Chemical and isotopic characterization of hydrocarbon gas traces in porewater of very low permeability rocks: The example of the Callovo-Oxfordian argillites of the eastern part of the Paris Basin     

Alain Prinzhofer  Jean Pierre Girard  Stphane Buschaert  Yvon Huiban  Sonia Noirez 《Chemical Geology》2009,260(3-4):269-277

A methodology has been developed to determine chemical and carbon isotopic compositions of trace amounts of hydrocarbon gas compounds (methane, ethane, propane, iso- and normal-butane) present as dissolved compounds in the porewater of the low permeability Callovo-Oxfordian argillites in eastern Paris Basin, France. Results indicate that the studied hydrocarbons contain significant amounts of ethane, butane and propane, in addition to methane. Carbon isotopic compositions reflect primarily thermogenic origin (thermal cracking of organic matter), and lack of any significant biodegradation. Because temperature did not exceed 50 °C in the studied argillites, investigated hydrocarbons must have originated in hotter/deeper organic-bearing formations, possibly Stephanian coals. Data supports the predominance of high maturity thermogenic gas in the upper part of the Callovo-Oxfordian, and low maturity thermogenic gas mixed with minor bacterially produced methane in the lower part of the formation. A mixing between three end-member gases models quite well the data: one thermogenic gas with a low maturity (42% methane, with a δ¹³C of − 53‰), a gas with higher maturity (55% methane, with a δ¹³C of − 47‰) and a bacterial gas (99.45% methane, with a δ¹³C of − 80‰). This study illustrates that migration of hydrocarbon gases can take place in rocks with very low permeability and porosity, such as compacted mudrocks, given enough time. It further suggests that the studied fluid migration and transfer in aquitards would help characterization and understanding of fluid movements in sedimentary basins, as a complement to studies focused on water aquifers and hydrocarbon reservoirs. Chemical and isotopic composition of dissolved hydrocarbons in porewater can be used as natural tracers of fluid circulation in sedimentary basins, in addition to more conventional tracers.  相似文献   

Marine pollution control in Europe: Regional approaches, 1972–80     

Sonia Boehmer-Christiansen 《Marine Policy》1984,8(1):44-55

This article evaluates the effectiveness of four regional pollution agreements concluded during the 1970s: The Bonn Agreement, the Oslo Convention, the Paris Convention and the Helsinki Convention. The treaties are described and their implementation to 1980 outlined. The issue of EEC participation in environmental protection in Europe is analysed and problems of overlap with the treaties under discussion are pointed out. A major conclusion of the article is the need for more implementation research to properly assess the effectiveness of such regional agreements.  相似文献   

A multi-disciplinary study of the 2002–03 Etna eruption: insights into a complex plumbing system     

Daniele Andronico  Stefano Branca  Sonia Calvari  Michael Burton  Tommaso Caltabiano  Rosa Anna Corsaro  Paola Del Carlo  Gaetano Garfì  Luigi Lodato  Lusia Miraglia  Filippo Murè  Marco Neri  Emilio Pecora  Massimo Pompilio  Guiseppe Salerno  Letizia Spampinato 《Bulletin of Volcanology》2005,67(4):314-330

The 2002–03 Mt Etna flank eruption began on 26 October 2002 and finished on 28 January 2003, after three months of continuous explosive activity and discontinuous lava flow output. The eruption involved the opening of eruptive fissures on the NE and S flanks of the volcano, with lava flow output and fire fountaining until 5 November. After this date, the eruption continued exclusively on the S flank, with continuous explosive activity and lava flows active between 13 November and 28 January 2003. Multi-disciplinary data collected during the eruption (petrology, analyses of ash components, gas geochemistry, field surveys, thermal mapping and structural surveys) allowed us to analyse the dynamics of the eruption. The eruption was triggered either by (i) accumulation and eventual ascent of magma from depth or (ii) depressurisation of the edifice due to spreading of the eastern flank of the volcano. The extraordinary explosivity makes the 2002–03 eruption a unique event in the last 300 years, comparable only with La Montagnola 1763 and the 2001 Lower Vents eruptions. A notable feature of the eruption was also the simultaneous effusion of lavas with different composition and emplacement features. Magma erupted from the NE fissure represented the partially degassed magma fraction normally residing within the central conduits and the shallow plumbing system. The magma that erupted from the S fissure was the relatively undegassed, volatile-rich, buoyant fraction which drained the deep feeding system, bypassing the central conduits. This is typical of most Etnean eccentric eruptions. We believe that there is a high probability that Mount Etna has entered a new eruptive phase, with magma being supplied to a deep reservoir independent from the central conduit, that could periodically produce sufficient overpressure to propagate a dyke to the surface and generate further flank eruptions.Editorial responsibility: J. Donnelly-Nolan  相似文献   

The Impact of Erosion on Soil Productivity—An Experimental Design Applied in São Paulo State, Brazil     

Anna Tengberg  Michael Stocking  & Sonia Carmela Falci Dechen 《Geografiska Annaler: Series A, Physical Geography》1997,79(1-2):95-107

Soil erosion is the principal threat to agricultural sustainability, affecting both the characteristics of the in situ soil and its productive potential. However, soils vary in their resilience and there are very few empirical data upon which to appreciate the degree and type of impact on the soil caused by erosion. This paper describes an experiment designed to generate such data based on soil loss and runoff plots, and it reports on nearly nine years of experience with the design at the Instituto Agronômico, Campinas, Brazil on a Latosol (Oxisol). After seven years of erosion induced by four levels of artificial cover, the effective rainfall on the most eroded soil was 20 percent less than on the control full cover. Crop yields were also found to be significantly affected: in 1995 by nearly 700 kg/ha and in 1996 by over 1000 kg/ha—a 50% decline in yield, amounting to a loss of 4 kg/ha of maize per tonne of cumulative soil loss. Losses of nutrients (organic C, P, K, Ca and Mg) in the runoff and eroded soil were also significant with far higher levels of loss associated with the eroded sediment. Changes in the in situ soil were less clear, but a test of trends showed that the decreases in organic matter and increases in acidity could unambiguously be attributed to soil erosion. Average enrichment ratios of the eroded sediment were 1.3 for organic C, 2.6 for P, 0.7 for K, 1.3 for Ca and 1.2 for Mg. Erosion has also affected the maize quality—mainly N, Ca and B nutrient content. Through these various measures, we conclude that seven years of induced erosion has had a marked effect on soil productivity, and for the first time we are now in a position to begin calculating the financial impact of the erosion process on future yields and farmer livelihoods.  相似文献   

On the origin of some mica-lamprophyres: experimental evidence from a mafic minette   总被引：7，自引：3，他引：7  

Sonia Esperança  John R. Holloway 《Contributions to Mineralogy and Petrology》1987,95(2):207-216

Experimental melting relationships for a mafic minette (mica-lamprophyre) from Buell Park, Arizona were determined under fO₂ conditions equivalent to the ironwüstite-graphite and quartz-fayalite-magnetite buffers, at pressures of 10–20 kbar. A comparison between experimental products and phenocrysts in the most primitive minettes indicates that those lavas preserve a near-liquidus assemblage of olivine, diopside and Ti-rich phlogopite crystallized in the upper mantle under fO₂QFM and in the presence of an H₂O-bearing fluid phase. It is suggested that micalamprophyric (minette) magmas may originate from a metasomatized, garnet-bearing peridotitic source at deeper levels in the mantle (P20 kbar) but can also be in equilibrium with a phlogopite-bearing wehrlite (±opx) source at pressures of 17–20 kbar, under reducing or oxidizing mantle conditions. Owing to their rapid crystallization rate and high liquidus temperatures, a series of potassic daughter melts (potassic latites and felsic minettes) can be formed by segregation from mafic minette parents during their ascent through the cooler continental crust. The preservation of olivine in equilibrium with phlogopite phenocrysts in primitive minettes precludes a petrogenetic process dominated by assimilation/fractional crystallization in a shallow magma chamber and supports a model by which some lamprophyric magmas are brought to near surface conditions at temperatures in the range of 1,000–1,200° C and chilled rapidly.  相似文献   

Rare earth elements as tracers of sediment contamination by phosphogypsum in the Santos estuary,southern Brazil     

Sonia Maria Barros de Oliveira  Paulo Sergio Cardoso da Silva  Barbara Paci Mazzilli  Deborah Ines Teixeira Favaro  Catia Heloisa Saueia 《Applied Geochemistry》2007

In the Cubatão region, southern Brazil, sediments are transported by several rivers from the Serra do Mar Ridge into the Santos estuary. Fertilizer plants have been operating along the margins of one of these rivers (Mogi River) producing a large volume of phosphogypsum, which is stockpiled in nearby areas. Surface sediments of the Mogi River were sampled upstream and downstream in relation to the point where the effluents of the phosphogypsum piles flow into the drainage system. In the vicinity of this point one sediment core was collected. Results show that REE, Ba, Zr and Th concentrations in the non-contaminated sediments are of the same order as those present in the upper continental crust. The contaminated samples present a composition affected by that of the phosphogypsum, marked by a higher concentration of these elements and a stronger degree of REE fractionation. These phosphogypsum characteristics are inherited from the Catalão igneous phosphate ore and were moderately modified by the industrial process of phosphoric acid production. The phosphogypsum signal decreases rapidly downstream, pointing to a limited area of influence of the stacks. The deepest sediments of the core are also free of contamination, representing a time interval prior to the deposition of phosphogypsum wastes on the banks of the estuary.  相似文献   

Modelling of 2016 Kumamoto earthquake by integrating site effect in semi-empirical technique     

Devi  Sonia  Sandeep  Kumar  Parveen  Monika  Joshi  A. 《Natural Hazards》2022,111(2):1931-1950

Natural Hazards - The 2016 Kumamoto earthquake (MJMA7.3) struck central area of Kyushu Island, Japan. The presence of near surface low velocity layer greatly amplified the ground motions and caused...  相似文献   

Magmatic source and metamorphic grade of metavolcanic rocks from the Granjeno Schist: was northeastern Mexico a part of Pangaea?     

Sonia Alejandra Torres Snchez  Carita Augustsson  Jos Rafael Barboza Gudio  Uwe Jenchen  Juan Alonso Ramírez Fernndez  Michael Abratis  Anders Scherstn 《Geological Journal》2016,51(6):845-863

The geochemistry of the metavolcanic rocks from the Granjeno Schist in northeastern Mexico indicates an origin in different tectonic environments: mid‐ocean ridge and ocean island. High ratios of Hf/Th and Th/Nb (4.4–14 and 0.08–0.15), low ratios of LaN/YbN and LaN/SmN (0.74–1.7 and 0.60–1.4) and depleted LREE patterns in metabasalt display mid‐ocean ridge characteristics. In contrast, the pattern of trace‐element ratios and REEs in metabasalt and metapillow lava 60 km to the west indicates a magma source with ocean‐island basalt characteristics. Both areas were metamorphosed during the Late Carboniferous (300 ± 4 Ma). Estimated metamorphic conditions deduced from white mica and chlorite compositions, distinguish greenschist facies (350 °C and 4 kbar) for the mid‐ocean ridge basalt, and prehnite–pumpellyite facies (250 °C and 2.5 kbar) for the ocean‐island‐type basalt. This metamorphism took place at an active continental margin during Pennsylvanian time. Our new tectonic model, which differs from earlier models, suggests that the origin of the Granjeno Schist is related to a subduction zone located at the western margin of Pangaea, active after Laurentia–Gondwana collision. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

A plausible link between the asteroid 21 Lutetia and CH carbonaceous chondrites          下载免费PDF全文

Carles E. Moyano‐Cambero  Josep M. Trigo‐Rodr¯guez  Jordi Llorca  Sonia Fornasier  Maria A. Barucci  Albert Rimola 《Meteoritics & planetary science》2016,51(10):1795-1812

A crucial topic in planetology research is establishing links between primitive meteorites and their parent asteroids. In this study, we investigate the feasibility of a connection between asteroids similar to 21 Lutetia, encountered by the Rosetta mission in July 2010, and the CH3 carbonaceous chondrite Pecora Escarpment 91467 (PCA 91467). Several spectra of this meteorite were acquired in the ultraviolet to near‐infrared (0.3–2.2 μm) and in the midinfrared to thermal infrared (2.5–30.0 μm or 4000 to ~333 cm⁻¹), and they are compared here to spectra from the asteroid 21 Lutetia. There are several similarities in absorption bands and overall spectral behavior between this CH3 meteorite and 21 Lutetia. Considering also that the bulk density of Lutetia is similar to that of CH chondrites, we suggest that this asteroid could be similar, or related to, the parent body of these meteorites, if not the parent body itself. However, the apparent surface diversity of Lutetia pointed out in previous studies indicates that it could simultaneously be related to other types of chondrites. Future discovery of additional unweathered CH chondrites could provide deeper insight in the possible connection between this family of metal‐rich carbonaceous chondrites and 21 Lutetia or other featureless, possibly hydrated high‐albedo asteroids.  相似文献   

Esterification of vertebrate-like steroids in the eastern oyster (Crassostrea virginica)     

Janer G  Mesia-Vela S  Wintermyer ML  Cooper KR  Kauffman FC  Porte C 《Marine environmental research》2004,58(2-5):481-484

The esterification of two model vertebrate steroid hormones - estradiol (E2) and dehidroepiandrosterone (DHEA) - was studied in the oyster Crassostrea virginica. The activity of acyl-CoA:steroid acyltransferase was characterized in microsomal fractions isolated from oyster digestive glands. The apparent Km and Vmax values changed with the fatty acid acyl-CoA used (C20:4, C18:2, C18:1, C16:1, C18:0 or C16:0), and were in the range of 9-17 microM, and 35-74 pmol/min/mg protein for E2, and in the range of 45-120 microM, and 30-182 pmol/min/mg protein for DHEA. Kinetic parameters were also assessed in gonadal tissue. The enzyme saturated at similar concentrations, although conjugation rates were lower than in digestive gland. Preliminary data shows that tributyltin (TBT) in the low microM range (1-50) strongly inhibits E2 and DHEA esterification, the esterification of E2 being more sensitive to inhibition than that of DHEA. Overall, results indicate that apolar conjugation occurs in oysters, in both digestive gland and gonads, at a very similar rate to mammals, suggesting that this is a well conserved conjugation pathway during evolution. Esterification, together with other mechanisms, can modulate endogenous steroid levels in C. virginica, and might be a target for endocrine disrupters, such as TBT.  相似文献