Use of stream response functions to determine impacts of replacing surface-water use with groundwater withdrawals   总被引：1，自引：0，他引：1  

Erik B. Pruneda  Michael E. Barber  Diana M. Allen  Joan Q. Wu 《Hydrogeology Journal》2010,18(5):1077-1092

A regional-scale numerical groundwater model is used to study the impacts of replacing surface-water use with groundwater wells to improve low-flow stream conditions for endangered species within the Bertrand and Fishtrap watersheds, southern British Columbia, Canada and Washington, USA. Stream response functions ranging from 0 to 1.0 were calculated for individual wells placed within a steady-state groundwater flow model at varying distances from the streams to determine the impact that these replacement wells, operating under sustained pumping rates, would have on summer instream flows. Lower response ratios indicate groundwater pumping will have less of an impact on streamflow than taking an equivalent amount of water directly from a surface-water source. Results show that replacing surface-water use with groundwater withdrawals may be a viable alternative for increasing summer streamflows. Assuming combined response factors should be ≤0.5 for irrigators to undergo the expense of installing new wells, ~57% of the land area within 0.8 km of Bertrand Creek would be suitable for replacement wells. Similarly, 70% of the land area within 0.8 km of Fishtrap Creek was found to be appropriate. A visual analysis tool was developed using STELLA to allow stakeholders to quickly evaluate the impact associated with moving their water right.  相似文献   

Magnetic study of Late Pleistocene loess/palaeosol sections from Siberia: palaeoenvironmental implications   总被引：7，自引：0，他引：7  

G. Matasova  E. Petrovský  N. Jordanova  V. Zykina  A. Kapi&#;ka 《Geophysical Journal International》2001,147(2):367-380

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Sodic amphiboles and pyroxenes from fenites in East Africa     

Diana S. Sutherland 《Contributions to Mineralogy and Petrology》1969,24(2):114-135

During alkali metasomatism of the country-rock associated with ijolite-carbonatite complexes the development of sodic amphibole and/or pyroxene is characteristic. In this paper, some new chemical analyses of these minerals, together with published analyses from fenites of Kenya, Uganda and Tanzania, include those of co-existing pairs of amphibole and pyroxene. The common amphiboles of the fenites are magnesioarfvedsonites with 100 Mg: Mg+Fe+Mn ranging from 67 to 36. They co-exist with aegirines having 0.75 to 0.89 ions Fe⁺³. Most of these minerals are poor in Ca; co-existing pairs tend to show corresponding increases in Ca and in Fe⁺². In the syenitic fenites of Tororo and Budeda, considered to have formed at higher temperatures, the stable mineral is aegirine-augite. New analyses of richterite, magnesioarfvedsonite and aegirine from carbonate-rich rocks are also presented, and the relation between fenites and carbonatites is discussed.  相似文献   

Analysis of State and Provincial Atlas Reviews*   总被引：1，自引：0，他引：1  

Diana Hocking  C. Peter Keller 《The Professional geographer》1993,45(1):73-83

Ninety-eight reviews of state and provincial atlases are examined in order to address several questions. Reviews are subjected to content analysis to identify the judgement criteria that experts use in evaluating a provincial or state atlas, and the aspects of each criterion that reviewers praise or condemn. An attempt is made to search for expert consensus and to identify a provincial or state atlas review recipe. The research reported here is part of a larger study undertaken to assist those in the process of planning a new provincial or state atlas initiative. This paper also assists individuals who are searching for rules and guidelines when undertaking an atlas review.  相似文献   

Velocity structure in northern Chile: evidence of subducted oceanic crust in the Nazca Plate     

Diana Comte  Steven W. Roecker  Gerardo Suárez 《Geophysical Journal International》1994,117(3):625-639

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Preliminary Study on the Effect of Water Glass Impregnation on the Rock-Magnetic Properties of Baked Clay     

Kostadinova  M.  Jordanova  N.  Jordanova  D.  Kovacheva  M. 《Studia Geophysica et Geodaetica》2004,48(3):637-646

A common practice in archaeomagnetic studies in many laboratories is the impregnation of the material with water glass (siliceous gel) in order to achieve better consolidation before cutting. The purpose of this study is to establish if and how the presence of water glass in the burnt clay material affects its magnetic properties during heating. We describe experiments designed to monitor the alterations in isothermal remanence and magnetic susceptibility for two sets of specimens - non-impregnated and impregnated with water glass. Our results show that water glass can cause considerable changes in magnetic susceptibility, but the remanent magnetization is not influenced significantly.  相似文献   

Storage and interaction of compositionally heterogeneous magmas from the 1986 eruption of Augustine Volcano, Alaska   总被引：2，自引：0，他引：2  

Diana C. Roman  Katharine V. Cashman  Cynthia A. Gardner  Paul J. Wallace  John J. Donovan 《Bulletin of Volcanology》2006,68(3):240-254

Compositional heterogeneity (56–64 wt% SiO₂ whole-rock) in samples of tephra and lava from the 1986 eruption of Augustine Volcano, Alaska, raises questions about the physical nature of magma storage and interaction beneath this young and frequently active volcano. To determine conditions of magma storage and evolutionary histories of compositionally distinct magmas, we investigate physical and chemical characteristics of andesitic and dacitic magmas feeding the 1986 eruption. We calculate equilibrium temperatures and oxygen fugacities from Fe-Ti oxide compositions and find a continuous range in temperature from 877 to 947°C and high oxygen fugacities (ΔNNO=1–2) for all magmas. Melt inclusions in pyroxene phenocrysts analyzed by Fourier-transform infrared spectroscopy and electron probe microanalysis are dacitic to rhyolitic and have water contents ranging from <1 to ∼7 wt%. Matrix glass compositions are rhyolitic and remarkably similar (∼75.9–76.6 wt% SiO₂) in all samples. All samples have ∼25% phenocrysts, but lower-silica samples have much higher microlite contents than higher-silica samples. Continuous ranges in temperature and whole-rock composition, as well as linear trends in Harker diagrams and disequilibrium mineral textures, indicate that the 1986 magmas are the product of mixing between dacitic magma and a hotter, more mafic magma. The dacitic endmember is probably residual magma from the previous (1976) eruption of Augustine, and we interpret the mafic endmember to have been intruded from depth. Mixing appears to have continued as magmas ascended towards the vent. We suggest that the physical structure of the magma storage system beneath Augustine contributed to the sustained compositional heterogeneity of this eruption, which is best explained by magma storage and interaction in a vertically extensive system of interconnected dikes rather than a single coherent magma chamber and/or conduit. The typically short repose period (∼10 years) between Augustine's recent eruptive pulses may also inhibit homogenization, as short repose periods and chemically heterogeneous magmas are observed at several volcanoes in the Cook Inlet region of Alaska.  相似文献   

"Detailed Pumping Test to Characterize a Fractured Bedrock Aquifer" by Jeffrey D. Gernand and Jeffrey P. Heidtman, July-August 1997 issue, v. 35, no. 4: 632–637.     

Diana M. Allen 《Ground water》1998,36(2):197-197

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Evaluation of Multi-Well Test Data in a Faulted Aquifer Using Linear and Radial Flow Models   总被引：1，自引：0，他引：1  

Diana M. Allen  Frederick A. Michel 《Ground water》1998,36(6):938-948

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Geomagnetic Field Variations as Determined from Bulgarian Archaeomagnetic Data. Part II: The Last 8000 Years     

Mary Kovacheva  Neli Jordanova  Vassil Karloukovski 《Surveys in Geophysics》1998,19(5):431-460

The knowledge about past secular variations of the geomagnetic field is achieved on the basis of archaeomagnetic researches of which the Bulgarian studies form an extended data set. In Part I (Kovacheva and Toshkov, 1994), the methodology used in the Sofia palaeomagnetic laboratory was described and the secular variation curves for the last 2000 years were shown. In Part II (this paper), the basic characteristics of the prehistoric materials used in the archaeomagnetic studies are emphasised, particularly in the context of the rock magnetic studies used in connection with palaeointensity determinations. The results of magnetic anisotropy studies of the prehistoric ovens and other fired structures are summarised, including the anisotropy correction of the palaeointensity results for prehistoric materials, different from bricks and pottery. Curves of the direction and intensity of the geomagnetic field during the last 8000 years in Bulgaria are given. The available directional and intensity values have been used to calculate the variation curve of the virtual dipole moment (VDM) for the last 8000 years based on different time interval averages. The path of virtual geomagnetic pole (VGP) positions is discussed.  相似文献