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Roy James W. Bordeleau Genevi&#;ve Rivard Christine Ryan M. Cathryn Malet Xavier Brown Susan J. Tremblay Vincent 《Hydrogeology Journal》2022,30(3):1005-1019
Hydrogeology Journal - Monitoring of dissolved methane concentrations in groundwater is required to identify impacts from oil and gas development and to understand temporal variability under... 相似文献
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E. A. MacLagan E. L. Walton C. D. K. Herd B. Rivard 《Meteoritics & planetary science》2020,55(7):1564-1580
Hyperspectral imaging can be used to rapidly identify and map the spatial distributions of many minerals. Here, hyperspectral mapping in three wavelength regions (visible and near‐infrared, shortwave infrared, and thermal infrared) was applied to drill cores (ST001, ST002, and ST003) penetrating a continuous sequence of crater‐fill breccias from the Steen River impact structure in Alberta, Canada. The combined data sets reveal distinct mineralogical layering, with breccias derived predominantly from sedimentary rocks overlying those derived from granitic basement. This stratigraphy demonstrates that the breccias were not appreciably disturbed following deposition, which is inconsistent with formation models of similar breccias (suevites) by explosive impact melt–fluid interaction. At Steen River, volatiles from sedimentary target rocks were an inherent part of forming these enigmatic breccias. Approximately three quarters of terrestrial impact structures contain sedimentary target rocks; therefore, the role of volatiles in producing so‐called suevitic breccias may be more widespread than previously realized. The hyperspectral maps, specifically within the SWIR wavelength region, also delineate minerals associated with postimpact hydrothermal activity, including ammoniated clay and feldspar minerals not detectable using traditional techniques. These nitrogen‐bearing minerals may have originated from microbial processes, associated with oil‐ and gas‐producing units in the crater vicinity. Such minerals may have important implications for the production of habitable environments by impact‐induced hydrothermal activity on Earth and Mars. 相似文献
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Experimental calibration of lake-sediment spectral reflectance to chlorophyll a concentrations: methodology and paleolimnological validation 总被引：1，自引：0，他引：1
Alexander P. Wolfe Rolf D. Vinebrooke Neal Michelutti Benoit Rivard Biplob Das 《Journal of Paleolimnology》2006,36(1):91-100
Chlorophyll a preserved in lake sediments reflects, in part, past primary production. This study assesses the spectral properties of sedimentary
chlorophyll a using visible-near infrared reflectance (VNIR) spectroscopy, with the objective of establishing a new, non-destructive paleolimnological
proxy. Reflectance spectra were determined from a dilution series (n = 10) involving incremental additions of pulverized modern algae to a lake sediment matrix of low organic content. This enabled
an assessment of the development of sediment reflectance spectra in relation to different sediment chlorophyll a concentrations, and subsequent regression of spectral features against measured concentrations of chlorophyll a and derivatives obtained by high performance liquid chromatography (HPLC). The experiment demonstrates that ubiquitous troughs
in sediment reflectance near 675 nm are attributable to chlorophyll a and derivative compounds. A significant correlation (r
2 = 0.98, P < 0.01) was obtained between the area of the reflectance trough in the 650–700 nm interval and summed concentrations of chlorophyll
a, all derivative isomers, and degradational pheopigments. A simple linear inference model derived from this experiment was
applied to a down-core sequence of VNIR spectra from a productive prairie lake (Alberta, Canada), where it produced inferred
sediment chlorophyll a concentrations in concordance with HPLC measurements. Although a larger training set is desirable to further refine the inference
model, the analyses reported here demonstrate that reflectance spectroscopy provides a rapid, semi-quantitative method for
assessing the chlorophyll a content of lake sediments. 相似文献
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AbstractThe potential impacts of future climate change on the evolution of groundwater recharge are examined at a local scale for a 546-km2 watershed in eastern Canada. Recharge is estimated using the infiltration model Hydrologic Evaluation of Landfill Performance (HELP), with inputs derived from five climate runs generated by a regional climate model in combination with the A2 greenhouse gas emissions scenario. The model runs project an increase in annual recharge over the 2041–2070 period. On a seasonal basis, however, a marked decrease in recharge during the summer and a marked increase during the winter are observed. The results suggest that increased evapotranspiration resulting from higher temperatures does not offset the large increase in winter infiltration. In terms of individual water budget components, clear differences are obtained for the different climate change scenarios. Monthly recharge values are also found to be quite variable, even for a given climate scenario. These findings are compared with results from two regional-scale studies.
Editor D. Koutsoyiannis; Associate editor M. Besbes 相似文献
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Regional recharge estimation using multiple methods: an application in the Annapolis Valley, Nova Scotia (Canada) 总被引：1，自引：0，他引：1
Recharge is a key parameter in groundwater resources management, and a reliable estimate of recharge is required for their sustainable development. Several methods are available to evaluate recharge; however, selecting the appropriate one is made difficult because each method has its advantages and drawbacks, and results can vary greatly from one method to another. Recharge methods can actually refer to different processes. This paper compares and discusses the results obtained from five regional-scale recharge assessment approaches applied to a fractured rock aquifer in a region with a temperate and humid climate (Annapolis Valley, Nova Scotia, Canada). These methods are distinguished between those providing estimates of the net infiltration (I) into the subsurface (river hydrograph separation and soil moisture balance) from those considering the net recharge (W) to the regional bedrock aquifer (river 7-day low-flows, the corrected soil moisture balance, a numerical groundwater flow model developed with FEFLOW and an infiltration model developed with HELP). The estimated net infiltration ranges from 160 to 250 mm/year, whereas the net recharge estimates range from 80 to 175 mm/year for the entire study area. Although different assessment methods were used, the estimated recharge range is still quite large, demonstrating the importance of using several methods. This case study should provide guidance on choices to be made in the development of a strategy for assessing representative values of aquifer recharge at the regional scale under similar geological and climatic conditions. The use of multiple complementary approaches should lead to a better understanding of the system dynamics and to better defined a representative range of recharge estimates. 相似文献
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Camille Rivard Emmanuelle Montargès-Pelletier Delphine Vantelon Manuel Pelletier Chithra Karunakaran Laurent J. Michot Frédéric Villieras Nicolas Michau 《Physics and Chemistry of Minerals》2013,40(2):115-132
In the context of radioactive waste repository in geological formation, kaolinite-metallic iron interaction in chlorine solution was conducted in batch experiments, under anoxic conditions at 90 °C during 9 months. After a mineralogical characterization at a global scale, products were analyzed at the micrometer and nanometer scales by X-ray absorption spectroscopic techniques (XAS and STXM). Absorption at Al, Si and Fe edges was investigated to have a complete overview of the distribution and status of constituting elements. Whereas Si K-edge results do not evidence significant evolution of silicon status, investigations at Al K-edge and Fe L-edges demonstrate variations at aggregate and particle scales of IVAl:VIAl and Fe2+:Fe3+ ratios. Spectroscopic data evidence the systematic crystallization of Fe-serpentines onto the remaining particles of kaolinite and the absence of pure species (kaolinite or Fe-serpentines). Combination of spatially resolved spectroscopic analyses and TEM-EDXS elemental distribution aims to calculate unit cell formulae of Fe-serpentines layers and abundance of each species in mixed particles. For most of the investigated particles, results reveal that the variations of particles composition are directly linked to the relative contributions of kaolinite and Fe-berthierine in mixed particles. However, for some particles, microscale investigations evidence crystallization of two other Fe-serpentines species, devoid of aluminum, cronstedtite and greenalite. 相似文献
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