Hydrotalcite-like minerals, containing Mg2+-Al3+-Xn− (Xn− = NO3−, Cl−, SO42−, or CrO42−), Zn2+-Al3+-NO3−, or Zn2+-Cr3+-NO3− ions, were intercalated with Co(CN)63− by an anion exchange method. For most of the minerals examined, the degree of anion exchange was 79–90%. X-ray powder diffraction patterns of the ion-exchanged samples revealed two peaks at about 8° and 11°2θ (CuKα radiation) attributable to reflections from expanded and non-expanded interlayers, respectively. The intensity of the peak at about 8°2θ was a linear function of the degree of anion exchange. The amount of hexane adsorbed onto the anion-exchanged sample increased linearly with the increase in degree of anion exchange. From these results, anions near the edge of the interlayers appear to have been preferentially replaced by Co(CN)63− at a low degree of anion exchange, whereas those at some distance from the edge were replaced only at a high degree of anion exchange. The adsorption capacity of the Co(CN)63−-exchanged sample for hydrocarbons was: hexane ≃ 2-methylpentane ≫ cyclohexane > methylcyclohexane. The adsorption of chain hydrocarbons and cyclic hydrocarbons was different.

A series of organo-montmorillonites and organo-hectorites was prepared by complete ion-exchange from the pure sodium form of the parent smectites. The organic cations were tetramethylammonium, trimethylated quaternary ammonium derivatives of the lysine and of the ornithine methyl esters, quaternarized polyammonium cations, or tetraphenylphosphonium (TPP). These organo-smectites were used as packing material for gas chromatography columns. Mixtures of light hydrocarbons (methane to n-butane; “C1” to “C4”) could be separated. The degree of separation depends on the presence of micropores or of organophilic mesopores. The BET surface area, the micropore and mesopore volumes, as well as the size distribution of micropores and mesopores were measured for several systems. As a general trend, the retention times of the light hydrocarbons decrease with an increase of the micropore volume. In the case of TPP-montmorillonite, characterized by a large mesopore volume but for which no microporosity could be detected, separation of longer linear hydrocarbons (n-pentane to n-octane) could also be achieved.

Empirical relationships between clay mineral transformations and temperature provide a basis for the use of clay minerals as geothermometers. Clay-mineral geothermometry has been applied mainly to diagenetic, hydrothermal, and contact- and burial-metamorphic settings to better understand the thermal histories of migrating fluids, hydrocarbon source beds, and ore and mineral formation.

Quantitatively, the most important diagenetic clay mineral reaction in sedimentary rocks is the progressive transformation of smectite to illite via mixed-layer illite/smectite (I/S). Changes in both the illite/smectite ratio and ordering of I/S, as determined from X-ray powder diffraction profiles, correlate with changes in temperature due to burial depth. Although the smectite-to-illite reaction may be influenced by several factors, reaction progress appears to be strongly controlled by temperature. Studies show that the model proposed by Hoffman and Hower in 1979 is applicable in burial diagenetic settings from about 5 to 330 Ma, and includes most rocks about Miocene to Mississippian in age. Reliability of the I/S geothermometer is, however, dependent upon a good understanding of the rock's original clay-mineral composition.

Changes in the ordering of I/S are particularly useful in the exploration for hydrocarbons because of the common coincidence between the temperatures for the conversion from random-to-ordered I/S and those for the onset of peak, or main phase, oil generation. Here, the utility of the I/S geothermometer is reviewed in hydrocarbon-bearing rocks of Miocene to Mississippian age. Using three common applications, the I/S geothermometer is compared to other mineral geothermometers, organic maturation indices, and grades of indigenous hydrocarbons. Good agreement between changes in ordering of I/S and calculated maximum burial temperatures or hydrocarbon maturity suggests that I/S is a reliable semiquantitative geothermometer and an excellent measures of thermal maturity.

The acidic properties of acid-modified montmorillonite and vermiculite were determined by pyridine and ammonia adsorption to correlate with the alkylating and dehydrating activity of the activated samples. Treatment of the minerals with different concentrations of hydrochloric acid results in the variation of overall acidity and density of acidic sites. Infrared (IR) spectral and differential scanning calorimetric analyses have revealed the presence of Bronsted and Lewis acid sites on the activated samples. The catalytic activity towards the above reaction has been correlated to the acid strength and density of Lewis acid sites. Treatment of montmorillonite with hydrochloric acid in the range of 0.1 and 0.3 M and vermiculite with 0.2 to 0.3 M seemed to be suitable for the conversion of methanol into olefin-rich hydrocarbons. Acid-activated montmorillonite catalyzed the isopropylation of benzene to a maximum extent of 16%, whereas acid-activated vermiculite gave a maximum conversion of only 4%.

A diapiric intrusion of clays in the Carlentini Formation (Tortonian) was discovered in a quarry at S. Demetrio High (Hyblean Plateau, Sicily, Italy). Seven clay samples were analyzed by different analytical methods, including X-ray powder diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy, to determine the composition and mechanism of formation (sedimentary vs. hydrothermal) of these clays. Ferric saponite, carbonates (calcite and traces of ankerite), quartz, pyrite, and zeolites (phillipsite and harmotome) were detected using XRD and FTIR. This mineral assemblage, dominated by Fe-rich saponite, and the abundance of light rare-earth elements (LREE), Eu, fluid-mobile elements (FME > 10 × primordial mantle: Li, Be, B, As, Sb, Pb, U, Ba, Sr, Cs), and other incompatible elements (Zr = 169 ppm, Nb = 46 ppm, Th = 11 ppm, on average) imply that S. Demetrio clays precipitated from a mixture of hot Si-rich hydrothermal fluids (350–400°C) and cold seawater. The evidence is in accord with the affinity of clays for hydrothermally modified mafic and ultramafic rocks, forming the Hyblean lower crust, based on multi-element comparisons, and on the occurrence of trace amounts of chrysotile 2Mc1 and sepiolite. The association of long-chain aliphatic-aromatic hydrocarbons (intensity ratios I2927/I2957 > 0.5) with hydrothermal clays, the lack of fossils, and the similarity of the IR absorption bands with those of organic compounds detected previously in some metasomatized Hyblean gabbroic xenoliths suggest a possible abiogenic origin of hydrocarbons via a Fischer-Tropsch-type reaction. The S. Demetrio clay diapir was emplaced at shallow crustal levels in the Late Miocene as a consequence of the interaction, at a greater depth, of an uprising basalt magma and the products of an early, serpentinite-hosted hydrothermal system.

Tracing interactions during burial-induced organic maturation and associated clay-material alteration is of prime importance for understanding both the individual and combined mineral and organic processes. In the present study the light elements B, Li, O, and H of a sample from oil-prone Eocene Kreyenhagen Shale from San Joaquin Basin (California) were examined. The natural burial-induced temperature increase was simulated by pyrolysis experiments at progressively increasing temperatures (270–365°C) and for varied durations (72–216 h) applied to the whole rock and its <2 μm fraction. The illite structure as well as the K-rich interlayers of the illite-smectite mixed layers were not affected by the pyrolysis experiments and the smectite-rich interlayers did not collapse, while the soluble minerals and the organic matter were altered. The distribution pattern of the rare-earth elements (REEs) from untreated whole rock and of its pyrolyzed equivalents are within analytical uncertainty, which confirms that the changes induced by pyrolysis experiments were minimal in the bulk sample. Conversely, the REEs from the <2 μm fractions were modified significantly, suggesting that the whole rocks and the <2 μm fractions may contain different types of organic materials. Also, only the carbonates, oxides, chlorides, and organic matter were affected together with the smectite-rich interlayers of the illite-smectite structure. Bitumen coating of the smectite interlayers probably increased the amount of B of organic origin in their sites. The δ11B and δ7Li of the successively expelled hydrocarbon phases changed with increasing pyrolysis temperatures, together with the B and Li contents of the hydrocarbon-related fluids. On the basis of the δ11B and δ7Li from pyrolyzed clay fractions, the B released successively was not isotopically homogeneous, probably depending on how the type of organic matter decomposed during the successive pyrolysis steps, and on which components were released. The δ11B of organic-B increased progressively from –2‰ at low experimental temperature up to +9‰ at the highest temperature. The calculated δ7Li that was released also increased relative to the value of the outcropping sample used as a reference, but it remained almost constant from –7‰ at 310°C for 72 h to –8‰ at 365°C for 216 h. The δ18O values of the <2 μm size fractions decreased significantly during pyrolysis above 300°C, but the δD changes were rather modest. The total organic carbon (TOC) remained statistically constant after pyrolysis to 300°C, as did the δ7Li values. The pyrolysis experiments in the present study suggest the presence of bitumen-coated smectite interlayers that could have been misidentified as dehydrated smectite in the literature. Together with abnormal illite K-Ar ages, the occurrence of such bitumen-coated illite-smectite interlayers occurring in source and reservoir rocks could indicate the timing of hydrocarbon maturation relative to illitization.

Providing evidence for possible oil-type occurrences on Mars means providing an indication for the past life on Mars. We do this via analysis of the combed (aligned) gravity strike angles, one of the gravity (gravitational) aspects (descriptors) derived from one of the recent gravitational field models of Mars, currently having the highest accessible precision and resolution. After intensive testing for features on the Earth and the Moon, the gravity aspects are applied for Mars. We detect candidates for the groundwater/hydrocarbon/mud/petroleum-bearing sites in the largest areas with as many as possible combed gravity strike angles, uniformly ordered into ‘plates’. They appear mainly but not only in the hypothetical northern Martian palaeo-ocean (the northern lowlands). It turns out that the combed strike angles are sensitive not only to uniformly ordered sediments of the basins, but also to supposed lahars.

Oil is a metonym for terms in books and articles in diverse disciplines in African studies. Some portray oil as a causal agent that thrusts formerly low-income countries into the highly competitive neoliberal global economy. Others present it according to the oil curse/blessing binary. As a curse, petroleum causes dysfunctional and costly behavior. But increased revenues from oil just as certainly result in concrete improvements demonstrating a resource blessing. Heilbrunn uses case materials to explore environmental degradation, oil theft, community-company relations, post-conflict reconstruction, local content in contracts, and corruption. These key concepts form a basis for the keyword/concept essay on oil in Africa.

The importance of fuel injection methods and their atomisation characteristics has been well described in literature. Also, there are a large number of studies in literature detailing the impact of bulk properties of conventional fuels on atomisation and spray characteristics. However, there is a lack of knowledge on how different alternative fuels, and specifically aromatic species, impact spray and atomisation characteristics. In this investigation, the impact of alternative fuels, selected aromatic species and their properties on spray atomisation was studied. Details of how different aromatic structures, bonds and other micro properties of aromatics species impact spray and atomisation characteristics were investigated. To achieve this objective, testing was conducted using a Rolls-Royce Tay engine fuel injector. It was found that the droplet sizes in the form of the Sauter Mean Diameter (SMD) correlate well with fuel properties including density, viscosity and surface tension, which is in line with other published literature. Moreover, it was found that there are several aromatic species (ethylbenzene, cumene and tert-butylbenzene) which display improved atomisation. This indicates that the size of the aliphatic groups attached to the benzene ring in the aromatic molecule impact on the drop size and thereby the combustion characteristics. The worst performers were polyaromatic naphthalene compounds. With the increasing push for fuels with selected aromatic species in the future, this study provides knowledge on the impact of their on the atomisation characteristics.

The studied seep carbonates from Tsushima, Japan, are embedded within marine siliciclastics of the lower Miocene Taishu Group and represent the earliest evidence of hydrocarbon seepage in the Sea of Japan. In contrast to Miocene and Pliocene examples from Honshu, which are often found above anticlines, the seeps from Tsushima formed within a pull-apart basin before major anticlines had formed. The three carbonates from Fukuzaki, Kanoura and Tanohama are composed chiefly of calcite, with significant admixture of ankerite only at Kanoura. The stable carbon isotope composition of calcites (δ13C as low as −40.2 ‰ VPDB for Fukuzaki, −41.8 ‰ VPDB for Kanoura, and −52.8 ‰ VPDB for Tanohama) indicate methanogenic origin of the carbonates. Textures of these deposits, including radiaxial and yellow cements, are indicative of formation at a methane seep. The stable oxygen isotope composition of calcites (δ18O values as low as −14.4 ‰ VPDB for Fukuzaki, −14.5 ‰ VPDB for Kanoura and −13.9 ‰ VPDB for Tanohama) indicate that they were influenced by burial fluids. Burial diagenesis is also indicated by the stable isotopic compositions of ankerite (δ13C ranging from −19.1 ‰ to −7.1 ‰ VPDB, δ18O from −11.1 ‰ to −9.7 ‰ VPDB). Molecular fossils from Tanohama comprise n-alkanes with short-chain predominance, interpreted to have formed due to thermal cracking of organic matter. The carbonates yield a chemosynthesis-based community comprising vesicomyids Pleurophopsis chitanii, P. cf. hamuroi, the bathymodiolin ‘Bathymodiolus’ akanudaensis, the lucinid Lucinoma sp. and the provannid Provanna? sp., which have never been hitherto identified. ‘Bathymodiolus’ akanudaensis, Lucinoma sp. and Provanna? sp. are the oldest records of these taxa in the Sea of Japan.

Owing to soaring energy needs and improved drilling technology, offshore hydrocarbon activities have been on the rise in recent years. A delimited maritime boundary is an essential precondition for the establishment of a safe and stable environment which will facilitate investment and development. Nevertheless, the conclusion of delimitation agreements can be a difficult task due to competing interests and long-standing enmities among neighbouring countries. Significant maritime areas remain undelimited. In order to avoid the problems of both unilateral activities and a complete ‘moratorium’ in undelimited areas, Articles 74(3) and 83(3) of the 1982 United Nations Convention on the Law of the Sea impose two obligations of conduct: pending delimitation agreement, States are under duty to ‘make every effort to enter into provisional arrangements of a practical nature’, while, at the same time, the interested parties should refrain from acts that might ‘jeopardize or hamper the reaching of the final agreement’. Bearing this in mind, it is argued that unilateral drilling and, under certain circumstances, unilateral seismic surveys in undelimited maritime areas should not be allowed and such conduct might trigger State responsibility. However, given that complete inactivity in such areas was not the intention of the drafters of the Convention, it is argued that several activities may be permitted as long as they are performed in good faith and do not put any final agreement at risk.

Hydrocarbons (bitumens sensu lato) in sandstones have been recorded in several instances to have partially replaced their host rock, including quartz grains. Many replacive hydrocarbons are uranium-rich: associated non-uraniferous hydrocarbons are not replacive. Uranium is transported as carbonate complexes, which may be decomposed by organic acids to yield UO22+ ions and CO2. The UO22+ will be absorbed onto hydrocarbons before reduction to a mineral phase, generally uraninite; and the CO2 may be aggressive towards the silicate grains of the host sandstone. Accretionary nodules of replacive uraniferous hydrocarbon in red beds (e.g. at the cores of reduction spots) can provide valuable information about petroleum migration. They occur particularly in the vicinity of faults, and may record the interactions between metal-rich groundwaters and hydrocarbons leaking along a fault from an underlying reservoir. A trial study in Devonian sandstones of Easter Ross successfully traced a hydrocarbon-bearing sandstone reservoir from an occurrence of uraniferous hydrocarbon nodules.

Degradation of contaminant hydrocarbons in groundwater by microbially mediated oxidation, linked to the reduction of electron acceptors, is fundamental to the strategy of ‘monitored natural attenuation’ (MNA) for oxidizable hydrocarbons, which is increasingly being adopted at polluted aquifer sites throughout Europe and North America. Commonly, oxygen is depleted and following the reduction of nitrate, solid-phase Fe oxides become the dominant electron acceptors. Arsenic, associated with Fe and Mn oxides in soils and sediments, may therefore be mobilized to groundwater and pose an additional threat to environmental receptors. In a pilot study of three aquifers in England, we have examined the extent to which arsenic is released to groundwater under Fe(III)-reducing conditions imposed by contaminant hydrocarbons. Results show that arsenic is locally mobilized in the Chalk to <10 μg/1, in Quaternary gravels to 70 μg/1 and in the Triassic sandstones to 160 μg/1. At the Chalk and Quaternary gravels sites arsenic mobilization is demonstrably linked to reduction of Fe- and Mn-oxides. This is not so at the Triassic sandstone site, where release of arsenic is related to elevated bicarbonate alkalinity. Redox-driven arsenic mobilization at other Triassic sandstone locations is possible. Further work is required on the solid-phase sources of arsenic in the aquifers, and to relate the hydrochemical observations to groundwater hydraulic conditions.

Nanodiamonds can be synthesized hydrothermally in the laboratory by using a C-O-H fluid in the graphite stability field, in which the graphite/nanodiamond transition depends on the crystal size as a function of temperature. In nature, the hydrothermal circulation of seawater in serpentinites plays an important role in the carbon speciation in the oceanic crust and exposed mantle, in which hydrocarbons (mainly CH4) of abiogenic origin (via Fischer-Tropsch-type reaction) and occasionally graphite particles are detected. Can nanodiamonds nucleate and grow in serpentinite-hosted hydrothermal systems? To answer this question, a theoretical modelling study which compares the physico-chemical conditions in hydrothermal synthesis with those observed in modern and fossil serpentinite-hosted hydrothermal systems is proposed. Nanodiamonds are predicted to precipitate from a C-O-H fluid, consisting of CH4-CO2-H2O at 350 – 400°C and P<0.2 GPa near the FMQ buffer (Fayalite-Magnetite-Quartz), which are conditions compatible with those existing in serpentinite-hosted hydrothermal systems. In these environments, carbon-supersaturated fluids can be derived from water consumption (serpentine formation) under low water/rock ratios, which may promote the growth of nanodiamonds. This theoretical approach sheds light on the intriguing problem of carbon speciation in abyssal-type hydrothermal systems, suggesting that serpentinites may host nanodiamond deposits, even though none have been found yet.

Uraniferous bitumens from Great Britain, Scandinavia and South Africa have been studied by oilimmersion reflected-light microscopy and categorised into those formed either by replacement of preexisting uraninite and pitchblende or by complexation/reduction mechanisms in pre-existing hydrocarbons. The former are characterised by displaying normal replacive textures, and containing high concentrations of non-mineral-bound uranium, or later, occasionally exotic, uraniferous fracturefilling phases. Uraniferous bitumens formed during complexation/reduction reactions display monotonous mineralogies and ordered mineral-inclusion distributions.

Radiolytic alteration of uraniferous bitumens induces both chemical and mechanical alteration. Early alteration is marked by the generation of mobile hydrocarbons during 'cracking reactions' with subsequent within-sample migration to form globular bitumens and dendritic interspersions of mineralrich and -poor uraniferous bitumen. Mobile hydrocarbons may act as lubricants during mechanical deformation. Advanced organic alteration is characterised by well-documented increased reflectance around uraniferous grains, and by fracturing of the bitumens.

A method of base metal exploration in sedimentary rocks which depends on detecting anomalous amounts of the light hydrocarbon gas methane in the host rocks has been applied in a number of orientation surveys in the British Isles and in Europe. The results of these studies are described, and the limitations of the method discussed. It is suggested that the principal difficulty lies in the extraction technique which is based on heating, and alternative methods are proposed. The preliminary results from these new methods are discussed and compared with those from the original study. A number of the samples analysed by the new methods are calcites of differing diagenetic origins. It is postulated that the differences in methane found in these samples may give a clue to the organic geochemistry of the rocks at the time when the calcites were deposited.