The stability of fission tracks in epidote and vesuvianite     

Udo Haack 《Earth and Planetary Science Letters》1976,30(1):129-134

The stability of fission tracks in epidote and vesuvianite (idiocrase) was studied at different temperatures for several periods of time. The tracks in epidote are almost as heat-resistant as those in garnet; in vesuvianite they are much less stable. These results are in line with the rule that tracks in minerals with high lattice energies need higher activation energies to fade than in minerals with low lattice energies.  相似文献   

Détermination par la Méthode K/Ar de l'âge des Intrusions et des Minéralisations Associées dans le Porphyre Cuprifère de Quellaveco (Sud Ouest du Pérou)     

J.-L. Zimmermann  A. Kihien Collado 《Mineralium Deposita》1983,18(2):207-213

Résumé Les âges K-Ar des roches granodioritiques du stock de Quellaveco, des rhyolites encaissantes et d'un dyke subvolcanique sont compris entre le Paléocène et le début de l'Eocène, avec un âge moyen de 53.7 M.A. Ces résultats concordent avec ceux obtenus pour bon nombre d'autres porphyres cuprifères du Sud-Ouest des Etats Unis et du Nord du Chili qui ont été formés au cours de l'orogenèse Laramienne. De plus, il n'y a quasiment pas de différence entre l'âge du substratum et celui de l'intrusif, ce qui semble indiquer que ces roches sont cogénétiques.

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Granodioritic rocks from the stock of Quellaveco, their surrounding rhyolites and a subvolcanic dyke give K-Ar ages between Paleocene and lower Eocene, with an mean age of 53.7 M.Y. These results agree with those of other porphyry-copper deposits in the South-Western USA, in Northern Chile, and, which have been generated during Laramian orogenesis. Furthermore, no significant age difference between the pluton and the basement, have been observed, is interpreted as indicative of a consanguineous origin for both rock types.

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Zum Problem der Redoxpotentialmessung in Abwässern und Schlämmen     

G. Zimmermann  E. Tiedemann  H. Ludwig 《洁净——土壤、空气、水》1977,5(3):299-307

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Determinations of particle size distributions in natural waters use of Zeiss Micro-Videomat image analyzer     

Dr. M. C. Kavanaugh  Dr. U. Zimmermann  Mrs. A. Vagenknecht Dipl.-Ing.  Eidg. Anstalt für Wasserversorgung. Abwasserreinigung und Gew?sserschutz  CH- Dübendorf  Switzerland 《Aquatic Sciences - Research Across Boundaries》1977,39(1):86-98

Use of a Zeiss Micro-Videomat electronic image analyzer for routine measurements of size distributions of particles found in natural waters greater than 0.3 μm has been investigated. Staining of particles with a solution of Gentiana-violet eliminated the multiple-count problem which has frustrated earlier attempts to use image analyzers for quantitative phytoplankton work. Concentration of samples from the lake water column was successfully achieved with an impact centrifuge. Losses of inorganic particles indicate that the centrifuge method must be evaluated on an individual case basis. Precision and accuracy of the Zeiss Micro-Videomat using either sedimentation (Utermöhl) or centrifugation for sample concentration were satisfactory for particles larger than 1 μm. The system appears promising for routine surveillance of raw water quality at water treatment plants, and performance of unit processes used for particulate removal, as well as for specific investigations of ecological phenomena in natural waters.  相似文献   

Ages K-Ar de l'Événement Hydrothermal et des Intrusions Associées dans le District Minéralisé Miocène d'Aīn-Barbar (Est Constantinois,Algérie)     

Chr. Marignac  J.-L. Zimmermann 《Mineralium Deposita》1983,18(3):457-467

The Ain-Barbar district (Edough — Cap de Fer massif, northeastern Algeria) displays numerous microgranitic plugs and several rhyolitic dykes. These intrusives are cross-cut by polymetallic ore veins (Fe-Cu-Zn-Pb), and are hydrothermally altered in association with the mineralization. K-Ar measurements were carried out in order to determine the age of this event. Measurements gave conventional “ages” in the interval 15 to 16 M.Y., as well as two “isochron ages”, respectively at 15.1 and 16.0 M.Y. The 16.0 M.Y. age could be representative for the intrusion of microgranites, and one of the rhyolitic dykes. The 15.1 M.Y. one is clearly the age of the intrusion for two other rhyolitic dykes, and is coeval with the age of their hydrothermal alteration. The 15.1 M.Y. age is equally the one for the hydrothermal alteration affecting previous intrusive rocks. These results are compatible with previous data concerning magmatic events within the Edough — Cap de Fer massif. They show that hydrothermal process occurred very close after the end of intrusion in the Ain-Barbar district. They give also indirect evidence for the age of the last folding event in the area.  相似文献   

Collocation formulations for the finite element analysis of tidal and transport processes in estuaries     

Udo Meissner  Rainer Ratke 《Advances in water resources》1982,5(4):217-220

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Gravity study of the Djibouti area     

J. Makris  J. Zimmermann  A. Balan  A. Lebras 《Tectonophysics》1975,27(2):177-185

In March and April 1972, 380 gravity stations were established in the T.F.A.I. The data were reduced to Bouguer anomalies of 5 mGal isolines. Qualitative and quantitative interpretation based on the gravity map, on seismic data and on the magnetics and physiography of the area revealed that: The crust of the Gulf of Tadjura and the central part of the T.F.A.I. is strongly oceanized and is the direct continuation of the Sheba Ridge.To the north of the Gulf, at the Dankali Mountains, the crust increases in thickness and most probably contains sialic fragments, indicating the continuation of the Danakil Chains in the T.F.A.I.To the south, the structure is bordered by a continental block, the Aysha Horst. The oceanization is concentrated only in the area of deep injections, marked by gravity maxima, whereas the rest of the area is to be described as sub-continental. The crust is attenuated from south (Aysha Horst) to north (Red Sea), from 30 to 15 km in thickness.The pattern of the gravity anomalies shows clearly liniations only along the coasts of the Gulf of Tadjura and the Straits of Bab el Mandeb. Inland the field breaks up into relative minima and maxima, indicating the fragmentation of the crust and the ‘triple junction’ nature of the area.The tectonic process is that of extension, with normal faults having maximum displacements at the northern border of the Gulf of Tadjura.The uppermost mantle has low velocity and density values due to thermal processes in the expanding zone. The state of the upper-mantle material must be that of partial melting due to high temperatures of the order of 800° to 1,000° C at about 15 km depth.  相似文献   

Trübeströme in Seen: Sauerstoffeintrag durch grundnah eingeschichtetes Flusswasser     

Dr. André Von Lambert  Dr. Kerry Kelts  Dr. Ulrich Zimmermann 《Aquatic Sciences - Research Across Boundaries》1984,46(1):41-50

Near-bottom current measurements in the main delta areas of the Walensee (Switzerland) and of Lake Constance yielded evidence that sporadic high influxes of clastic suspensions caused by flood stage discharges of tributaries generate turbidity underflows. Turbid suspensions plunge down the delta front as hyperpycnal inflows with speeds up to 130cm/s. These periodic intrusions of well oxygenated river water may influence the oxygen budget of the basal hypolimnion, thus possibly antagonizing eutrophication in marginal cases, supported by the adsorption of phosphate by suspended clay particles.   相似文献   

Experimentelle Untersuchungen über die ökologische Wirkung der Strömungsgeschwindigkeit auf die Lebensgemeinschaften des fliessenden Wassers     

Peter Zimmermann 《Aquatic Sciences - Research Across Boundaries》1961,23(1):1-81

Ohne Zusammenfassung  相似文献   

Einjährige Feldstärkemessungen im UKW-Rundfunkband in Kolberg bei Berlin     

Dr. Udo Kühn 《Pure and Applied Geophysics》1957,38(1):157-168

Zusammenfassung Es wird über einjährige UKW-Ausbreitungsmessungen auf festen Meßstrecken im UKW-Rundfunkband berichtet. Im jährlichen Verlauf der Empfangsfeldstärken konnten im Mittel in den Monaten Juni und Dezember die niedrigsten Feldstärken festgestellt werden. Es zeigte sich ein Zusammenhang zwischen den Temperatursprüngen an Inversionen und den Feldstärken sowohl bei den Monatsmitteln als auch bei den Einzelwerten. Bei der Untersuchung des Korrelationskoeffizienten zwischen den Temperatursprüngen an Inversionen und den Feldstärken ließ sich eine Entfernungsabhängigkeit nachweisen. Auch die Amplitude des Tagesganges und die Schwankungen der Tagesmittelwerte zeigen eine eindeutige Entfernungsabhängigkeit mit Höchstwerten in 200 bis 300 km Entfernung. Mit einem Korrelationskoeffizienten von 0.49 wurde ein guter Zusammenhang zwischen den Feldstärken und dem Bodenluftdruck ermittelt. Da sich außerdem eine Abhängigkeit der Feldstärken von den Temperaturschwankungen der unteren Troposphärenschichten gezeigt hatte, wurde unter Heranziehung des Luftdruckverlaufes und der Temperaturänderungen der 700 mb-Fläche eine Erhöhung des Korrelationskoeffizienten bei Verwendung von Tageswerten auf 0.58 festgestellt. Neben der Abhängigkeit der Feldstärken von der jeweils herrschenden Luftmasse, von der Höhe der 700 mb-Fläche u.a. wurden die Feldstärkeerhöhungen bei Vergrößerung des vertikalen Temperatursprunges an Inversionen untersucht und in Diagrammen mitgeteilt. Die Feldstärkeabhängigkeit mit der Entfernung ergab eine Kurve, die für Entfernungen über 300 km etwas unterhalb der vom Meteorologischen Observatorium Kühlungsborn mitgeteilten Kurve lag und außerdem etwas höhere Werte zeigt als die auf der CCIR-Konferenz in Warschau 1956 neuen mitgeteilten amerikanischen Feldstärkekurven.

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Summary The results of field-strength-measurements over some propagation paths in the frequency range from 88–100 Mc are presented. On the average the lowest field-strength could be observed in June and December. There was found a correlation between the temperature gradient at inversions and the field-strength when using the average values of field-strenght and the single values. The correlation coefficient between the field-strength and the temperature gradient at the inversions is a function of the length of the propagation path. In the same way the amplitude of the daily variation of field-strength depends on the length of the propagation path; the values being a maximum at a distance of 200 to 300 km. With a coefficient of 0.49 there was found a good correlation between the field-strength and the air pressure variation at ground level. As there also exists a correlation between the field-strength and the temperature variations in the lower part of the troposphere a better correlation coefficient of 0.58 was found when comparing the field-strength with the air pressure variation and the variation of the temperature at the 700 mb-level.There are given some diagrams of the field-strengt dependent upon the available air mass, the height of the 700 mb-level a.o. Some diagrams present the field-strength variation with varying temperature gradient on inversions.As to the field-strength variation with distance there was found a curve which for more than 300 Km is somewhat below this curve that was measured by the Meteorological Observatory Kühlungsborn. The curve showed somewhat higher values compared with one curve which wac published in a document of the USA presented at the CCIR Assembly in Warsaw in 1956.

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