Cyclotella-taxa (Bacillariophyceae) in lakes of the Alpine region and their relationship to environmental variables     

Sybille Wunsam  Roland Schmidt  Rolf Klee 《Aquatic Sciences - Research Across Boundaries》1995,57(4):360-386

Surface sediment diatom assemblages for 86 Alpine lakes were analysed focusing on the dominant genusCyclotella and corresponding environmental data. The range of morphological variability of theCyclotella bodanica/radiosa, C. distinguenda, C. ocellata, C. comensis andC. stelligera complexes was documented. Significance tests included in the canonical correspondence analysis (CCA) indicated that total phosphorus, conductivity and surface water temperature were significantly correlated withCyclotella taxa assemblage distribution. Numerical species optima and tolerances were calculated in respect to these significant variables using weighted averaging (WA) regression and calibration. CCA and WA were able to provide information about the environmental preferences of the various morphotypes observed.  相似文献   

EDITORIAL     

Klaus  Helbig 《Geophysical Prospecting》1987,35(2):127-128

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Trends in Atlantic equatorial current variability     

Dr. William J. Emery  Dr. Walter Zenk  Dr. Klaus Huber  Dr. Pierre Rual  Dr. Paul Nowlan 《Ocean Dynamics》1987,40(6):261-276

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Vertical profiles of wind speed,snow concentration,and humidity in blowing snow   总被引：1，自引：1，他引：1  

R. A. Schmidt 《Boundary-Layer Meteorology》1982,23(2):223-246

To estimate the sublimation rate of snow during relocation by wind, sizes and concentration of ice crystal fragments were measured at 6 levels in the lowest 1 m, during ten 10-min runs, in a nocturnal blizzard. Power-law functions of height described the decrease in mean particle diameter and concentration. The vertical gradient of water vapor, measured with a thermocouple psychrometer, was approximately linear from 0.2 to 1.0m above the surface. Evaporation of blowing snow over 3 km of transport distance was estimated to be 39% of transport rate, under conditions of the experiment.  相似文献   

Mineralogy and petrology of the Abee enstatite chondrite breccia and its dark inclusions     

Alan E. Rubin  Klaus Keil 《Earth and Planetary Science Letters》1983,62(1):118-131

The Abee E4 enstatite chondrite breccia consists of clasts (many rimmed by metallic Fe, Ni), dark inclusions and matrix. The clasts and matrix were well equilibrated by thermal metamorphism, as evidenced by uniform mineral compositions, recrystallized chondrules, low MnO content of enstatite and high abundance of orthoenstatite. The clasts acquired their metal-rich rims prior to this metamorphic episode. The occurrence in Abee of relatively unmetamorphosed dark inclusions, clasts with nearly random magnetic orientations and a matrix with a uniform magnetic orientation [18,19] indicates that clast and matrix metamorphism occurred prior to the agglomeration of the breccia.The dark inclusions are an unusual kind of enstatite chondritic material, distinguished from the clasts and matrix by their relative enrichments in REE [21–23], low relative abundances of kamacite, total metallic Fe, Ni and silica, lower niningerite/(total sulfide) ratios, high relative abundances of oldhamite and martensite, smaller euhedral enstatite, more heterogeneous enstatite and metallic Fe, Ni, more calcic enstatite and more nickeliferous schreibersite.We propose the following model for the petrogenesis of the Abee breccia: The maximum metamorphic temperature of breccia parent material was?- 840°C (the minimum temperature of formation of Abee niningerite) and perhaps near 950–1000°C (the Fe-Ni-S eutectic temperature). Euhedral enstatite crystals in metallic Fe, Ni- and sulfide-rich areas grew at these metamorphic temperatures into pliable metal and sulfide. Breccia parent material was impact-excavated from depth, admixed with dark inclusions and rapidly cooled (700 to 200°C in about 2 hours) [15]. During this cooling, clast and matrix material acquired thermal remanent magnetization. Random conglomeration of clasts and unconsolidated matrix materials caused the clasts to have random magnetic orientations and the matrix areas to have net magnetic intensities of zero (due to the cancellation of numerous randomly oriented magnetic vectors of equal intensity in the matrix). A subsequent ambient magnetic field imparted a uniform net magnetic orientation to the matrix and caused the magnetic orientations of the clasts to be somewhat less random. The Abee breccia was later consolidated, possibly by shock or by shallow burial and very long-period/low-temperature (< 215°C) metamorphism.  相似文献   

Stadtbedingte Niederschlagseffekte im Großraum von Mexiko City     

Prof. Dr. D. Klaus  Dr. E. Jaurequi  Prof. W. Lauer 《Theoretical and Applied Climatology》1983,33(3):275-288

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Spectra of the earthquake sequence February-March, 1981, in south-central Sweden     

Ota Kulhnek  Torild Van Eck  Norris John  Klaus Meyer  Rutger Wahlstrm 《Tectonophysics》1983,93(3-4)

On February 13, 1981 a relatively strong earthquake occurred in the Lake Vänern region in south-central Sweden. The shock had a magnitude ofM_L = 3.3 and was followed within three weeks by three aftershocks, with magnitudes 0.5 ≤ M_L ≤ 1.0. The focal mechanism solution of the main shock indicates reverse faulting with a strike in the N-S or NE-SW direction and a nearly horizontal compressional stress. The aftershocks were too small to yield data for a full mechanism solution, but first motions of P-waves, recorded at two stations, are consistent for the aftershocks. Dynamic source parameters, derived from Pg- and Sg-wave spectra, show similar stress drops for the main shock (2 bar) and the aftershocks (1 bar), while the differences in seismic moment (1.5·10²⁰ resp. 4·10¹⁸dyne cm), fault length (0.7 resp. 0.2 km) and relative displacement (0.15 resp. 0.03 cm) are significant.  相似文献   

A comparison between the fabric camera and texture goniometer methods of fabric analysis by X-ray diffraction     

Professor John Starkey  Stefan Schmidt 《International Journal of Earth Sciences》1983,72(2):529-539

The effects of grain size on the analysis of fabrics by X-ray diffraction using both the fabric camera and the texture goniometer are discussed. Simple calculations show the interdependance between the mean grain diameter and the number of crystals which are measured by each instrument. The effects of both grain size and modal composition of the specimen are illustrated by comparative analyses. Both the fabric camera and texture goniometer are well suited to the analysis of specimens in which the mean grain diameter is between approximately 10 and 100 microns. The texture goniometer is more suitable when the grain size is less than this, while the fabric camera is better suited when the grain size is coarser, especially when the specimen is not monomineralic.  相似文献   

The coalification pattern in the Northern Apennines and its palaeogeothermic and tectonic significance     

Prof. Dr. Klaus -J. Reutter  Marlies Teichmüller  Rolf Teichmüller  Giorgio Zanzucchi 《International Journal of Earth Sciences》1983,72(3):861-893

The rocks of the Northern Apennines predominantly consist of non-metamorphic terrigeneous deposits (flysches and molasses) some of which are preorogenic, some synorogenic and others postorogenic with respect to the nappe tectonics (Miocene). As plant fragments frequently occur in these sediments, a study of coal rank based on reflectance measurements on vitrinites (% Rm = mean value of the random reflectance in non polarized light) contributes to the clarification of the relation between the orogenic and the palaeogeothermal development. The determination of the Rm values of more than 180 samples from outcrops and three deep drillings revealed some important features. Within the pile of Liguride and Tuscanide nappes, the coal rank increases from the uppermost nappe to the lower nappes until lowgrade metamorphism is reached in the Lower Tuscanides. In the single nappes the rank decreases from the Tyrrhenian coast (internal zone) towards the Po Plain (external zone). This regional trend is disturbed only locally by young post-coalification tectonics. In the uppermost Liguride nappe (M. Antola Unit) a pre-Oligocene (i. e. pre-Apenninic) thermal event was detected. Postorogenic heating is connected with the magmatic activity of Late Miocene to Pleistocene age in Tuscany. Except for these preorogenic and postorogenic thermal events, the main coalification is generally younger than the emplacement of the nappes in the nappe pile during the Apenninic orogeny in the Miocene, but it is older than the last thrust movements and the final tensional tectonics in the internal zones of the chain. For these reasons, the main regional thermal event has to be considered as synorogenic or, more precisely, as late-synorogenic.  相似文献   

Supporting large-scale hydrogeological monitoring and modelling by time-variable gravity data   总被引：1，自引：0，他引：1  

Andreas Güntner  Roland Schmidt  Petra Döll 《Hydrogeology Journal》2007,15(1):167-170

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