Measuring Rates of Biodegradation in a Contaminated Aquifer Using Field and Laboratory Methods   总被引：5，自引：0，他引：5  

Francis H. Chapelle  Paul M. Bradley  Derek R. Lovley  Don A. Vroblesky 《Ground water》1996,34(4):691-698

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The Annual Earthquake Prediction Conference in China (National Consultative Meeting on Seismic Tendency)   总被引：2，自引：0，他引：2  

Francis T. Wu 《Pure and Applied Geophysics》1997,149(1):249-264

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Evaluation of a Carbon Adsorption Method for Sampling Gasoline Vapors in the Subsurface     

Edward D. Wallingford  Francis A. DiGiano  Cass T. Miller 《Ground Water Monitoring & Remediation》1988,8(4):85-92

Monitoring of the vapor phase has emerged as a very convenient method for detecting volatile organic contaminants in the subsurface. It can provide a reliable way of placing ground water monitoring and recovery wells. The most common method uses a driveable ground probe (DGP) to extract a vapor-phase sample followed by direct injection of the vapor into a portable gas chromatograph (GC). However, many regional offices of regulatory agencies and consultants do not have ready access to such equipment. This research explores an alternative–the carbon adsorption method—in which the vapor is withdrawn by the DGP but concentrated on a small activated carbon trap (150mg). The carbon traps can be returned to a central laboratory for solvent extraction and GC analysis. This provides the advantages of increased sensitivity, reduction in field equipment and convenience of in-lab analyses (multiple GC injections are possible). A simple DGP and carbon trap system was constructed and tested at a field site. Vapor-phase concentrations of target compounds present in gasoline were mapped quite conveniently, ranging from 10,000μg/liter (vapor phase) to less than 10μg/L. These concentrations were also shown to decrease in the direction of the ground surface, as expected. Measurements of target compounds in soil showed that the vapor phase contributed a large fraction of the total contaminant burden where a non-aqueous-phase layer (NAPL) had been identified; as important, however, is the rather uniform contamination of the soil outside the NAPL region. Finally, the concentrations of target compounds in the vapor phase and ground water could be related in a manner roughly described by a simple equilibrium model, although exceptions were noted.  相似文献   

The 16 September 1986 eruption of Lascar volcano,north Chile: Satellite investigations     

L. S. Glaze  P. W. Francis  S. Self  D. A. Rothery 《Bulletin of Volcanology》1989,51(3):149-160

Landsat Thematic Mapper (TM) images acquired in 1984 and 1985 revealed a pronounced thermal anomaly on Lascar volcano, north Chile. Subsequent images showed that the anomaly was persistent but variable and that after a significant eruption on 16 September 1986 it was weaker and divided into several sources. TM studies and other observations of Lascar indicate that the persistent thermal anomaly may be due to high-temperature fumaroles within the summit crater. GOES weather satellite images and field investigations confirm that the 16 September event was a short-lived, Vulcanian-type eruption, which produced an ash column that reached 15 km altitude. The ash cloud can be tracked on GEOS images to about 400 km downwind and covered an area > 112 000 km². Transport occurred in the upper troposphere at speeds up to 180 km/h. Ash fall from the plume was well sorted and moderately fine grained (Md 200 µm). Formation and fallout of ash as aggregates was unimportant in the deposition of the ash layer. Although small, the Lascar 16 September eruption is significant because few historic eruptions have been recorded in the central Andes. Little would have been known of the eruption in the absence of remote-sensed data.  相似文献   

Nitrogen-Isotope Ratios of Nitrate in Ground Water Under Fertilized Fields, Long Island, New York   总被引：5，自引：0，他引：5  

William J. Flipse  Jr.  Francis T. Bonner 《Ground water》1985,23(1):59-67

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Precise lead isotope measurements by the double spike technique: A reconsideration   总被引：1，自引：0，他引：1  

Bruno Hamelin  Gérard Manhes  Francis Albarede  Claude J. Allègre 《Geochimica et cosmochimica acta》1985,49(1):173-182

A reappraisal of the “Double Spike Method” for correction of the mass discrimination in lead isotope analysis is presented in view of the possible efficiency of this method, especially as related to the improved performance of the new multi-collector mass spectrometers.First, the effects of mass discrimination during lead isotope analysis, using the silica-gel phosphoric acid method, are discussed in order to verify the validity of the linear discrimination law. In this discussion, we give evidence of a slight bias of the isotopic composition of the SRM 981 NBS lead standard, commonly used for mass discrimination calibrations.A rigorous way to deal with the propagation of the within-run statistical errors on the precision of the double spike correction is then presented. This allows the optimization of the parameters of the method (spike isotopic composition and precision, spiking proportion) and the calculation of the respective error associated with each corrected isotopic ratio. The perturbation of the double spike correction due to analytical contamination, which has caused previous failure in the application of the method, is avoided by preparation of the mixture between the spike and the sample at the very end of the chemical separation procedure.Using a single collector mass spectrometer, examples of application on lead standards and on a set of samples suggest a possible improvement in the precision by a factor of 3 compared to the usual method of fractionation normalization and confirm the usefulness of the method with the new generation of mass spectrometers.  相似文献   

The assessment of REE patterns and Nd/Nd ratios in fish remains     

Patricia Grandjean  Henri Cappetta  Annie Michard  Francis Albare&#x;de 《Earth and Planetary Science Letters》1987,84(2-3)

The REE content and isotopic composition of Sr and Nd have been determined in fish teeth ranging in age from the Trias to the present and from various localities mostly around the Atlantic. These measurements have been carried out on Selachian and Teleost remains from the same locality in Togo and show no appreciable difference, which suggests, with the help of a mass balance calculation of the Ce anomaly, that diagenetic effects are not responsible for the REE enrichment of biogenic phosphates.One group of fossil teeth has about 3 times the REE abundances of shale and a shale-normalized pattern with a minimum at Sm: it is thought to reflect deposition in the open-sea environment. A second group has REE concentration about 10 times higher than the first group with either a regular light REE enrichment or, more frequently, a maximum in the middle REE, both being probably indicative of deposition in estuarine or near-shore conditions. The shape of the REE spectra and the size of the Ce anomaly can be used semi-quantitatively to determine the depth of deposition. The results presented here on Late Cretaceous/Eocene fish teeth samples from Morocco reflect an increasing influx of deep waters with a lowLa/Yb ratio and strong negative Ce anomaly, which agrees well with the evolution of sediment chemistry and microfauna associations.In contrast, _Nd is typical of the water mass in which the fish debris decayed. Examples of nearly isolated basins identified with Nd isotopes include the South Atlantic prior to the Lutetian (_Nd ≈ −13.5), the Miocene Persian Gulf (_Nd = −3.1), and Bolivia during the Late Cretaceous (_Nd = −12.8). Togo and Guinea-Bissau results suggest that, in the South Atlantic, the meridional oceanic circulation had not started before 45 Ma ago.Combination of REE and_Nd data suggests that the assignment of Jurassic-Cretaceous samples measured so far to open-sea water masses is still ambiguous.  相似文献   

The deep layers of a Paleozoic arc: geochemistry of the Copley-Balaklala series, northern California   总被引：3，自引：0，他引：3  

Marc Brouxel  Henriette Lapierre  Annie Michard  Francis Albarde 《Earth and Planetary Science Letters》1987,85(4)

REE, Zr, Nb concentrations and Sr, Nd isotope compositions have been measured in Copley basalts and andesites, Balaklala rhyolites, and Mule Mountain trondhjemites (northern California) which represent the deep layers of a well preserved intra-oceanic island arc of Siluro-Devonian age.⁸⁷Sr/⁸⁶Sr is shifted towards high values (up to 0.707) whereas Ce is preferentially removed from rhyolites. A large proportion of the analyzed samples including some acidic rocks shows a pronounced depletion in light REE. The ε_Nd(T) values of most Copley, Balaklala, and Mule Mountain rocks fall in the range +6 to +8 which suggests that they originated from a normal MORB-type source (ε_Nd(T) ≈ +9) contaminated with either sediments or an OIB-type component.In modern island arcs, only the shallow levels are accessible: comparison with the Copley-Balaklala-Mule Mountain Series suggests that, at depth, an immature island arc is likely to comprise thick layers of LILE-depleted tholeiites and rhyolites intensely altered by pervasive circulation of seawater. Least-square solutions of trace element models suggest that rhyolites and trondhjemites represent remelting of mafic volcanics from the arc basement rather than residual melts of basalt-andesite differentiation.  相似文献   

Solid state C NMR studies of selected oil shales from Queensland, Australia     

Francis P. Miknis  Arthur W. Lindner  A. John Gannon  Mark F. Davis  Gary E. Maciel 《Organic Geochemistry》1984,7(3-4)

Solid state ¹³C NMR techniques of cross polarization with magic-angle spinning, and interrupted decoupling have been employed to examine the nature of the organic matter in eight kerogen concentrates representing five Tertiary deposits in Queensland, Australia. The NMR results show that five of the kerogens have high proportions of aliphatic carbon in their organic matter and correspond to Type I–II algal kerogens. Three of the kerogens, derived from carbonaceous shales, have a high proportion of aromatic carbon in their organic matter and correspond to Type III kerogens. The fractions of aliphatic carbon in all the kerogens, regardless of type, are shown to correlate with the conversion characteristics of the corresponding raw shales during Fischer assay. Interrupted decoupling NMR results show the presence of more oxygen-substituted carbon in the carbonaceous shales, which may account for the greater CO₂ evolution and phenolic materials found in the pyrolysis products of the carbonaceous shales.  相似文献   

Sur la structure,l'âge et l'origine des « brèches de Bosmendiette » (Pyrénées-Atlantiques)     

Joseph Canérot  Jacques Bauer  Michel Bilotte  Chantal Bourdillon  Jean-Paul Colin  Elie-Jean Debroas  Françoise Magniez  Francis Mediavilla  Yves Ternet 《Comptes Rendus Geoscience》2004,336(10):951-958

By us considered as Albo-Aptian in age and generated through halokinetic processes, the Bosmendiette breccias have been recently interpreted as Selandian (Palaeocene) globigerine-bearing sediments deposited in sub-marine canyons within a deep trough crossing the Pyrenees, from the Mediterranean Sea to the Atlantic Ocean. These breccias are really azoic in their lower part and contain a scarce microfauna including radolarians and benthic foraminifera at the top of the formation. They are unconformably covered by the Urgo-Aptian limestones and marls and indicate, under opening marine conditions, Lower Cretaceous collapse movements and northward sliding of the Jurassic slumped cover, related to the growth of the Béloscare–Apoura diapir. To cite this article: J. Canérot et al., C. R. Geoscience 336 (2004).  相似文献