Chlorine stable isotope ratios as tracer for pore‐water advection rates in a submarine gas‐hydrate field: implication for hydrate concentration

At Ocean Drilling Program Site 997 in Blake Ridge gas‐hydrate field in West Atlantic, pore‐water studies revealed a pronounced downward depletion of the heavy chlorine isotope to nearly ?4‰δ³⁷Cl at approximately 750 m below sea floor (mbsf) associated with a 10% downward chlorinity decrease. This is one of the stronger ³⁷Cl depletions hitherto reported for marine pore waters. Chlorinity reductions in hydrate‐bearing sediments commonly result from fresh‐water release by hydrate melting. However, in situ measurements at Site 997 suggest that >50% of the chlorinity reduction occurred prior to hydrate dissociation. Modeling the chlorinity profile shows that advection of a strongly ³⁷Cl‐depleted, low‐chlorinity water (506 mm ) from below the drilled sequence can explain the reduction prior to sampling. Fitting the model to the δ³⁷Cl curve yielded an advection rate of 0.18 mm year^?1. Diffusive mixing with near‐0‰‐δ³⁷Cl paleo‐seawater with maximum chlorinity at shallow subsurface depths (561 mm at approximately 20 mbsf) produced the smooth, steady trend. Separating that part of the freshening caused by advection and diffusion from that due to hydrate dissociation allowed estimation of average hydrate concentrations of 3.8% of the pore space (up to 24.5% in hydrate‐rich layers; near‐100% in rare massive hydrate layers). The deep‐seated source of the ³⁷Cl‐depleted, low‐chlorinity water remains unknown and might be located below the sedimentary section in the oceanic basement.     

Direct evidence of the use of beehive products in pre-Roman Sardinia

Written sources and iconographic evidence suggest that honey and beehive products, used in culinary, medicinal, and technological functions since pre-Neolithic times, were likely known and used in Phoenician and Punic Sardinia. The role of these resources is nonetheless poorly understood because no direct evidence survives on a macroscopic level. Significant advances in the knowledge about beeswax and beehive products processing in the past have been offered in recent decades by organic residue analyses (ORA), an approach that enables the characterisation of surviving chemical compounds or suites of compounds that provide information relating to human activity in the past. The relatively recalcitrant nature of lipid compounds comprising beeswax means that this commodity is among the products that can be unambiguously identified through ORA. Here we present and discuss the results of analyses undertaken on 368 pottery sherds from Phoenician and Punic Sardinia (eighth to third century BCE). These analyses offer direct evidence for the presence of beehive products on the island, suggesting the use of honey for culinary purposes in pots, and possibly connecting one specific vessel category with beeswax decanting during beekeeping and honey production processes. Our results also now clearly illustrate the widespread use of beehive products in pre-Roman Sardinia.     

Study of coal gas wettability for CO2 storage and CH4 recovery

To quantify and rank gas wettability of coal as a key parameter affecting the extent of CO₂ sequestration in coal and CH₄ recovery from coal, we developed a contact angle measuring system based on a captive gas bubble technique. We used this system to study the gas wetting properties of an Australian coal from the Sydney Basin. Gas bubbles were generated and captivated beneath a coal sample within a distilled water‐filled (pH 5.7) pressurised cell. Because of the use of distilled water, and the continuous dissolution and shrinkage of the gas bubble in water during measurement, the contact angles measured correspond to a ‘transient receding’ contact angle. To take into account the mixed‐gas nature (CO₂, CH₄, and to a lesser extent N₂) of coal seam gas in the basin, we evaluated the relative wettability of coal by CH₄, CO₂ and N₂ gases in the presence of water. Measurements were taken at various pressures of up to 15 MPa for CH₄ and N₂, and up to 6 MPa for CO₂ at a constant temperature of 22°C. Overall, our results show that CO₂ wets coal more extensively than CH₄, which in turn wets coal slightly more than N₂. Moreover, the contact angle reduces as the pressure increases, and becomes < 90° at various pressures depending on the gas type. In other words, all three gases wet coal better than water under sufficiently high pressure.     

Unconventional Gas Development: Why a Regional Community Said No

Public concern resulting from unconventional coal seam gas (CSG) exploration and production has become a contentious planning issue in regional Australia, with public concern drawing attention to government planning obligations. To assist Lismore City Council (Northern New South Wales) in its deliberations on the topic, a referendum‐style poll on the issue of CSG industry development was held in conjunction with the local government elections of September 2012. The poll question, ‘Do you support CSG exploration and production in the Lismore City Council area?’, elicited a poll response rate of 97% of eligible voters, of which 87% voted ‘no’. This paper reports the results of an exit poll survey using the Theory of Planned Behaviour to frame motivations behind the poll result, and examines the role of the poll and exit poll survey in providing a process of deliberative democracy in the context of the CSG debate. Key details highlighted by the results were that non‐supporters of CSG exploration were primarily concerned about water quality, while supporters saw the primary benefit being regional employment. Emerging themes of this study are the need for more independent research on potential risks and benefits of CSG developments, increase in institutional transparency, and the development of renewable alternatives. The study concludes that the principles of deliberative democracy involved in the Lismore City Council poll and subsequent exit poll survey have provided an opportunity for a more open discussion and genuine discourse within the CSG debate.     

Changes in sub‐water table fluid flow at the end of the Proterozoic and its implications for gas pulsars and MVT lead–zinc deposits

A fundamental change in the nature of sub‐water table fluid flow occurred at roughly the Proterozoic–Phanerozoic boundary when organic matter began to be buried in sufficient quantities that nonaqueous fluids could occupy a significant fraction of the pore space. This allowed the formation of remarkably durable capillary seals that could trap gas in large portions (hundreds of kilometers) of a basin for hundreds of millions of years. Gas loss from these gas zones can be highly dynamic, especially during gas generation. Under the right circumstances, hundreds of cubic kilometers of gas can be rapidly discharged into adjacent permeable aquifers. In Pennsylvanian/Permian time, the Arkoma Basin may have repeatedly discharged such volumes of gas into the very permeable Cambrian sandstone and karstic carbonate aquifers of the mid‐continent of the United States. This could have displaced brines rapidly enough to form the Mississippi Valley‐type (MVT) lead–zinc deposits of this age that are associated with the Arkoma Basin, heating them only briefly as required by maturity indicators. Sea level rise accompanying the melting of Permian continental glaciers may have triggered the gas expulsion events. This radically new mechanism for the formation of MVT deposits is just one example of the nonlinear dynamics of gas accumulations that are possible since Late Proterozoic time.     

The age of the manager is over? Shale gas fracking and the challenge to the post-political regime for English planning

Planning systems developed through the period of ‘normative’, ‘third way’ neoliberalism were critiqued as being ‘post-political’. Planning systems were developed that bypassed political conflicts through technocratic and consensus-seeking approaches following a so-called ‘end of history’ in which left/right ideological conflicts were deemed settled. Following the North Atlantic financial crisis of 2007/8 though, scholars have begun to question whether this is a suitable critique of planning, and state institutions more generally, as political and economic conditions shift. This paper examines a case of an exemplar post-political planning system: England. The paper identifies three key logics of a ‘post-political regime’ for planning: techno-managerialism, consensus and participation. Through an analysis of texts and interviews of contested planning decisions made over shale gas fracking sites, this paper shows a ‘post-political regime’ for planning facing a crisis of legitimacy as it is challenged by an anti-fracking movement and reactionary interventions from central government. The paper provides an institutional level analysis of the crisis of post-political planning, which has lost legitimacy amidst the slow collapse of normative neoliberalism.     

Klinkenberg gas slippage measurements as a means for shale pore structure characterization

Established techniques that have been successfully used to characterize pore systems in conventional reservoir rocks lack the resolution and scalability required to adequately characterize the nano‐ to micrometer scale pore systems found in shale and cannot be applied on stressed samples. We have therefore investigated the utility of Klinkenberg gas slippage measurements for shale pore structure characterization. In contrast to other approaches, slippage measurements characterize the effective porosity of core samples and can be applied at stress conditions experienced in the reservoir during production. Slippage measurements on horizontally and vertically oriented samples from the Eagle Ford Shale Formation, Texas, USA, at a range of stress states revealed two orders of magnitude in slippage variation over five orders of magnitude permeability range. Slippage measurements are negatively correlated with permeability and follow similar trends to those found in other studies on higher permeability rocks. The samples had varying degrees of slippage anisotropy, which allowed interpretation of the relative contribution of tortuosity and pore size to permeability anisotropy. Slippage and therefore average effective pore size was found to vary up to one order of magnitude at a given permeability, warranting investigation of the significance this might have on flow properties and ultimately hydrocarbon production from shale.     

The Impact of Energy,Transport, and Trade on Air Pollution in China

A team of U.S.- and China-based geographers examines the relationship between China's economic development and its environment by modeling the effects of energy, transport, and trade on local air pollution emissions (sulfur dioxide and soot particulates) using the Environmental Kuznets model. Specifically, the latter model is investigated using spatial econometrics that take into account potential regional spillover effects from high-polluting neighbors. The analysis finds an inverted-U relationship for sulfur dioxide but a U-shaped curve for soot particulates. This suggests that soot particulates such as black carbon may pose a more serious environmental problem in China than sulfur dioxide. Journal of Economic Literature, Classification Numbers: C50, F10, Q43, R40. 4 figures, 3 tables, 47 references.     

Geodynamic processes in the NW Bohemian swarm earthquake region,Czech Republic,identified by continuous gas monitoring

The time series of two continuously operating gas monitoring stations at Oldřišská and Nový Kostel located along seismoactive faults in the epicentral area of the NW Bohemian swarm earthquakes (Czech Republic) are compared with water level fluctuations in two boreholes positioned along these faults and with gas flux variations of a mofette at the Soos mofette field at 9 km distance. The seasonal trend of the monitored CO₂ concentration with a maximum in November and a minimum in March/April is governed by groundwater temperatures, superimposed in spring by soil temperatures. CO₂ concentration variations identified at Oldřišská are also reflected in gas flux variations in the Soos mofette and/or water level fluctuations of two boreholes. Variations in the gas monitoring recordings of station at Nový Kostel are also linked with variations at Oldřišská. In all data sets, diurnal variations generated by earth tides occur, reflecting a daily stress – fault permeability cycle. Additional stress interferes with this cycle. Significant, abrupt changes are attributed to geodynamic processes linked with seismic events, as revealed by local seismicity or by the transient of waves of a strong remote earthquake. Simultaneous variations of the gas concentrations in the Nový Kostel area and in the gas flux in the Soos point to an interconnected hydraulic conductive fault systems present in the northern part of the Cheb Basin. Sharp falls in gas concentration, during or subsequent to, earthquake swarms may reflect fault compression associated with impeded gas migration. However, gas variations also occur in periods without seismic activity, indicating changes in fault permeability were caused by local aseismic fault movements, as revealed by events with opposite trends in the gas recordings at Oldřišská, Nový Kostel and the Soos. Therefore, a mathematical approach to establish a correlation between seismicity and gas geochemical variations is not possible.     

The Clean Energy Dilemma in Asia: Observations on Russia and China

Two American economic geographers and prominent specialists, respectively, in the energy industries and resources of Russia and related economic developments in China, evaluate and supplement the material presented in the preceding paper on the clean energy dilemma in Asia (Wilbanks, 2008). The paper covers changes in the relationship between energy consumption and economic growth globally as well as in Russia and China, Russian oil and gas exports to Asia (more specifically to China), the development of energy resources and production in China, and energy intensities in both countries.