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51.
Dr. D. Knöfel Prof. Dr. W. v. Engelhardt 《Contributions to Mineralogy and Petrology》1964,9(6):503-518
Zusammenfassung Das Tuffvorkommen vom Heilsberg bei Gottmadingen im Hegau wurde neu kartiert und mineralogisch untersucht. Die Korngrößenverteilung zeigt ein deutliches Maximum bei 0,6–1,2 mm. Der Tuff besteht aus 40% magmatogenem Material und 60% Bestandteilen des durchschlagenen Untergrundes. Die magmatogenen Komponenten sind 17% Einzehnineralien, 10% Grundmasse und 13 % Auswürflinge. Unter den Einzelmineralien wiegt der Pyroxen (Fassait) vor, daneben kommen Amphibol, Biotit und Magnetit, ferner Apatit und Analcim sowie einige seltenere Mineralien vor. Für Pyroxen, Amphibol, Biotit und Magnetit werden chemische Analyse und optische Eigenschaften mitgeteilt. Die größte Menge der magmatogenen Auswürflinge sind kugelförmige Lapilli, die hinsichtlich ihrer Entstehung genauer untersucht und chemisch analysiert wurden. Seltener sind grobkristalline, dunkle und belle Bomben, deren Mineralgehalt und chemische Zusammonsetzung genauer beschrieben werden. Sic stellen wahrscheinlich Differentiate des Heilsbergmagmas dar. Die ehemals glasige, magmatogene Grundmasse des Tuffs liegt heute als ein Gemenge von Montmorillonit und Calcit vor.Aus den nichtmagmatogenen Bestandteilen kann auf den Untergrund im Bereich des Heilsbergvulkans geschlossen werden. Aus dem Deckgebirge wurden Tertiär, Mahn, Dogger, Jura, Keuper und Muschelkalk nachgewiesen. Das Grund-gebirge besteht hauptsächlich aus granodioritischen bis granitischen Gesteinen und enthält auffallenderweise nur wenig Gneise. Der Herd der Eruption dürfte mindestens 4000 m tief liegen.Der Chemismus des Heilsbergmagmas ist hornblenditisch. Es ist dem Magma der Melilithite verwandt und leitet zu den Phonolithen des Hegau über. Das Gestein ist als hornblenditischer Pyroxen-Analcim-Tuff zu bezeichnen.Zwei unabhängige Bestimmungen nach der K-Ar-Methode ergaben für den Biotit des Tuffs ein obermiozänes Alter von 14,0 bzw. 14,5 Mill. Jahren.Mit 2 Textabbildungen 相似文献
52.
Antonín Papež 《Studia Geophysica et Geodaetica》1964,8(2):200-204
Резюме Дабление воздуха, переснитанное иа уровень моря по стандартной атмосфере в Q-коде обозчачается через QNH. Давление воздуха
пересчитанное на уровень моря по высотной барометрической формуле обознаеается через QFF. Для целей авиационной службы погоды
должны быть известны значения QNH, однако Зе барическое поле на синоптических картах выражается через QFF. С помощью рис.
1 для соответствующей температуры воздуха на станцин и ее высоты н. у. м. можно определить разность значений QFF—QNH при давленин
QFF=1000мб. Далее по табл. 2 можно определить поправку для каждого значения QFF отличного от значения QFF при ином давлении, чем 1000мб путем умножения табулированного значения ва разность QFF—1000мб и его алгебраического сложения со значением, полученным по рис. 1.
相似文献
53.
F. Steinhauser W. Mörikofer K. Cehak W. Müller 《Theoretical and Applied Climatology》1965,13(4):558-568
Ohne Zusammenfassung 相似文献
54.
F. Steinhauser W. Mörikofer J. Drimmel Peter Steinhauser 《Meteorology and Atmospheric Physics》1965,15(2):251-264
Ohne Zusammenfassung 相似文献
55.
Jesús M. Mercado Teodoro Ramírez Dolores Corts Marta Sebastin Andreas Reul Begoa Bautista 《Estuarine, Coastal and Shelf Science》2006,69(3-4):459
The changes in the phytoplankton absorption properties during a diurnal cycle were investigated at one station located in the north-western area of the Alborán Sea. The experiment was performed in spring when the water column was strongly stratified. This hydrological situation permitted the establishment of a deep chlorophyll a (chl a) fluorescence maximum (DFM) which was located on average close to the lower limit of the mixed layer and the nutricline. The relative abundance of pico-phytoplankton (estimated as its contribution to the total chl a) was higher in the surface, however, micro-phytoplankton dominated the community at the DFM level. Chl a specific absorption coefficient (a*(λ)) also varied with optical depth, with a* (the spectrally average specific absorption coefficient) decreasing by 30% at the DFM depth with respect to the surface. A significant negative correlation between the contribution of the micro-phytoplankton to the total chl a and a* was obtained indicating that a* reduction was due to changes in the packaging effect. Below the euphotic layer, a* increased three-fold with respect to the DFM, which agrees with the expected accumulation of accessory pigments relative to chl a as an acclimation response to the low available irradiance. The most conspicuous change during the diurnal cycle was produced in the euphotic layer where the chl a concentration decreased significantly in the afternoon (from a mean concentration of 1.1 μg L−1 to 0.7 μg L−1) and increased at dusk when it averaged 1.4 μg L−1. In addition, a* and the blue-to-red absorption band ratio increased in the afternoon. These results suggest that a*(λ) diurnal variability was due to increase in photo-protective and accessory pigments relative to chl a. The variation ranges of a*(λ) at 675 and 440 nm (the absorption peaks in the red and blue spectral bands, respectively) in the euphotic layer were 0.01–0.04 and 0.02–0.10 m2 mg−1 chl a, respectively. Approximately 30% out of this variability can be attributed to the diurnal cycle. This factor should therefore be taken into account in refining primary production models based on phytoplankton light absorption. 相似文献
56.
C. Riedel A. Tryggvason B. Brandsdottír T. Dahm R. Stéfansson M. Hensch R. Böðvarsson K. S. Vogfjord S. Jakobsdottír T. Eken R. Herber J. Holmjarn M. Schnese M. Thölen B. Hofmann B. Sigurdsson S. Winter 《Marine Geophysical Researches》2006,27(4):267-281
Between June 2004 and September 2004 a temporary seismic network was installed on the northern insular shelf of Iceland and onshore in north Iceland. The seismic setup aimed at resolving the subsurface structure and, thus, the geodynamical transition from Icelandic crust to typical oceanic crust along Kolbeinsey Ridge. The experiment recorded about 1,000 earthquakes. The region encloses the Tjörnes Fracture Zone containing the Husavik–Flatey strike-slip fault and the extensional seismic Grimsey Lineament. Most of the seismicity occurs in swarms offshore. Preliminary results reveal typical mid-ocean crust north of Grimsey and a heterogeneous structure with major velocity anomalies along the seismic lineaments and north–south trending subsurface features. Complementary bathymetric mapping highlight numerous extrusion features along the Grimsey Lineament and Kolbeinsey Ridge. The seismic dataset promises to deliver new insights into the tectonic framework for earthquakes in an extensional transform zone along the global mid-ocean ridge system. 相似文献
57.
The Acid-Producing Potential (APP) and the Acid-Consuming Capacity (ACC) are introduced as basic parameters for long-term
pollution assessment of mud disposal. They can be obtained by a four-step sequential leaching technique. The concentration
of Ca extracted by the first Na-acetate step permits calculating the ACC. Both the Fe- and S-fractions deliberated by subsequent
leaching steps are used to calculate the APP. When the APP of a sample is substacted from its ACC, a negative value indicates
a potential increase of the bioavailability of the toxic metal load upon disposal of this mud in oxic environments. 相似文献
58.
Determinations of copper consumption capacity (CuCs.C) and labile copper concentrations in surface coastal seawater, using a copper ion selective electrode (Cu-ISE) potentiometric method under predominantly diffusive conditions, are reported. For evaluation of the copper concentrations, the points of the endpoint contiguity zone of the CuCs.C titration curve were treated by an ISE multiple standard addition technique. The results were compared with those obtained by means of a Chelex-100 (calcic form) ‘batch’ procedure-potentiometric stripping analysis.The labile copper of the sample was determined at concentrations down to 10.70 nM with an average RSD of 12%, independent of the Cu-ISE employed. For adjacent subsamples, the mean CuCs.C values obtained for El Way seawater were equivalent to 81.05 and 48.00 nM copper, with an RSD of 4 and 7%, and for Isla Santa Maria seawater the value was equivalent to 70.27 nM copper, with an RSD of 7%. The theoretical approach of the electrode diffusive mechanism proposed, which would depend, fundamentally, on the adsorptive, complexing and reducing properties of the dissolved organic matter in the seawater sample, allows simultaneous analytical determination of CuCs.C and labile copper concentration in seawater. 相似文献
59.
Abstract. The stomach contents of poor cod, Trisopterus minutus capelanus (Lacepède), were taken at monthly intervals off the eastern coast of the Gulf of Valencia (Spain). A total of 1276 were analyzed to determine diet according to fish size and season. The basic food consists of crustaceans (Mysidacea and Decapoda) and teleosts. Feeding habits varied with size: decapods and fishes were more abundant in the stomachs of larger specimens. Little seasonal variation in food habits was recorded. 相似文献
60.
Marta Sebastin Javier Arístegui María F. Montero Jose Escanez F. Xavier Niell 《Progress in Oceanography》2004,62(2-4):131
The enzymatic activity of alkaline phosphatase (APA) was studied in the transition zone between the African upwelling system and the open ocean waters of the Canary Islands region. This region is recurrently dominated by the presence of upwelling filaments that may transport nutrient-enriched waters out into the open ocean before nutrients become exhausted by plankton. Turnover rates by APA were generally low in the whole region, but detectable in all the measurements carried out. On average, turnover rates were higher in the upwelling stations, and APA in those waters seemed to be mainly generated by heterotrophic bacteria to supply easily assimilable organic C. APA outside the upwelling area showed an inverse hyperbolic relationship with increasing phosphate, suggesting the presence of both constitutive and Pi-inducible APA. In these offshore waters, a threshold of 0.1 μM of phosphate could be defined for the regulatory function of Pi on APA. Thus, APA in nutrient-poor waters seemed to be induced to compensate for Pi-deficiency. Turnover rates in the filaments showed basal (probably constitutive) levels, whereas they increased in the surrounding waters, where phosphate concentration presumably did not satisfy plankton P-demands. The fertilising effect of the filaments and associated cyclonic eddies extended to at least 175 km offshore, where basal alkaline phosphatase activities were still found. The magnitude of this effect depends probably on the intensity of upwelling events and the degree of recirculation of filament water back to the coastal jet. 相似文献