Steady state geotherm,thermal disturbances,and tectonic development of the lower lithosphere underneath the Gibeon Kimberlite Province,Namibia

The Gibeon Kimberlite Province of southern Namibia comprises more than 75 group 1 kimberlite pipes and dykes. From the Gibeon Townsland 1 pipe, 38 upper mantle xenoliths (23 garnet lherzolites and 15 garnet harzburgites) were collected and minerals were analysed by electron microprobe for major elements. Pressures and temperatures of crystallisation for xenoliths with either coarse equant, porphyroclastic and mosaic-porphyroclastic textures were estimated by a number of combinations of geothermometers and geobarometers judged to be reliable and accurate for peridotites by Brey and Köhler (1990): The P-T estimates for equilibrated xenoliths agree within the errors of the methods and plot within the stability field of graphite. The P-T values for coarse equant xenoliths fall close to a geothermal gradient of about 44?mW/m² within a very restricted pressure range. The porphyroclastic xenoliths yield similar and higher temperatures at similar depths. In these xenoliths Ca in orthopyroxene and Ca in olivine increase towards the rims and are high in the neoblasts indicating a stage of transient heating at depth. The mosaic-porphyroclastic xenolith minerals yield the highest temperatures, are unzoned and indicate internal mineral equilibrium. The depth of origin for the xenoliths from Gibeon Townsland 1 ranges from 100 to 140 km. The “cold”, coarse equant peridotites are relatively enriched garnet lherzolites with comparatively (to the “hot” peridotites) low modal orthopyroxene contents, whereas the “hot”, mosaic-porphyroclastic peridotites are depleted garnet harzburgites with high modal amounts of orthopyroxene. This is opposite to the findings for peridotites from the Kaapvaal craton where the cold peridotites are depleted harzburgites with high modal orthopyroxene and many of the hot peridotites are fertile lherzolites with low modal abundance of orthopyroxene. We present a model in which the high temperature, depleted garnet harzburgites are equated to the cold, coarse equant peridotites from the Kaapvaal craton. It is envisaged that this material was detached and transported laterally by an upwelling, deflected plume.     

Determination of the miscibility gap on the solid solution series paragonite-margarite by means of the infrared spectroscopy

In order to study the miscibility gap of the solid solution series margarite-paragonite oxide mixtures corresponding to intermediate compositions were crystallized at H₂O-pressures between 1 and 6 kb at 400 to 600 °C. Run products were examined by x-ray method and IR-spectroscopy; the latter proved to be the tool which allowed to distinguish between the two phases, the calcic and the sodic mica. A solvus exists in the region between 20 and 50 mole% margarite. Its width is temperature-dependent with a critical temperature above 600 °C.     

Genauigkeit von Zeitsignalaufnahmen bei verschiedenen Registriermethoden

Zusammenfassung Es wird untersucht, ob die Einführung der Registrierung von Zeitzeichen mittels eines elektronischen Dezimalzählers beim Zeitdienst gegenüber der Registrierung mittels Drehspulschnellschreiber eine Verminderung der zufälligen Aufnahmefehler erbracht hat. Es zeigt sich eine Genauigkeitssteigerung im Rahmen des zu Erwartenden.Ein Vergleich mit den Ergebnissen einiger anderer Aufnahmeverfahren zeigt, daß die elektronische Registrierung bezüglich der zufälligen Aufnahmefehler international durchaus Schritt halten kann.

---

On the precision of time signal records of different recording methods

Summary It is examined whether or not the introduction of an electronic decimal counter into the Time Service of the German Hydrographic Institute for the record of time signals has resulted in a decrease of the accidental errors occurring in the reception of time signals in comparison with the accidental errors met with when using a high speed siphon recorder. The increase in precision corresponds to what was to be expected from this method.A comparison with the results obtained from some other recording methods shows that with regard to accidental recording errors electronic recording comes fully up to international standard.

---

Sur la précision de la réception des signaux horaires dans les méthodes différentes d'enregistrement

Résumé Dans le travail actuel on examine si l'introduction d'un compteur électronique décimal dans les services horaires du Deutsches Hydrographisches Institut pour l'enregistrement des signaux horaires a réduit les erreurs aléatoires de la réception des signaux par comparaison avec les erreurs se présentant dans l'enregistrement d'un siphon recorder rapide. L'augmentation de la précision est égale à ce que l'on pouvait en espérer.La comparaison avec les résultats obtenus à l'aide de plusieurs d'autres méthodes d'enregistrement montre que par rapport aux erreurs aléatoires de réception les enregistrements électroniques correspondent tout à fait à l'étalen international de précision.

     

Geochemie des Apatits in Tiefengesteinen am Beispiel des Odenwaldes

Summary The apatite in various igneous rocks (from quartzmonzonitic to gabbroic composition) in one and the same area of differentiation was geochemically examined. The samples were taken from 24 different localities in the Odenwald (Germany) and the thin sections were determined petrographically with a point counter. 25 kg of each sample were dressed and the apatite separated from the heavy mineral concentrates. The pure apatite was analysed quantitative chemically. The variable components of the apatite are represented diagrammatically as functions of the rockchemistry, the physical- and the X-ray constants and their relationships are discussed. The following relations were established: The F-content of magmatic apatites increases in the acidic rocks without showing a stringent lawfulness to the rockchemistry. F remains in all apatites, compared with Cl, OR and 0, alwavs in predominance.With increase in the content of F the refractive index, as well as the lattice constants of the apatites, decrease.The Cl-content of magmatic apatites increases towards the basic rocks, but here too it remains much less than the amount of F. Further more all other statements refering to F can be applied to Cl, but with opposite meaning.A comparison of the chemical analyses of apatites from the newer literature and these of the author reveals in all probability that there is only a limited miscibility between F- and Cl-apatites. The limit being 20 atom per cent Cl. The relation of F : Cl as 1:1 in some apatites might be attributed to an orderly arranged state of the F- and Cl-apatites.OH behaves in a similar manner as Cl, except that the results have wider dispersion effect.According to the chemical equivalence calculations there is generally a small excess of cations. This means that Oxygen must fill up free halogen-places in the lattice.The content of SiO₂ of the apatites shows an increasing tendency towards in the basic rocks and the content of P₂O₅ a decreasing one.The contents of the rare earths of magmatic apatites increase in acidic rocks and only those ones with even numbers (with the exception of La) appear.Only apatites from rocks with metamorphic characteristics had an amount of SO₃.By means of a comparison between the exploit of apatite and P₂O₅-contents of the rocks can be supposed with probability that the principal quantity of the P₂O₅ in the magmatic rocks is not bound to the apatite but to the silicates. This supposition will shortly be further examined.The relative increasing of the intensity of the line (0002) and (0004) in the X-ray-graphs (X-ray-goniometer) in the F-rich apatites suggests a better (0001)-cleavage as in the Cl-rich apatites. This observation can be explained easily with the different structures of the F- and the Cl-apatites.     

Untersuchungen über den Anteil bestimmter Atmosphärenschichten am Zustandekommen von Bodendruckänderungen

Zusammenfassung Um den Beitrag verschiedener atmosphärischer Schichten am Zustandekommen der Bodendruckänderungen zu studieren, wird mit Hilfe der Kontinuitätsgleichung und der Vorticitygleichung die sogenannte reziproke Wirbelgleichung abgeleitet. An Hand eines konkreten Falles wird das Integral über diese Gleichung über die ganze Atmosphäre numerisch ausgewertet. Der Integrand kann hiebei als Beitrag einer bestimmten Schicht zur Bodendruckänderung angesehen werden, da nur die lokale und zweidimensional-konvektive Änderung der reziproken Vorticity maßgeblich ist. Im Zusammenhang mit dieser Analyse werden auch Aussagen über das kompensierende Verhalten der Schichten der freien Atmosphäre gemacht. Die Schwierigkeiten und Ungenauigkeiten der Wirbelanalyse werden dann durch Einführung einer skalaren Größe (potentielle Temperatur) zu umgehen versucht. Hiebei wird die Divergenz auf denp-Flächen aus entsprechenden Änderungen der potentiellen Temperatur abgeleitet. Qualitativ zeigen beide Methoden im wesentlichen dieselben Ergebnisse, nämlich daß im Mittel den größten Beitrag zu den Bodendruckänderungen die höheren Schichten der Troposphäre liefern; allerdings wurde der Einfluß der bodennahen Schicht in der Untersuchung nicht berücksichtigt.

---

Summary The so-called reciprocal vorticity equation is derived with the aid of the continuity equation and the vorticity equation to study the part the different atmospheric layers have in Bringing about surface pressure variations. By a concrete example the integral of this equation over the entire atmosphere is numerically evaluated. Therein the integrand can be considered as contribution of a determined layer to the variation of the surface pressure, as only the local and two-dimensionally convective variation of the reciprocal vorticity is to be referred to. In connection with this analysis the compensating effect of the layers of the free atmosphere is discussed, too. An attempt has been made to avoid difficulties and inaccuracies in analyzing the vorticity by introduction of a scalar quantity (potential temperature). Thereby the divergence on thep-surfaces is deduced from corresponding variations of the potential temperature. Qualitatively, both methods lead practically to the same results which means that, on the average, the higher layers of the troposphere contribute mostly to the variations of the surface pressure; it is true, however, that the influence of the surface layer was not considered in this investigation.

---

Résumé Pour déterminer la part des différentes couches de l'atmosphère dans les variations de pression au sol, on a établi l'équation dite tourbillonnaire réciproque à l'aide de l'équation de continuité et de celle de vorticity. Sur la base d'un cas concret on calcule l'intégrale de cette équation, étendue à toute l'atmosphère. On peut considérer l'intégrande comme apport d'une couche déterminée à la variation de pression au sol, puisque seule la variation convective à deux dimensions de la vorticity réciproque est déterminante. Cela amène aussi à considérer l'effet compensateur des couches de l'atmosphère libre. On tente d'éviter les difficultés et les inexactitudes de l'analyse tourbillonnaire en introduisant une grandeur scalaire (température potentielle). La divergence sur les surfacesp peut alors se déduire des variations correspondantes de la température potentielle. Du point de vue qualitatif les deux méthodes fournissent à peu près les mêmes résultats, c'est à dire qu'en moyenne ce sont les couches supérieures de la troposphère qui fournissent le plus grand apport aux variations de pression au sol; il est vrai que le rôle de la couche voisine du sol n'a pas été considéré.

---

---

Mit 6 Textabbildungen     

Gewinnung biokinetischer Daten von Altwässern mit dem Respirationsfermentor. Teil 1: Methodische Grundlagen und die Bestimmung der spezifischen Wachstumsund Sauerstoffaufnahmerate

Es wird eine Fermentationsvorrichtung für die Messung des Sauerstoffverbrauchs bei wählbaren Sauerstoffpartialdrucken vorgestellt, die in einem geschlossenen Gaskreislauf einen Laboratoriumsfermentor mit Meß- und Regeleinrichtungen sowie Möglichkeiten der Probenahme aufweist. Die Druckregression durch die Kohlendioxidadsorption steuert die synchron registrierte Nachlieferung von Sauerstoffgas. Durch diskontinuierliche Kultivation eines adaptierten Belebtschlammes wurden von einem Braunkohlenpyrolyseabwasser die Sauerstoffverbrauchskurven aufgenommen. Es wurde ein polyauxischer Kurvenverlauf erhalten, wobei auf den Abbau der niederen Fettsauren, im wesentlichen Azetat, 70 … 80% des Gesamtsauerstoffverbrauchs entfielen. Hierfür werden biokinetische Daten bestimmt; ; ; μ_max = 0,56 h^–1 (ausgewählte Werte). Die bei der Erfassung und Errechnung der Daten auftretenden Probleme wurden diskutiert.     

Die Verbindung Cu2FeSnSe3,8 im Vergleich zum Zinnkies

Zusammenfassung Die Phase Cu₂FeSnSe_3,8 ist tetragonal, Raumgruppe mit ₀=5.69 undc ₀=11,26 Å.Z=2,D _x=5,441. Synthesetemperatur: 410°C.

---

The compound Cu₂FeSnSe_3,8 in comparison to stannite

Summary The phase Cu₂FeSnSe_3,8 is tetragonal, space-group with ₀=5.69 andc ₀=11.26 Å.Z=2,D _x=5.441. Temperature of synthesis: 410°C.

     

Simultane interpretation geophysikalischer messdatensysteme

Summary After general definitions in1 and deducing a special method in2, it will be shown in3 on a simple concrete example the effectiveness of the simultaneous interpretation of two series of data belonging two different geophysical methods, namely, it can be determined in the simultaneous way deep values, too, although both methods, separately, are not capable under the given conditions even for estimation of the great order of the deep. In4 there are some conclusions; above all it is emphasized for any geophysical method the necessity and importance of the general applicable form of the interpretation procedures.     

Die Zielsetzung einer allgemeinen quantitaiven Methode in der Gravimetrie

Summary After introduction in 1. and definitions in 2.A. the separately well known or evident relations representing the fundamental problems of the interpretation in the gravity are perpicuously summarised in 2.b. by means of the group theory. From the the following conclusions can be drawn (in 2.C.): 1.) from the point of view of the quantitative interpretation all gravity-maps are totally equivalent in respect of both their ambiguity and the informations that they are able to give, 2.) the quantity of the informations obtained from the gravity maps is growing withthe increasing number of other informations and with greater accuracy of the measurements. Therefore the development of a general quantitative method is proposed (with concrete points of views), to realise the theoretical possibilities.-In 3.) some problems of the derivative maps are discused in connection with the foregoings.