The upper mantle beneath Kapfenstein and the Transdanubian volcanic region,E Austria and W Hungary: A comparison     

Prof. Dr. Gero Kurat  Dr. Antal Embey-Isztin  Dr. Alfred Kracher  Prof. Dr. Heinz G. Scharbert 《Mineralogy and Petrology》1991,44(1-2):21-38

Summary A representative suite of ultramafic xenoliths from Kapfenstein, Austria, has been investigated petrographically. Textures and mineral chemistries are compared with published data on Hungarian xenoliths and discussed within the framework of the hypothesis of a mantle diapir beneath the Transdanubian Volcanic Region (TVR) of E Austria and W Hungary. We succeeded in recognizing important differences which seem to support the TVR mantle diapir concept. Below the external part of the TVR (Kapfenstein) the upper mantle seems to be essentially untectonized and lithologically rather monotonous (e.g., Type II clinopyroxenites are absent). In contrast, both deformed (equigranular) and undeformed (protogranular) peridotite xenoliths occur in the internal part (Balaton area) where Type II clinopyroxenite xenoliths as well as Type I/Type II composite rocks are present. It is remarkable that at Gérce (Hungary), situated approximately mid-way between the internal and external regions, almost exclusively porphyroclastic xenoliths occur.The undeformed xenoliths from Kapfenstein are largely unfractionated. A small proportion exhibits depletions in basaltic component or some mild influence of mantle metasomatism. Several mineral chemical parameters, such asmg-number of olivine, Al₂O₃ content of spinel and clinopyroxene, apparent pyroxene equilibration temperature, etc., show a narrow distribution with a pronounced maximum in the undeformed Kapfenstein xenoliths. By contrast, the deformed xenoliths from the internal TVR show a much broader range of values with no distinct maximum, attesting to a more complex chemical and physical evolution. Thus a direct relationship between deformation and chemistry seems to be confirmed. The deformed rocks can be extreme in two ways: they can either be strongly depleted or strongly enriched as documented by the high contents of clinopyroxene in equigranular xenoliths from Szigliget. Tectonization apparently opens the way for mass transport in either direction.

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Der obere Mantel unterhalb Kapfenstein und der Transdanubischen Vulkanischen Region, E-Österreich und W-Ungarn: Ein Vergleich

Zusammenfassung Eine repräsentative Suite von ultramafischen Xenolithen von Kapfenstein, Steiermark, wurde petrologisch untersucht. Die Gefüge und Mineralchemismen werden mit publizierten Daten von ungarischen Vorkommen verglichen und im Rahmen der Mantel-Diapir-Hypothese für die Transdanubische Vulkanische Region (TVR) diskutiert. Der Vergleich ergab wesentliche Unterschiede, welche das TVR-Mantel-Diapir-Konzept unterstützen. Der Mantel unterhalb des äußeren Teiles der TVR (Kapfenstein) ist praktisch untektonisiert und lithologisch monoton (z.B. fehlen Typ II Klinopyroxenite). Im Gegensatz dazu finden sich im inneren Teil (Balaton-Region) sowohl deformierte (equigranulare) als auch nicht-deformierte (protogranulare) Xenolithe zusammen mit Typ II Klinopyroxeniten. Auch zusammengesetzte Xenolithe, bestehend aus Typ I und Typ II Gesteinen sind vorhanden. Bemerkenswert ist, daß bei Gérce (Ungarn), eine Lokalität, welche sich zwischen dem inneren und äußeren Teil der TVR befindet, fast ausschließlich nur porphyroklastische Xenolithe vorkommen.Die undeformierten Xenolithe von Kapfenstein sind größtenteils unfraktioniert. Einige wenige zeigen Verarmungen oder geringfügige metasomatische Anreicherungen. Histogramme mineralchemischer Parameter zeigen sehr deutlich die Unterschiede zwischen den undeformierten Kapfenstein Xenolithen und den deformierten der inneren TVR. Die Kapfenstein Xenolithe zeigen typischerweise regelmäßige Verteilungen mit einem deutlichen Maximum. Die Xenolithe der inneren TVR hingegen zeigen eine flache Verteilung und weisen damit auf eine wesentlich komplexere chemische Entwicklung hin. Unsere Daten scheinen einen direkten Zusammenhang zwischen Deformation und chemischer Veränderung aufzuzeigen. Die deformierten Gesteine können in dieser Hinsicht zwei Extreme annehmen: Sie können entweder stark verarmt oder stark angereichert sein. Letzeres wird z.B. beeindruckend durch die hohen Gehalte an Klinopyroxen der equigranularen Xenolithe von Szigliget dokumentiert. Tektonisierung scheint die Wege für Massen-Transporte in beiden Richtungen zu öffnen.

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Unified Management of Surface- and Ground-Water Quality Through Clean Water Act Authorities     

Alfred M. Duda 《Ground water》1989,27(3):351-362

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Elastic wave propagation simulation in the presence of surface topography   总被引：20，自引：0，他引：20  

Ekkehart Tessmer  Dan Kosloff  Alfred Behle 《Geophysical Journal International》1992,108(2):621-632

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Melt inclusions and crystal-liquid separation in rhyolitic magma of the Bishop Tuff     

Fangqiong Lu  Alfred T. Anderson  Andrew M. Davis 《Contributions to Mineralogy and Petrology》1992,110(1):113-120

Melt inclusions in quartz phenocrysts from a single clast of pumice near the base of the plinian pumice fall of the Bishop Tuff were studied to test ideas concerning separation of melt and crystals in silicic magmas. Ten analyzed inclusions from the pumice clast are of high silica rhyolite composition with very low contents of the highly compatible elements Ba, Sr, and Eu, consistent with extensive fractionation. The concentrations of U, La, Ce, Mg, and Ca of these ten melt inclusions vary considerably as determined by ion microprobe. Petrologic considerations indicate that uranium is an incompatible element with a maximum bulk partition coefficient D of about 0.2 and that the evolution of the uranium content of the melt was controlled by crystallization of the magma. A minimum of 33 wt% perfect fractional crystallization is required to explain the observed range in uranium. However, only 17 wt% crystals occurred in the pumice clast. The greater calculated fraction of crystals requires significant separation of crystals and melt before the eruption of the plinian pumice fall in spite of the fact that crystal mixing (settling, etc.) did not occur in the Bishop magma.  相似文献   

Urban vulnerability and adaptation to heatwaves: a case study of Graz (Austria)     

Christiane Reischl  Romana Rauter  Alfred Posch 《Climate Policy》2018,18(1):63-75

The increasing frequency of heatwaves, particularly in urban contexts, is one of the perceptible consequences of climate change. A city’s vulnerability to these heatwaves must be determined to develop proper adaptation measures. This article addresses the vulnerability of a medium-sized city in Central Europe, Graz, to heatwaves. Based on secondary data and primary data gathered from expert interviews, we identified certain determinants of vulnerability for the city: temperature, proportion of open and green spaces to developed areas, construction period of buildings, distribution of age and poverty risk, adaptation strategies used, and risk perception levels assessed for decision makers in the city administration. Certain city districts can be classified as particularly vulnerable. A high level of risk perception was detected among all decision makers and some adaptation measures have already been enacted. In particular, inter-organizational collaboration in adaptation networks works effectively. A deficit in efficient communication between researchers, policy makers, and members of the public was perceived to be the main barrier. This case study exemplifies the assessment of a city’s vulnerability to heatwaves on the basis of particular determinants and can be applied to many other cities.

Policy relevance

The method applied revealed potential improvements and opportunities on the policy level. Strong networks for climate change adaptation are most effective if regular meetings take place, allowing trust and friendship to grow between decision makers. More target-group-oriented information is needed. Emergency organizations, in particular, need more information, because the perception of heatwave risks has only been based thus far on personal experiences. By establishing a central authority, more information could be provided on heatwaves in cities. The need to raise the perception of members of the population and motivate them to take personal responsibility during disasters was emphasized by interviewed decision makers. This can be supported by providing advice during heatwaves through newspapers, TV, and radio. People in risk groups and their relatives could be trained in workshops. City areas that are at high risk should be marked on maps to make relevant information more tangible for decision makers.  相似文献   

Visualizing and quantifying the movement of vegetative drought using remote-sensing data and GIS     

Coco M. Rulinda  Alfred Stein  Ulan D. Turdukulov 《International journal of geographical information science》2013,27(8):1481-1496

Remote-sensing-based drought monitoring methods provide fast and useful information for a sustainable management strategy of drought impact over a region. Common pixel-based monitoring methods are limited in the analysis of the dynamics of this impact at regional scale. For instance, these hardly allow us to quantify the movement of drought in space and time and to compare drought with rainfall deficits without losing the variability of these events within a region. This study proposed an object-based approach that allowed us to visualize and quantify the spatio-temporal movement of drought impact on vegetation, called vegetative drought, in a region. The GIS software Dynomap was used to extract and track objects. Measures of distance and angle were used for determining the speed and direction of vegetative drought and rainfall deficit objects, calculated from the National Oceanic and Atmospheric Administration's (NOAA's) normalized difference vegetation index and rainfall estimates data. The methods were applied to the two rainy seasons during the drought year 1999 in East Africa. Results showed that vegetative drought objects moved into the southwestern direction at an average angle of??138.5° during the first season and??144.5° during the second season. The speed of objects varied between 38 km dekad^?1 and 185 km dekad^?1 during the first season and between 33 km dekad^?1 and 144 km dekad^?1 during the second season, reflecting the rate of spread between dekads. Vegetative drought objects close to rainfall deficit objects showed similar trajectories and sometimes regions overlapped. This indicated that the two events are related. We conclude that a spatiotemporal relationship existed between the two types of events and that this could be quantified.  相似文献   

Using geographically weighted regression kriging for crop yield mapping in West Africa     

Muhammad Imran  Alfred Stein  Raul Zurita-Milla 《International journal of geographical information science》2013,27(2):234-257

Geographical information systems support the application of statistical techniques to map spatially referenced crop data. To do this in the optimal way, errors and uncertainties have to be minimized that are often associated with operations on the data. This paper applies a spatial statistical approach to upscale crop yields from the field level toward the scale of Burkina Faso. Observed yields were related to the Normalized Difference Vegetation Index derived from SPOT-VEGETATION. The objective was to quantify the uncertainties at the subsequent steps. First, we applied a point pattern analysis to examine uncertainties due to the sampling network of field surveys in the country. Second, geographically weighted regression kriging (GWRK) was applied to upscale the yield observations and to quantify the corresponding uncertainty. The proposed method was demonstrated with the mapping of sorghum yields in Burkina Faso and results were compared with those from regression kriging (RK) and kriging with external drift using a local kriging neighborhood (KEDLN). The proposed method was validated with independent yield observations obtained from field surveys. We observed that the lower uncertainty range value increased by 39%, and the upper uncertainty range value decreased by 51%, when comparing GWRK with RK and KEDLN. Moreover, GWRK reduced the prediction error variance as compared to RK (20 vs. 31) and to KEDLN (20 vs. 39). We found that climate and topography had a major impact on the country’s sorghum yields. Further, the financial ability of farmers influenced the crop management and, thus, the sorghum crop yields. We concluded that GWRK effectively utilized information present in the covariate datasets and improved the accuracies of both the regional-scale mapping of sorghum yields and was able to quantify the associated uncertainty.  相似文献   

Cooling rates of Plinian-fall and pyroclastic-flow deposits in the Bishop Tuff: inferences from water speciation in quartz-hosted glass inclusions   总被引：1，自引：0，他引：1  

Paul J. Wallace  Josef Dufek  Alfred T. Anderson  Youxue Zhang 《Bulletin of Volcanology》2003,65(2-3):105-123

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Observations and temperatures of Io's Pele Patera from Cassini and Galileo spacecraft images     

Jani Radebaugh  Alfred S. McEwen  Laszlo P. Keszthelyi  Elizabeth P. Turtle 《Icarus》2004,169(1):65-79

Pele has been the most intense high-temperature hotspot on Io to be continuously active during the Galileo monitoring from 1996-2001. A suite of characteristics suggests that Pele is an active lava lake inside a volcanic depression. In 2000-2001, Pele was observed by two spacecraft, Cassini and Galileo. The Cassini observations revealed that Pele is variable in activity over timescales of minutes, typical of active lava lakes in Hawaii and Ethiopia. These observations also revealed that the short-wavelength thermal emission from Pele decreases with rotation of Io by a factor significantly greater than the cosine of the emission angle, and that the color temperature becomes more variable and hotter at high emission angles. This behavior suggests that a significant portion of the visible thermal emission from Pele comes from lava fountains within a topographically confined lava body. High spatial resolution, nightside images from a Galileo flyby in October 2001 revealed a large, relatively cool (<800 K) region, ringed by bright hotspots, and a central region of high thermal emission, which is hypothesized to be due to fountaining and convection in the lava lake. Images taken through different filters revealed color temperatures of 1500±80 K from Cassini ISS data and 1605±220 and 1420±100 K from small portions of Galileo SSI data. Such temperatures are near the upper limit for basaltic compositions. Given the limitations of deriving lava eruption temperature in the absence of in situ measurement, it is possible that Pele has lavas with ultramafic compositions. The long-lived, vigorous activity of what is most likely an actively overturning lava lake in Pele Patera indicates that there is a strong connection to a large, stable magma source region.  相似文献   

Vertical vibration of an elastic strip footing on saturated soil     

Y. Q. Cai  Y. M. Cheng  S. K. Alfred Au  C. J. Xu  X. H. Ma 《国际地质力学数值与分析法杂志》2008,32(5):493-508

Based on Biot's dynamic coupled equations, the vertical vibration of an elastic strip footing on the surface of saturated soil is studied. Utilizing the Fourier transform, the governing dynamic differential equations for saturated poroelastic medium are solved. Considering the mixed boundary value conditions at the bottom of the foundation, a pair of dual integral equations about the vertical vibration of an elastic strip footing is derived, which can be converted to a set of linear equations by means of infinite series of orthogonal functions. The relation between the dynamic compliance coefficients and the dimensionless frequency tends to be gentle with decreasing footing rigidity, while the dimensionless frequency has only small effect on the dynamic compliance coefficients. When the dynamic permeability is large, its effect on the dynamic compliance coefficients should be taken into consideration. Furthermore, the dynamic compliance coefficients are found to be not sensitive to Poisson's ratio of the soil for footing on saturated soil. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献