Beitrag zur quantitativen Analyse von Mineralphasen mittels Röntgendiffraktion

Zusammenfassung Bei der Durchführung quantitativer Gemenge-Analysen mit Hilfe der Röntgendiffraktionsmethode kann man den Massenschwächungskoeffizienten (^*) verwenden, den man bei der Röntgenfluoreszenzanalyse Röhrenhauptlinienverfahren vonSchroll-Stepon erhalten hat. Er wird von der Wellenlänge der Röntgenfluoreszenzstreustrahlung auf die Wellenlänge der Diffraktionsröhre transformiert. Ein Intensitäts-Konzentrationsdiagramm, in dem die Intensität der gewählten Diffraktionslinie durch das Produkt von Intensität und dem jeweiligen Wert von ^* ersetzt wird, ergibt eine allgemeingültige Eichgerade. Als Beispiel werden Messungen an Zweistoffsystemen wie Magnesit-Quarz, Albit-Quarz, Calcit-Quarz, Stilpnomelan-Quarz und Siderit-Quarz angeführt.Die vorgeschlagene Methode ist für kombinierte Diffraktions- und Röntgenfluoreszenzanalysen sehr zweckmäßig.

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Summary Applicating the quantitative X-ray-diffraction-analysis für mixtures of minerals the use of the mass absorption coefficient (^*) is possible, which is received by the X-ray-fluorescence-analysis of the same sample following the method proposed by the authors. The mass absorption coefficients must be transformed to the new wave length of the X-ray-diffraction tube. In the intensity-concentration-diagram the intensity is substituted by the product of intensity and mass absorption coefficient. An uniform standard line is received, as the measurement of quartz shows in the systems of two-substances, such as magnesite-quartz, albite-quartz, calcite-quartz, stilpnomelan-quartz and siderite-quartz.The proposed method is very useful for the combined X-ray-diffraction and X-ray fluorescence analysis.

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Mit 6 Textabbildungen     

Structural characteristics of zooplankton of the Shardarinskoe Reservoir and their use in water quality assessment

Data on the Shardarinskoe Reservoir are used to assess the indicator role of zooplankton community under unstable hydrological regime. The structural characteristics of zooplankton featured significant seasonal variations. The averaged indices characterized reservoir water quality at the level of mesotrophic and eutrophic water bodies. The possible use of cyclopidas to characterize toxic pollution of water is discussed.     

PEDOGENESIS IN LATE PREHISTORIC INDIAN MOUNDS,UPPER MISSISSIPPI VALLEY

Inceptisols are developed on silt loam, loam, and sandy loam Indian mounds at the Keller Mound Group and Bluff Top Mound in northeastern Iowa. The mounds date to the Allamakee Phase of the Late Woodland Period (ca. 1650–1250 B.P.) and are built with fill obtained from the A, E, and upper B horizons of pre-existing soils (Alfisols). Differences in the morphologic and chemical characteristics of soils on different mounds are attributed to textural differences of the mounds' fill. Coarse-textured mound fill is pedogenically altered at a faster rate than fine-textured fill, but total carbon percentage of the A horizon attains a steady state faster in fine-textured mound fill. Total phosphorus content is used to determine from which horizons of pre-existing soils the specific layers of mound fill originated. Rates and pathways of pedogenesis in mound fill may not provide good analogues for the early stages of soil development in materials that have not undergone previous weathering and subsequent modification by humans. Nevertheless, mound soils are useful benchmarks for some pedologic studies since they provide time lines for evaluating minimum rates for development of argillic and albic horizons, as well as attainment of the Alfisol order.     

Noble gases in eleven H-chondrites

He, Ne, Ar and Xe were measured in aliquots of 11 H-chondrites, to complement trace element studies on the same meteorites (Laulet al., 1972). Bielokrynitschie, Charsonville, Pultusk and Supuhee have lost radiogenic gases before cosmic-ray exposure and Doroninsk, during exposure.     

Meteorological and synoptic aspects of the formation and evolution of the Novorossiysk Bora

The genetic and synoptic classifications of the Novorossiysk Bora are created using the data of daily observations at the Novorossiysk meteorological station and other available synoptic information. Obtained are the quantitative criteria of these classifications, and on this base worked out are the basic scenarios of the generation and evolution of this dangerous phenomenon on the Black Sea coast of Russia. According to the genetic classification, the Bora was divided into four types: frontal, air-mass, monsoon, and gravity. Quantitative criteria worked out for each type can be used for the more accurate forecast of this destructive phenomenon near Novorossiysk. According to the synoptic classification, four classes were distinguished: Azores, North Atlantic, Siberian, and Arctic.