarkers lycopane and 28,30-bisnorhopane, which at present are found in the anoxic marine such as Black Sea (Wakeham et al., 1993) and Monterey Formation (Schoell et al., 1992), respectively. The extent of water column anoxia gradually intensified and peaked during OAE 2 when the presence of hopanoid thiophenes and free isorenieratane indicate euxinic conditions in the water column, at times reaching the photic zone. This long-term progression of marine de-oxygenation coincides with a gradual increase in SSTs at the site. TEX86-based SSTs indicate a long-term warming of ∼ 7 °C during the Cenomanian to maximum values of 41 °C during OAE 2. The abrupt declined in SSTs following OAE 2 during the Turonian indicates termination of long-term anoxia via re-oxygenation of water column in phase with low TOC and absence of anoxia and euxinia biomarkers. This study highlights the impact of Earth’s climate state on marine oxygenation with an increase in temperature driving the ocean’s state from hypoxia into severe anoxia and eventually euxinia, likely due to weathering feedback mechanisms related to warming and changes in the hydrological cycle.
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Changes of Biomarkers, Isotopes and Macerals of Polish Coals and Shales: Maturation Simulated by Hydrous Pyrolysis
Authors M. Kotarba, M. Słowakiewicz, K. Jurek, M. Waliczek and D. WięcławSummaryThe bitumen yields of Carboniferous coals and shales from USCB and LCB after 330oC HP are higher than in initial coals and shales and somewhat higher than of coals and shales after 360oC HP. The distribution of exsudatinite in coals is higher at 330°C and decreases at 360°C HP. Contrary to shales at 360°C HP the exsudatinite content slightly increases. This phenomenon could be caused by the presence of clay minerals in shales which have a general retention effect during hydrocarbon generation. The results of biomarker and isotope analyses reveal that bitumen is always co-genetic with corresponding kerogen in coals and shales, and their deposition was in a brakish-lacustrine environment, and the microbially reworked organic matter could be caused by: (i) contribution of planktonic or benthic algae organic matter, (ii) more anoxic conditions in sedimentation basin, which impede bacterial growth and reworking of organic matter and (iii) contribution of terrestrial organic matter was higher than in other cases, and more organic matter could preserve in primal form.
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Molecular Investigation of Archaeological Ambers from Alsace (Ne France): Origins and Alteration Processes
Authors S. Schmitt, P. Adam, P. Schaeffer, C. Féliu, N. Schneider-Schwien, D. Minni, M. Châtelet, E. Boes, D. Azar and A. NelSummaryA set of amber samples collected from archaeological burials at three different sites in Alsace (NE France) and dated back to the Bronze Age and the high Middle Age, as well as European ambers from potential geological sources have been investigated. Based on GC-MS analysis of lipid biomarkers occurring in the solvent extract and of those released by chemical degradation which comprised various diterpenoids and succinates, it appears that the archaeological samples correspond to Baltic amber, confirming that the Baltic region was a source of amber for Alsace, at least during the Bronze Age and the High Middle Age. Identification of the source of ambers using lipid distributions was possible despite alteration of the molecular signatures by natural degradation processes.
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HYDROCARBON PROPERTIES OF THE BAZHENOV FORMATION SOURCE ROCKS WITH DIFFERENT MATURITY
Authors M. Tikhonova, A. Kalmykov, O. Vidishcheva, D. Ivanova, V. Levkina, R. Borisov and G. KalmykovSummaryBazhenov formation source rocks from wells with different maturity of organic matter were investigated by sequential extraction. Hydrocarbons extracted with hexane from open pores and with chloroform from blocked pores were investigated by FID-GC and GC-MS methods. It was found that hydrocarbons composition in open and blocked pores depends not only on maturity, but also on lithological composition of rocks and migration processes. In one well not only maturation, but also sedimentary condition biomarker parameters may vary through the depth of section. Reservoirs are filled with migrated hydrocarbons, that are of higher maturity and contain higher amount of n-alkanes with shorter chains in hexane extracts. Hydrocarbons formed in continental conditions were also found in the rocks at the bottom of Bazhenov formation, formed in marine conditions, which means there was another source rock deeper than Bazhenov formation. Concentration of silica, carbonates and pyrite affect the processes of hydrocarbons generation and influence some biomarker parameters values. That is lithological and reservoir properties of the Bazhenov source rocks as well as maturity of organic matter should be analyzed for investigation of oil and gas generation and migration processes.
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The Stable Carbon Isotope Geochemistry of Natural Gas After 20 Years of Shale Gas Development
Authors J. Cesar, B. Mayer and O. H. ArdakaniSummaryThis study discusses the new perspectives on the stable carbon isotope distribution in natural gas hydrocarbons, with special focus on the evidence of a tendency to equilibrium isotope fractionation in gases from low-permeability hydrocarbon reservoirs. It also describes how the isotope equilibration expresses (or not) in the molecular composition of the produced fluids.
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STRUCTURAL INVESTIGATION OF THE MACROMOLECULAR COMPONENT OF BALTIC AMBER BY SELECTIVE CHEMICAL DEGRADATION
Authors S. Schmitt, P. Schaeffer, P. Adam, C. Féliu, N. Schneider-Schwien, D. Minni, M. Châtelet, E. Boes, D. Azar and A. NelSummaryThe constitution of Baltic amber, the role of succinic acid and, more generally, of ester bonds in the constitution of macromolecular components of amber has been further investigated by chemical degradation of the solvent insoluble part of Baltic amber using butanolysis (BuOH/HCl). Succinic acid derivatives were the sole compounds released upon butanolysis whereas other compounds which could correspond to the alcohol counterparts of succinates could not be detected by GC-MS. This result indicate that these counterparts are all located on high molecular weight structural moieties. Succinic acid thus plays a key role as cross-linking agent between oligomeric structural moieties based on diterpenoids necessarily bound by at least one non-hydrolysable C-O or C-C bond.
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New Paleoenvironmental Proxies for the Permian Irati Black Shales Based on Acidic O1 and O2 Compounds Assessed by FT-ICR-MS
SummaryVariations of the acidic polar composition of the Early Permian Irati black shales and Serra Alta shales were assessed by ESI(-) FT-ICR-MS to investigate their significance for the paleoenvironmental studies by comparison with known features in the northeastern and central-eastern Paraná Basin (Brazil). The high O>2 classes in the Serra Alta shales points to high input of terrigenous OM deposited in oxic waters. In addition, seven parameters based on O1 and O2 compounds are proposed as new paleoenvironmental proxies: phenol index (%DBE 4; O1 class); C27/C28 DBE 4 (O1 class); C27/C28 DBE 5 (O1 class); Even/OddFA; TARFA Odd (terrigenous/aquatic ratio); C36 hopanoic acid index; and hopanoic/steranoic acids ratio. Higher values of the phenol index and the TARFA indicate higher land plant input during the final black shale deposition, and higher Even/OddFA to northeastern basin samples reflects their higher content of terrigenous OM. Furthermore, variations of C27/C28 (DBE 4) and C27/C28 (DBE 5) is useful to reconstruct paleosalinity, in which higher values indicate higher salinity. The C36 hopanoic acid index is higher for the marine hypersaline basal samples from the northeastern basin, while a significant bacterial biomass signal is stored as a higher hopanoic/steranoic acids ratio for central-eastern basin samples.
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OILS OF NONMARINE GENESIS WITH AN ABNORMALLY LIGHT ISOTOPE COMPOSITION OF CARBON
Authors I. Goncharov, R. Kashapov, S. Fadeeva, A. Litvinova, A. Zherdeva, K. Kozyreva and N. OblasovSummaryThe results of the study for oils formed by organic matter of non-marine origin, which accumulated under moderately oxidizing conditions, are presented. Oils are characterized by an increased content of a light carbon isotope, which is unusual for hydrocarbons formed in such conditions.
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Carbon Isotopic Composition and Components of the Petroleum Gases from Fields in the Western Pre-Caucasus Area (Russia)
Authors I. Goncharov, N. Oblasov, M. Veklich and I. EftorSummaryThis study is about differences and similarities in the isotopic and component composition of the petroleum gases from fields in the Western Pre-Caucasus area. These gases were differentiate into three genetic types. The 1st genetic type (Akhtyrsky type) were generated by the rocks of the Middle Eocene Kuma Formation. Gases with the higher δ13C values of gas components from ethane to pentane were assigned to the 2nd (Sladkovsky) genetic type. These gases are associated with oils, the source of which was marine organic matter but the exact stratigraphic confinement of the source rock remains unclear. And the 3rd genetic type of gases (Nikolaevsky type) which the initial organic matter associated with higher terrestrial plants, which accumulated under oxidizing conditions (for oils Pr/Ph = 3.1–4.3, C27–C28–C29 steranes is 0.23–0.22–0.55). The source rock of these gases and oils remains unknown, but its age should be no younger than the Lower Cretaceous.
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OBTAINING THE KINETIC SPECTRUM OF ORGANIC MATTER AT DIFFERENT STAGES OF NATURAL THERMAL EVOLUTION
Authors R. Kashapov, I. Goncharov, N. Oblasov and V. SamoilenkoSummaryThe dependence between the Arrhenius constant and the activation energy is obtained using the results of kinetic studies of the Bazhenov formation rocks at various stages of catagenesis. Based on this dependence, a kinetic spectrum is obtained that reflects the realization of the generation potential of organic matter in the process of thermal evolution.
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Metagenomic Insight into the Metabolic Activities of Potential Btex-Degrading Populations
By M. EzeSummaryEnvironmental contamination by petroleum hydrocarbons is of concern due to the carcinogenicity and neurotoxicity of these compounds. Successful bioremediation of organic contaminants requires bacterial populations with degradative capacity for these contaminants. Through successive enrichment of microorganisms from a petroleum-contaminated soil using diesel fuel as the sole carbon and energy source, we successfully isolated a bacterial consortium that can degrade diesel fuel hydrocarbons. Metagenome analysis revealed the specific roles of different microbial populations involved in the degradation of benzene, toluene, ethylbenzene and xylene (BTEX), and the metabolic pathways involved in these reactions. One hundred and five putative coding DNA sequences (CDSs) were identified as responsible for both the activation of BTEX and central metabolism (ring-cleavage) of catechol and alkylcatechols during BTEX degradation. The majority of the CDSs were affiliated to Acidocella, which was also the dominant bacterial genus in the consortium. The inoculation of diesel fuel contaminated soils with the consortium resulted in approximately 70% hydrocarbon biodegradation, indicating the potential of the consortium for environmental remediation of petroleum hydrocarbons.
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GASEOUS POLLUTANTS GENERATED DURING DRY AND HYDROUS PYROLYSIS OF COAL WASTE: SIMULATION OF THE SELF-HEATING PROCESSES
Authors D. Więcław, K. Jurek, A. Kowalski, E. Bilkiewicz, M.J. Fabiańska, M. Misz-Kennan and J. CiesielczukSummaryPyrolysis experiments were conducted without and with water in temperatures 250, 360 and 400oC during 72 h to simulate pollutants generation from self-heating coal wastes under oxygen-depleted conditions. The molecular composition of gases generated during these experiments and their relationship with the amount of organic matter in the rock (TOC), its maturity, the temperature of the process and the influence of the water was determined. Alkanes up to C8 and alkenes to C4 were identified. The sulphur-containing compounds comprise inorganic (H2S, COS/SO2) and organic (methyl- and ethyl mercaptans, and methyl-, ethyl-, propyl- and butyl sulphides) components. The H2, CO, CO2 and N2 were recorded among the inorganic gases. The molecular composition of generated gases strongly relates to the temperature of the process. The concentration of usually increase with the increasing temperature of pyrolysis. Presence of water and elevated TOC amounts boost generation S-compounds (dominated by H2S). Presented results helped to understand and evaluate the emission of gaseous pollutants during pyrolysis of the stored coal wastes induced by self-heating. The most dangerous to the environment is the 300–400°C regime connected with the emission of elevated concentrations of hydrocarbons and S-containing compounds, especially from TOC-rich rocks.
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GEOCHEMICAL CHARACTERISTICS AND SOURCE DISCRIMINATION OF DEEP PERMIAN OILS FROM WELL XJC 1 IN THE SOUTHEASTERN JUNGGAR BASIN
Authors H.J. Zhang, S.M. Li and L. ZhangSummaryThe Junggar Basin is one of the most important superimposed basins in southeastern China, characterized by multiple source rocks and hydrocarbons productive horizons. Well XJC1 is one of the recently drilled wells with deep commercial tight oil/gas (>4000m) discovered in the Perman Lucaogou Formation (P2l) in the southeast of the basin, which suggests a great petroleum potential in this relatively low-level exploration area. Oil-oil and Oil-source rock correlation showed that the P2l oil from the XJCJ well were sourced from the P2l argillutite, which have a high hydrocarbons generation potential with large scale and a relatively wide range of thermal maturity (low to high level). It suggests a great petroleum exploration potential about normal and unconventional hydrocarbon resources in the southeastern Junggar Basin. This study would be helpful for the further petroleum exploration and exploitation in the area.
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Cyanobacterial Aromatic Carotenoids
Authors R. Summons, F. Husain, X. Cui, S. Rohret, X. Liu, P. Welander, G. Shen and D. BryantSummaryContrary to common perceptions, cyanobacteria can be the source of aromatic carotenoids preserved in sediments. Their distribution patterns differ, somewhat, from those produced by the phototrophic sulfur bacteria and are distinguished by the presence of C38 and C39 compounds which are diagenetic products of mono- and dicarboxylic acid precursors. Cyanobacterial aromatic carotenoids are most in evidence in samples from lacustrine environments and their existence likely explains some of the carbon isotopic variability of carotenoid assemblages previously thought to be derived from Chlorobi.
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Application of Biomarkers and Compound Specific Sulfur Isotope in Oil-Source Rock Correlation in the Wenliu Oilfield, Bohai Bay Basin
More LessSummaryDongpu Depression is an important petroliferous depressions in the Bohai Bay Basin, eastern China, which is a typical saline lacustrine depression. Wenliu Oilfield is the biggest oilfield in the depression. There is still some controversy about the oil source for the Wenliu oilfield. The dispute is focused on the location (in-situ or the adjacent Qianliyuan Sag) and the horizons (the Es3M or the Es3L-Es4u) of the key source rocks. Quite a few geologists suggested that the Es3M in-situ should be the most important source rocks, which is primarily dark shales with great hydrocarbon generation potential. To help unravel the origin and source rocks of the Wenliu oils, a total of 44 rock samples and 66 oil samples were collected for study by conventional geochemical methods combined with compound specific carbon/sulfur isotopic analysis. We suggested that the Wenliu Oils are mixed sources derived from both the Es3M and the Es3L-Es4U strata, and the latter should be responsible for the majority of the crude oils in the Wenliu Oifleld based on oil-oil and oil-source correlation as well as semi-quantitative comparison of biomarkers abundances. The results would be instructive for further petroleum exploration and petroleum resource evaluation in the area.
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Study of Favorable Conditions for Shale Oil and Gas Formation in Nenjiang Formation in South-Eastern Uplift Area of Songliao Basin
More LessSummaryRecently, three wells have all produced over 10m³ oil per day, which are deployed in the Cretaceous shale horizons in the Songliao Basin, indicating great potential for unconventional shale oil in that area. Great progress has been made in understanding the formation mechanisms of oil shale in the basin in terms of petrography, minerals, and sedimentary facies. However, comparatively little research has been carried out on the rock types of the provenance, which is significantly enriched in organic matter, and their influence on the shale. To assist in unravelling its geochemical characteristics and formation mechanisms, 21 rock samples were selected from the late Cretaceous Nenjiang Formation (K2n) in the southeastern uplift of the basin for analysis. The K2n dark mud shale was formed in a brackish, strongly reducing, algae enriched sedimentary environment. The lacustrine paleo-environment had high productivity and a large sedimentation rate, which was conducive to the generation and preservation of organic matter. The input of large amounts of iron, magnesium, and calcium materials to the provenance promoted the formation of oil shale. The source rock contains high levels of transition metals, which played a significant role in catalysing the evolution of kerogen and thus in hydrocarbon generation.
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A comparison of hydrocarbon loss between pyrolysis S1 and crude oils: A case study of Qingshankou shale-oil system, Songliao Basin
More LessSummaryIt is well known that oil content ( pyrolysis S1 or soluble EOM ) in a shale is under-estimated due to light hydrocarbon loss during measurement procedure, and the restoration of such loss is a great challenge while estimating shale oil resources and determining mobility. In this paper, the light hydrocarbon losses of fresh shale cores from Qingshankou Formation of northern Songliao Basin and their produced oils were compared. The results show that under ambient conditions, the hydrocarbon losses of pyrolysis S1 and crude oils overall increase with shale maturity (Ro) and oil API gravity. However, a shale with greater maturity (e.g. Ro>1.6%) tends to have better seal capacity and the hydrocarbon loss may be much lower than expected. Compared with their produced oils, shales tend to lose more light hydrocarbons. The cause of such difference is that S1 yields of a shale are composed of more light hydrocarbons and less heavy ends as indicated by gas chromatography analysis. It is suggested that restoring light hydrocarbon loss based only on oil density as proposed by previous studies will significantly under-estimated shale oil resources and more controlling factors should be considered.
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Diversity of Nitrogen-Containing Bacteriohopanepolyols: Biomarkers for Aerobic Methane Oxidation in Terrestrial CH4 Seeps
SummaryThe greenhouse gas CH4 plays an important role in the Earth’s carbon cycle as it actively influences climate change. The aerobic oxidation of CH4 (AMO) plays a key role in oxidizing CH4 before it reaches the atmosphere. AMO can be traced using different lipid biomarkers, specifically bacteriohopanepolyols (BHPs) with nitrogen-containing side chains such as aminotetrol or aminopentol. Soils are one of the largest microbial sinks for atmospheric CH4 but, to date, they have only been investigated for soil-specific BHPs and not AMO-characteristic BHPs. In this study, a new UHPLC-HRMS2 method was applied to investigate the diversity of non-derivatized BHPs in soils near two continuous terrestrial CH4 seeps in Sicily, Italy. The microbial diversity of methanotrophic bacteria was assessed by 16S rRNA gene amplicon sequencing. Overall, our data suggest that AMO-specific BHPs (e.g. aminopentol) in tandem with novel identified composite BHPs such as BHPs with an ethenolamine head group and acylated aminotriol BHPs reveal consistent trends with AMO activity in sampling transects from high to low CH4 availability. Their abundance relatively to common soil-BHPs like adenosylhopanes may potentially be used to reconstruct recent and paleomethanotrophy in terrestrial environments.
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Identification of methyl-branched alkenones with up to five double bonds in saline lakes
More LessSummaryWe demonstrate new C38 and C39 found in Lake Van and Lake Fryxell are methyl-branched alkenones (brC38Me and brC39Et). Previous assignments of these compounds as straight chain C38Me and C39Et were incorrect. Double bond positions, determined based on mass spectra of corresponding DMDS adducts, are Δ 4, Δ 7, Δ 14, Δ 21 and Δ 28 for penta-unsaturated branched alkenones. Based on published DNA data and changes of branched alkenone percentages of Lake Van, we hypothesize that branched alkenones function as storage of energy and are produced by a yet unknown species of Isochrysidales. UKbr38Me based on brC38Me alkenones has a similar trend with UK37 in the past 270 ka of Lake Van, suggesting the high temperature sensitivity of branched alkenones, same as other straight chain alkenones. Such proxies based on branched alkenones might be more reliable than UK37 and UK'37 to provide temperature record in sites with mixed alkenone productions.
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Marine fungi and the biological carbon pump - a quest for novel biomarkers for key players in the carbon cycle
Authors E. Cooper, S. Thomas, S. Ussher, D. Rush, M. Cunliffe and S. LenggerSummaryThis PhD project will study the lipidome of marine fungi in order to find lipid biomarkers that can help deduce the role marine fungi play in the marine biological carbon pump. This will be done by growing marine fungi under different nutrient regimes that mimic natural variations in the ocean.
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Organic Geochemical Characterization of Lower Cretaceous Sediments from the Sw Barents Sea
Authors E. Krasnova, A. Suslova and T. KolesnikovaSummaryThe Norwegian Barents Sea is a prolific hydrocarbon province on the Norwegian Continental Shelf (NCS) and is a key region for reconstructing the Early Cretaceous geological history of the Barents Sea region. This study presents a brief overview of the generative potential (TOC & Rock-Eval), thermal maturity and geochemical signature (Isotopes (SARA fractions), Gas-Chromatography/mass spectrometry) of Lower Cretaceous source rocks.
The samples from the SW Barents Sea show variation in thermal maturity ranging from immature to mid-mature. The data set exhibits high variability in primary organic matter precursors and hydrocarbon generation potential, which implies heterogeneous organic facies.
All samples suggest a mixture of terrestrial and marine organic matter deposited under varying redox depositional environments. Likewise, secondary processes such as thermal maturity and contamination may hamper interpretation of the original organic matter precursors.
It can be concluded that the source rock potential of the analyzed Lower Cretaceous samples is of minor importance. Our interpretation, in general, agrees with that of Bjorøy & Hall (1983) who reached a similar conclusion concerning North Sea Cretaceous rocks and in the Lower Cretaceous Kolje and Rurikfjellet formations ( Abay et al, 2018 ).
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THE POTENTIAL OF BIOMARKERS TO DISTINGUISH LOWER AND MIDDLE MIOCENE LIGNITES FROM THE COAL-MINING DISTRICT OF LUSATIA
Authors I. Kojic, J. Kus, D. Zivotic and K. StojanovicSummaryThe organic geochemical study of Lower and Middle Miocene lignites from the coal-mining district of Lusatia in eastern Germany has been performed. Since the samples showed a uniform and low degree of maturity (0.32–0.37 %Rr), it can be considered that maturity has no significant impact on biomarker distributions. Therefore, the objective of the study is to examine the potential of biomarkers to distinguish Lower and Middle Miocene lignites in relation to sources and depositional environment of organic matter (OM). The biomarker patterns show relatively similar compositions in studied lignites, indicating no significant change in palaeclimate from Lower to Middle Miocene. Middle Miocene lignites are characterized by more pronounced variations of biomarker signatures due to the more pronounced fluctuation of water-level and/or palaeo-wildfires. Peatification was performed under stable water-level. The main differences between Middle and Lower Miocene coals are expressed by higher dehydroicetexane content, Paq index, the tetracyclic/tricyclic diterpanes ratio and non-hopanoid triterpenoids content, as well as by lower content of hopenes and fernenes in the latter one. Mentioned results indicate decreasing contribution of Cupressaceae and emergent macrophytes, associated with increased input of Pinaceae, angiosperms and ferns to the precursor OM of Middle Miocene samples in comparison to Lower Miocene samples.
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HYDROLOGICAL AND BIOGEOCHEMICAL CYCLING DURING RAPID WARMING EVENTS IN THE CONTINENTAL INTERIOR UNITED STATES
Authors A. Elson, M. Rohrssen, J. Marshall, G. Inglis and J. WhitesideSummaryThe Green River Formation of the western US represents a ∼15 million-year record of unusually large, productive Eocene lakes. The development of a particularly organic-rich (up to 43% total organic content) Mahogany oil shale (49.3 to 48.7 Ma) occurred at a key climate transition and during the decline of the Early Eocene Climatic Optimum (EECO).
Hydrogen isotopic compositions (δ2H) of leaf wax (n-alkanes) and algal (phytane) lipids preserved in the Mahogany Zone are used to reconstruct precipitation and lake water δ2H, respectively. Algal lipid and leaf wax δ2H values exhibit a strong linear relationship (R2 = 0.8), suggesting that algae and higher plants are utilising the same hydrogen-bearing sources for biosynthesis (i.e. lake water δ2H).
δ2H in n-alkanes and phytane become increasingly depleted upward through the Mahogany Zone, indicating increased precipitation during the demise of the EECO. Similarly, biomarker trends differ from those expected during a lacustrine drying-up cycle, revealing a continental-interior hydrological response to cooling.
Results of algal lipid and leaf wax δ2H, with additional lipid and terrestrial biomarker profiles and petrographic data, allow hydrological change to be differentiated from broader ecosystem change during the EECO.
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Species mixing in alkenone producers brings new opportunities in paleoclimate and paleoceanographic reconstruction
More LessSummaryAlkenones are a type of ketones produced by a certain order of algae. Its unsaturation degree has been widely applied as a sea surface temperature proxy. Our studies focus on differentiating alkenone producing species, which can reveal information about paleo sea ice and sea surface salinity.
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Biomarkers from Fossilised Hot Spring Sinters: Implications for the Search for Life on Mars
Authors S. George, B. Teece, J. Hartz, T. Djokic, S. Ruff, O. Alard, K. Campbell and M. Van KranendonkSummaryThe search for life on Mars has been guided in part by the search for biosignatures in Martian analogues on Earth. Siliceous hot springs are key astrobiological targets as they provide ideal conditions for biogenesis. This work documents biomarker analyses carried out on siliceous hot spring sinters from El Tatio, Chile, and from the Taupo Volcanic Zone, New Zealand, with an age range from actively forming to fossil deposits (∼1–21 ka). In addition, older samples (Pliocene–Miocene) were analysed from the Coromandel Volcanic Zone, New Zealand. Some of the data have already been published. The key hydrocarbons detected in some (or all) of the samples include n-alkanes, isoprenoids, monomethylalkanes, tricyclic and tetracyclic terpanes, hopanes, 2α-methylhopanes, steranes, and some aromatic hydrocarbons. A series of biomarker and aromatic hydrocarbon maturity parameters suggest that most samples have entered the oil generation window, and that maturity is strongly variable between samples and by parameter. These signals are indicative of organic matter sourced from subsurface hydrothermal fluids migrating from deeper immature source rocks that have been hydrothermally altered, rather than from the in situ material preserved within the samples in the hot spring environment.
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THERMOGENIC GAS HYDRATES IN SOUTH CHINA SEA: EVIDENCE FROM HYDRATE-BEARING SEDIMENT RELEASED VOLATILE MOLECULAR MARKERS
More LessSummaryThe volatile components released from hydrate-bearing sediment collected in South China Sea via home-made apparatus comprise high abundance of diamondoids and show high stage of molecular maturity parameters, implying that they should be mainly derived from the mature to postmature source rock beds in the QND Basin. This supports that thermogenic gas does significantly contribute the gas hydrate in this area.
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Laboratory Modeling of Organic Matter Maturation in Bazhenov Source Rocks: Hydrocarbons Composition Variation in Time
Authors A. Kalmykov, M. Tikhonova, V. Levkina, D. Ivanova, G. Savostin, G. Kalmykov and A. BychkovSummaryThe abstract represents the results of pyrolysis and GC-MS investigations of step-by-step laboratory modeling of organic matter maturation in Bazhenov formation rocks. Two rock samples with immature kerogen were heated in autoclaves under 300°C and 30 MPa, with sampling of liquid products and rock pieces each 12 h. The results have shown that pyrolysis parameters TOC, S2 and HI decreased exponentially, simulating all steps of kerogen maturation, and hydrogen index reached 70 mg HC/g TOC in 7–8 days, representing the kerogen achieve end of oil window. N-alkanes were generated only during first 5–8 days depending on the sample, with predomination of n-alkanes with odd number of carbon atoms after 3–5 days. Biomarker parameters that characterize both maturity and deposition conditions change during kerogen cracking, which means kerogen not only become more mature, but have complicated structure and consists of algae and marine organisms. Patterns for hydrocarbons generation depending on different nature of kerogen were determined. Further studies on larger amount of Bazhenov samples are necessary, but obtained results allow to investigate kinetics of kerogen cracking and specified compounds production.
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Integrated Approach to the Determination of the Origin of Hydrogen Sulfide in the Oil Field (Russia)
Authors D. Kalacheva, N. Morozov, D. Abramov, M. Kremenetskiy, E. Kazak and E. AblyaSummaryDue to its high reactivity and toxicity, hydrogen sulfide is an undesirable component of oil associated gas, since it reduces its economic value and shortens the service life of technological equipment. In this paper we consider the main results of integrated geological, geochemical and hydrodynamical studies for determination of the causes of the origin and mechanisms of hydrogen sulfide formation in the composition of oil associated gas from the Y reservoir of the oil field in the Volga-Ural oil and gas basin. The research is focused on creating a quantitative model for predicting the generation of hydrogen sulfide depending on the technological parameters of the field development.
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Alteration of Soil Organic Matter Composition After 130 Years of Afforestation Assessed by Molecular Markers
Authors T.C. Speckert and G.L.B. WiesenbergSummaryAfforestation reduces carbon emissions through increased soil organic matter (SOM) stocks as well as long-term carbon sequestration. However, little is known about the alterations in the composition of organic matter (OM) after afforestation, specifically on a molecular level. The analysis of plant- and microorganism-derived molecular proxies in soil allows to trace different sources of OM and its transformation once incorporated into soil. However, focusing only on one compound class may result in flawed or incomplete conclusions due to missing information offered by other compound classes. One approach to a more reliable conclusion on the SOM dynamics is the combination of multiple compound classes.
The objective of this project is to identify the major source of SOM in a subalpine afforestation sequence (40–130 years) with Norway spruce (Picea abies L.) on a former pasture in Jaun, Switzerland with the combination of multiple plant- and microorganism-derived molecular proxies. Within this project we expect a decline in SOC stocks after 50 years (72.2 t ha-1) and a recovering after 130 years (116.8 t ha-1) of afforestation. Overall, we expect an increase in SOM, a decline in SOM quality and a higher fungal PLFA content in older forests.
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INFLUENCE OF MARINE INCURSIONS ON SOURCE ROCKS IN A SALINIZED LACUSTRINE BASIN IN THE PALEOGENE EASTERN CHINA
More LessSummaryMarine incursion is one of the possible mechanisms for the salinization of lacustrine basins, especially in the Paleogene eastern China. However, the influence of marine incursions on source rocks in salinized lacustrine basins is challenging and controversial. Here, we examine this issue using a case of the Paleogene Biyang Depression (BD) eastern China, addressing organic matter (OM) accumulation and unconventional hydrocarbon potential. Our data suggests that marine incursions have positive influence on both OM accumulation and unconventional hydrocarbon potential of source rocks in salinized lacustrine basin. However, further study on influence of different degrees (e.g., landward distance, overall water depth, and seawater-freshwater mixing) of marine incursions on source rocks in salinized lacustrine basins are still needed, especially during sea-level fluctuations.
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Elucidation of the Biosynthetic Pathway of Butanetriol Dialkyl Glycerol Tetraethers Reveals a Novel Energy-Saving Adaptation
Authors S. Coffinet, L. Mühlena, J. Lipp, C. Neubauer and K. HinrichsSummaryButanetriol dialkyl glycerol tetraethers (BDGTs) are a novel class of archaeal membrane lipids possibly related to methanogenesis. Their structure deviates from the other archaeal lipid structures, such as the glycerol dialkyl glycerol tetraethers (GDGTs), as they possess a four-carbon backbone instead of the universal glycerol moiety. Here, we combined compound-specific stable isotope probing and high-resolution mass spectrometry to investigate the biosynthetic pathway of BDGTs. We demonstrated that BDGTs result from a post-synthesis methylation of GDGTs. We further observed that biosynthesis of BDGTs was stimulated by energy and/or nutrient depletion both in vitro and in the environment. We hence posit that production of BDGTs act as an adaptation strategy to survive in energy or nutrient deprived environments such as in the deep sub-seafloor.
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IDENTIFYING CONTROLS ON ORGANIC MATTER ENRICHMENTS IN HEMIPELAGIC SETTINGS: A BIOMARKER APPROACH
Authors A. Riboulleau, M. Quijada, A. Caillaud, J. Reynaud, J. Ferry, F. Baudin and N. TribovillardSummaryThe biomarker content of several dark coloured and/or organic-rich levels from the Marnes Bleues Formation (Aptian-Albian) from the Vocontian Basin (South-eastern France) was analysed in order to compare the modes of formation of such deposits in a hemipelagic, basinal setting. The studied levels include the Goguel and Paquier Levels, deposited during oceanic anoxic events (OAE) 1a and 1b, respectively. Unexpectedly, most studied samples show comparable biomarker contents, regardless of their richness in organic matter. The data indicates an organic matter of marine algal origin, deposited under oxygenated conditions. The Paquier level, however, shows an abundance of archaea-derived biomarkers and of organo-sulfur compounds in the extract, indicating deposition under reducing conditions. The Paquier level excepted, the biomarker content indicates that depositional conditions remained overall stable during deposition of the Marnes Bleues formation, including during OAE1a. Nevertheless variations of the relative proportions of steranes, hopanes, terrestrial plant biomarkers and fire-derived polyaromatic hydrocarbons, suggest that minor environmental changes occurred and occasionally favoured organic matter enrichment in the sediment. In the end, no unique mechanism explaining the deposition of these dark coloured and/or organic-rich levels can be identified.
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LARGE REGIONAL GLACIAL-INTERGLACIAL CHANGES IN HYDROGEN ISOTOPIC COMPOSITION OF ALKENONES NEAR THE CHILEAN MARGIN
Authors K. Haettig, D. Varma, S. Schouten and M.T.J. Van der MeerSummaryPaleosalinity is an important oceanographic parameter which cannot be reconstructed with reasonable accuracy based on sedimentary records yet. Sea water isotopes correlate with salinity and are incorporated by organisms e.g. in a calcitic shell or organic material. Published down-core reconstructions of salinity from hydrogen isotope ratios of alkenones are promising but show different sensitivities regionally.
Here we present a new hydrogen isotope ratio record of long-chain alkenones (δ2HC37 ratio) in combination with oxygen isotopes of foraminifera (δ18OForaminifera) from the same samples, from the Chilean margin (ODP site 1235). We observed a decrease in both δ2HC37 and δ18OForaminifera during the last deglaciation (from 20–0 ka) and detected hydrogen isotope enrichment before the last glaciation (∼100–30 ka). Weiss et al. (2019) observed similar shifts in δ2HC37 of >20‰ and in the δ18OForaminifera in the same time frame, suggesting a consistent regional pattern.
The δ2HC37 ratios suggest salinity changes of >2 psu between now and the Last Glacial Maximum, larger than assumed ( Adkins 2002 ; Broecker, 2002 ). Further analysis of both hydrogen and oxygen isotopes of both cores combined with paleo seasurfacetemperature will help to determine why the salinity shift reconstructed based on hydrogen isotopes does not match with other proxies or models.
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Differences in δ13C Values of Levoglucosan from Lignite and Biomass Low-Temperature Combustion
Authors M. Rybicki, L. Marynowski, A. Bechtel and B.R.T. SimoneitSummaryWe showed that stable carbon levoglucosan-specific isotope analysis may be one possible way to determine the relative contributions from coal combustion versus biomass burning sources. PM samples were collected from low-temperature burning/smoldering of Miocene lignites from Poland and basket willow (Salix viminalis L.) representative of biomass.
The calculated levoglucosan δ13C values of xylites varied from −23.6 to−21.6‰, while for detritic coal samples they ranged from −24.2 to −23.1‰, with means of −22.7 and −23.7‰, respectively. The calculated levoglucosan δ13C value of baske twillow wood was−27.1‰. Values of willow wood mixtures with xylite varied from−25.8 to−23.4‰ (with an increasing proportion of xylite), while values of mixtures of willow and detritic coal ranged from−26.9 to−24.6‰ (with an increasing proportion of detritic coal). The hopanoid distributions characteristic for low-temperature lignite/peat burning, with a predominance of 22R-α,β-homohopane, ββ-hopanes and hopenes, as well as low or very low values of the homohopane index, were observed in smoke PM from most lignite samples and absent in the basket willow sample. Thus, the relatively high content of hopanes (with the occurrence of 22R-α,β-homohopane, ββ-hopanes and hopenes) in atmospheric PM samples can be treated as additional tracers of lignite combustion.
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CONTROLLED DRILL BIT METAMORPHISM (DBM) USING INDOOR RIG FLOOR EXPERIMENTS
Authors D. Strapoc, D. Gonzalez and L. GerbaudSummaryFirst time controlled drill bit metamorphism experiments using one-of-a-kind laboratory in Pau, southern France, with indoor rig floor with full capacity of controlling drilling conditions and with a closed drilling fluid loop, allowing extraction, analysis and sampling of the mud gas while-drilling, showing alkanes and alkenes being generated, as drilling conditions create more heat. Stepwise increase of WOB or RPM is followed by likewise increase in generated DBM-gases via base oil cracking at the bit cutter-rock interface.
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