Strontium isotope systematics of mixing groundwater and oil-field brine at Goose Lake in northeastern Montana,USA     

Zell E. Peterman  Joanna Thamke  Kiyoto Futa  Todd Preston 《Applied Geochemistry》2012

Groundwater, surface water, and soil in the Goose Lake oil field in northeastern Montana have been affected by Cl⁻-rich oil-field brines during long-term petroleum production. Ongoing multidisciplinary geochemical and geophysical studies have identified the degree and local extent of interaction between brine and groundwater. Fourteen samples representing groundwater, surface water, and brine were collected for Sr isotope analyses to evaluate the usefulness of ⁸⁷Sr/⁸⁶Sr in detecting small amounts of brine. Differences in Sr concentrations and ⁸⁷Sr/⁸⁶Sr are optimal at this site for the experiment. Strontium concentrations range from 0.13 to 36.9 mg/L, and corresponding ⁸⁷Sr/⁸⁶Sr values range from 0.71097 to 0.70828. The local brine has 168 mg/L Sr and a ⁸⁷Sr/⁸⁶Sr value of 0.70802. Mixing relationships are evident in the data set and illustrate the sensitivity of Sr in detecting small amounts of brine in groundwater. The location of data points on a Sr isotope-concentration plot is readily explained by an evaporation-mixing model. The model is supported by the variation in concentrations of most of the other solutes.  相似文献   

Changes of water level in the Eemian palaeolake at Imbramowice (SW Poland) based on isotopic and cladoceran data     

Joanna Miros?aw-Grabowska  Micha? G?siorowski 《Quaternary Research》2010,73(1):143-150

Isotopic and cladoceran investigations of Eemian (MIS 5e) lake sediments from Imbramowice, SW Poland, allow us to reconstruct the environmental conditions, especially changes of water level and trophic status, during the early and middle Eemian Interglaciation. We analyzed the sediments from 6.5 to 11.0 m depth in a core provided by Mamakowa (1989). The upper 6.5 m had insufficient carbonates and cladoceran contents for analyses. The analyzed section consists of sandy and organic silts at the bottom, followed by gyttja characterized by increasing CaCO₃ content. Measured δ¹⁸O values oscillate from ca. - 9 to - 4‰ and δ¹³C from - 3.5 to above + 6‰. Based on stable isotope analyses of carbonates, we define and characterize eight isotopic horizons (Is). We identify 26 taxa of subfossil Cladocera and seven zones (CLZ) of faunal development. Probably the greatest depth of the lake occurred with pollen zone E2; shallowing then took place. During pollen zones E2-E3, gradual warming is observed and expressed through a positive trend in both δ¹⁸O and δ¹³C values. Pollen zone E4 is characterized by frequent changes of water level. During the Eemian Interglaciation, excluding the initial phase of lake evolution, the lake was meso-eutrophic and eutrophic with high phytoplankton productivity.  相似文献   

Determination of particulate organic carbon (POC) in seawater: The relative methodological importance of artificial gains and losses in two glass-fiber-filter-based techniques   总被引：1，自引：0，他引：1  

Robert Turnewitsch  Barbara M. Springer  Konstadinos Kiriakoulakis  Juan Carlos Vilas  Javier Arístegui  George Wolff  Florian Peine  Stephan Werk  Gerhard Graf  Joanna J. Waniek 《Marine Chemistry》2007,105(3-4):208-228

Particulate matter in aquatic systems is an important vehicle for the transport of particulate organic carbon (POC). Its accurate measurement is of central importance for the understanding of marine carbon cycling. Previous work has shown that GF/F-filter-based bottle-sample-derived concentration estimates of POC are generally close to or higher than large-volume in-situ-pump-derived values (and in some rare cases in subzero waters are up to two orders of magnitude higher). To further investigate this phenomenon, water samples from the surface and mid-water Northeast Atlantic and the Baltic Sea were analyzed. Our data support a bias of POC concentration estimates caused by adsorption of nitrogen-rich dissolved organic material onto GF/F filters. For surface-ocean samples the mass per unit area of exposed filter and composition of adsorbed material depended on the filtered volume. Amounts of adsorbed OC were enhanced in the surface ocean (typically 0.5 μmol cm^− 2 of exposed filter) as compared to the deep ocean (typically 0.2 μmol cm^− 2 of exposed filter). These dependencies should be taken into account for future POC methodologies. Bottle/pump differences of samples that were not corrected for adsorption were higher in the deep ocean than in the surface ocean. This discrepancy increased in summer. It is shown that POC concentration estimates that were not corrected for adsorption depend not only on the filtered volume, true POC concentration and mass of adsorbed OC, but also on the filter area. However, in all cases we studied, correction for adsorption was important, but not sufficient, to explain bottle/pump differences. Artificial formation of filterable particles and/or processes leading to filterable material being lost from and/or missed by sample-processing procedures must be considered. It can be deduced that the maximum amounts of POC and particulate organic nitrogen (PON) that can be artificially formed per liter of filtered ocean water are  3–4 μM OC (5–10% of dissolved OC) and  0.2–0.5 μM ON (2–10% of dissolved ON), respectively. The relative sensitivities of bottle and pump procedures, and of surface- and deep-ocean material, to artificial particle formation and the missing/losing of material are evaluated. As present procedures do not exist to correct for all possible biasing effects due to artificial particle formation and/or miss/loss of filterable material, uncertainties of filtration-based estimates of POC concentrations need further testing. The challenge now is to further constrain the magnitude of the biasing effects that add to the adsorption effect to reduce the uncertainties of estimates of POC concentrations, inventories and fluxes in the ocean.  相似文献   

The evolution of the Onaping Formation at the Sudbury impact structure     

Richard A. F. GRIEVE  Doreen E. AMES  Joanna V. MORGAN  Natalia ARTEMIEVA 《Meteoritics & planetary science》2010,45(5):759-782

Abstract– The 1.4–1.6 km thick Onaping Formation consists of a complex series of breccias and “melt bodies” lying above the Sudbury Igneous Complex (SIC) at the Sudbury impact structure. Based on the presence of shocked lithic clasts and various “glassy” phases, the Onaping has been described as a “suevitic” breccia, with an origin, at least in part, as fallback material. Recent mapping and a redefined stratigraphy have emphasized similarities and differences in its various vitric phases, both as clast types and discrete intrusive bodies. The nature of the Onaping and that of other “suevitic” breccias overlying impact melt sheets is reviewed. The relative thickness, internal stratigraphic and lithological character, and the relative chronology of depositional units indicate multiple processes were involved over some time in the formation of the Onaping. The Sudbury structure formed in a foreland basin and water played an essential role in the evolution of the Onaping, as indicated by a major hydrothermal system generated during its formation. Taken together, observations and interpretations of the Onaping suggest a working hypothesis for the origin of the Onaping that includes not only impact but also the interaction of sea water with the impact melt, resulting in repeated explosive interactions involving proto‐SIC materials and mixing with pre‐existing lithologies. This is complicated by additional brecciation events due to the intrusion of proto‐SIC materials into the evolving and thickening Onaping. Fragmentation mechanisms changed as the system evolved and involved vesiculation in the formation of the upper two‐thirds of the Onaping.  相似文献   

Pulsar PSR B2303+30: a single system of drifting subpulses, moding and nulling     

Stephen L. Redman  Geoffrey A. E. Wright  Joanna M. Rankin 《Monthly notices of the Royal Astronomical Society》2005,357(3):859-872

Analyses of multiple pulse sequences of the pulsar PSR B2303+30 reveal two distinct emission modes. One mode (B) follows a steady even–odd pattern and is more intense. The second mode (Q) is characteristically weak, but has intermittent drift bands with a periodicity of approximately 3 P ₁/cycle, and nulls much more frequently than the B mode. Both modes occur with roughly equal frequency, and their profiles have a similar single-humped form with a slight asymmetry. Our observations and analyses strongly suggest that the subpulse drift rates in both modes are linked in a series of cycles, which can be modelled as relaxing oscillations in the underlying circulation rate.  相似文献   

Towards an Understanding of Radial Velocity Shift in Uv Spectra of Symbiotic Stars     

Joanna Mikołajewska  Michael Friedjung 《Astrophysics and Space Science》2005,296(1-4):441-444

A systematic redshift of high ionization resonance emission lines relative to the intercombination lines was found by Friedjung et al. (1883, A & A 126, 4071983) in the UV spectra of a number of symbiotic binaries. The interpretation was not then clear. We present a study of archival IUE and GHRS/HST spectra of the symbiotic binary CI Cyg. The shift varies during the orbital cycle which can be understood in terms of the presence of strong circum-binary line absorption formed in an outer expanding region.  相似文献   

Great-power politics,order transition,and climate governance: insights from international relations theory     

Maximilian Terhalle  Joanna Depledge 《Climate Policy》2013,13(5):572-588

The complex politics of climate change cannot be properly understood without reference to deeper geopolitical trends in the wider international system. Chief among these is the growing resurgence of ‘great-power politics’ between China and the US, along with failures of socialization and enmeshment into global governance structures in relation to these two powers. Traditional theoretical frameworks have failed to adequately account for these developments. Nonetheless, this current great-power contestation is at the core of an order transition that has prevented the large-scale institutional redesign required to remove deadlocks in existing global governance structures, including climate governance. Examples from the 2009 Copenhagen Climate Change Conference provide ample evidence for these claims. The slow progress of the climate change negotiations are due not just to the politics of the issue itself, but to the absence of a new political bargain on material power structures, normative beliefs, and the management of the order amongst the great powers. Without such a grand political bargain, which could be promoted through a forum of major economies whose wide-ranging remit would go beyond single issues, the climate change regime is only ever likely to progress in a piecemeal fashion.

Policy relevance

Despite the achievements of the 2012 Doha Climate Change Conference, the climate negotiations are not on course to limit warming to 2 °C, and thereby avoid ‘dangerous’ climate change. Several factors have been invoked to account for such slow progress: notably, the nature of the climate change problem itself, the institutional structure of the climate regime, and lack of political will among key players. An alternative explanation is proposed such that the failure to seriously address climate change – as well as other global problems – reflects a resurgent meta-struggle between the ‘great powers’ of China and the US over the nature of the global order. Without such a broader understanding of the deeper dynamics underlying the stalemates of the climate change negotiations, there is little chance of turning those negotiations around.  相似文献   

A new era for climate policy     

Frank Jotzo  Harald Winkler  Joanna Depledge 《Climate Policy》2013,13(2):111-112

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Seasonal and annual variability of days with strong winds and wind damage in Krakow (Poland) during the period 2000�C2007     

Joanna Wi?c?aw-Michniewska  Katarzyna Piotrowicz 《Natural Hazards》2011,59(2):949-965

The study analyses the numbers of days with strong winds in Krakow during the period 2000?C2007 using anemometric records and fire department data. Patterns are identified in the seasonal and annual variation of strong winds. Particular attention is devoted to extreme events. Based on measurements, the study finds that strong winds mostly occurred in winter. Fire department call-out data show that repair of damage caused by strong winds and gusts of wind was needed equally as frequently in summertime. Strong winds accompanying summer storms are often of a local nature and are not always recorded by weather stations. Wind damage was mapped using requests for fire department assistance.  相似文献   

Geophysical monitoring and reactive transport modeling of ureolytically-driven calcium carbonate precipitation     

Wu Y  Ajo-Franklin JB  Spycher N  Hubbard SS  Zhang G  Williams KH  Taylor J  Fujita Y  Smith R 《Geochemical transactions》2011,12(1):7-20

Ureolytically-driven calcium carbonate precipitation is the basis for a promising in-situ remediation method for sequestration of divalent radionuclide and trace metal ions. It has also been proposed for use in geotechnical engineering for soil strengthening applications. Monitoring the occurrence, spatial distribution, and temporal evolution of calcium carbonate precipitation in the subsurface is critical for evaluating the performance of this technology and for developing the predictive models needed for engineering application. In this study, we conducted laboratory column experiments using natural sediment and groundwater to evaluate the utility of geophysical (complex resistivity and seismic) sensing methods, dynamic synchrotron x-ray computed tomography (micro-CT), and reactive transport modeling for tracking ureolytically-driven calcium carbonate precipitation processes under site relevant conditions. Reactive transport modeling with TOUGHREACT successfully simulated the changes of the major chemical components during urea hydrolysis. Even at the relatively low level of urea hydrolysis observed in the experiments, the simulations predicted an enhanced calcium carbonate precipitation rate that was 3-4 times greater than the baseline level. Reactive transport modeling results, geophysical monitoring data and micro-CT imaging correlated well with reaction processes validated by geochemical data. In particular, increases in ionic strength of the pore fluid during urea hydrolysis predicted by geochemical modeling were successfully captured by electrical conductivity measurements and confirmed by geochemical data. The low level of urea hydrolysis and calcium carbonate precipitation suggested by the model and geochemical data was corroborated by minor changes in seismic P-wave velocity measurements and micro-CT imaging; the latter provided direct evidence of sparsely distributed calcium carbonate precipitation. Ion exchange processes promoted through NH4+ production during urea hydrolysis were incorporated in the model and captured critical changes in the major metal species. The electrical phase increases were potentially due to ion exchange processes that modified charge structure at mineral/water interfaces. Our study revealed the potential of geophysical monitoring for geochemical changes during urea hydrolysis and the advantages of combining multiple approaches to understand complex biogeochemical processes in the subsurface.  相似文献