Origin and Migration of Petroleum in the Gidgealpa Ridge Area, Cooper /Eromanga Basins, South Australia

The oil play of the Permo-Carboniferous Cooper and Jurassic-Cretaceous Eromanga Basins in South Australia is complicated to unravel due to the presence of multiple source rocks that bear similar geochemical characteristics and has consequently been subject to intense debate. The underlying Warburton Basin, although initially regarded an exploration target, subsequently has never been seriously considered to having participated in the oil play. The Cooper/Eromanga couplet is Australia's largest onshore petroleum province and still bears potential for undiscovered commodities, making a profound understanding of origin and migration of petroleum a prerequisite for efficient future exploration. Being a typical example of structurally trapped oils in stacked fluvial sandstone reservoirs, the Gidgealpa Ridge was chosen as subject for this study. A suite of 13 sandstone cores, 11 source rocks and 24 drill stem test (DST) oils were processed at the University of Cologne by extraction, sequential extraction of sandstone cores to yield residual oils, preparative liquid chromatography and solid phase extraction to yield fractions of saturated hydrocarbons, aromatic hydrocarbons, maltene resins and a carbazole enriched fractions. While biomarker analyses on saturates and aromatics were performed by Dr. Khaled Arouri at the University of Adelaide, molecular characterisation of carbazoles and bulk geochemical characterisation was also done at the University of Cologne. Sequentially extracted residual oils are particularly useful because they allow a temporal resolution of petroleum reservoir filling histories. While hydrocarbon compositions are quickly equilibrated over a few tens of metres in oil columns, there is substantial evidence that the same is not true for polar species such as e.g. carbazoles and for lateral variations in hydrocarbon composition. Carbazoles were initially regarded as molecular markers indicating relative migration distances. However, counterevidence soon appeared, showing the dependency of carbazole distributions on other factors. The results of this study show that, while the distribution of benzocarbazoles seems to depend only on fractionation processes during primary and secondary migration, alkylated carbazole distribution patterns are governed by source rock facies. This new finding allowed the recognition of a Warburton Basin contribution in certain residual oil fractions, yielding the first conclusive evidence that Warburton Basin rocks bear a source potential and have actively participated in the oil play of the Cooper and Eromanga Basins. The application of carbazole facies parameters, benzocarbazole migration parameters and aromatic maturity data on oils and residual oils from the Gidgealpa Field has allowed the reconstruction of its charging history. Generally, Cooper Basin oils exhibit large maturity variations but a uniformly short migration distance, indicating their origin from a nearby deep trough (eastern source kitchen). Eromanga Basin oils are characterized by similarly low maturity values but highly varying migration distances, suggesting that they were sourced by an extensive and shallow source kitchen. More precise consideration of the carbazole distribution in Eromanga Basin oils shows that the Gidgealpa Field has received two discrete Birkhead charges: a Late Cretaceous pulse from an eastern source kitchen, which migrated a short distance, and became locally displaced by a Tertiary charge from a western source kitchen, which had to migrate further before reaching the Gidgealpa Field. Residual oil fractions from the sandy intervals of the Toolachee and Patchawarra Formations indicate that while the former is a source for Cooper Basin Family 2 oils, the latter can unambiguously be tied to the production of Cooper Basin Family 1 oils. After petroleum generation in the Patchawarra Formation, this petroleum was probably retained by the coaly Patchawarra source rock, and underwent further maturation before it was expelled as condensate-like light oil in gaseous solution. The analysis of sequentially extracted residual oils promises to become a powerful tool in reservoir geochemical studies by adding a temporal resolution to otherwise time-integrated samples, thereby allowing a relatively precise reconstruction of an oil field's charging history. The finding of facies dependent markers in the polar fraction of oils is a constructive motivation for further research into the facies and maturity dependency of NSO compounds. As many residual oils are characterized by minimum extracts yields and a high percentage of NSO compounds, conventional biomarker analyses are complicated and polar markers are necessary for a more precise evaluation

Influence of an Angular Hatching Exposure Strategy on the Surface Roughness During Picosecond Laser Ablation of Hard Materials

AbstractInnovative chip breakers for cutting tools made of very hard materials require laser ablation and demand a high quality regarding the manufactured surface. When processing materials such as polycrystalline cubic boron-nitride or tungsten carbide the surface roughness by laser ablation reaches Sa = 1,0-2,9 μm compared to Sa = 0,42 μm achieved by grinding. Therefore in the presented research the influence of the hatching exposure strategy on surface roughness during picosecond laser ablation of tungsten carbide is examined. The areal, layerwise ablation process is separated into its elements which are represented by intersection zones between single and multiple laser vectors. Thus two mechanisms of roughness formation are identified and described by model functions. Further the mechanisms are transferred to areal ablation in which surface roughness decreases due to improved hatching angles compared to a commonly used one of φ= 0°/90°. With this approach the roughness is reduced by approximately factor 2,0-3,5 to Sa = 0,82 μm. In conclusion guidelines are derived which present favorable settings for high quality laser ablation processes

Polar constituents of oils and bitumens – new applications to Petroleum Geochemistry and (Palaeo)Biogeochemistry

Polar organic molecules are defined by differences in electronegativity between their atomic constituents and the resulting asymmetrical structures. They represent the basic chemical building blocks of life. Having a strong affinity to water (H[subscript]2O), which is essential for life on Earth, polar molecules are studied by the discipline of biochemistry and their origin, distribution, and function in living systems is relatively well understood. Polar constituents of sedimentary organic matter and petroleum have been previously studied but they are, in general, yet far from being understood. They can be present as primary biogenic molecules, rearranged biogenic molecules, or secondary functionalized hydrocarbons. The studies compiled in this thesis use selected polar organic compounds as molecular tools: phospholipids as indicators of biomass, high-molecular-weight polycyclic aromatic hydrocarbons as combustion markers, phenols as indicators of oil-water interaction processes, and carboxylic acids in general.Chapter 2 studies the biological oxidation of petroleum accumulations; a process mediated by microbes that inhabit the deep subsurface and affect the long-term storage of living carbon as sedimentary biomass of the ‘deep biosphere’. The results presented in chapter 2 suggest that intact bacterial cells are present in biodegraded petroleum, as indicated by the detection of membrane lipid fragments, termed phospholipids, in these oil samples. Carboxylic acids released from phospholipids (i.e. phospholipid fatty acids, PLFA) in oil samples vary in concentration (~2.0 - ~10.0 µg/g oil) and composition (i-C[subscript]14:0 dominated vs. i-C[subscript]15:0 and i-C[subscript]17:0 dominated) during progressive petroleum biodegradation, thereby showing that the microbial community increases in size during the removal of petroleum constituents, and that the community structure changes. Not one but at least two structurally different microbial consortia are shown to be responsible for petroleum degradation. Chapter 4 evaluates the rapid oxidation of biomass during the impact of an extraterrestrial bolide, which occurred during the late Neoproterozoic.The co-occurrence of a -3.5‰ negative sedimentary stable carbon isotope excursion and a molecular combustion-marker anomaly (coronene; 0.48 ppb, relative to a 0.04 ppb background), which are followed by a diversification of Acritarch species, suggests that combustion of ‘early’ terrestrial and marginallymarine biomass might have caused extensive smoke and atmospheric dimming, as well as subsequent photosynthetic stress. Moreover, the sharp combustion marker anomaly can probably provide a long-sought chronostratigraphic marker for the late Neoproterozoic, when also detected in other locations around the globe. Chapter 5 evaluates the effects of petroleum interaction with water. For this purpose oils produced from one reservoir were monitored during a 335-day period following the rationale that oil-water interaction increases during petroleum production. Based on a selective depletion of volatile aromatics and invariant phenol concentrations the results exclude both evaporative and oil-water partitioning processes. Petroleum compositional changes, recorded mainly in the low-molecular-weight aromatic and phenol fractions, were tentatively attributed to abiotic oxidation processes. Furthermore, methodological advances in the analysis of carboxylic acids of low molecular weight, evaluated for the execution of the other studies, are presented in chapter 4.Overall, the presented results shed more light on carbon export fluxes from different sedimentary carbon reservoirs by shedding new light on deep biosphere metabolism, elucidating the significance of the Neoproterozoic Acraman impact event, and contributing to our knowledge of petroleum destruction through its interaction with water in sedimentary basins. Moreover, they show that, in contrast to traditional belief, NSO compounds in oils and bitumens can form useful molecular tools to study questions in petroleum geochemistry, biogeochemistry, and palaeobiogeochemistry. Understanding the size of carbon reservoirs and fluxes on Earth, as well as the mechanisms that cause these carbon fluxes, can increase our appreciation of global biogeochemical cycling and, in turn, explain ecosystem dynamics, past evolutionary events, and predict future change of current climatic conditions

Familie aus der Perspektive von Kindern zwischen 9 und 14 Jahren

"Dieser Beitrag referiert die Ergebnisse einer mehrjährigen repräsentativen Befragung von Kindern zwischen 9 und 14 Jahren. Die wichtigsten Einflussfaktoren auf das kindliche Wohlbefinden in der Familie sind familiäre Wärme, keine zu starke Kontrolle durch die Mutter, hohe Kommunikationsqualität und geringe Dominanz der Eltern." (Autorenreferat)"This text reports the results of a representative perennial survey of 9 to 14 year olds. The most important influences on the child's well-being in their families are warmth, no over-control through the mother, high quality communication and low dominance of the parents." (author's abstract

Distinct patterns of mitochondrial genome diversity in bonobos (Pan paniscus) and humans

<p>Abstract</p> <p>Background</p> <p>We have analyzed the complete mitochondrial genomes of 22 <it>Pan paniscus </it>(bonobo, pygmy chimpanzee) individuals to assess the detailed mitochondrial DNA (mtDNA) phylogeny of this close relative of <it>Homo sapiens</it>.</p> <p>Results</p> <p>We identified three major clades among bonobos that separated approximately 540,000 years ago, as suggested by Bayesian analysis. Incidentally, we discovered that the current reference sequence for bonobo likely is a hybrid of the mitochondrial genomes of two distant individuals. When comparing spectra of polymorphic mtDNA sites in bonobos and humans, we observed two major differences: (i) Of all 31 bonobo mtDNA homoplasies, i.e. nucleotide changes that occurred independently on separate branches of the phylogenetic tree, 13 were not homoplasic in humans. This indicates that at least a part of the unstable sites of the mitochondrial genome is species-specific and difficult to be explained on the basis of a mutational hotspot concept. (ii) A comparison of the ratios of non-synonymous to synonymous changes (<it>d</it>_<it>N</it><it>/d</it>_<it>S</it>) among polymorphic positions in bonobos and in 4902 <it>Homo sapiens </it>mitochondrial genomes revealed a remarkable difference in the strength of purifying selection in the mitochondrial genes of the F₀F₁-ATPase complex. While in bonobos this complex showed a similar low value as complexes I and IV, human haplogroups displayed 2.2 to 7.6 times increased <it>d</it>_<it>N</it><it>/d</it>_{<it>S </it>}ratios when compared to bonobos.</p> <p>Conclusions</p> <p>Some variants of mitochondrially encoded subunits of the ATPase complex in humans very likely decrease the efficiency of energy conversion leading to production of extra heat. Thus, we hypothesize that the species-specific release of evolutionary constraints for the mitochondrial genes of the proton-translocating ATPase is a consequence of altered heat homeostasis in modern humans.</p

Microdistribution of Magnetic Resonance Imaging Contrast Agents in Atherosclerotic Plaques Determined by LA-ICP-MS and SR-μXRF Imaging

Purpose: Contrast-enhanced magnetic resonance imaging (MRI) has the potential to replace angiographic evaluation of atherosclerosis. While studies have investigated contrast agent (CA) uptake in atherosclerotic plaques, exact CA spatial distribution on a microscale is elusive. The purpose of this study was to investigate the microdistribution of gadolinium (Gd)- and iron (Fe) oxide-based CA in atherosclerotic plaques of New Zealand White rabbits. Procedures: The study was performed as a post hoc analysis of archived tissue specimens obtained in a previous in vivo MRI study conducted to investigate signal changes induced by very small superparamagnetic iron oxide nanoparticles (VSOP) and Gd-BOPTA. For analytical discrimination from endogenous Fe, VSOP were doped with europium (Eu) resulting in Eu-VSOP. Formalin-fixed arterial specimens were cut into 5-μm serial sections and analyzed by immunohistochemistry (IHC: Movat’s pentachrome, von Kossa, and Alcian blue (pH 1.0) staining, anti-smooth muscle cell actin (anti-SMA), and anti-rabbit macrophage (anti-RAM-11) immunostaining) and elemental microscopy with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and synchrotron radiation μX-ray fluorescence (SR-μXRF) spectroscopy. Elemental distribution maps of Fe, Eu, Gd, sulfur (S), phosphorus (P), and calcium (Ca) were investigated. Results: IHC characterized atherosclerotic plaque pathomorphology. Elemental microscopy showed S distribution to match the anatomy of arterial vessel wall layers, while P distribution corresponded well with cellular areas. LA-ICP-MS revealed Gd and Fe with a limit of detection of ~ 0.1 nmol/g and ~ 100 nmol/g, respectively. Eu-positive signal identified VSOP presence in the vessel wall and allowed the comparison of Eu-VSOP and endogenous Fe distribution in tissue sections. Extracellular matrix material correlated with Eu signal intensity, Fe concentration, and maximum Gd concentration. Eu-VSOP were confined to endothelium in early lesions but accumulated in cellular areas in advanced plaques. Gd distribution was homogeneous in healthy arteries but inhomogeneous in early and advanced plaques. SR-μXRF scans at 0.5 μm resolution revealed Gd hotspots with increased P and Ca concentrations at the intimomedial interface, and a size distribution ranging from a few micrometers to submicrometers. Conclusions: Eu-VSOP and Gd have distinct spatial distributions in atherosclerotic plaques. While Eu-VSOP distribution is more cell-associated and might be used to monitor atherosclerotic plaque progression, Gd distribution indicates arterial calcification and might help in characterizing plaque vulnerability

Rapid, direct and non-destructive assessment of fossil organic matter via microRaman spectroscopy

Raman spectroscopy is widely used to evaluate the nature and potential origins of carbonaceous matter in Earth's oldest rocks and minerals. It is also the tool that will be used for organic detection on the next vehicles to remotely explore the surface of Mars. Here we present, for the first time, a novel quantitative method in which previously neglected Raman spectral features are correlated directly, linearly, and with excellent accuracy, to the microchemistry of carbonaceous materials through the elemental H:C ratio, regardless of contamination. We show applicability and predictive capabilities of this methodology in evaluating H:C ratios between 0.01 and 0.65 in Archean and type III kerogens. We demonstrate its application to chemical microRaman mapping by statistical analysis of a 750Ma microfossil and its encompassing sediments. Raman-derived H:C data can also be used to estimate the degree to which kerogen C-isotopic data has been shifted from its original values due to the effects of metamorphism. The new methodology directly and non-invasively affords spatially resolved assessments of organic matter preservation and microscale chemical diversity within any geologically preserved terrestrial or extraterrestrial sample, including in the use of organic matter in technological applications.Organismic and Evolutionary Biolog

Heterogeneity of free and occluded bitumen in a natural maturity sequence from Oligocene Lake Enspel

Sedimentation in Oligocene Lake Enspel was rapidly terminated by a basaltic lava flow. This introduced a preservational barrier while imparting a ‘natural flash pyrolysis’, during which the organic matter in underlying stratigraphic units was subjected to rapid thermal maturation resulting in hydrocarbon generation. Samples from these strata exhibit a steep maturity gradient (0.25–1.07% optical vitrinite reflectance, or RO) over uniform organofacies. This offers the opportunity to investigate bitumen generation during rapid thermal maturation mechanistically, in particular the nature of Bitumen 2—occluded bitumen, which is only recoverable after the digestion of the mineral matrix and was frequently dismissed as an artifact of incomplete extraction. Elaborate sequential extraction of the contact metamorphic sequence of oil shales at Enspel revealed systematic changes in bitumen composition. These trend progressively towards those of occluded bitumen, which exhibits a systematically elevated thermal maturity, a higher degree of catalytic biomarker-rearrangement and the conspicuous absence of molecular signatures from vascular plants that are present in the free bitumen. One plausible explanation involves a contribution of allochthonous clay-adsorbed organic matter to Bitumen 2. This could represent a mixture of older reworked bitumen and an early-diagenetic snapshot of clay adsorbed organic matter. Alternatively, a close association of early-generated bitumen with clay minerals may have led to enhanced isomerization and catalytically influenced ‘uniformization’ of alkane signatures. Deviations from the expected relationships between various thermal maturity parameters suggest variable dependence on the time-pressure-temperature pathway (i.e. metamorphic facies). The maturation of organic matter likely behaves differently under a contact metamorphic regime or during rapid subsidence and exhumation, as compared to slow maturation during regional subsidence. Our data also suggest that geologically brief shallow intrusive or extrusive magmatism might not be as destructive to the sedimentary hydrocarbon inventory as hitherto thought. This study draws attention to the small-scale compositional heterogeneity of bitumen that can be studied using sequential extraction methods. More importantly, it suggests that occluded bitumen could potentially harbor information on organic matter that pre-dates in situ primary productivity and may be derived from allochthonous biomass and detrital input

Ancient steroids establish the Ediacaran fossil Dickinsonia as one of the earliest animals

The enigmatic Ediacara biota (571 million to 541 million years ago) represents the first macroscopic complex organisms in the geological record and may hold the key to our understanding of the origin of animals. Ediacaran macrofossils are as “strange as life on another planet” and have evaded taxonomic classification, with interpretations ranging from marine animals or giant single-celled protists to terrestrial lichens. Here, we show that lipid biomarkers extracted from organically preserved Ediacaran macrofossils unambiguously clarify their phylogeny. Dickinsonia and its relatives solely produced cholesteroids, a hallmark of animals. Our results make these iconic members of the Ediacara biota the oldest confirmed macroscopic animals in the rock record, indicating that the appearance of the Ediacara biota was indeed a prelude to the Cambrian explosion of animal life.The study is funded by Australian Research Council grants DP160100607 and DP170100556 (to J.J.B.), Russian Foundation for Basic Research project 17-05-02212A (A.I. and I.B.), and the Max-Planck-Society (C.H.). I.B. gratefully acknowledges an Australian Government Research Training Program stipend scholarship, and B.J.N. acknowledges a Geobiology fellowship of the Agouron Institute