Über die Natur des Sedimentgleichgewichtes im Litoral

Zusammenfassung Unter Beachtung der Fortschritte der modernen Brandungsforschung sowie neuerer Beobachtungsergebnisse im Litoral erscheint die vonCornaglia entwickelte Theorie der neutralen Linie, die das einzelne Sedimentkorn isoliert in Ansatz brachte, unhaltbar. An ihre Stelle tritt die den tatsächlichen Verhältnissen besser Rechnung tragende Theorie des «Massenmomentes» der brandenden Wellen, die nicht mehr das einzelne Korn, sondern die gesamte unter der Einwirkung der Oszillation entstehende Suspensionswolke betrachtet. Die Vorteile dieser neuen Betrachtungsweise werden kurz skizziert und an Hand einiger Beispiele näher erläutert.

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Summary With respect to the attainments of the modern surf phenomena research and based on new results of observations in the littoral zone the theory of the neutral line, developed byCornaglia, which looked upon the wave-moved grain as an isolated individual, is no longer useful. In its place the better theory of the surging wave's «momentum of mass» is set, which considers the whole cloud of material whirled up by the oscillatory undulation near the bottom. The advantages of this new consideration are shortly sketched and particularly illustrated by means of some examples.

     

Die Temperatur in Grönlandischen Inlandeis

Zusammenfassung Auf Grund der Temperaturmessungen in Schächten 1930/31 und Bohrungen 1948/1951, die berichtigt wurden, wird die wahrscheinlichste Temperaturverteilung in Inlandeis gewonnen.

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Summary The measurements of temperature in holes 1930/1931 and the (corrected) measurements of the temperature in drilled holes 1948/1951 are used, to construct the distribution of the temperature in the inlandice of Greenland.

     

Die östliche Fortsetzung des Kaukasus

Ohne ZusammenfassungDie älteren Arbeiten sind nur dann angeführt, wenn sie im Text genannt sind; weitere Literatur siehe in den Verzeichnissen bei den jüngeren Arbeiten.Die russischen Orts- und Verfassernamen sind in deutschen Lautwerten umschrieben mit sh==franz. j.     

The metamorphic evolution of garnet-cordierite-sillimanite-gneisses of the Gruf-Complex,Eastern Pennine Alps

Metapelitic gneisses occuring as lenses and bands within the migmatites of the Gruf-Complex in the eastern Pennine Alps contain various combinations of the minerals quartz, biotite, cordierite, garnet, sillimanite, plagioclase. K-feldspar, spinel, orthopyroxene, anthophyllite and muscovite. The most common rock type is represented by a darkschistosebiotiterichcordierite-garnet-sillimanite-gneiss. A consistent pressure-temperature range of 3–4 kb and 600–650° C has been calculated for the last metamorphic equilibration from six geological thermobarometers. However, from textural evidence it may be concluded that the rocks were at both higher temperatures and pressures prior to the PT-conditions calculated from thermobarometry. Although the maximum conditions reached are unknown and earlier stages are poorly preserved it is suggested that they coincide with the maximum conditions deduced from rare occurrences of sapphirine granulite in the Gruf-Complex. These are 10 kb and 800° C (Droop and Bucher 1983). Sillimanite+K-feldspar, orthopyroxene+quartz, spinel+quartz and garnet-K-feldspar persisting in rocks with low activity of H₂O are strong evidence for this. The H₂O required to make the observed high degree of equilibration at 3–4 kb and 600–650° C possible was presumably released by crystallizing migmatitic melts present in the quartzo-feldspathic gneisses of the Gruf-Complex. Further evidence comes from the PT-coordinates of the H₂O-saturated muscovite granite solidus which coincides with the high temperature limits of inferred equilibration above and which the rocks must have crossed along the decompression and cooling path during their metamorphic evolution.     

Dislocation structure of the crust-mantle boundary and low-velocity body within the crust beneath the Dabie Shan collision orogen

The Dabie Shan is located on the eastern side of the Qinling-Dabie orogenic belt, which marks a geological boundary between the Sino-Korean and Yangtze cra- ton. Since the 1980s, the discovery of coesite and mi- crodiamond in the Dabie Shan orogen motivates an extensive interest to the ultra-high pressure (UHP)metamorphism and its exhumation[1,2]. Many results about them were published, which deal with different disciplines, including tectonics, petrology and chro- nology[3?8]. Up to now,…     

Summer flows in experimental catchments with different forest covers, Chile

Runoff and peak flows in four experimental catchments with different land uses are analyzed for summer periods. The catchments have a rainy temperate climate with annual precipitations between 2000 and 2500 mm, 70% of which is concentrated in the winter period between May and August. The final harvest of the forest plantation in one of these catchments generated increases in summer runoff. Also, differences between the maximum instantaneous discharge and the flow at the beginning of the storm then almost duplicated those registered in rainfall events of similar magnitude when the catchment was fully forested. Runoff analysis in this catchment is difficult because the two post-harvesting summer periods are much wetter than the two pre-harvesting ones but a double mass analysis shows the effect of harvesting clearly. In a paired catchment study, low cover in one of the two neighbour catchments explains higher direct runoff and base flows although lower maximum instantaneous specific discharge occurred in the less vegetated but larger catchment. Low vegetation cover explains increases in summer flows, although the size, topography, rainfall conditions, road density, extent of affected area and runoff generation processes play an important role in the hydrological effects of different land uses.     

Piecewise 1D laterally constrained inversion of resistivity data

In a sedimentary environment, layered models are often capable of representing the actual geology more accurately than smooth minimum structure models. Furthermore, interval thicknesses and resistivities are often the parameters to which non‐geophysicist experts can relate and base decisions on when using them in waste site remediation, groundwater modelling and physical planning. We present a laterally constrained inversion scheme for continuous resistivity data based on a layered earth model (1D). All 1D data sets and models are inverted as one system, producing layered sections with lateral smooth transitions. The models are regularized through laterally equal constraints that tie interface depths and resistivities of adjacent layers. Prior information, e.g. originating from electric logs, migrates through the lateral constraints to the adjacent models, making resolution of equivalences possible to some extent. Information from areas with well‐resolved parameters will migrate through the constraints in a similar way to help resolve the poorly constrained parameters. The estimated model is complemented by a full sensitivity analysis of the model parameters, supporting quantitative evaluation of the inversion result. Examples from synthetic 2D models show that the model recognition of a sublayered 2D wedge model is improved using the laterally constrained inversion approach when compared with a section of combined 1D models and when compared with a 2D minimum structure inversion. Case histories with data from two different continuous DC systems support the conclusions drawn from the synthetic example.     

The influence of impurities on the dissolution of Ca- and Sr-bearing barite at room temperature

1INTRODUCTION BARITE(BASO4)ISANEXTREMELYINSOLUBLESALT;THISAROUSESPROBLEMSINPETROLEUMINDUSTRYBECAUSE BASO4ISAPARTICULARLYINTRACTABLESCALINGAGENT.BARITE PRECIPITATIONINTHEWELLBOREENVIRONMENTGENERALLYRE QUIRESMECHANICALREMOVAL,WITHCONSIDERABLEASSOCIAT EDEXPE…