ALBERT

Description: In order to better understand the role of fluids during subduction and subsequent exhumation, we have investigated whole-rock and mineral chemistry (major and trace elements) and Li, B as well as O, Sr, Nd, Pb isotopes on selected continuous drill-core profiles through contrasting lithological boundaries from the Chinese Continental Scientific Drilling Program (CCSD) in Sulu, China. Four carefully selected sample sets have been chosen to investigate geochemical changes as a result of fluid mobilization during dehydration, peak metamorphism, and exhumation of deeply subducted continental crust. Our data reveal that while O and Sr-Nd-Pb isotopic compositions remain more or less unchanged, significant Li and/or B isotope fractionations occur between different lithologies that are in close contact during various metamorphic stages. Samples that are supposed to represent prograde dehydration as indicated by veins formed at high pressures (HP) are characterized by element patterns of highly fluid-mobile elements in the veins that are complementary to those of the host eclogite. A second sample set represents a UHP metamorphic crustal eclogite that is separated from a garnet peridotite by a thin transitional interface. Garnet peridotite and eclogite are characterized by a 〉10% difference in MgO, which, together with the presence of abundant hydroxyl-bearing minerals and compositionally different clinopyroxene grains demonstrate that both rocks have been derived from different sources that have been tectonically juxtaposed during subduction, and that hydrous silicate-rich fluids have been added from the subducting slab to the mantle. Two additional sample sets, comprising retrograde amphibolite and relatively fresh eclogite, demonstrate that besides external fluids, internal fluids can be responsible for the formation of amphibolite. Li and B concentrations and isotopic compositions point to losses and isotopic fractionation during progressive dehydration. On the other hand, fluids with isotopically heavier Li and B are added during retrogression. On a small scale, mantle-derived rocks may be significantly metasomatized by fluids derived from the subducted slab. Our study indicates that during high-grade metamorphism, Li and B may show different patterns of enrichment and of isotopic fractionation.

Description: The Itajaí Basin located in the southern border of the Luís Alves Microplate is considered as a peripheral foreland basin related to the Dom Feliciano Belt. It presents an excellent record of the Ediacaran period, and its upper parts display the best Brazilian example of Precambrian turbiditic deposits. The basal succession of Itajaí Group is represented by sandstones and conglomerates (Baú Formation) deposited in alluvial and deltaic-fan systems. The marine upper sequences correspond to the Ribeirão Carvalho (channelized and non-channelized proximal silty-argillaceous rhythmic turbidites), Ribeirão Neisse (arkosic sandstones and siltites), and Ribeirão do Bode (distal silty turbidites) formations. The Apiúna Formation felsic volcanic rocks crosscut the sedimentary succession. The Cambrian Subida leucosyenogranite represents the last felsic magmatic activity to affect the Itajaí Basin. The Brusque Group and the Florianópolis Batholith are proposed as source areas for the sediments of the upper sequence. For the lower continental units the source areas are the Santa Catarina, São Miguel and Camboriú complexes. The lack of any oceanic crust in the Itajaí Basin suggests that the marine units were deposited in a restricted, internal sea. The sedimentation started around 600 Ma and ended before 560 Ma as indicated by the emplacement of rhyolitic domes. The Itajaí Basin is temporally and tectonically correlated with the Camaquã Basin in Rio Grande do Sul and the Arroyo del Soldado/Piriápolis Basin in Uruguay. It also has several tectono-sedimentary characteristics in common with the African-equivalent Nama Basin.

Description: Most studies dealing with material properties of sandstones are based on a small data set. The present study utilizes petrographical and petrophysical data from 22 selected sandstones and ~300 sandstones from the literature to estimate/predict the material and weathering behaviour of characteristic sandstones. Composition and fabric properties were determined from detailed thin section analyses. Statistical methods applied consist of data distributions with whisker plots and linear regression with confidence regions for the petrophysical and weathering properties. To identify similarities between individual sandstones and to define groups of specific sandstone types, principal component and cluster analyses were applied. The results confirm an interaction between the composition, depositional environment, stratigraphic association and diagenesis, which leads to a particular material behaviour of sandstones. Three different types of pore radii distributions are observed, whereby each is derived from different pore space modifications during diagenesis and is associated with specific sandstone types: (1) bimodal with a maximum in capillary and micropores, (2) unimodal unequal with a maximum in smaller capillary pores and (3) unimodal equable with a maximum in larger capillary pores. Each distribution shows specific dependencies to water absorption, salt loading and hygric dilatation. The strength–porosity relationship shows dependence on the content of unstable lithic fragments, grain contact and type of pore radii distribution, cementation and degree of alteration. Sandstones showing a maximum of capillary pores and micropores (bimodal) exhibit a distinct hygric dilatation and low salt resistance. These sandstones are highly immature sublitharenites–litharenites, characterized by altered unstable rock fragments, which show pointed-elongated grain contacts, and some pseudomatrix. Quartz arenites and sublitharenites–litharenites which are strongly compacted and cemented, show unimodal unequal pore radii distributions, low porosity, high strength and a high salt resistance. The presence of swellable clay minerals in sublitharenites–litharenites leads to a medium to high hygric dilatation, whereas quartz arenites show little hygric dilatation. Sandstones with unimodal equal pore radii distribution mostly belong to weakly compacted and cemented mature quartz arenites. These are characterized by high water absorption and high porosity, low to medium strength and a low salt resistance. The data compiled in this study are used to create a sandstone quality catalogue. Since material properties are dependent on many different parameters of influence, the transition between different lithotypes is fluent.

Description: The lattice-preferred orientation (LPOs) of two late-Variscan granitoids, the Meissen monzonite and the Podlesí dyke granite, were determined from high-resolution time-of-flight neutron diffraction patterns gained at the diffractometer SKAT in Dubna, Russia. The results demonstrate that the method is suitable for the LPO analysis of polyphase, relatively coarse-grained (0.1–6 mm) rocks. The Meissen monzonite has a prominent shape-preferred orientation (SPO) of the non-equidimensional minerals feldspar, mica and amphibole, whereas SPO of the Podlesí granite is unapparent at the hand-specimen scale. The neutron diffraction data revealed distinct LPOs in both granitoids. The LPO of the non-equidimensional minerals feldspar, mica and amphibole developed mainly during magmatic flow. In the case of the Meissen monzonite, the magmatic flow was superimposed by regional shear tectonics, which, however, had no significant effect on the LPOs. In both samples, quartz shows a weak but distinct LPO, which is atypical for plastic deformation and different in the syn-kinematic Meissen monzonite and the post-kinematic Podlesí granite. We suggest that, first of all, the quartz LPO of the Meissen monzonite is the result of oriented growth in an anisotropic stress field. The quartz LPO of the Podlesí granite, which more or less resembles a deformational LPO in the flattening field of the local strain field, developed during magmatic flow, whereby the rhombohedral faces of the quartz crystals adhered to the (010) faces of aligned albite and to the (001) faces of zinnwaldite. Due to shape anisotropy of their attachments, the quartz crystals were passively aligned by magmatic flow. Thus, magmatic flow and oriented crystal growth are the major LPO-forming processes in both granitoids. For the Meissen monzonite, the solid-state flow was too weak to cause significant crystallographic re-orientation of the minerals aligned by magmatic flow. Finally, the significance of our results for the evaluation of the regional tectonic environment during magma emplacement is discussed. The discussion on the regional implications of the more methodologically oriented results provides the basis for future, more regionally aimed studies in view of the fabric characteristics of such plutons and their developing mechanisms.

Description: The Eastern Sierras Pampeanas were structured by three main events: the Ediacaran to early Cambrian (580–510 Ma) Pampean, the late Cambrian–Ordovician (500–440 Ma) Famatinian and the Devonian-Carboniferous (400–350 Ma) Achalian orogenies. Geochronological and Sm–Nd isotopic evidence combined with petrological and structural features allow to speculate for a major rift event (Ediacaran) dividing into two Mesoproterozoic major crustal blocks (source of the Grenvillian age peaks in the metaclastic rocks).This event would be coeval with the development of arc magmatism along the eastern margin of the eastern block. Closure of this eastern margin led to a Cambrian active margin (Sierra Norte arc) along the western margin of the eastern block in which magmatism reworked the same crustal block. Consumption of a ridge segment (input of OIB signature mafic magmas) which controlled granulite-facies metamorphism led to a final collision (Pampean orogeny) with the western Mesoprotrozoic block. Sm–Nd results for the metamorphic basement suggest that the TDM age interval of 1.8–1.7 Ga, which is associated with the less radiogenic values of εNd(540) (−6 to −8), can be considered as the mean average crustal composition for the Eastern Sierras Pampeanas. Increasing metamorphic grade in rocks with similar detrital sources and metamorphic ages like in the Sierras de Córdoba is associated with a younger TDM age and a more positive εNd(540) value. Pampean pre-540 Ma granitoids form two clusters, one with TDM ages between 2.0 and 1.75 Ga and another between 1.6 and 1.5 Ga. Pampean post-540 Ma granitoids exhibit more homogenous TDM ages ranging from 2.0 to 1.75 Ga. Ordovician re-activation of active margin along the western part of the block that collided in the Cambrian led to arc magmatism (Famatinian orogeny) and related ensialic back-arc basin in which high-grade metamorphism is related to mid-crustal felsic plutonism and mafic magmatism with significant contamination of continental crust. TDM values for the Ordovician Famatinian granitoids define a main interval of 1.8–1.6, except for the Ordovician TTG suites of the Sierras de Córdoba, which show younger TDM ages ranging from 1.3 to 1.0 Ga. In Devonian times (Achalian orogeny), a new subduction regime installed west of the Eastern Sierras Pampeanas. Devonian magmatism in the Sierras exhibit process of mixing/assimilation of depleted mantle signature melts and continental crust. Achalian magmatism exhibits more radiogenic εNd(540) values that range between 0.5 and −4 and TDM ages younger than 1.3 Ga. In pre-Devonian times, crustal reworking is dominant, whereas processes during Devonian times involved different geochemical and isotopic signatures that reflect a major input of juvenile magmatism.

Description: The expansion processes that develop in building stones upon changes of moisture content may be an important contributing factor for their deteriorations. Until recently, few data could be found in the literature concerning this parameter and weathering processes. Moreover, the processes that may be responsible for the moisture related expansion of natural building stones are not yet completely understood. To further elucidate this process, extensive mineralogical, petrophysical and fabric investigations were performed on eight German sandstones in order to obtain more information regarding the weathering process and its dependence on the rock fabric. The analysed sandstones show a wide range of pore size distributions and porosities. A positive correlation with the fabric and the pore space can be found for all studied petrophysical parameters. The intensity of the expansion and related swelling pressure cannot be attributed only to the swelling of clay minerals. The investigations suggest that the micropores and the resulting disjoining pressure during wet/dry cycles also play an important role. The results obtained suggest that the mechanism is related to the presence of liquid water within the porous material.

Description: The profitable production of dimension stone mainly depends on the extractable block size. The regularity and volume of the blocks are of critical importance, and are controlled by the three-dimensional pattern of the discontinuity system. Therefore, optimization of block size has to be the aim when quarrying for natural stone. This is mainly connected to the quantification of joints and fractures, i.e., their spacing and orientation. The problem of finding unfractured blocks within arbitrarily oriented and distributed planes can be solved effectively by a numerical algorithm. The main effects of joint orientations on block sizes and shapes will be presented in this article. Quantification of unfractured blocks with the aim of optimization is illustrated by detailed studies on several quarries. The algorithm used in this study can be applied as a powerful tool in the planning of a quarry and the future exploitation of dimension stone. Application of the described approach is demonstrated on practical examples of quarrying natural stones, namely, sandstone, granite, rhyolite, etc. Block quarrying can be optimized by using the new 3D-BlockExpert approach. The quantification of unfractured rock masses is also shown to contribute to a more ecological protection and the sustainable use of natural resources.

Description: Damages to natural building stones induced by the action of frost are considered to be of great importance. Commonly, the frost resistance of building stones is checked by standardised freeze–thaw tests before using. Corresponding tests normally involve 30–50 freeze–thaw action cycles. In order to verify the significance of such measurements, we performed long-term tests on four selected rocks over 1,400 freeze–thaw action cycles. Additionally, numerous petrophysical parameters were analysed to compare the behaviour of rocks in the weathering tests according to the current explanatory models of stress formation by growing ice crystals in the pore space. The long-term tests yield more information about the real frost sensibility of the rocks. A clear deterioration cannot be determined in most cases until 50 weathering cycles have been completed. In the freeze–thaw tests, the samples are also stressed by changing temperature and moisture, indicating that different decay mechanisms can interfere with each other. Thus, thermohygric and moisture expansion are important damage processes.

Description: Owing to its long building history, different types of building stones comprised the construction of the Cologne Cathedral. Severe damage is observed on the different stones, e.g., sandstones, carbonate, and volcanic rocks, especially when the different stone materials neighbor the medieval “Drachenfels trachyte” from the “Siebengebirge”. The question arises, “Is the insufficient compatibility of the implemented building materials causatively related to the strong decay of the Drachenfels trachyte?” The present investigations focus on the petrography and mineralogical composition of eight different stones from the Cologne Cathedral. Petrophysical data, i.e., phase content, moisture and thermal characteristics as well as strength properties are determined and discussed in correlation to each other, showing that not only in terms of lithology great differences exist, but also the petrophysical properties strongly diverge. The ascertained parameters are discussed in view of the deterioration behavior and decay mechanisms of the different stones. To evaluate the compatibility of original, replacement and modern building materials, the properties of the investigated stones are compared to those of Drachenfels trachyte by means of constraints given in the literature. Besides optical properties, petrophysical criteria are also defined as well as strength values. It could be shown that primarily moisture properties, i.e., capillary and sorptive water uptake, water saturation, drying processes and moisture dilatation can be addressed to the deterioration processes.

Description: The range of substrates that the bone-eating marine worm Osedax is able to consume has important implications for its evolutionary history, especially its potential link to the rise of whales. Once considered a whale specialist, recent work indicates that Osedax consumes a wide range of vertebrate remains, including whale soft tissue and the bones of mammals, birds and fishes. Traces resembling those produced by living Osedax have now been recognized for the first time in Oligocene whale teeth and fish bones from deep-water strata of the Makah, Pysht and Lincoln Creek formations in western Washington State, USA. The specimens were acid etched from concretions, and details of the borehole morphology were investigated using micro-computed tomography. Together with previously published Osedax traces from this area, our results show that by Oligocene time Osedax was able to colonize the same range of vertebrate remains that it consumes today and had a similar diversity of root morphologies. This supports the view that a generalist ability to exploit vertebrate bones may be an ancestral trait of Osedax.

Description: Forests in lowland Bolivia suffer from severe deforestation caused by different types of agents and land use activities. We identify three major proximate causes of deforestation. The largest share of deforestation is attributable to the expansion of mechanized agriculture, followed by cattle ranching and small-scale agriculture. We utilize a spatially explicit multinomial logit model to analyze the determinants of each of these proximate causes of deforestation between 1992 and 2004. We substantiate the quantitative insights with a qualitative analysis of historical processes that have shaped land use patterns in the Bolivian lowlands to date. Our results suggest that the expansion of mechanized agriculture occurs mainly in response to good access to export markets, fertile soil, and intermediate rainfall conditions. Increases in small-scale agriculture are mainly associated with a humid climate, fertile soil, and proximity to local markets. Forest conversion into pastures for cattle ranching occurs mostly irrespective of environmental determinants and can mainly be explained by access to local markets. Land use restrictions, such as protected areas, seem to prevent the expansion of mechanized agriculture but have little impact on the expansion of small-scale agriculture and cattle ranching. The analysis of future deforestation trends reveals possible hotspots of future expansion for each proximate cause and specifically highlights the possible opening of new frontiers for deforestation due to mechanized agriculture. Whereas the quantitative analysis effectively elucidates the spatial patterns of recent agricultural expansion, the interpretation of long-term historic drivers reveals that the timing and quantity of forest conversion are often triggered by political interventions and historical legacies.

Description: David, E,: Materie im Erdinnern . . . 1 ; Reich, H.: Über die Ausbreitung seismischer Impulse in de Malmkalkplatte des schwäbisch-fränkischen Jura . . .8 ; Pietsch, D.: Ein Verfahren zur direkten Berechnung der Schichgeschwindigkeiten in der Reflexionsseismik . . . 25 ; Jung, K.: „Schweydarsche“ Formeln für die Geländewirkung auf g . . . 47 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Burkhart, K..: Mikropulsationen des Erdstroms und der erdmagnetischen Horizontalkomponenten . . . . . . . . 57 ; Wiese, H. I Tiefentellurik . . . . . . . . . . 74 ; Meißner, R.: Untersuchungen über die Zusammenhänge zwischen Luftdruck und Brunnenspiegel . . . . . . . . . 81 ; Joksch, H. G.: Statistische Analyse der hypsometrischen Kurve der Erde . . 109 ; ZUSAMMENFASSUNG 1 [Burkhart, K..: Mikropulsationen des Erdstroms und der erdmagnetischen Horizontalkomponenten]: Die Erdstrombeobachtungen bei großen Elektrodenentfernungen werden denen bei kurzen Abständen gegenüber gestellt. Die Phasenverschiebung zwischen den magnetischen und den Erdstromvariationen wird durch das bekannte Verhältnis von Reaktanz und Resistanz bestimmt. Bei großen Elektrodenentfernungen und kurzen Perioden nimmt erstere stärker zu als letztere. Auch bei den Pulsationen gilt die gleiche induktive Abhängigkeit des Erdstroms von den magnetischen Schwankungen wie bei den langen Perioden. Daher kann für die Untersuchung der Erdströme von der gleichen Grundformel ausgegangen werden, die zur Bestimmung der Eichwerte der Induktionsapparatur von H und D herangezogen wird. Bei den großen Dimensionen der von den Erdströmen zurückgelegten Strecken muß die Erhöhung des wirksamen Widerstandes durch den Skineffekt noch berücksichtigt werden. Während die induktive Umsetzung für beide Komponenten konform verläuft, hat der meridional fließende Erdstrom einen etwa 3 mal so großen Erdwiderstand zu überwinden wie der zonal fließende. Die Eigeninduktivität in nordsüdlicher Richtung ist etwa 2,5 mal so groß wie in ostwestlicher. Diese Anisotropie ist tektonisch und geologisch durch die Alpen begründet. Die Auszählung der Pulsationen für verschiedene Periodenklassen zeigt ein auffallendes Maximum der Perioden von 10 bis 30 sec über die Mittagstunden. Ein Vergleich mit der EK-Kurve der E- und F1-Schicht läßt darauf schließen, daß der Ladungsaufbau dieser Schichten mit Pulsationen dieser Perioden in Zusammenhang steht. Die Tagespulsationen (10-40 Sek.) übertreffen an Häufigkeit im ganzen Pulsationsspektrum die von der Partikelstrahlung erzeugten Pulsationen langer Perioden. Letztere zeigen eine 27-tägige Wiederholungstendenz. ZUSAMMENFASSUNG 2 [Wiese, H. I Tiefentellurik - Erforschung der großräumigen elektrischen Leitfähigkeitsstruktur des tiefen Untergrundes durch geomagnetische Variationen]: Bei erdmagnetischen Variationen von weniger als 2 Stunden Dauer zeigen sich im europäischen Raum in der Vertikalkomponente auf der einen Seite gleiche Variationen an teilweise weit entfernten Observatorien, auf der anderen Seite entgegengesetzte an benachbarten Observatorien. Das ist die Wirkung einer sich im tiefen Untergrund erstreckenden Zone erhöhter elektrischer Leitfähigkeit, die sich von Spanien über Norddeutschland zum Bosperus und nach Nordafrika zieht. Eine qualitative Erklärung der Z-Variationen wird gegeben. Auch außerhalb Europas machen sich elektrische Leitfähigkeitsstrukturen im Untergrund, z. B. in Japan, Südafrika, China, Nordamerika bemerkbar. Geologisch gesehen liegen alle Strukturen außerhalb der schon im Erdaltertum konsolidierten Kratone. Für diese Methode zur Erforschung des tiefen Untergrundes wird der Name Tiefentellurik vorgeschlagen. ZUSAMMENFASSUNG 3 [Meißner, R.: Untersuchungen über die Zusammenhänge zwischen Luftdruck und Brunnenspiegel]: Aufgrund von Durchströmversuchen durch Sande der verschiedensten Durchfeuchtung und Korngröße wird ein Durchflußgesetz für Luft (ähnlich dem Darcy’schen Gesetz für Wasserdurchfluß) gefunden. Es dient als Grundlage zur Berechnung des Eindringens von Luftdruckschwankungen in den Erdboden. Durch Druckfifferenzen zwischen dieser in den Erdboden eindringenden Luft und dem gerade am Brunnenspiegel herrschenden äußeren Luftdruck können bei sehr feinen Böden und größeren Grundwassertiefen dem Luftdruckverlauf ähnliche Brunnenspiegelschwankungen hervorgerufen werden. Weitere Versuche mit einem künstlichem Grundwasserspiegel zeigten jedoch, daß es besonders die im Saugsaum aller feinen Sande (auch Tone, Lehme u. dergl.) enthaltenen großen eingeschlossenen Luftvolumina (in Form von Luftbläschen sind, die für die vielerorts auftretenden luftdruckähnlichen Brunnenspiegelschwankungen verantwortlich sind. Registrierungen vom künstlichen Brunnen, von vielen natürlichen Brunnen sowie von 2 Quellen weisen die verschiedensten, z. T. bis zu 10 cm groß werdenden, rein luftdruckbedingten Schwankungen auf. ZUSAMMENFASSUNG 4 [Joksch, H. G.: Statistische Analyse der hypsometrischen Kurve der Erde]: Zusammenfassung: Die hypsometrische Kurve der Erde läßt sich in zwei logarithmische Normalverteilungen und eine wahrscheinlich logarithmische Normalverteilung zerlegen. Es wird versucht, eine formale Erklärung dafür zu geben.

Description: Burkhart, K..: Mikropulsationen des Erdstroms und der erdmagnetischen Horizontalkomponenten . . . . . . . . 57 ; Wiese, H. I Tiefentellurik . . . . . . . . . . 74 ; Meißner, R.: Untersuchungen über die Zusammenhänge zwischen Luftdruck und Brunnenspiegel . . . . . . . . . 81 ; Joksch, H. G.: Statistische Analyse der hypsometrischen Kurve der Erde . . 109 ; ABSTRACT 1 [Burkhart, K..: Mikropulsationen des Erdstroms und der erdmagnetischen Horizontalkomponenten]: An observation of earth—currents obtained with electrodes of large distances is compared with that of short distances. The phasedifferences of the magnetic and earth-current-variations are fixed by the proportion of reactance and resistance. The first one increases more than the second one with large distances and short periods. The same law of induction between magnetism and earth-currents comes true in the case of the pulsations. It is possihle to use the same fundamental formula in earth-current-problems as it is done for the calculation of the values of sensitivity of the H- and D—equipment. But in the case of earth-currents the increasing effective resistance by the influence of skin-effect has to be considered. The phase-difference can be calculated. The agreement with the recordings is very good. The inductive transposition is conform with the two components, but the current running meridional has to subdue a resistance 3 times so strong as the current of the other direction. The meridional inductivity is 2,5 times so strong as that in zonal direction. This anisotropy is caused by the tectonic and the geology of the Alps. The statistic of the pulsations for different classes of periods ShowS a distinct maximum of periods (10-40 sec) at noon. If the curves are compared with the EC-curve of the E-and F1-layer it is possible to conclude a relation between the two effects. The frequency of pulsations of sunlight-hours surpass that of the long periods produces by particles. The pulsations of long periods Show a 27-day recurrence. ABSTRACT 2 [Wiese, H. I Tiefentellurik]: Abstract: Geomagnetic Z-variations of less than 2 hours duration show in Europe on one side similar variations at sometimes far distant observatories on the other side opposite variations at observat‘ories in the neighbourhood. This is the effect of a zone of high electric conductivity in the deep earthcrust, which extends from Spain over North Germany to the Bospours and North Afrika. A qualitative explanation of the Z-variations is given. Besides there appear electrical conductivity-structures in other continents e.g. in Japan, South Afrika, China, North America. Viewed geologically all structures are situated outside the cratons already consolidated in the palaeozoicum. For this method explorating the deep earthcrust the name “deep telluric” is proposed. ABSTRACT 3 [Meißner, R.: Untersuchungen über die Zusammenhänge zwischen Luftdruck und Brunnenspiegel]: After many experiments in the laboratory a formula for the flow of air through sands of different size and different moisture has been found. (Similar to Darcy’s Low for the flow of water). With aid of this formula it has been calculated, in what kind the natural fluctuation of the airpressure get into the upper stratum of the earth untill to the grormd-water-level. The materials above being of small size and the ground-water-level being at least 4-6 meter deep there occure pressure-differences between the slowly invading air pressure and the alternating air pressure outside being in the well too. As the result of these horizontal pressure-differences ground-water will flow in the direction of the well and cause fluctuations quite similar to those of the air-pressure. By further experiments with an artificial well and an artificial ground-water level another more important factor has been found: Many inflated pores existing in all fine materials in the zone of capillarity cause the most fluctuations of the levels in the wells by compriming and expanding when air-pressure altemate. Registrations of the artificial well, of many natural wells, of two springs show the diffelrent fluctuations being in maximum 10 cm, only caused by the natural variations of the air-pressure. ABSTRACT 4 [Joksch, H. G.: Statistische Analyse der hypsometrischen Kurve der Erde]: The frequency-distribution of levels on the earth’s surface is found to be composed of three unimodal distributions: two logarithmico-normal ones and one probably logarithmico—normal. A formal interpretation of these distributions and their composition is given.

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Belluigi, A.: Neue Theorie für elektrische Sondierungen . . . 113 ; Kautzleben H.: Über das geomagnetische Normalfeld nach Fanselau . . . 143 ; Buchbesprechungen: Řihánek, L. V. und Postráneckẏ, J.: Bourky a ochrana pied bleskem (H. Israёl) . . . 158 ; Künstliche Erdsatelliten (H. Dolezalek) . . . 159 ; Personalien . . . 160 ;

Description: research

Description: DFG, SUB Göttingen

Description: Kremser, G.: Ergebnisse erdmagnetischer Tiefensondierung in der Umgebung von Göttingen . . . 1 ; Gutdeutsch, R.: Über Vielfacheinsätze elastischer Wellen an Schichten . . . 11 ; Friedemann, H.: Von neuen Erfindungen Meßeinrichtungen für sprengseismische Bodenuntersuchungen . . . 47 ; Mitteilungen . . . 49 ; Buchbesprechung . . . 51 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: ROSSBACH, A.: Die Geokorona und ihre Bedeutung für die Hochatmosphäre . . . 557 ; Binder, O.: Untersuchungen von Intensitätsschwankungen der kosmischen Strahlung im Periodenbereich zwischen 20 und 28 Stunden . . . 565 ; LIEGER, P. F.: Eine im Winter bei mittlerer Breite auftretende Senke des Elektroneninhalts . . . 581 ; NEGI, J. G., and T. LAL: Deformation of the Shape of Seismic Pulses by a Layer of Non-Uniform Velocity Distributions . . . 589 ; Briefe an den Herausgeber: WOOSTER, W. S.., A. J. LEE, G. DIETRICH: Redefinition of Salinity . . . 611 ; In memoriam: O. LUCKE, B. BROCKAMP, F. ERRULAT . . . 615

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Colonial non-zooxanthellate corals from deep-water coral reefs, Lophelia pertusa and Madrepora oculata, produce large amounts of extracellular mucus (EMS). This mucus has various functions, e.g., an antifouling capability protecting the coral skeleton from attacks of endolithic and boring organisms. Both corals show thick epithecal and exothecal skeletal parts with a clear lamellar growth pattern. The formation of the epitheca is unclear. It is supposed that the EMS play a central role during the calcification process of the epithecal skeletal parts. Staining with the fluorochrome tetracycline has shown an enrichment of Ca2+ ions in the mucus. In order to investigate this hypothesis, the protein content of the mucus and the intracrystalline organic matter from newly formed epithecal aragonite of Madrepora oculata was determined via sodium dodecyl sulfate (SDS) gel electrophoresis. Identical band patterns within both substances could be detected, one around 45 kDa molecular weight and a cluster around 30-35 kDa molecular weight. The occurrence of identical protein patterns within the mucus and in the newly formed aragonite confirms the idea that the mucus plays an important role during the organomineralization of the coral epitheca.

Description: Characeae, a family of calcifying green algae, are common in carbonate-rich freshwaters. The southwestern shoreline of Lake Ganau (Kurdistan Region, northeastern Iraq) harbors dense and thick mats of these algae (genus Chara). On the lake bottom and along the shore, carbonate sands and rocks rich in the remains of stems, branches, nodes, and whorls of Chara are deposited. These deposits show all stages of growth and degradation of characean algae, including replacement and lithification into limestone. The replacement of the fragments by fine-grained calcite preserved delicate microstructures of Chara, such as cortical walls, cell shape, inner and outer layers of the stems, and reproductive organs. Based on roundness, sorting, the degree of lithification, and preserved microstructures of the grains (fragments), three facies were recognized. The first is represented by a newly formed lime sand facies showing elongated grains, poor sorting, and reduced roundness, with pristine preservation of characean surface microstructures. The second is a weathered lime sand facies, which shows better sorting and good roundness, whereas internal structures of characean fragments are still well preserved. The third is comprised of a lithified lime sand facies (grainstone), with very well sorted and rounded grains, and poorly preserved external and internal structures of the characeans. As compared to the newly formed lime sand facies, the grainstone facies shows an increase in grain size by more than 30 %, owing to precipitation of micritic lamina of possible microbial origin. Eventually, the Characeae-derived lime sands are lithified into oolitic limestones with sparry calcite cement, forming a grainstone microfacies. The present study has important implications for the interpretation of pre-Quaternary environments, as it records all stages of the fossilization process of characean green algae and highlights the role of these algae in the formation of oolitic carbonate rocks.

Description: The Mantiqueira Province represents a series of supracrustal segments of the South-American counterpart formed during the Gondwana Supercontinent agglutination. In this crustal domain, the process of escape tectonics played a conspicuous role, generating important NE–N–S-trending lineaments. The oblique component of the motions of the colliding tectonic blocks defined the transpressional character of the main suture zones: Lancinha-Itariri, Cubatão-Arcádia-Areal, Serrinha-Rio Palmital in the Ribeira Belt and Sierra Ballena-Major Gercino in the Dom Feliciano Belt. The process as a whole lasted for ca. 60 Ma, since the initial collision phase until the lateral escape phase predominantly marked by dextral and subordinate sinistral transpressional shear zones. In the Dom Feliciano Belt, southern Brazil and Uruguay, transpressional event at 630–600 Ma is recognized and in the Ribeira Belt, despite less coevally, the transpressional event occurred between 590 and 560 Ma in its northern-central portion and between ca. 625 and 595 Ma in its central-southern portion. The kinematics of several shear zones with simultaneous movement in opposite directions at their terminations is explained by the sinuosity of these lineaments in relation to a predominantly continuous westward compression.

Description: SCHULT, A.: Über die Magnetisierung der Basaltvorkommen in der Umgebung von Göttingen . . . l ; SOFFEL, H.: Untersuchungen an einigen ferrimagnetischen Oxyd- und Sulfid-Mineralien mit der Methode der Bitterschen Streifen . . . 21 ; LANGE-HESSE, G.: Jahreszeitliche Einflüsse auf die Rückstrahlung ultrakurzer Wellen an Polarlichtern in Mitteleuropa . . . 35 ; ERTEL, H.: Polygonale Koordination von Seezufluß und Wasserstand . . . 45 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Inhalt: GIESE, P.: Die Geschwindigkeitsverteilung im obersten Bereich des Kristallins, abgeleitet aus Refraktionsbeobachtungen auf dem Profil Böhmischbruck—Eschenlohe . . . 197 ; BOSE, S. K.: A Wave Theory for the Generation of Love, G and Sa Waves . . . 215 ; ÖCAL‚ N.: Aufbau der Erdkruste in Anatolien . . . 227 ; PLAUMANN, S.: Kontinuierliche Schweremessungen im Roten Meer mit einem Askania-Seegravimeter vomTyp GssZ nach GRAF . . . 233 ; Verzeichnis der geophysikalischen Vorlesungen . . . 257 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Inhalt: BHATTACHARYA, J. and DAS GUPTA, S. C.: On leaking modes coupled with shear waves . . . 101 ; TEUPSER, CH. und ULLMANN, W.: Ein neuer Vertikalseismograph mit galvanometrischer Registrierung . . . 115 ; BURKARD‚ O.: Ionosphärenbeobachtungen zur Sonnenfinsternis am 15. Februar 1961 . . . 123 ; (ROSENBACH‚ O. und SCHMITT, 0.: Programmsteuerung der Empfindlichkeit seismischer Meßapparaturen . . . 129 ; Buchbesprechungen . . . 145 ; Berichtigung . . . 148 ,

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS: SEITZ, K.: Altersbestimmung nach der RaD-Methode mit gasförmigen Bleiverbindungen . . . 149 ; GROTEN, E.: Untersuchung der zeitlichen Variation des Gravimeterfaktors . . . 169 ; FRIEDEMANN, H.: Von neuen Erfindungen. Ring für Seismische Seemessungen . . . 173 ; SCHUCH, M.: Beobachtungen von Eigenpotentialen an Torflagerstätten mit verschiedenartigen Elektroden . . . 175 ; Mitteilung . . . 196 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS : FUCHS, K.: Investigation on the Wave Propagation in Wedge-shaped Media . . . 51 ; CHATTERJEE, N. D.: Paläomagnetische Untersuchungen an ladinischen Eruptiven der westlichen Dolomiten, Norditalien . . . 90 ; Vorlesungsverzeichnis . . . 107 ; Buchbesprechungen . . . 111 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS : FRIEDRICH BURMEISTER zum 75. Geburtstag . . . 227 ; DEMNATI, A. und G. DOHR: Reflexionsseismische Tiefensondierungen im Bereich des Oberrheintalgrabens und des Kraichgaues . . . 229 ; GUTDEUTSCH, R. und M. KOENIG: Über die Signalgeschwindigkeit gebeugter elastischer Wellen . . . 246 ; TÄRCZY-HORNOCH, A.: Über die Genauigkeit der berechneten durchschnittlichen Geschwindigkeit bei der seismischen Reflexionsmethode . . . 260 ; Briefe an den Herausgeber . . . 273 ; Verzeichnis der geophysikalischen Vorlesungen (Wintersemester 1965/66) . . . 276 ; Mitteilung . . . 280 ; Buchbesprechungen . . . 281 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALT: Lucke, O.: Die dynamischen Gleichungen des Plasmas in der Magnetosphäre (S. 105); Irsraël, H.: On the Sun-Rise Effect of Sferics Activity at 27 kc (S. 138); Bosum, W.: Erdmagnetische Messungen im Deckdiabasgebiet der Dillmulde und ihre Auswertung (S. 144); Wilhelm Schweydar † (K. Jung) (S. 158).

Description: research

Description: DFG, SUB Göttingen

Description: INHALT: Harth, W.: VLF-Atmospherics ‒ Ihre Messung und ihre Interpretation (S. 815); Kremser, G., A. Korth, K. H. Saeger, P. A. Jensen, V. N. Jensen, J. Taagholt: On the Longitudinal Extension of Electron Precipitation During Magnetospheric Substorms (S. 815); Stüdemann, W.: Untersuchung der Richtungsverteilung energiereicher Elektronen und Protonen im Morgensektor der Polarlichtzone während erhöhten Teilcheneinfalles (S. 863); Klostermeyer, J.: Influence of Viscosity, Thermal Conduction, and Ion Drag on the Propagation of Atmospheric Gravity Waves in the Thermosphere (S. 881); Schmidt, G.: Determination of the Height of Ionospheric Irregularities with the Holographic Method (S. 891); Eichmeier, J.: Vergleich der Beweglichkeitsspektren von „natürlichen“ Luftionen und der verwendeten Meßverfahren (S. 915); Kohnen, H.: Über die Beziehung zwischen seismischen Geschwindigkeiten und der Dichte in Firn und Eis (S. 925); D. Heye und H. Meyer: Ein Meßverfahren zur paläomagnetischen Messung an Tiefseesedimentkernen an Bord eines Schiffes (S. 937); Ernstson, K.: Geoelektrische Messungen im Nördlinger Ries ‒ Zum Verlauf des inneren Walls (S. 949); ‒ Brief an den Herausgeber ‒ R. Kramm, K. Schlegel and W. Weiss: Partial Reflection Measurements with FM-CW ‒ A Preliminary Investigation (S. 953); ‒ Brief an den Herausgeber ‒ Losecke, W.: Über die Bestimmung von Salzstockgrenzflächen mit Hilfe der Magnetotellurik (S. 959); Buchbesprechungen (S. 963).

Description: research

Description: DFG, SUB Göttingen

Description: INHALT: Rastogi, R. G.: Some Aspects of the F2 Region at Medium Latitudes of the Northern and Southern Hemispheres (S. 217); Freiburg, Ch. und W. Kertz: Anordnung von Stabmagneten zur Erzeugung homogener Feldbereiche (S. 227); Schulz, G.: Über ein Refraktionsproblem (S. 236); Haalck, F. und R. Schulze: Die mit dem UTM erreichbare Genauigkeit (S. 246); Brockamp, B.: Zur hypsographischen Kurve des Mondes (S. 271).

Description: research

Description: DFG, SUB Göttingen

Description: The Sierras Pampeanas in central and north-western Argentina constitute a distinct morphotectonic feature between 27°S and 33°S. The last stage of uplift and deformation in this area are interpreted to be closely related to the Andean flat-slab subduction of the Nazca plate beneath the South American plate. K–Ar fault gouge dating and low-temperature thermochronology along two transects within the Sierra de Comechingones reveal a minimum age for the onset of brittle deformation about 340 Ma, very low exhumation rates since Late Paleozoic time, as well as a total exhumation of about 2.3 km since the Late Cretaceous. New Ar–Ar ages (7.54–1.91 Ma) of volcanic rocks from the San Luis volcanic belt support the eastward propagation of the flat-slab magmatic front, confirming the onset of flat-slab related deformation in this region at 11.2 Ma. Although low-temperature thermochronology does not clearly constrain the signal of the Andean uplift, it is understood that the current structural relief related to the Comechingones range has been achieved after the exhumation of both fault walls (circa 80–70 Ma).

Description: The incorporation of hydrogen in enstatite in a hydrous system containing various amounts of NaCl was investigated at 25 kbar. The hydrogen content in enstatite shows a clear negative correlation to the NaCl-concentration in the system. The most favourable explanation is the reduction of water fugacity due to dilution. Other reasons for the limited hydrogen incorporation at high NaCl levels, such as a significant influence of Na+ on the defect chemistry or an exchange between OH- and Cl-in enstatite, appear much less important. A partition coefficient D Na En/Fluid = 0.0013 could be determined, demonstrating that Na is less incompatible in enstatite than H. The new results support the idea that dissolved components have to be considered when the total hydrogen storage capacity in nominally anhydrous minerals is estimated, especially in geological settings with high levels of halogens, such as subduction zones.

Description: The coprecipitation of U (VI) with iron corrosion products from aqueous solutions by zero valent iron was investigated. The evidence of coprecipitation was demonstrated by conducting experiments with well characterized scrap iron,pyrite and a mixture of both materials with experimental durations of up to four months. Results indicate that under anoxic conditions only less than one tenth of the immobilized U(VI) was associated with the surface of scrap iron, whereas theremaining amount is entrapped in aging corrosion products.

Description: The Palaeogene was the most recent greenhouse period on Earth. Especially for the Late Palaeocene and Early Eocene, several superimposed short-term hyperthermal events have been described, including extremes such as the Palaeocene–Eocene Thermal Maximum. Major faunal and floral turnovers in the marine and terrestrial realms were recorded in association with these events. High-resolution palynological analysis of the early Middle Eocene maar lake sediments at Messel, near Darmstadt, Germany, provides an insight into the dynamics of a climax vegetation during the Middle Eocene greenhouse climate in a time span without significant climatic excursions. Numerical techniques like detrended correspondence analysis and wavelet analysis have been applied to recognize cyclic fluctuations and long-term trends in the vegetation through a time interval of approximately 640 kyr. Based on the numerical zoning of the pollen diagram, three phases in the development of the vegetation may be distinguished. Throughout these phases, the climax vegetation did not change substantially in qualitative composition, but a trend towards noticeably less humid conditions probably in combination with a drop of the water level in the lake may be recognized. A shift in algal population from the freshwater dinoflagellate cyst Messelodinium thielepfeifferae to a dominance of Botryococcus in the uppermost part of the core is interpreted as a response to changes in acidity and nutrient availability within the lake. Time series analyses of pollen assemblages show that variations in the Milankovitch range of eccentricity, obliquity and precession can be distinguished. In addition, fluctuations in the sub-Milankovitch range are indicated. This demonstrates that floral changes during steady depositional conditions in the Middle Eocene of Messel were controlled by orbital forcing.

Description: In the presented case study, ascomycete fungi and green algae on a marble monument were identified by comparisons of the 18S rRNA gene sequences, which were obtained from DNA either from environmental samples or from enrichment cultures. The organisms were found to be responsible for either black or green surface coverings on different areas of the monument surface. Most fungi were related to plant-inhabiting genera, corresponding to a heavy soiling of the marble surface with honeydew. Whereas green algae of the genera Stichococcus, Chloroidium and Apatococcus were found to be dominant in all samples, isolates of two additional genera were recovered only from enrichment cultures. A reference strain of Apatococcus lobatus and an isolate of Prasiolopsis sp. were investigated with respect to putative surface adhesive structures of the cell envelope. The Prasiolopsis cell walls were covered with a thin adhesive exopolysaccharide layer involved in biofilm formation.

Description: Bowing is a well-known phenomenon seen in marbles used as building veneers. This form of rock weathering occurs as a result of external factors such as temperature, humidity, the system for anchoring the marble slabs or the panel dimensions. Under the same external conditions, many factors will determine the degree of deformation including petrography, thermal properties and residual locked stresses. The usual way to solve the problem of bowed marble slabs is to replace them with other materials, such as granites, in which the deformation still exists but is less common. In this study, eight ornamental granites with different mineralogy, grain size, grain shape, porosity and fabric were tested in a laboratory to assess their susceptibility to bowing. Three slabs of granite, each cut with a different orientation, were studied under different conditions of temperature (90 and 120°C) and water saturation (dry and wet) to investigate the influence of these factors together with that of anisotropy. At 90°C, only the granite with the coarsest grain size and low porosity exhibited deformation under wet conditions. At 120°C and wet conditions, three of the granites showed evident signs of bowing. Again, the granite with the coarsest grain size was the most deformed. It was concluded that the wide grain size distribution influences microcracking more than other expected factors, such as the quartz content of the rock. Also, mineral shape-preferred orientation and porosity play an important role in the bowing of the studied granites.

Description: The emplacement of the Mesoproterozoic Götemar Pluton into Paleoproterozoic granitoid host rocks of the Transscandinavian Igneous Belt is re-examined by microfabric analysis, including cathodoluminescence microscopy. Field data on the pluton-host rock system are used to strengthen the model. The Götemar Pluton, situated on the Baltic Shield of SE Sweden, is a horizontally zoned tabular structure that was constructed by the intrusion of successive pulses of magma with different crystal/melt ratios, at an estimated crustal depth of 4–8 km. Initial pluton formation involved magma ascent along a vertical dike, which was arrested at a mechanical discontinuity within the granitoid host rocks; this led to the formation of an initial sill. Subsequent sill stacking and their constant inflation resulted in deformation and reheating of existing magma bodies, which also raised the pluton roof. This multi-stage emplacement scenario is indicated by complex dike relationships and the occurrence of several generations of quartz (Si-metasomatism). The sills were charged by different domains of a heterogeneous magma chamber with varying crystal/melt ratios. Ascent or emplacement of magma with a high crystal/melt ratio is indicated by syn-magmatic deformation of phenocrysts. Complex crystallization fabrics (e.g. oscillatory growth zoning caused by high crystal defect density, overgrowth and replacement features, resorbed and corroded crystal cores, rapakivi structure) are mostly related to processes within the main chamber, that is repeated magma mixing or water influx.

Description: Slates are internationally known as roof and façade-cladding material since prehistoric times. The methods required to mine and manufacture these dimensional stones are relatively simple in comparison to those utilized in granitic dimensional stones. This has led to a worldwide rentable commercialization of slate in the last centuries and also to the development of characteristic cultural landscapes. In Uruguay several slates are mined and used in architecture, especially as façade cladding and floor slabs. The most important slates regarding their production and utilization are the dolomitic slates. These dolomitic slates are associated with the Neoproterozoic thrust and fold belt of the Dom Feliciano belt. Representative samples have been geochemically and petrographically characterized, as well as petrophysically and petromechanically analyzed. The petrophysical and petromechanical properties were investigated in a very systematic way with respect to the new European standards, showing values comparable to those registered for internationally known slates. Detailed structural and deposit analysis were carried out in Uruguay in order to evaluate the dolomitic slate deposits. The slates are linked to calc-silicate strata in a greenschist facies volcano-sedimentary sequence and the deposits are located in the limb of a regional fold, where bedding and cleavage are parallel. The main lithotype is a layered and fine-grained dolomitic slate with a quite diverse palette of colors: light and dark green, gray, dark gray, reddish and black. The mined slate is split into slabs 0.5–2 cm thick. In the past, the average production in Uruguay was around 4,000 tons/year and a historical maximum of 13,000 tons was reached in 1993 (Oyhantçabal et al. in Z dt Ges Geowiss 158(3):417–428, 2007). The oscillations in the regional demand were the cause of several flourishing and decay cycles in the activity, but our investigation shows a considerable volume of indicated resources and therefore a very good potential.

Description: Microstructure‐based finite-element analysis with a microcracking algorithm was used to simulate an actual degradation phenomenon of marble structures, i.e., microcracking. Both microcrack initiation and crack propagation were characterized, as were their dependence on lattice preferred orientation (LPO), grain shape preferred orientation (SPO), grain size, marble composition (calcite and dolomite) and grain‐boundary fracture toughness. Two LPOs were analyzed: a random orientation distribution function and an orientation distribution function with strong directional crystalline texture generated from a March–Dollase distribution. Three SPOs were considered: equiaxed grains; elongated grains and a mixture of equiaxed and elongated grains. Three different grain sizes were considered: fine grains of order 200 μm (only calcitic marble); medium size grains of order 1 mm (calcitic and dolomitic marbles); and large grains of order 2 mm (only dolomitic marble). The fracture surface energy for the grain boundaries, γig, was chosen to be 20 and 40 % of the fracture surface energy of a grain, γxtal, so that both intergranular and transgranular fracture were possible. Studies were performed on these idealized marble microstructures to elucidate the range of microcracking responses. Simulations were performed for both heating and cooling by 50 °C in steps of 1 °C. Microcracking results were correlated with the thermoelastic responses, which are indicators related to degradation. The results indicate that certain combinations of LPO, SPO, grain size, grain‐boundary fracture toughness and marble composition have a significant influence on the thermal-elastic response of marble. Microstructure with the smallest grain size and the highest degree of SPO and LPO had less of a tendency to microcrack. Additionally, with increasing SPO and LPO microcracking becomes more spatially anisotropic. A significant observation for all microstructures was an asymmetry in microcracking upon heating and cooling: more microcracking was observed upon cooling than upon heating. Given an identical microstructure and crystallographic texture, calcite showed larger thermal stresses than dolomite, had an earlier onset of microcracking upon heating and cooling, and a greater microcracked area at a given temperature differential. Thermal expansion coefficients with and without microcracking were also determined.

Description: In Uruguay commercial granite varieties comprise mafic rocks, granitoids, and syenitoids. There is a long tradition in Uruguay, as well as worldwide, of using dimensional stones in architecture and art, specially granitic ones. Some of the present applications of these dimensional stones are as façade cladding, countertops, and outdoor and indoor floor slabs. The color spectrum of the Uruguayan granitic dimensional stones varies from black to light gray, covering a wide variety of red and pink and minor greenish-gray. The décor of these granitic dimensional stones is mainly determined by their fabric, fundamentally the grain size and the color distribution between the different minerals that compose the rocks. In the present research the most important commercial granites were sampled to analyze their petrography and petrophysical properties. A detailed structural analysis has been performed in several deposits, as well as the application of the software 3D Block Expert for modeling the possible raw block size distribution. Other factors controlling the mining viability of the deposits were also studied (e.g., homogeneity/heterogeneity of color and décor) and the possible reserves were calculated.

Description: The old mining city of Guanajuato in middle Mexico preserves one of the most important historical legacies in colonial buildings, the UNESCO declared the city World Heritage Site in 1988. Practically all the colonial constructions were built with natural stones from the neighbourhood, of which stands a greenish to reddish vulcanite, called Loseros Tuff. Although the Loseros Tuff is widely used in historical buildings in the city. It shows significant deterioration and weathering effects, principally in the parts where the tuff shows a coarse grain size. The petrographic, petrophysical, mineralogical and geochemical properties of the Loseros Tuff were analysed in order to determine the causes, effects, behaviour and response to deterioration of this volcanic rock. The results of the investigations suggest that in addition to the parameters like the grain size and the porosity properties, the pore radii distribution is decisive for the effectiveness of porosity and the water transport into the rock. It is recognized that once the liquid water invades the rock the dissolution of the matrix occurs, which is accompanied by a sudden moisture expansion favoured by the newly formed secondary porosity and the high content of expandable clay minerals.

Description: The degree of weathering in natural stones on buildings and sculptures has been determined for many years in numerous cases by means of ultrasonic measurements. Conclusions concerning the strength of the rock and the type of weathering can thus be drawn. This relationship has not been established for all rock types. Most of the progress utilizing this method has been made in the analysis of marbles, where an increasing degree of weathering shows lower ultrasonic velocities. In the present study, four Carrara marble samples showing similar rock fabrics, but with respect to weathering exhibit considerable differences are investigated. Porosity varies between 0.2 vol. % and ca. 2.4 vol. %, whereby with increasing porosity the pore radii changes as well. Parallel to this the ultrasonic velocities change in dry samples from about 5.5 to 1.6 km/s, respectively. Model calculations reveal that the velocity reduction is caused by cracks with an extremely small aspect ratio of about 0.005 or even less. After a specific loss of strength, however, solution processes can become active, which modify the microcracks and generate an opposite trend. In the process a strong porosity increase correlates to a relatively small velocity reduction. With the presence of water the Vp porosity weathering relationship experiences a considerable modification. Parallel to the reduction of the ultrasonic velocities, it was determined that the mechanical strength (compressive strength, flexural strength, etc.) as well as the static Young’s modulus is reduced almost equally by a progressive advancement of the weathering front. In one case study dealing with tensile strengths, it was clearly documented how tensile cracks develop and propagate in dependence of the rock fabric. The rock mechanical and ultrasonic velocity data were used for stability assessments applied to the marble statuaries from the Schlossbrücke in Berlin. Stability assessments of the sculpture group 4 reveal that some critical parts must be replaced due to safety reasons.

Description: Fabrics of Cambrian sedimentary dykes formed in Proterozoic granites of the Västervik area (Southeast Sweden) evidence repeated opening/filling and mineralisation/cementation events under varying conditions. Diagnostic features include (1) wall-parallel boundaries between epiclastic fillings and (2) early formed dyke sediments that appear as lithoclasts in subsequently formed sedimentary fillings. The psammitic components mostly consist of well-rounded quartz grains related to a coastal environment and fragments from the granitic host rock. Platy calcitic fragments embedded in the epiclastic matrix originally formed as microveins within already-lithified dyke sediments and the adjacent host rock. Convex downward-pointing, internal sagging structures, together with the preferred orientation of compositional boundaries and long axes of grains/rock fragments parallel to the dyke walls, are interpreted as the result of suction-controlled flow of unconsolidated fillings during episodes of downward dyke growth. Pressure solution of quartz grains are evidence of extensional phases with dyke propagation that were interrupted by phases of horizontal compression normal to the dyke walls. The N–S and NE–SW striking sedimentary dykes formed by opening of a pre-existing joint set during NW–SE oriented rifting during the Cambrian.

Description: Moisture expansion in natural building stones is considered one of the most important factors affecting their weathering and deterioration. The processes that may be responsible for the expansion under determinate relative humidity (hygric dilatation) and water-saturated conditions (hydric dilatation) are generally attributed to the presence of swellable clay minerals. In contrast to this assumption, our investigations show that moisture expansion also takes place in volcanic tuff building stones almost free from clay minerals. To provide a deeper understanding of the processes, swelling and deterioration were performed on 14 volcanic tuffs used as important building stones of different ages, compositions and weathering stages from Mexico, Germany and Hungary. The investigations undertaken include extensive chemical, petrophysical and fabric analyses. The samples show a wide range of effective porosity, microporosity, capillary water absorption, moisture expansion, and CEC values. High moisture expansion does not seem to depend on clay mineral content alone. We also observed that there is no significant effect on dilatation if clay minerals are present but only form a thin coat on the outer shell of bigger pores. Moreover, we identified a correlation between microporosity, average pore radius and moisture expansion. The investigations highlight the fact that moisture expansion cannot only be attributed to swellable clay minerals, and suggest that the presence and accumulation of micropores and their average radius and distribution play an important role for non-clay associated swelling intensity, which can most probably be attributed to the disjoining pressure.

Description: Investigation by Raman spectroscopy of samples from different geological settings shows that the occurrence of TiO2 polymorphs other than rutile can hardly be predicted, and furthermore, the occurrence of anatase is more widespread than previously thought. Metamorphic pressure and temperature, together with whole rock chemistry, control the occurrence of anatase, whereas variation of mineral assemblage characteristics and/or fluid occurrence or composition takes influence on anatase trace element characteristics and re-equilibration of relict rutiles. Evaluation of trace element contents obtained by electron microprobe in anatase, brookite, and rutile shows that these vary significantly between the three TiO2 phases. Therefore, on the one hand, an appropriation to source rock type according to Nb and Cr contents, but as well application of thermometry on the basis of Zr contents, would lead to erroneous results if no phase specification is done beforehand. For the elements Cr, V, Fe, and Nb, variation between the polymorphs is systematic and can be used for discrimination on the basis of a linear discriminant analysis. Using phase group means and coefficients of linear discriminants obtained from a compilation of analyses from samples with well-defined phase information together with prior probabilities of groupings from a natural sample compilation, one is able to calculate phase grouping probabilities of any TiO2 analysis containing at least the critical elements Cr, V, Fe, and Nb. An application of this calculation shows that for the appropriation to the phase rutile, a correct-classification rate of 99.5% is obtained. Hence, phase specification by trace elements proves to be a valuable tool besides Raman spectroscopy.

Description: A new U–Pb SHRIMP age of 551 ± 4 Ma on a mylonitic porphyry that intruded into the Sierra Ballena Shear Zone (Southernmost Dom Feliciano Belt, Uruguay) and a review of relevant published data make possible a more refined correlation and reconstruction of Brasiliano/Pan-African transpressional events. Paleogeographic reconstruction, kinematics and timing of events indicate a connection between the shear systems of the Dom Feliciano and Kaoko Belts at 580–550 Ma. Sinistral transpression recorded in shear zones accommodates deformation subsequent to collision between the Congo and Río de la Plata Cratons. The correlation is strengthened by the similarity of magmatic and metamorphic ages in the Coastal Terrane of the Kaoko Belt and the Punta del Este Terrane of the Dom Feliciano Belt. This post-collisional sinistral transpression brought these units near to their final position in Gondwana and explains the different evolution at 550–530 Ma. While in the Kaoko Belt, an extensional episode resulted in exhumation as a consequence of collision in the Damara Belt, in the Dom Feliciano Belt, sinistral transpression occurred associated with the closure of the southern Adamastor Ocean due to Kalahari-Río de la Plata collision.

Description: This study documents the chemical and textural responses of zircon in the Elba igneous complex, with particular reference to the 7- to 7.8-Ma-old Monte Capanne pluton in relation to its coeval volcanic counterpart (Capraia), using BSE imaging and quantitative electron microprobe analyses. The Monte Capanne pluton displays multiple field and geochemical evidence for magma mixing. The samples we have investigated (including monzogranitic, mafic enclave and dyke samples) display similar zircon textures and are associated with an extremely large range of trace and minor element (Hf, Y, HREE, Th, U) compositions, which contrast with relatively simple textures and zoning patterns in zircons from a Capraia dacite. We have used a relatively simple textural classification (patchy zoning, homogenous cores, oscillatory zoning and unzoned zircon) as the basis for discussing the chemical composition and chemical variation within zircons from the Monte Capanne pluton. Based on these data and other works (Dini et al. 2004 in Lithos 78:101–118, 2004) , it is inferred that mixing between metaluminous and peraluminous melts occurred early in the evolution of the Monte Capanne magma chamber. In particular, mixing was responsible for the development of the patchy-zoning texture in the zircon cores, which was associated with reactions between other accessory phases (including monazite, apatite, allanite), which we infer to have significantly affected the Th distribution in zircon. Zircons from the MC pluton displaying “homogeneous cores” have chemical affinities with zircons in the coeval Capraia volcanic system, consistent with the participation of a Capraia-like mantle end-member during mixing. Further zircon growth in the MC pluton produced the oscillatory zoning texture, which records both long-term (crystal fractionation) and transient (recharge with both silicic and mafic magmas) events in a hybrid magma chamber. It is inferred that Hf and the Th/U ratio cannot be used alone to infer magmatic processes due to their dependency on temperature, nor are they a diagnostic feature of xenocrystic grains. This study shows that zircon chemistry coupled with detailed textural analysis can provide a powerful tool to elucidate the complex evolution of a magma system.

Description: The bowing of natural stone panels is especially known for marble slabs. The bowing of granite is mainly known from tombstones in subtropical humid climate. Field inspections in combination with laboratory investigations with respect to the thermal expansion and the bowing potential was performed on two different granitoids (Cezlak granodiorite and Flossenbürg granite) which differ in the composition and rock fabrics. In addition, to describe and explain the effect of bowing of granitoid facade panels, neutron time-of-flight diffraction was applied to determine residual macro- and microstrain. The measurements were combined with investigations of the crystallographic preferred orientation of quartz and biotite. Both samples show a significant bowing as a function of panel thickness and destination temperature. In comparison to marbles the effect of bowing is more pronounced in granitoids at temperatures of 120°C. The bowing as well as the thermal expansion of the Cezlak sample is also anisotropic with respect to the rock fabrics. A quantitative estimate was performed based on the observed textures. The effect of the locked-in stresses may also have a control on the bowing together with the thermal stresses related to the different volume expansion of the rock-forming minerals.

Description: Multi-isotope study including whole-rock Nd–Sr, single zircon Hf, and SIMS δ18O analyses of zircons sheds light on magma sources in the northernmost Arabian–Nubian Shield (ANS) during ~820–570 Ma. Reconnaissance initial Nd and Sr isotope data for the older rocks (~820–740 Ma) reaffirms previous estimates that early crustal evolution in this part of the shield involved some crustal contamination by pre-ANS material. Prominent isotope provinciality is displayed by post-collisional calc-alkaline and alkaline igneous rocks of ~635–570 Ma across a NW-SE transect across basement of the Sinai Peninsula (Egypt) and southern Israel. Silicic rocks of the NW-region are characterized by lower εNd(T)–εHf(T) and higher Sri and δ18O compared with rocks of the SE-region, and the transition between the regions is gradual. Within each region isotope ratios are independent of the extent of magma fractionation, and zircon cores and rims yield similar δ18O values. Comparison with southern segments of the ANS shows that the source for most ~635–570 Ma rocks can be modeled as the isotopically aged lower-intermediate crust in the ANS core (SE-region) and its northern, more contaminated ANS margins (NW-region). Nevertheless, Nd–Sr isotope enrichment of the lithospheric mantle is indicated by some basic magmas of the NW-region displaying the most enriched Nd–Sr isotope compositions. Comparison of Nd and Hf depleted mantle model ages for rocks of the SE-region may indicate that crustal formation events in the ANS geographical core took place at 1.1–1.2 Ga and were followed by crustal differentiation starting at ~0.9 Ga.

Description: Oligoclase and labradorite crystals have been experimentally replaced by albite in an aqueous sodium silicate solution at 600°C and 2 kbars. The replacement is pseudomorphic and is characterised by a sharp chemical interface which progresses through the feldspar while preserving the crystallographic orientation. Reaction rims of albite, up to 50 μm thick, can be readily achieved within 14 days. Re-equilibration of plagioclase in an 18O-enriched sodium- and silica-bearing solution results in oxygen isotope redistribution within the feldspar framework structure. The observed characteristics of the reaction products are similar to naturally albitised plagioclase and are indicative of an interface-coupled dissolution–reprecipitation mechanism. Chemical analyses demonstrate that the albitisation is accompanied by the mobilisation of major, minor and trace elements also including elements such as Al and Ti which are commonly regarded as immobile during hydrothermal alteration. The results contribute to developing our understanding of the close association between large-scale albitisation and secondary ore mineralisation which is common in nature.

Description: The Sierra de San Luis forms the southern tip of the Eastern Sierras Pampeanas in central Argentina. Two narrow belts of low-grade phyllites and quartz arenites, i.e. the San Luis Formation, have accommodated part of the strain-related differential exhumation of the medium- to high-grade metamorphic domains that constitute to the basement complex of the sierra. Eleven phyllite samples were subjected to the K/Ar fine-fraction dating technique. Results are interpreted in relation to the Kübler index of the illites, which indicate epimetamorphic conditions for the majority of the samples. Obtained ages between 330 and 290 Ma cover a period of compressional tectonics in the late Mississippian (Visean/Serpukhovian boundary) followed by the subsidence during the formation of the Paganzo Basin in the provinces of La Rioja and San Luis. These tectonic movements are coincident with the Toco orogeny in northern Chile and southern Bolivia. This suggests that the older K/Ar ages document the compressional stage and that younger ages record the cooling of the basement during the subsequent extensional uplift of the basement.

Description: A review of the lithostratigraphic units in the Río de la Plata Craton and of new and previously published geochronological, isotopic and geophysical data is presented. Sm–Nd TDM model ages between 2.6 and 2.2 Ga characterize the Piedra Alta Terrane of this craton. Crystallization ages between 2.2 and 2.1 Ga for the metamorphic protoliths and 2.1–2.0 Ga for the post-orogenic granitoids indicate juvenile crust, followed by a short period of crustal recycling. Cratonization of this terrane occurred during the late Paleoproterozoic. Younger overprinting is not observed, suggesting it had a thick and strong lithosphere in the Neoproterozoic. A similar scenario is indicated for the Tandilia Belt of Argentina. Sm–Nd TDM model ages for the Nico Pérez Terrane show two main events of crustal growth (3.0–2.6 and 2.3–1.6 Ga). The crystallization ages on zircon ranges between 3.1 and 0.57 Ga, which is evidence for long-lived crustal reworking. The age for cratonization is still uncertain. In the Taquarembó Block, which is considered the prolongation of the Nico Pérez Terrane in southern Brazil, a similar scenario can be observed. These differences together with contrasting geophysical signatures support the redefinition of the Río de la Plata Craton comprising only the Piedra Alta Terrane and the Tandilia Belt. The Sarandí del Yí Shear Zone is regarded as the eastern margin of this Craton.

Description: The volcaniclastic Tepoztlán Formation (TF) represents an important rock record to unravel the early evolution of the Transmexican Volcanic Belt (TMVB). Here, a depositional model together with a chronostratigraphy of this Formation is presented, based on detailed field observations together with new geochronological, paleomagnetic, and petrological data. The TF consists predominantly of deposits from pyroclastic density currents and extensive epiclastic products such as tuffaceous sandstones, conglomerates and breccias, originating from fluvial and mass flow processes, respectively. Within these sediments fall deposits and lavas are sparsely intercalated. The clastic material is almost exclusively of volcanic origin, ranging in composition from andesite to rhyolite. Thick gravity-driven deposits and large-scale alluvial fan environments document the buildup of steep volcanic edifices. K-Ar and Ar-Ar dates, in addition to eight magnetostratigraphic sections and lithological correlations served to construct a chronostratigraphy for the entire Tepoztlán Formation. Correlation of the 577 m composite magnetostratigraphic section with the Cande and Kent (1995) Geomagnetic Polarity Time Scale (GPTS) suggests that this section represents the time intervall 22.8–18.8 Ma (6Bn.1n-5Er; Aquitanian-Burdigalian, Lower Miocene). This correlation implies a deposition of the TF predating the extensive effusive activity in the TMVB at 12 Ma and is therefore interpreted to represent its initial phase with predominantly explosive activity. Additionally, three subdivisions of the TF were established, according to the dominant mode of deposition: (1) the fluvial dominated Malinalco Member (22.8–22.2 Ma), (2) the volcanic dominated San Andrés Member (22.2–21.3 Ma) and (3) the mass flow dominated Tepozteco Member (21.3–18.8 Ma).

Description: The Sierra Ballena Shear Zone (SBSZ) is part of a high-strain transcurrent system that divides the Neoproterozoic Dom Feliciano Belt of South America into two different domains. The basement on both sides of the SBSZ shows a deformation stage preceding that of the transcurrent deformation recognized as a high temperature mylonitic foliation associated with migmatization. Grain boundary migration and fluid-assisted grain boundary diffusion enhanced by partial melting were the main deformation mechanisms associated with this foliation. Age estimate of this episode is 〉658 Ma. The second stage corresponds to the start of transpressional deformation and the nucleation and development of the SBSZ. During this stage, pure shear dominates the deformation, and is characterized by the development of conjugate dextral and sinistral shear zones and the emplacement of syntectonic granites. This event dates to 658–600 Ma based on the age of these intrusions. The third stage was a second transpressional event at about 586 to 〈560 Ma that was associated with the emplacement of porphyry dikes and granites that show evidence of flattening. Deformation in the SBSZ took place, during the late stages, under regional low-grade conditions, as indicated by the metamorphic paragenesis in the supracrustals of the country rocks. Granitic mylonites show plastic deformation of quartz and brittle behavior of feldspar. A transition from magmatic to solid-state microstructures is also frequently observed in syntectonic granites. Mylonitic porphyries and quartz mylonites resulted from the deformation of alkaline porphyries and quartz veins emplaced in the shear zone. Quartz veins reflect the release of silica associated with the breakdown of feldspar to white mica during the evolution of the granitic mylonites to phyllonites, which resulted in shear zone weakening. Quartz microstructures characteristic of the transition between regime 2 and regime 3, grain boundary migration and incipient recrystallization in feldspar indicate deformation under lower amphibolite to upper greenschist conditions (550–400°C). On the other hand, the mylonitic porphyries display evidence of feldspar recrystallization suggesting magmatic or high-T solid-state deformation during cooling of the dikes.

Description: Movement within the Earth’s upper crust is commonly accommodated by faults or shear zones, ranging in scale from micro-displacements to regional tectonic lineaments. Since faults are active on different time scales and can be repeatedly reactivated, their displacement chronology is difficult to reconstruct. This study represents a multi-geochronological approach to unravel the evolution of an intracontinental fault zone locality along the Danube Fault, central Europe. At the investigated fault locality, ancient motion has produced a cataclastic deformation zone in which the cataclastic material was subjected to hydrothermal alteration and K-feldspar was almost completely replaced by illite and other phyllosilicates. Five different geochronological techniques (zircon Pb-evaporation, K–Ar and Rb–Sr illite, apatite fission track and fluorite (U-Th)/He) have been applied to explore the temporal fault activity. The upper time limit for initiation of faulting is constrained by the crystallization age of the primary rock type (known as “Kristallgranit”) at 325 ± 7 Ma, whereas the K–Ar and Rb–Sr ages of two illite fractions 〈2 μm (266–255 Ma) are interpreted to date fluid infiltration events during the final stage of the cataclastic deformation period. During this time, the “Kristallgranit” was already at or near the Earth’s surface as indicated by the sedimentary record and thermal modelling results of apatite fission track data. (U–Th)/He thermochronology of two single fluorite grains from a fluorite–quartz vein within the fault zone yield Cretaceous ages that clearly postdate their Late-Variscan mineralization age. We propose that later reactivation of the fault caused loss of helium in the fluorites. This assertion is supported by geological evidence, i.e. offsets of Jurassic and Cretaceous sediments along the fault and apatite fission track thermal modelling results are consistent with the prevalence of elevated temperatures (50–80°C) in the fault zone during the Cretaceous.

Description: The application of the SHRIMP U/Pb dating technique to zircon and monazite of different rock types of the Sierras de Córdoba provides an important insight into the metamorphic history of the basement domains. Additional constraints on the Pampean metamorphic episode were gained by Pb/Pb stepwise leaching (PbSL) experiments on two titanite and garnet separates. Results indicate that the metamorphic history recorded by Crd-free gneisses (M2) started in the latest Neoproterozoic/earliest Cambrian (553 and 543 Ma) followed by the M4 metamorphism at ~530 Ma that is documented in the diatexites. Zircon ages of 492 Ma in the San Carlos Massif correlate partly with rather low Th/U ratios (〈0.1) suggesting their growth by metamorphic fluids. This age is even younger than the PbSL titanite ages of 506 Ma. It is suggested that the fluid alteration relates to the beginning of the Famatinien metamorphic cycle in the neighbouring Sierra de San Luis and has not affected the titanite ages. The PTt evolution can be correlated with the plate tectonic processes responsible for the formation of the Pampean orogene, i.e., the accretion of the Pampean basement to the Río de La Plata craton (M2) and the later collision of the Western Pampean basement with the Pampean basement.

Description: Aspidochirote holothurian ossicles were discovered in Upper Ordovician-aged Öjlemyr cherts from Gotland, Sweden. The well-preserved material allows definitive assignment to the family Synallactidae, a deep-sea sea cucumber group that is distributed worldwide today. The new taxon Tribrachiodemas ordovicicus gen. et sp. nov. is described, representing the oldest member of the Aspidochirotida. The further fossil record of Synallactidae and evolutionary implications are also discussed.

Description: Kasemir, H. W.: Der Gewittergenerator im luftelektrischen Stromkreis Tl. II (S. 65) ; Repsold‚ H.: Ergebnisse der Messung natürlicher Erdströme bei Göttingen (S. 97) ; Israёl, H.: Der Diffusionskoeffizient des Radons in der Bodenluft (S. 104) ; Siebert, M.: Die solaren Gezeiten im Barogramm des Juli 1959 (S. 109).

Description: research

Description: DFG, SUB Göttingen

Description: Schneider, G.: Zum Wellencharakter der mikroseismischen Bodenunruhe . . . 161 ; Fischer, G.: Die Mitschwinggezeiten der Nordsee, errechnet mit einem Differenzverfahren . . . 186 ; Lange-Hesse, G: Durchschnittlicher Tagesgang der F1-Schicht-Grenzfrequenzen und seine Abhängigkeit von geographischer Breite und Jahreszeit . . . 199 ;

Description: research

Description: DFG, SUB Göttingen

Description: The configurational heat capacity, shear modulus and shear viscosity of a series of Na2O–Fe2O3–Al2O3–SiO2 melts have been determined as a function of composition. A change in composition dependence of each of the physical properties is observed as Na2O/(Na2O + Al2O3) is decreased, and the peralkaline melts become peraluminous and a new charge-balanced Al-structure appears in the melts. Of special interest are the frequency dependent (1 mHz–1 Hz) measurements of the shear modulus. These forced oscillation measurements determine the lifetimes of Si–O bonds and Na–O bonds in the melt. The lifetime of the Al–O bonds could not, however, be resolved from the mechanical spectrum. Therefore, it appears that the lifetime of Al–O bonds in these melts is similar to that of Si–O bonds with the Al–O relaxation peak being subsumed by the Si–O relaxation peak. The appearance of a new Al-structure in the peraluminous melts also cannot be resolved from the mechanical spectra, although a change in elastic shear modulus is determined as a function of composition. The structural shear-relaxation time of some of these melts is not that which is predicted by the Maxwell equation, but up to 1.5 orders of magnitude faster. Although the configurational heat capacity, density and shear modulus of the melts show a change in trend as a function of composition at the boundary between peralkaline and peraluminous, the deviation in relaxation time from the Maxwell equation occurs in the peralkaline regime. The measured relaxation times for both the very peralkaline melts and the peraluminous melts are identical with the calculated Maxwell relaxation time. As the Maxwell equation was created to describe the timescale of flow of a mono-structure material, a deviation from the prediction would indicate that the structure of the melt is too complex to be described by this simple flow equation. One possibility is that Al-rich channels form and then disappear with decreasing Si/Al, and that the flow is dominated by the lifetime of Si–O bonds in the Al-poor peralkaline melts, and by the lifetime of Al–O bonds in the relatively Si-poor peralkaline and peraluminous melts with a complex flow mechanism occurring in the mid-compositions. This anomalous deviation from the calculated relaxation time appears to be independent of the change in structure expected to occur at the peralkaline/peraluminous boundary due to the lack of charge-balancing cations for the Al-tetrahedra.

Description: Fanselau, G. und Lücke, O.: Über die Veränderlichkeit des erdmagnetischen Hauptfeldes und seine Theorien . . . 121 ; ZUSAMMENFASSUNG: Abschnitt A. Die Veränderlichkeit des geomagnetischen Feldes und seiner Energiedichte wird auf Grund seiner Potentialentwicklungen in neuer Weise dargestellt. Die beiden Pole des Quadrupols führen neben einer Westwärtsdrift von 240/100 Jahren noch eine ebenso kräftige nord- bzw. südwärtige Bewegung aus. Abschnitt B. Es wird gezeigt, wie die Multipole durch einfache zonale Stromsysteme erzeugt gedacht werden können. Ihr Skineffekt wird betrachtet. Abschnitt C. Die großräumigen Konvektionsströme, die die säkulare Änderung der Tageslänge bewirken, sind auf Ebenen senkrecht zur Drehachse beschränkt. Sie stehen in keinem direkten Zusammenhang mit der säkularen Veränderlichkeit des geomagnetischen Feldes, dessen Entstehung auf eine Grenzschicht an der oberen Grenze des Erdkerns beschränkt sein muß. Sie kann nicht durch hydromagnetische Theorien beschrieben werden. Abschnitt D. Wenn man im Anschluß an H. Miki die Materie des äußeren Erdkerns als hochionisiertes Plasma betrachtet, kann das geomagnetische Feld als Grenzschichteffekt gedeutet werden. Seine Westwärtsdrift ist dann die Westwärtswanderung langer hydrodynamischer Wellen. Die Wanderung der Pole des Quadrupols wird durch das Vorzeichen ihres Drehsinnes beeinflußt.

Description: Fanselau, G. und Lücke, O.: Über die Veränderlichkeit des erdmagnetischen Hauptfeldes und seine Theorien . . . 121 ; ABSTRACT: Part A. The variability of the geomagnetic field and its density of energy is described by means of its potential developments in a new manner. The two poles of the quadrupole still show besides a westward drift of 240/100 years a movement northward resp. southward of the same strength. Part B. It is shown, how multipoles can be produced by simple zonal current systems. Their skin-effect is considered. Part C. The extended convection streams, which effect the secular variation of the length of the day are confined to planes perpendicular to the axis of rotation. They are not connected directly with the secular variability of the geomagnetic field, the origin of which must be confined on a boundary layer of the upper border of the core. It may not be described by means of hydromagnetic theories. Part D. lf one regards in agreement with H. Miki the matter of the outer core as highly ionizised plasma, the geomagnetic field may be interpreted as an effect of boundary layer. Its westward drift now is the westward migration of long hydrodynamic waves. The migration of the poles of the quadrupole is influenced by the sign of its turning direction.

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Closs, H. and Morelli, C. : Seismic Experiments in the Dolomites (Lago Lagorai) to investigate the Earth’s Crust in the Eastern Alpine Area . . . 249 ; Müller, St, Stein, A. and Vees, R.: Seismic Scaling Laws for Explosions on a Lake Bottom . . . 258 ; Koch, H., Sehminder, R. and Kürschner, D.: Ein neues automatisches Registriergerät für ionosphärische Driftmessungen . . . 28l ; Israel, H. and Haas, R.: Absorption of natural fallout in soil . . . 289 ; Buchbesprechungen . . . 293 ;

Description: CLOSS, H. and MORELLI, C. : Seismic Experiments in the Dolomites (Lago Lagorai) to investigate the Earth’s Crust in the Eastern Alpine Area. Summary: The “Sous-Commission des Explosions Alpines” carried out a series of explosions; the aim of experiments is described, the choice of a lake as shotpoint is discussed, operational details are illustrated, data on seismic parties and instruments are tabulated. - - - MÜLLER, St, STEIN, A. and VEES, R.: Seismic Scaling Laws for Explosions on a Lake Bottom. Summary: In September 1961 a series of 22 explosions was set off for experimental purposes on the bottom of a lake near Trento in Italy. During these tests the Charge size varied between 2 and 760 kg of TNT. A11 shots were recorded along three refraction profiles using calibrated equipment. The maximum recording distance was 168 km. Three seismic stations were kept at the same locations during the entire operation. Their main object was to determine the relationship between ground amplitudes of first arrivals and weight of the explosive Charge. The distances between the shotpoint and these permanent stations were 1.50, 21.15, and 34.05 km, respectively. The response curves of the instrumental equipment are discussed. Examples of seismograms are shown which demonstrate that the frequency spectrum of the first arrivals does not change systematically with increasing charge size. Characteristic second and later arrivals, clearly recorded in a distance of 21.15 km, must be interpreted as signals radiated from the rising gas bubble. It must be ascribed to the low background noise level that excellent seismograms could be obtained in a distance of 34.05 km from the shotpoint even with charges as small as 5 kg. The amplitudes of true ground motion were determined for first arrivals. Ten sets of data were then fitted to power laws of the form: ɑ = const · Wn (ɑ = amplitude in mµ; W = charge weight in kg) by least-square methods. The average value of the exponent n equals 0.65 for the entire series, while the mean deviation of the individual values from the power functions is about 16 per cent. If the relation between seismic amplitudes and Charge weight is plotted on a log—log scale a systematic curvature is noticed for some sets of data which indicates that a simple power law is not sufficient to fit the observations. This efiect has been investigated more closely for two sets of the experimental data. - - - KOCH, H., SEHMINDER, R. and KÜRSCHNER, D.: Ein neues automatisches Registriergerät für ionosphärische Driftmessungen. Summary: A recorder for ionospheric drift measurements according to KRAUTKRÄMER’S method is described, which allows of directly the time differences between corresponding extremes in the signal voltage curves. The apparatus offers economy in operation and in evaluation of measurements and permits of making continuous registrations. Comparative measurements using conventional techniques have shown that, in spite of some inherent limitations, the apparatus is capable of yielding sufficiently accurate mean values of drift velocity and drift direction. - - - ISRAEL, H. and HAAS, R.: Absorption of natural fallout in soil. Summary: lt is shown by Laboratory experiments on the problem of fall-out distribution in soil that radioactivity is absorbed in the uppermost layers of the ground. The measurements were made by sprinkling water activated with ThB on different types of soil. The distributions in the soil are found to be very similar t0 these of the Sr90-fallout. By these results the conclusion is justified that ThB can be used as tracer to detect the fall-out distribution in soil.

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Mal, A. K.: On the fild of an electric dipole in presence of a layered media . . . 209 ; Brockamp, B.: Barographisch-topographische Höhenkurve . . . 219 ; Ghosh, M. L.: Relection of Love Wave from a rigid obstacle . . . 223 ; Siebert, M: Die Zerlegung eines zweidimensionalen Magnetfeldes in äußeren und inneren Anteil mit Hilfe der CAUCHYschen Integralformel . . . 231 ; Friedmann, H. Von neuen Erfindungen, Verstärkerschaltung zur Reflexionsüberhöhung für seismische Registrierungen . . . 237 ; Dolezalek, H.: On the Measurement of Mobility and Conductivity in the Mesosphere . 239 ; Buchbesprechungen . . . 244 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Rönicke, G.: Erfahrungen mit luftelektrischen Sondierungen in der freien Atmosphäre. . . 105 ; Schulz, G. : Der mittlere Fehler bei Geschwindigkeitsberechnungen aus der Krümmung von Reflexionen . . . 127 ; Meitzner, W. : Magnetische Untersuchungen am Backenberg bei Güntersen . . . 137 ; Friedemann, H. : Patentbericht. Erschütterungsmesser, insbesondere Seismograph . . . 155 ; Mitteilung . . . 156 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: FABIAN, P. and W. F. LIBBY: Ozone in the Atmesphere of Venus . . . 1 ; KOENIG, M.: Digitalisierung modellseismischer Signale . . . 9 ; RUMMEL F.: Studies of time-dependent deformation of some granite and eclogite rock samples under uni-axial, constant compressives tress and temperatures up to 400 °C . . . 17 ; BEHREHS, J., L. DRESEN und E. HINZ: Modellseismische Untersuchungen der dynamischen Parameter von Kopfwelle und Reflexion im überkritischen Bereich . . . 43 ; SCHMIDTKE, G.: EUV-Laborspektrophotometrie zur Vorbereitung von optischen Flugexperimenten (mit Falttafeln} . . . 69 ; STROWALD, J.: Schlierenoptische Untersuchung der Ω-Welle . . . 83 ; STILLER H. und C. WAGNER: Eine Einrichtung für Ultraschallmessungen an Gesteinen unter hydrostatischem Druck bis 2 kbar . . . 97 ; Buchbesprechungen . . . 103

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS: BOSUM, W. & HAHN, A.: Diagrams for the computation of magnetic field components, for their transformation into one another and for their upward continuation (two-dimensional case) . . . 1 ; FRÖLICH, F. und H. LÖFFLER: Einflüsse auf die Korundtyp-Wechselwirkungen im System Hämatit-Ilmenit . . . 26 ; SCHNEIDER, G.‚ MÜLLER, ST. und L. KNOPOFF: Gruppengeschwindigkeitsmessungen an kurzperiodischen Oberflächenwellen in Mitteleuropa . . . 33 ; Briefe an den Herausgeber . . . 58 ; Buchbesprechungen . . . 61 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Lorch, S.: Messung des Wassergehaltes in Böden mit der Neutronensonde. ; Thrasher, J. E. & Scheidegger, A. E.: On the Connection Between Stress and Displacements in Faulted Regions. SUMMARY 1 [Lorch, S.: Messung des Wassergehaltes in Böden mit der Neutronensonde.]: Based on results of experimental and theoretical investigations it is shown that the calibration curve of a neutron probe depends essentially on the configuration between neutron source and detector. SUMMARY 2 [Thrasher, J. E. & Scheidegger, A. E.: On the Connection Between Stress and Displacements in Faulted Regions. ]: This paper demonstrates a method of obtaining the principal direction of the stress tensor in a faulted area when the principal directions of the displacement tensor are known. Also, the mean and standard deviation of the maximum principal stress axes are determined for a randomly faulted area with null axes parallel to a plane, provided the displacement component normal to this plane has always the same sign; it is then shown that the mean is normal to the plane of the null axes. This result is important in connection with the statistical analysis of earthquake fault plane solutions inasmuch as it proves that the tectonic motion direction obtained as the “most orthogonal” direction to the null axes of an area must coincide with the average (maximum) principal stress direction.

Description: Lorch, S.: Messung des Wassergehaltes in Böden mit der Neutronensonde. ; Thrasher, J. E. & Scheidegger, A. E.: On the Connection Between Stress and Displacements in Faulted Regions. ZUSAMMENFASSUNG 1 [Lorch, S.: Messung des Wassergehaltes in Böden mit der Neutronensonde.]: An Hand der Ergebnisse experimenteller und theoretischer Untersuchungen an der Neutronensonde wird gezeigt, daß die Form der Eichkurven im wesentlichen von der Art der Anordnung Quelle-Detektor abhängt. ZUSAMMENFASSUNG 2 [Thrasher, J. E. & Scheidegger, A. E.: On the Connection Between Stress and Displacements in Faulted Regions.]: Die Arbeit präsentiert eine Methode, die gestattet, die tektonischen Hauptspannungsrichtungen in einem von Brüchen durchzogenen Gebiet aus den Hauptachsen des Verzerrungstensors herzuleiten. Der Mittelwert und die Streuung der größten Hauptspannungsrichtung sind für eine willkürlich von Brüchen durchzogene Gegend berechnet, solange man annimmt, daß die Nullachsen der Brüche einer Ebene parallel sind und die Verschiebungskomponente normal zu dieser Nullachse immer dasselbe Vorzeichen aufzeigt. Dieses Resultat ist im Zusammenhange mit der Theorie der Verschiebungsebenen in Erdbebenherden wichtig, da es zeigt, daß die tektonische Bewegungsachse, die man dadurch erhält, daß man die beste Normale zu den Nullachsen in einem Gebiet findet, dieselbe sein muß, wie die mittlere Hauptspannungsrichtung.

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS: Angenheister, G. und C. v. Consbruch: Pulsationen des erdmagnetischen Feldes in Göttingen von 1953 - 1958 . . . 3 ; Israël, H.: Der Diffusions-Koeffizient des Radons in Bodenluft . . . 13 ; Hiersemann, L.: Aufzeichnung langperiodischer Bodendeformationen mit einem Strainseismometer . . . 18 ; Kundorf, W. und D. Rotter: Über die Anwendung der seismischen Eigenimpulsmethode bei der Erforschung dynamischer Auswirkungen des Gebirgsdruckes . . . 35 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS: Militzer, H.: Nahseismische Untersuchungen mit einem Bodenvibrator . . . 49 ; Schmelovsky, K. H.: Untersuchungen über die tages- und jahreszeitlichen Variationen des Plasmas der äußeren Ionosphäre und ihre theoretische Deutung . . . 59 ; Knothe, Ch: Homogene Dreikomponentenanordnungen für tiefenseismische Untersuchungen . . . 67 ; Korb, H. G.: Über die Analyse der Schwankungen des Grundwasserspiegels in dem überfluteten Bergwerk Sontra . . . 75 ; Stiller, H .‚ Frölich, F. und F. Ch. Wagner: Zustandsänderungen in magnetischen Gesteinsproben . . . 89 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS: Angenheister, G. und v. Consbruch C.: Pulsation des erdmagnetischen Feldes in Göttingen von 19531-1958 . . . 103 ; Fritsch, V.: Die geoelektrische Untersuchung der Heilwässer in der Umgebung des Neusiedlersees im Burgenland . . . 112 ; Schneider, G.: Mikroseismik-Ausbreitung in Nord- und Mitteleuropa . . . 118 ; Frölich, F.‚ Stiller, H. und Wagner, F. Ch: Erfahrungen mit Laborverfahren für Gesteinsuntersuchungen . . . 136 ; Druckfehlerberichtigung . . . 149 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS: Hédervári, P.: On the Geophysical Interpretation of the Seismical Great-circle of the Earth . . . 1 ; Kunkis, A., und G. Ries: Anlage zur Messung und Registrierung der luftelektrischen Elemente mit automatischer Stundenmittelauswertung . . . 5 ; Stiller, H., and F. Frölich: Studies on Rock Forming Magnetic Minerals . . . l3 ; Macke, W., P. Rennert, F. Rieger und K. Voss: Über die Gestalt und das Schwerefeld der Erde . . . 21 ; Weaver, J. T.: On the Separation of Local Geomagnetic Fields . . . 29 ; Angenheister‚ G.: Kolloquium zum Thema: Gesteinsmagnetismus . . . 37 ; Der radioaktive Kollektor bei luftelektrischen Sondierungen . . . 43 ; Briefe an den Herausgeber . . . 45 ; Buchbesprechungen . . . 48 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS: Berckhemer H.‚ St. Müller und M. Sellevoll: Die Krustenstruktur in Südwestdeutschland aus Phasen-Geschwindigkeitsmessungen an Rayleigh-Wellen . . . 151 ; Schäffner, H. J.: Interpretation von Herdmechanismen durch asymmetrische Dislokationen . . . 164 ; Refai E.: Magnetic anomalies and magnetization of basalts in the area around Kemnath (Oberpfalz) . . . 175 ; Dürschner, H. : Über den Reflexionscharakter und die Laufzeitkurven nach Geschwindigkeitslogs . . . 188 ; Duda S. J.: Phänomenologische Untersuchung einer Nachbebenserie aus dem Gebiet der Aläuten- Inseln . . . 207 ; Bewersdorff, A.: Der Einfluß der Entmischung auf remanente Magnetisierung von Titanomagnetiten . . . 213 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS : SCHEUBE, H.-G. und J. UNTIEDT: Magnetische Messungen in der Rhön im Rahmen einer Studienfahrt . . . 283 ; HEINRICH, H.: Elastische Wellen in Eis . . . 293 ; SCHEIDEGGER, A. E.: Großtektonische Bedeutung von Erdbebenherdmechanismen . . . 300 ; Voos, K.: Über die Gestalt und das Schwerefeld der Erde . . . 313 ; PLAUMANN, S.: Berechnung der Schwerewirkung beliebig geformter dreidimensionaler Massen mit Hilfe von Auszähldiagrammen . . . 327 ; MEITZNER,W.: Zur Anwendung der FÖRSTER-Sonde bei gesteinsmagnetischen Arbeiten . . . 332 ; SOFFEL, H.: Magnetic domains of polycrystalline natural magnetite . . . 345 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Inhaltsverzeichnis : Übersichtsartikel: ENGELHARD, L.: Absorptionszellen-Magnetometer . . . l ; MÜLLER, H. J: Suche nach einer systematischen Änderung im Laufe des Jahres in der Phase der zweiten Harmonischen der täglichen Variation der kosmischen Strahlung . . . 39 ; CASTEN, U. and H. HIRSCHLEBER: Seismic Measurements in Jutland 1969 . . . 47 ; DRESEN, L.: Amplitudenuntersuchungen an seismischen Wellen zur Charakterisierung von Verwitterungsschichten mit vertikalem Geschwindigkeitsanstieg . . . 71 ; FUCHS, K: The Method of Stationary Phase Applied to the Reflection of Spherical Waves from Transition Zones with Arbitrary Depth-Dependent Elastic Moduli and Density . . . 89 ; HÄNEL, R.: Bestimmungen der terrestrischen Warmestromdichte in Deutschland . . . 119 , HÉDERVÁRI, P.: Map of Tectonic Flux of Japan . . . 135 ; Briefe an den Herausgeber: KIND, R.: Berechnung der Quellenfunktion einer Explosion im Flachwasser mittels einer Dekonvolutionsmethode . . . 141 ; WEICHERT, D. H.: Short-Period Spectral Discriminant for Earthquake-Explosion Differentiation . . . 147 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Probleme des Gesteins- und Paläomagnetismus. INHALTSVERZEICHNIS : SOFFEL, H.‚und N. PETERSEN: Vorwort . . . 303 ; BLEIL, U.: Cation Distribution in Titanomagnetites . . . 305 ; O’REILLY, W.‚ and P. W. READMAN: The Preparation and Unimixing of Cation Deficient Titanomagnetites . . . 321 ; READMAN, P. W., and W. O’REILLY: Oxidation Processes in Titanomagnetites . . . 329 ; PRÉVOT, M.: A Method for Identifying Naturally Occuring Titanomagnetites . . . . 339 ; PUCHER, R.: Magnetic and X-Ray Diffraction Measurements of the Synthetic Spinel System FeFe2O4 — MgFe2O4 — NiFe2O4 . . . . 349 ; SCHULT, A.: On the Strength of Exchange Interactions in Titanomagnetites and its Relation to Self-Reversal of Magnetization . . . . 357 ; HARGRAVES, R. B.‚ and N. PETERSEN: Notes on the Correlation between Petrology and Magnetic Properties of Basaltic Rocks . . . 367 ; CREER, K. M.: Geophysical Interpretation of Remanent Magnetization in Oxidized Basalts . . . 383 ; HEDLEY, I. G.: The Weak Ferromagnetism of Geothite . . . . 409 ; SCHMIDBAUER, E.: Magnetization of Fe-Cr Spinels and its Application for the Identification of Such Ferrites in Rocks . . . 421 ; SCHMIDBAUER, E.: Electrical Resistivity of Fe-Cr Spinels . . . 425 ; MANSON, A. J. : Rotational Hysteresis Measurements on Oxidized Synthetic and Natural Titanomagnetites . . . 431 ; ANDERS, W.: Untersuchung von Gesteinen mit ferrimagnetischen Mineralen mittels der Resonanz der Spin-Präzession der die Erscheinung des Ferromagnetismus bewirkenden Elektronen . . . 443 ; SOFFEL, H.: The Single Domain — Multidomain Transition in Natural Intermediate Titanomagnetites . . . 451 ; BIQUAND, D. ‚ and M. PRÉVOT: A.F.-Demagnetization of Viscous Remanent Magnetization in Rocks . . . 471 ; STORETVEDT, K. M.: Some Paleomagnetic Problems of Strongly Oxidized Rocks . . . 487 ; BUREK, P. J.: An Advanced Device for Chemical Demagnetization of Red Beds . . . 493 ; MARKERT, H., and N. STEIGENBERGER: On the Size Distribution of Submicroscopic Magnetite and Titanomagnetite Fine Particles in Basalt . . . 499 ; SOFFEL, H.: The Effect of Radiation with Fast Neutrons on the Saturation Remanence of a Basalt . . . 519 ; MARKERT, H.: On Some Magnetic and Magneto-Optic Properties to be Studied on Fine Precipitations in Glasses . . . 525 ; POHL, J.: On the Origin of the Magnetization of Impact Breccias on Earth . . . 549 ; HELLER, F.: Remanent Magnetization of the Bergell Granite . . .557 ; MÄUSSNEST, O.: Anomalien des erdmagnetischen Feldes im Gebiet der jungen Vulkane Südwestdeutschlands . . . 573 ; BOCK, G.‚ and H. STOFFEL: Paleomagnetic Investigation on Igneous Rocks from the Rhön, Germany . . . 581 ; WAGNER, J. J.: Rockmagnetic Studies on Ophiolites from Montgenevre (French-Italian Alps) . . . 589 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: INHALTSVERZEICHNIS : GUTLINO, G.: Ausbau eines Wechsellichtmonochromators und seine Anwendung zur Messung des Luftleuchtens während der Dämmerung und in der Nacht . . . 115 ; RAHMAN, A.: A New Type of Wave Discovered in the Schlieren Photographs . . . 146 ; KUHN, W.: Zur Theorie der endlichen elastischen Verschiebungen und ihre Anwendung auf isotrope elastische Körper, die unter beliebigen Anfangsverzerrungen stehen . . . 159 ; MÜNCH, J. Das Auftreten von pc-Pulsationen des erdmagnetischen Feldes in Abhängigkeit von der erdmagnetischen Aktivität . . . 192 ; DUTTA. S.: Note on the Propagation of Love-Waves in a Two-Layer Heterogeneous Medium . . . 200 ; EDER, G.: Der Zuwachs des Erdradius . . . 206 ; STILLER, H. und H. VOLLSTÄDT: Bestimmung ferri- und antiferromagnetischer CURIE-Temperaturen mittels Differentialthermoanalye . . . 212 ; Briefe an den Herausgeber . . . 219 ; Mitteilungen . . . 222 ; Buchbesprechung . . . 223 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Dieser Band enthält Artikel zu Themengebieten des Erdmagnetismus und der Ionosphäre, veröffentlicht durch die Deutsche Geophysikalische Gesellschaft in dem Jahr 1970.

Description: 〈ul style="line-height:2;"〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0004.pdf"〉Heft 1〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0005.pdf"〉Titelseite〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0006.pdf"〉Inhaltsverzeichnis 〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0007.pdf"〉[Impressum]〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0008.pdf"〉Satellite Techniques for Observing Water Vapor-Height Profiles (Bolle, H.-J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0015.pdf"〉Time Variation of Low Energy Protons in the Inner Radiation Belt (Achtermann, E., Freden, S. C., Hovestadt, D.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0017.pdf"〉Solarer Wind und Halbjahreswelle der erdmagnetischen Aktivität (Siebert, M.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0019.pdf"〉A Method for the Interpretation of Ionospheric Absorption Measurements during the Sunrise Effect in the D-Region (Cumme, G., Knuth, R., Wagner, C.-U.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0023.pdf"〉Simultane Beobachtungen verschiedener ionosphärischer Phänomene während des erdmagnetischen Sturmes vom 31. Oktober bis 2. November 1968 (Czechowsky, P., Kochan, H., Lange-Hesse, G., Lauche, H., Möller, H. G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0026.pdf"〉Laufzeitanomalien von P-Wellen, beobachtet an den Stationen Stuttgart und Strasbourg (Röwer, P.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0027.pdf"〉Buchbesprechungen (Israël, H., Roesner, H. A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0028.pdf"〉[Werbung]〈/a〉〈/li〉 〈/ul〉

Description: research

Description: DFG, SUB Göttingen, DGG

Description: INHALT: Raschke, E.: Die Strahlungsbilanz des Systems Erde-Atmosphäre — neuere Ergebnisse von Satellitenmessungen (S. 967); Harjes, H.-P.: Seismic Waves in Inhomogeneous Media (S. 1001); Haenel, R.: Heat Flow Measurements in the Red Sea and the Gulf of Aden (S. 1035); ‒ Brief an den Herausgeber ‒ G. WINTERER: Messung der Horizontalkomponente der elektrostatischen Feldstärke in der niederen Atmosphäre (S. 1049); ‒ Brief an den Herausgeber ‒ D. HEYE,: Ein Meßverfahren zur paläomagnetischen Untersuchung von Lockersedimenten im Gelände (S. 1055); ‒ Brief an den Herausgeber ‒ S. THYSSEN-BORNEMISZA,: Possible Improvement of Seismic Signal to Noise Ratio by Vertical Gravity Gradients (S. 1059).

Description: research

Description: DFG, SUB Göttingen

Description: Übersichtsartikel: Dohr, G.: Reflexionsseismische Tiefensondierung (S. 193); Behle, A., W. Ehrismann, J. Makris, H. Menzel, O. Rosenbach und P. Steinhauser: Gravimetrische Untersuchungen in den Ostalpen II (Meßgebiet Salzburg ‒ Kärnten ‒ Tirol) (S. 221); Grafarend, E.: Isotropietests von Lotabweichungsverteilungen in Westdeutschland II (S. 243); Weidelt, P.: The Inverse Problem of Geomagnetic Induction (S. 257); Böhm, J.: Measurements of MeV-Electrons During the Recovery-Phase of a Polar Magnetic Substorm on March 6, 1970 (S. 291); Voigt, G.-H.: A Three Dimensional, Analytical Magnetospheric Model With Defined Magnetopause (S. 319); In memoriam KARL JUNG (S. 347); Buchbesprechungen (S. 351).

Description: research

Description: DFG, SUB Göttingen

Description: Dieser Band enthält Artikel zu Themengebieten der Geophysik, veröffentlicht durch die Deutsche Geophysikalische Gesellschaft in dem Jahr 1970.

Description: 〈ul style="line-height:2;"〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0113.pdf"〉Heft 5〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0114.pdf"〉Titelseite〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0115.pdf"〉Inhaltsverzeichnis〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0116.pdf"〉[Impressum]〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0117.pdf"〉A Possible Scattering Mechanism for Lunar Seismic Waves (Berckhemer, H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0119.pdf"〉On the Determination of Velocity Depth Distributions of Elastic Waves from the Dynamic Characteristics of the Reflected Wave Field (Fuchs, K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0125.pdf"〉Auswertung seeseismischer Messungen mit einer digitalen Methode unter Anwendung der Theorie der Schallwellenausbreitung im Flachwasser (Kind, R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0128.pdf"〉On Chemical Magnetization in Some Permian Lava Flows of Southern Norway (Storetvedt, K. M., Petersen, N.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0132.pdf"〉Auswertung von Gravimeter-Messungen in der Münchberger Gneismasse längs eines Profils von Konradsreuth nach Niederlamitz (Soffel, H., Peters, K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0133.pdf"〉Deutung der Schwereanomalien im Nördlinger Ries (Kahle, H.-G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0135.pdf"〉Eine Methode zur direkten Bestimmung der sogenannten "Geometrischen Tortuosität" (Bitterlich, W., Wöbking, H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0137.pdf"〉Observations With Synchronously-Offset Beams on a 77 km path at 1.8 and 4 cm (Jeske, H., Seehars, H. D., Pucher, G., Cassebaum, H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0139.pdf"〉Scattering of Seismic Waves and Lunar Seismograms (Strobach, K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0140.pdf"〉Berechnung eines Stromsystems in der Polaren E-Region (Czechowsky, P.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0141.pdf"〉Mitteilung〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0142.pdf"〉Buchbesprechungen (Zürn, W., Seiler, E., Theile, B., Diem, Walk, )〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN101433392X_0036/LOG_0143.pdf"〉[Werbung]〈/a〉〈/li〉 〈/ul〉

Description: research

Description: DFG, SUB Göttingen, DGG

Description: INHALT: Behrens, J.:Refraktionsseismische Messungen auf See (S. 161); Bosum, W.: Erdmagnetische Messungen im Deckdiabasgebiet der Dillmulde und ihre Auswertung [Fortsetzung] (S. 177).

Description: research

Description: DFG, SUB Göttingen

Description: Five volcanic tuffs ranging from dacitic tuffs of Hungary to rhyolite, phonolite and basaltic tuffs of Germany were consolidated under laboratory conditions. Prior to consolidation an anti-hygro, a hydrous consolidant, which reduces the swelling ability of clay minerals, was applied. The three consolidants, a silicic acid ester (SAE), an elastic silicic acid ester (eSAE) and an acrylate resin (PMMA) were applied on test specimens under vacuum. Petrographic characterisation (polarizing microscopy, XRD, SEM) provided data for fabric analyses and the mineral composition of the tuffs. Changes in fabric, effective porosity, density, tensile strength, ultrasonic wave velocity were evaluated after the treatment. Weathering simulation tests such as hygric dilatation and thermal dilatation aimed to prove the effectiveness of consolidation and the durability of consolidated tuff samples. More than 500 samples were analysed. The tests showed that SAE caused the highest increase in indirect tensile strength. The water absorption and the pore size distribution of the tuffs were modified by consolidation. The PMMA reduced the water absorption the most, whereas SAE modified it the least. All the tested consolidants increased the thermal dilatation of the tuffs. The changes in hygric dilatation were not uniform: for most tuffs SAE increased and PMMA decreased the hygric dilatation, although the clay-rich Habichtswald tuff showed the opposite trend. The changes in hygric and thermal behaviour of consolidated tuff require special care when specific consolidants are chosen. These products modify the physical properties of consolidated tuffs and change the behaviour of weathering.

Description: The giant ignimbrites that erupted from the Cerro Galán caldera complex in the southern Puna of the high Andean plateau are considered to be linked to crustal and mantle melting as a consequence of delamination of gravitationally unstable thickened crust and mantle lithosphere over a steepening subduction zone. Major and trace element analyses of Cerro Galán ignimbrites (68–71% SiO2) that include 75 new analyses can be interpreted as reflecting evolution at three crustal levels. AFC modeling and new fractionation corrected δ18O values from quartz (+7.63–8.85‰) are consistent with the ignimbrite magmas being near 50:50 mixtures of enriched mantle (87Sr/86Sr ~ 0.7055) and crustal melts (87Sr/86Sr near 0.715–0.735). Processes at lower crustal levels are predicated on steep heavy REE patterns (Sm/Yb = 4–7), high Sr contents (〉250 ppm) and very low Nb/Ta (9-5) ratios, which are attributed to amphibolite partial melts mixing with fractionating mantle basalts to produce hybrid melts that rise leaving a gravitationally unstable garnet-bearing residue. Processes at mid crustal levels create large negative Eu anomalies (Eu/Eu* = 0.45–0.70) and variable trace element enrichment in a crystallizing mush zone with a temperature near 800–850°C. The mush zone is repeatedly recharged from depth and partially evacuated into upper crustal magma chambers at times of regional contraction. Crystallinity differences in the ignimbrites are attributed to biotite, zoned plagioclase and other antecrysts entering higher level chambers where variable amounts of near-eutectic crystallization occurs at temperatures as low as 680°C just preceding eruption. 40Ar/39Ar single crystal sanidine weighted mean plateau and isochron ages combined with trace element patterns show that the Galán ignimbrite erupted in more than one batch including a ~ 2.13 Ma intracaldera flow and outflows to the west and north at near 2.09 and 2.06 Ma. Episodic delamination of gravitationally unstable lower crust and mantle lithosphere and injection of basaltic magmas, whose changing chemistry reflects their evolution over a steepening subduction zone, could trigger the eruptions of the Cerro Galán ignimbrites.

Description: The construction suitability of a dimension stone depends on its weathering properties along with the petrology and the petrophysical properties. The aim of this study was to evaluate the suitability of the dimension stones from the “Drei Gleichen” area for construction and replacement purposes. In total, six sandstones (Ingersleben, Wachsenburg, Hindfelden, Seeberg, Röhnberg, Gleichenberg; Upper Triassic) as well as two carbonates (Wachsenburg sinter; Quaternary, Wandersleben dolomite; Middle Triassic) were analysed. The results from our laboratory and on-site studies of the dimension stones show that rocks from the same stratigraphic layer, like the sandstones from the upper Triassic, can show major differences in their petrophysical and weathering properties. These differences are attributed to their different diagenesis, resulting, e.g. in varying pore space, water balance and strength properties. The pore size distribution can be divided into four different groups based on their occurring maxima and micropore content. The determined water balance properties as well as moisture expansion and salt attack depend on these groups. Next to this, the mineralogical composition significantly influences the weathering resistance. Sandstones with a high content of altered lithoclasts show a high amount of moisture expansion, low strength and, in consequence, a low weathering resistance against salt attack. Based on the results of the present study, an evaluation of construction suitability could be accomplished. From the analysed sandstones, only the Seebergen sandstone is suitable for construction purposes due to its good availability, good strength properties (high compressive and tensile strength, low softening degree) as well as a low porosity. Furthermore, the Wachsenburg sandstone also shows good petrophysical and petrological properties, but exploitable deposits are too sparse to be of commercial interest. From the carbonates, the Wachsenburg sinter shows very suitable rock parameters, but only sparse outcrops occur, which are not appropriate for mining.

Description: In the Aztec period and in colonial times different natural stones originating in the Valley of Mexico were used for building construction. Stone weathering was investigated onsite at various historical buildings within the old quarter of Mexico City. In this study, different aspects of weathering and deterioration at three significant historical buildings will be presented, the Aztec excavation site Templo Mayor, the Metropolitan Cathedral, and the colonial palace of the dukes of Heras Soto. Petrophysical properties of the main building stones of these structures were investigated like density, porosity, pore radii distribution, water uptake rate and coefficient, thermal and hygric expansion, and the mechanical properties of uniaxial compressive strength. A relationship between single critical property values, according to anisotropy fabric characteristics, and specific weathering forms could be deduced.

Description: A 782 d solubilization study using not shaken batch experiments and involving one uranium-bearing rock and three natural carbonate minerals was conducted to characterize uranium (U) leaching under oxic conditions. Results showed that aqueous U concentration increased continuously with a solubilization rate of 0.16 mgm-2h-1 for the first 564 d (1.5 y). After 1.5 y, U concentration reached a maximum value (saturation) and decreased afterwards. The saturation concentration of 54 mgL-1 (mean value) was influenced to various extent by the presence of carbonate minerals. Dissolution/precipitation, adsorption or ion exchange processes appear to control U solubilization.

Description: Korschunow, A: Tiefherdbeben aus Göttinger Seismogrammen . . . 113 ; Belluigi, A: Über ein geoelektrisches inverses Problem . . . 135 ; Berckhemer, H.‚ Oliver, J.: Zur Deutung seismischer Einsätze mit parallelen Laufzeitkurven . . . 152 ; Dohr, C.: Perioden der ersten Vorläufer in Göttinger Seismogrammen . . . 165 ; Buchbesprechung . . . 175 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Argence, E.: Kritische Betrachtung der Wellenausbreitung in einem isotropen, absorbierenden Medium . . . l ; Kunetz, G.: Einfluß vertikaler Schichten auf elektrische Sondierungen . . . 10 ; Wilckens, F.: Die Grundlage der Eigenpotentialmethode . . . . 25 ; Hellbardt, G.: Seismische Versuche auf einer Eisplatte . . . . . 41 ; Cipa, W.: Kurzbericht über einige erdmagnetische Untersuchungen an Lavaströmen und Tuffschloten in der Vordereifel . . . . 48 ; Schmidt, H.: Untersuchungen zur photoelektrischen Schwingzeitmessung . . . 53 ; ZUSAMMENFASSUNG 1 [Argence, E.: Kritische Betrachtung der Wellenausbreitung in einem isotropen, absorbierenden Medium]: Der Einfluß der Absorption auf die Ausbreitung der Kurzwellen in der Ionosphäre wird untersucht. Das Problem kann von zwei verschiedenen Gesichtspunkten her behandelt werden, entweder nach der Methode von Epstein (1930) oder nach denen von Mc Cullagh, Cauchy, Arzeliäs, die zur Behandlung der Metall-Reflexion ausgearbeitet wurden. Im vorliegenden ersten Teil werden die für die Metall-Reflexion erhaltenen Ergebnisse benutzt. ZUSAMMENFASSUNG 2 [Kunetz, G.: Einfluß vertikaler Schichten auf elektrische Sondierungen]: Obwohl diese Frage Gegenstand eines jüngst in "GEOPHYSICS" erschienenen Artikels war, halten wir es für lohnenswert, unsererseits über die auf diesem Gebiet in unabhängiger Weise von uns erzielten Ergebnisse zu berichten. Die von uns angewandte Lösungsmethode ist in der Tat nicht die gleiche: wir wenden sie für eine andere Form der Elektroden an und dehnen sie auf eine andere und kompliziertere Anordnung der Gesteinkörper aus. Unsere Arbeit betrifft hauptsächlich die Einwirkung von ebenen, dünnen Schichten mit sehr hohem oder, im Gegenteil, sehr niedrigem elektrischen Widerstand auf die Potentialverteilung, die durch Gleichstrom, der mittels punktförmiger Elektroden in die Erde gesendet wird, entsteht. Es wird zuerst angenommen, daß die genannte Schicht in einem unendlichen, homogenen Medium eingebettet ist, alsdann aber wird das Medium nach oben durch die horizontale Erdoberfläche und nach unten durch die ebenso horizontale Fläche eines elektrisch nicht leitenden Substratums begrenzt, und die dünne Schicht vertikal vorausgesetzt. Aus dieser Potentialverteilung wird das elektrische Feld an der Erdoberfläche im Mittelpunkt von zwei Stromelektroden ermittelt, wobei die Elektroden parallel oder senkrecht zu der Schicht angeordnet werden. Nach Multiplikation mit einem zum Quadrat der Elektrodenentfernung proportionalen Faktor erhält man den sog. „scheinbaren spezifischen Widerstand", ein wohlbekannter Parameter, der in einem homogenen Medium dem wahren spezifischen Widerstand gleich ist. Die numerischen Ergebnisse für verschiedene Anordnungen der Schichten und ihrer Widerstände werden als Funktion der Länge der Meßanordnung durch mehrere Kurvengruppen dargestellt. Anschließend werden auch Ergebnisse für vertikalen Kontakt von zwei weitausgedehnten horizontalen Schichten verschiedener Leitfähigkeiten, die auf einem nichtleitenden Substratum liegen, angegeben. ZUSAMMENFASSUNG 3 [Wilckens, F.: Die Grundlage der Eigenpotentialmethode]: Nach einer Erörterung der WidersPrüche im Schrifttum über die Eigenpotentialmethode wird gezeigt, daß durch die Berücksichtigung des Potentialsprunges an der Grenzfläche Erz/ Elektrolyt eine Erklärung der mittels der Eigenpotentialmethode gewonnenen Meßergebnisse im Rahmen der bisherigen Oxydations-Reduktions—Theorie möglich ist. Weitere Probleme der elektrochemischen Vorgänge im Bereich von Erzlagerstätten sowie der Meßmethodik bei Eigenpotentialuntersuchungen werden diskutiert. ZUSAMMENFASSUNG 4 [Hellbardt, G.: Seismische Versuche auf einer Eisplatte]: Die Ausbreitungsgeschwindigkeit der elastischen Wellen in einer Eisplatte wurde gemessen. Dabei wurden Dehnungs-, SH- (Love-) und Riegewellen beobachtet sowie nicht erklärte Einsätze. Die gemessenen Geschwindigkeiten und und die daraus berechneten Elastizitätskonstanten stimmen gut mit den Ergebnissen anderer Autoren und mit der Theorie überein. Eine Berechnung zur Ausbreitung von Impulsen bei vorhandener Dispersion veranschaulicht die Entstehung der Wellenzüge in den Seismogrammen. ZUSAMMENFASSUNG 5 [Cipa, W.: Kurzbericht über einige erdmagnetische Untersuchungen an Lavaströmen und Tuffschloten in der Vordereifel]: In Fortsetzung der Arbeiten von Ahrens (1932) und Kienow (194l) führte der Verfasser im Vulkangebiet der Eifel Untersuchungen mit einem magnetischen Vertikalvariometer durch. In der Umgebung von Gillenfeld und Gerolstein-Hillesheim ermittelte er die Grenzen einiger Lavaströme, die mit Tuff und Alluvionen bedeckt sind. Die hoch magnetischen basaltiscben Aschen ermöglichten es, einen Vulkanschlot und die Form einiger Vulkane, die nur Tuffe gefördert haben, ausfindig zu machen. ZUSAMMENFASSUNG 6 [Schmidt, H.:Untersuchungen zur photoelektrischen Schwingzeitmessung]: Die Bewegungen eines am Faden hängenden, horizontal schwingenden Magneten wurden in vier Freiheitsgraden berechnet. Hieraus folgt das kürzestmögliche Meßintervall. Eine neue Methode optischer Impulsverkürzung wird angegeben, die eine höhere Genauigkeit in der Erfassung eines einzelnen Durchgangs als frühere Methoden liefert. Eine automatisch arbeitende Schwingzeitmeßanlage wird beschrieben und Meßergebnisse werden mitgeteilt.

Description: Argence, E.: Kritische Betrachtung der Wellenausbreitung in einem isotropen, absorbierenden Medium . . . l ; Kunetz, G.: Einfluß vertikaler Schichten auf elektrische Sondierungen . . . 10 ; Wilckens, F.: Die Grundlage der Eigenpotentialmethode . . . . 25 ; Hellbardt, G.: Seismische Versuche auf einer Eisplatte . . . . . 41 ; Cipa, W.: Kurzbericht über einige erdmagnetische Untersuchungen an Lavaströmen und Tuffschloten in der Vordereifel . . . . 48 ; Schmidt, H.: Untersuchungen zur photoelektrischen Schwingzeitmessung . . . 53 ; ABSTRACT 1 [Argence, E.: Kritische Betrachtung der Wellenausbreitung in einem isotropen, absorbierenden Medium]: The influence of absorption on ionospheric short wave propagation is studied. We may handle the problem from two different view points: or with Epstein’s method (1930), or with those of Mc. Cullagh, Cauchy, Arzelies. The latter have been developed for the treatment of reflexion from metals. In this first part results obtained for reflexion from metals are used. ABSTRACT 3 [Wilckens, F.: Die Grundlage der Eigenpotentialmethode]: After a discussion of the contradictions in literature concerning the self-potential (SP) method, it is shown that the SP curve measured near ore bodies is mostly due to the potential drop on the boundary ore/electrolytes. This explanation is in accordance to the hitherto existing oxidation theory. Further problems are discussed concerning electrochemical actions near ore bodies and the surveying method of SP investigations. ABSTRACT 4 [Hellbardt, G.: Seismische Versuche auf einer Eisplatte]: The propagation of elastic waves in an ice-sheet was observed. Dilational, flexural and SH (=Love) waves were observed, as well as onsets not yet explained. The measured velocities and the elastic constants computed therefrom agree well with the results of other authors and with theory. The generation of the wave trains in the seismogram is discussed in a computation of the propagation of model pulses. ABSTRACT 5 [Cipa, W.: Kurzbericht über einige erdmagnetische Untersuchungen an Lavaströmen und Tuffschloten in der Vordereifel.]: Continuing the works of Ahrens (1932) und Kienow (1941) the author made researches with a magnetic verticalvariometer in the volcanic area of the Eifel. In the surroundings of Gillenfeld and Gerolstein-Hillesheim he ascertained the limitations of some lava flows, covered with tuffs and alluvions. The highly magnetic basaltic ashes made it possible to find out a volcanic vent and the form of some volcanoes, which only had produced tuffs. ABSTRACT 6 [Schmidt, H.:Untersuchungen zur photoelektrischen Schwingzeitmessung]: Motions of an oscillating magnet, horizontally suspended and movable in four rates of libration, have been computed. Hence it follows the shortest possible measuring-interval. A new method of optical puls-shortening is suggested, which gives higher precision in fixing a single passage than preceding methods. A apparatus for automatic measuring the period of oscillation is described and results are given.

Description: RESUME 2 [Kunetz, G.: Einfluß vertikaler Schichten auf elektrische Sondierungen] : Cette note est principalement consacree ä l ’etude de la distribution des potentiels resultant de l’envoi d’un courant continu dans le sol, par une electrode ponctuelle, en presence d’ une couche plane tres mince et dont la resistivite celectrique est, soit tres elevee, soit au contraire tres basse,par rapport a celledu milieu environnant. On suppose d ’abord que cette couche est plongee dans un milieu homogene indefini, puis, considerant la couche comme verticale, on admet que le milieu environnant est limite’ vers le haut par la surface horizontale du sol et vers le bas par un substratum egalement horizontal, infiniment resistant ou infiniment conducteur au point de vue electrique.

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Gutenberg, B.: Untersuchungen zur Bodenunruhe in Südkalifornien . . . 177 ; Strobach, K: Zum Studium der mikroseismischen Bodenunruhe in Hamburg . . . 190 ; Bibl, K, Dolobeau, F.: Ionosphärische Beobachtungen während der totalen Sonnenfinsternis vom 30. Iuni 1954. . . 215 ; In Memoriam Dr. Friedrich Trappe . . . 229 ; In Memoriam Dr. phil. Hubert Lückerath . . . 233 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Gutdeutsch, R. : Über Vielfacheinsätze elastischer Wellen an Schichten Teil 2 . . . 53 ; Petersen, N. : Untersuchungen magnetischer Eigenschaften von Titanomagnetiten im Basalt des Rauhen Kulm (Oberpfalz) in Verbindung mit elektronenmikroskopischer Beobachtung . . . 79 ; Krumm, H.-Chr.: Der weltzeitliche Tagesgang der Gewitterhäufigkeit . . . 85 ;

Description: research

Description: DGG, DFG, SUB Göttingen

Description: Übersichtsartikel: REMER, M.: Das raumzeitliche Verhalten der Hochatmosphäre, erschlossen aus Bahnänderungen künstlicher Satelliten . . . 217 ; ASHOUR, A. A.: The Effect of the Earth‘s Conductivity on Ionosperic Shielding . . . 269 ; BROCKAMP, B. und H. RÜTER: Die Abhängigkeit der elastischen Parameter des Eisens vom hydrostatischen Druck bis zu 400 bar . . . 277 ; PROS, Z., J. VANĚK, K. KLÍMA und V. BABUŠKA: Experimentelle Untersuchungen des Wellenbildes bei der Ultraschall-Durchstrahlung einer Kugel . . . 287 ; SCHÖDEL, J. P.: On the Existence of Sometimes Considerable Transport Effects in the Nighttime Ionosphere . . . 297 ; NITZSCHE, P.: The dependence of ionospheric absorption of radio waves on equivalent frequency, with special emphasis on the winter anomaly . . . 303 ; Berichtigung und Ergänzung: HASSE, L.: Zum Einfluß von Instrumententrägheit . . . 311 ; Briefe an den Herausgeber: NIX, N.: Anreicherungsverfahren für atmosphärische Ionen mittels elektrostatischer Linse . . . 313 ; Kurzmitteilung . . . 315

Description: research

Description: DGG, DFG, SUB Göttingen

Description: SCHULT, A. and M. SCHOBER: Measurement of electrical conductivity of natural olivine at temperatures up to 950 °C and pressures up to 42 kbar . . . 105 ; STROBACH, K.: Über die Natur der elastischen Wellen der Seegangs-Mikroseismik . . . 113 ; FUCHS, K: On the properties of deep crustal reflectors . . . 133 ; VOPPEL, D.: Ein Spulentheodolit zur Messung der erdmagnetischen Komponenten mit dem Protonenmagnetometer . . . 151 ; FRITSCH, V. und A. F. TAUBER: Geoelektrische Untersuchungen von Salzwasservorkommen . . . 161 ; BEHRENS, J. und L. DRESEN: Eine Möglichkeit zur Laufzeitbestimmung reflektierter Wellen im Bereich der kritischen Entfernung . . . 175 ; WEIDELT, P.: Zur Tiefenlage und Größe des Dichtemaximums der induzierten Erdströme . . . 191 ; Briefe an den Herausgeber: ISRAËL, H., und N. NIX: Ein neues Verfahren zur Untersuchung von Kondensation und Verdampfung an Einzelteilchen von Kleinaerosolen . . . 207 ; ROSE‚ G. und H. U. WIDDEL: Zur Möglichkeit des direkten Nachweises vertikaler Luftbewegungen im Höhenbereich 75 - 80km . . . 211 ; Buchbesprechungen . . . 213

Description: research

Description: DGG, DFG, SUB Göttingen