Chemical composition and physical properties of lithium-iron micas from the Krušné hory Mts. (Erzgebirge)

Compositions of natural lithium-iron micas are approximated best by the sidero-phyllite-polylithionite join. These micas contain little or no magnesium and manganese. Their octahedral sheets contain close to two trivalent cations (mainly aluminum) in small crystallographic sites and a variable quantity of lithium and R⁺² (mainly iron) in large sites. Octahedral vacancies are situated mostly in large sites. Lithium and R⁺² approach a 44 replacement relationship in micas with octahedral occupancy close to six. Lithium and fluorine show a good positive correlation (small excess of fluorine over lithium), which indicates a crystallochemical association between them. There is a less distinct positive correlation between lithium and R⁺⁴.Based on simplifications, a calculation shows that about two-thirds of octahedral vacancies are caused by substitutions within the octahedral sheet, one-third, by tetrahedral substitutions. Different methods of calculating the crystallochemical formula yield slightly different numbers of octahedral vacancies, but do not affect the mica's position in plots of physical parameters against composition. If a crystallochemical formula is calculated from analysis of a mica contaminated with quartz, topaz, or feldspar, the apparent number of octahedral vacancies increases; such a formula exhibits unusual behavior in composition plots.     

Measurements of gradients of gravity in mines

¶rt;am mu ¶rt; m mua nu¶rt;nmuaa u nmm a u n¶rt;nuu, m nmm m u u amu m ma u. auam mam a¶rt;ua¶rt;um ama mamau, nu nu nu ¶rt;u m¶rt;.     

Griquait mit rhombischem Pyroxen (Granatwebsterit) von Borek bei Stupná bei Křemže (Krems) in Böhmen

Zusammenfassung Es wird das Vorkommen von Griquait mit rhombischem Pyroxen (Granatwebsterit) von einem Feld am Borekwald, kaum 1 km westlich von der Gemeinde Stupná bei Keme südöstlich von eské Budjovice (Böhm. Budweis), beschrieben. Den Mineralgehalt des untersuchten Gesteines bilden Enstatit, Endiopsid, Pyrop, Amphibol, Spinell, Plagioklas und ein Mineralgemengteil in Form von Kelyphit oder Symplektit. Das Gestein fällt durch seinen hohen Gehalt an Magnesium auf. Es wird für saures Äquivalent der Peridotite gehalten.

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Griquaite with orthorhombic pyroxene (Garnetic Websterite) from Borek at Stupná near Keme in Bohemia

Summary The occurrence of griquaite with orthorhombic pyroxene (garnetic websterite) is described; it lies in a field near the Borek forest, scarcely 1 km west of the village Stupná near Keme, SE of eské Budjovice (South Bohemia). The mineral content of the rock studied consists of enstatite, endiopside, pyrope, amphibole, spinel, plagioclase and a mixture of minerals in the form of kelyphite or symplectite. The rock is interesting because of its high magnesium content. It is considered to be an acid equivalent of peridotite.

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Mit 1 Abbildung     

Die lokale Beeinflussung eines stehenden Gewässers durch eine punktförmige Abwasserbelastung; ein direkter Nachweis der wachstumsbegrenzenden Wirkung des Phosphors im Vierwaldstättersee

Zusammenfassung Die Beeinflussung des Vierwaldst?ttersees (Horwer Bucht) durch den mit dem Abwasser von 10 000 Einwohnern belasteten Steinibach liess sich im Oberfl?chenwasser auf eine Distanz von mehr als 2 km verfolgen (Abb. 1a, 1b, 1c). Es zeigte sich, dass eine erh?hte Phosphorzufuhr eine verst?rkte biogene Nitratzehrung erm?glicht. Die Abh?ngigkeit der Pigmentkonzentration y von der Gesamtphosphorkonzentrationx liess sich durch die folgende Mitscherlich-Gleichung beschreiben: log(30-y)=log 30–0,012 (x−6) Damit wurde im Vierwaldst?ttersee erstmals unter v?llig natürlichen Bedingungen die Beeinflussung der Prim?rproduktion durch eine erh?hte Phosphorkonzentration nachgewiesen (Abb. 2). Die Erfolgsaussichten von Abwassersanierungsmassnahmen an Seen verschiedener Trophiegrade werden diskutiert.

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Summary The influence of the ‘Steinibach” tributary, into which the wastewater of 10,000 inhabitants is discharged, on the Lake of Lucerne (Horwer Bucht) is detectable in the surface water over a distance of more than 2 km (Picture 1a, 1b, 1c). It was revealed that the increased phosphorus supply enables more intensive biological nitrate consumption. The dependence of the pigment concentration,y, on the total phosphorus concentration,x can be expressed by the following Mitscherlich equation: log (30−y)=log 30–0.012 (x−6). This was the first time that the influence of an increased phosphorus concentration on primary production was proved in the Lake of Lucerne under completely natural conditions (Picture 2). The possibilities of implementing successful water pollution control measures in lakes with various trophic levels are discussed.

     

Core waves recorded in central Europe

Summary The core waves recorded at four seismograph stations in Central Europe were investigated with the aim to find the most suitable set of travel-time curves and a fitting model of the core structure. Another travel-time curve was constructed by means of time differences between the core phases. The differences in the features of the travel-time curves were studied using records of shallow, intermediate and deep shocks from the same focal region (Tonga).     

Magnetism of natural pyrrhotite,haematite and ilmenite

Summary The paper deals with the magnetic properties of the natural minerals haematite, ilmenite and pyrrhotite. The natural remanent magnetization J_n, the volume susceptibility , the specific magnetization of saturation _so, the Curie temperature , the A.C. demagnetization of natural remanent magnetization, the thermal demagnetization J_n, the temperature dependence of the specific magnetization of saturation, and several other parameters were determined for the individual sets of minerals. Since natural minerals can and do contain various heterogeneous and isomorphic admixtures, their magnetic properties may change depending on the content and type of these admixtures. Therefore, all the investigations of the magnetic properties described in this paper were carried out with extensive sets of minerals, representing various Czechoslovak and world localities. A number of interesting results were obtained from the executed experiments, e.g., the different stability of the natural remanent magnetization of haematite with respect to A.C. demagnetization, the presence and type of heterogeneous inclusions in ilmenite, the phase changes connected with the -transition in natural pyrrhotites, etc. The types of distributions of the investigated values of the magnetic properties were also determined.     

Volles Gewicht einer im Refraktionsmilieu gemessenen Grösse (Teil I)

Summary As regards the concept of complete weight p with which an observed quantity (e.g., the direction of theA–G net) should enter the net adjustment, according to Eq.(1), apart from the fundamental weight p ₀ ), determined by the number of repetitions, it should also contain the time parameter p_t according to Eq.(11), where c>1 is a constant, and t is the number of days of observation, and also the refraction factor p_r according to Eqs(17, 18), where q is the structural weight of the direction. The condition for being able to determine p_r with the directions is observation by means of the three-directional vertex method[2], because it is not possible to localize lateral refraction by angular methods. The theory of complete weight is in favour of observations with a high fundamental weight p ₀ which automatically yield higher values of t, and also of p_t. The introduction of the complete weight into the experimental directional net in Fig. 2 caused the mean value of the uneliminated refraction error to decrease from 0.24 to 0.12, the mean square error of the adjusted direction being 0.17. The value of the constant c was investigated and the method of determining the parameter p_r was derived also for lengths measured electro-optically. Mention is made of the effect of complete weights on the length adjustment of a net in[6].     

Comment on some relations between the shape of streamlines and frontal interface in the proximity of a cyclonic vortex

Zusammenfassung Es wird ein einfaches Modell des zykolnalen Wirbels vorgeschlagen und die Beziehung zwischen seiner Intensität, der Form der Stromlinien und der Deformation der frontalen Grenzoberfläche in seiner Nähe diskutiert. Die Arbeit verfolgt das Ziel, die Kriterien der sogenannten dynamischen Klassifikation der aus den meteorologischen Satelliten photographierten Bewölkung zu finden.     

Die Ersatzkugel in geodätischen Berechnungen

Summary For precise geodetic computations over larger distances the reference surface of an ellipsoid of rotation should be used. However it is often replaced by a sphere of an adequate radius. The formulae are derived from figures which usually represent the conditions in a cross-section of the ellipsoid and the reference sphere through the normal plane. Equation (9) is given for the differences s of the length of the ellipse arc of the normal section and the corresponding arc of the circle with radius R. Also Eq. (19) is given for the distance d between the ellipse of the normal section and the circle (at the end point). Both equations are applied for various radii of the reference sphere. Table 1 shows the values s, Tab. 2 and Fig. 2 give the d-values for chosen lengths. It was found that especially the distance between the ellipsoid and the sphere need not always be negligible.     

Quadruplet orientation of aerial photographs

Summary A new procedure of the relative orientation of pencils of light reconstructed from aerial photographs having 60% end and side overlaps is suggested. The basic unit for the procedure is a quadruplet of photographs forming a square. The geometrical characteristics of a block of photographs with 60% overlaps are exploited fully, and, the present author believes, that way an optimum relative orientation of all photographs within the block can be achieved.