Microscope-photometric methods for non-destructive Fe²⁺ – Fe³⁺ determination in chloritoids (Fe²⁺, Mn²⁺, Mg)₂ (Al,Fe³⁺)₄ Si₂O₁₀(OH)₄     

Ulf Hålenius  Klaus Langer 《Lithos》1980,13(3):291-294

Six natural chloritoid crystals with Fe²⁺ and Fe³⁺ contents ranging from 4.15 to 12.81 and from 0.411 to 0.849g-atoms/l, respectively, as determined by means of microprobe and Mössbauer techniques, served as reference material to develop non-destructive microscope-spectrophotometric methods for quantitative Fe²⁺ – Fe³⁺ determinations in chloritoids from unpolarized spectra of (001) platelets. Fe²⁺ concentrations in g-atom/l can be obtained from [ [Fe³⁺]=C₁xD₁/t where D₁ = log₁₀(I_0/I at 28,000 cm^-1 and t=crystal thickness in cm; C₁ is a conttant that may be influenced somewhat by experimental conditions and is found to be 0.002289 with the experimental set-up used in this study. Fe²⁺ concentrations in g-atom/l can be obtained from [Fe²⁺]=C₁xD₁/D₁-C₃ with D₂=log₁₀(I₀/I) at 16,300 cm^?1 and constants C₄ = 45.36 and C₅ = 3.540. Due to the uncertainties in absorbance measurements, D₁ and D₂ and the thickness measurements, the accuracies are ±0.05 and ±0.15 g-atom/l for [Fe³⁺] and [Fe²⁺], respectively. The determinations may be carried out on chloritoid grains in normal thin sections with an areal resolution of ～10 μm.  相似文献   

Faziesverzahnung von diamantführenden Konglomeraten und Bändererzen (BIF) in der südlichen Serra do Espinhaço (Minas Gerais,Brasilien)     

Dr. Klaus Paternoster 《International Journal of Earth Sciences》1980,69(2):437-451

Zusammenfassung Die untersuchten Gesteine wurden im Altproterozoikum als Schelfsedimente vorwiegend in Flachwasserfazies abgelagert. In ihrer Verbreitung sind Unterschiede zwischen Bildungen turbulenter Bereiche (Sande, Konglomerate und vereinzelte Breccien) und Stillwasserbildungen (Hämatitquarzit, Itabirit und Phyllit) festzustellen. Im Übergangsbereich beider Faziesbereiche kam es zu Verzahnungen von klastischen mit chemischen Sedimenten. Die chemisch gefällten Bändererze sind in zwei Typen zu trennen, zum einen in klastisch beeinflußte aus Bereichen unruhiger Sedimentationsbedingungen, zum anderen in klastisch nicht beeinflußte aus ruhigen Bereichen. Klastische Beeinflussung und intraformationale Aufarbeitung der BIF fand während allen Stadien der Verfestigung statt. Intraformationale Aufarbeitungsprodukte der Bändererze treten gemeinsam mit Konglomeraten großer Gerölldurchmesser entlang einer Nord-Süd streichenden Zone auf, wo sie sich lateral mit ungestörten chemischen Eisenerzen verzahnen. Konglomerate und BIF wurden zeitgleich sedimentiert. Charakteristisch für diese Zone sind außerdem synsedimentär aufgedrungene Vulkanite, deren Vorkommen einen Bereich tektonischer Unruhe nachzeichnet.

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The investigated rocks were deposited as shelf-sediments during the lower Proterozoic, predominantly in a shallow marine environment. It can be distinguished between sediments formed under turbulent conditions (sands, conglomerates and occasional breccias) and sediments of undisturbed environments (hematite-quartzite, itabirite and phyllite). In the transition of both facies-zones detritic and chemical sediments are interfingering. The chemically precipitated banded iron ores can be separated into two types — clastically influenced BIF formed in areas of agitated sedimentary conditions, and BIF with no clastic admixtures formed in quiet regions. Banded iron ores were clastically influenced and intraformationally reworked during all states of lithification. Products of intraformationally reworked BIF appear together with conglomerates of large diameters along a north-south-striking zone where they interfinger laterally with undisturbed chemically precipitated iron ores. Conglomerates and BIF were deposited here at the same time. Significant for this zone are also synsedimentary volcanites accentuating the presence of a tectonically active zone.

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Resumo Os metasedimentos aqui analisados foram predominantemente depositados em ambientes plataformais do Proterozoico inferior. Na sua distribuição constata-sc depósitos de águas calmas (hematita-quartzitos, itabiritos e filitos) e turbulentas) areias, conglomerados e esporadicamente brechas). Na zona de transição entre as duas facies sedimentares ocorreu interdigatação de sedimentos clásticos e químicos. Os minérios bandeados de ferro (BIF), quimicamente precipitados, podem ser classificados em dois grupos: o primeiro com interferência clástica, típico de ambientes agitados de sedimentação; o segundo sem componentes clásticos e característico de ambientes calmas. Interferência clástica como retrabalhamento intraformational ocorreu durante todos os estágios de processo sedimentar e de consolidação de BIF. Produtos do retrabalhamento intraformacional dos minérios bandeados ocorrem simultaneamente com conglomerados (seixos de diámetros grandes) ao longo de uma faixa Norte-Sul e interdigitados lateralmente com sedimentos químicos não perturbados. Conglomerados e BIF foram sedimentados concomitantemente. Característico para esta faixa são vulcanitos de extrusão sinsedimentar cuja presença tipifica um ambiente de instabilidade tectônica.

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Elemental abundances in chondrules from unequilibrated chondrites: Evidence for chondrule origin by melting of pre-existing materials     

James L. Gooding  Klaus Keil  Takaaki Fukuoka  Roman A. Schmitt 《Earth and Planetary Science Letters》1980,50(1):171-180

Bulk abundances of Na, Mg, Al, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, La, Sm, Eu, Yb, Lu, Ir, and Au were determined by neutron activation analysis of chondrules separated from unequilibrated H-, L-, and LL-chondrites (Tieschitz, Hallingeberg, Chainpur, Semarkona) and correlated with chondrule petrographic properties. Despite wellknown compositional differences among the whole-rock chondrites, the geometric mean compositions of their respective chondrule suites are nearly indistinguishable from each other for many elements. Relative to the condensible bulk solar system (approximated by the Cl chondrite Orgueil), chondrules are enriched in lithophile and depleted in siderophile elements in a pattern consistent with chondrule formation by melting of pre-existing materials, preceded or attended by silicate/metal fractionation. Relative to nonporphyritic chondrules, porphyritic chondrules are enriched in refractory and siderophile elements, suggesting that these two chondrule groups may have formed from different precursor materials.  相似文献   

Echo sounding on suspended particulate matter in the elbe estuary     

Jobst Hülsemann  Hendrik Eden  Klaus Ricklefs 《Ocean Dynamics》1995,47(1):23-45

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High-Precision Trace Element Data for the USGS Reference Materials BCR-1, BCR-2, BHVO-1, BHVO-2, AGV-1, AGV-2, DTS-1, DTS-2, GSP-1 and GSP-2 by ID-TIMS and MIC-SSMS   总被引：2，自引：0，他引：2  

Ingrid Raczek  Brigitte Stoll  Albrecht W. Hofmann  Klaus Peter Jochum 《Geostandards and Geoanalytical Research》2001,25(1):77-86

Different batches of the new US Geological Survey (USGS) reference materials (RMs) BCR-2, BHVO-2, AGV-2, DTS-2 and GSP-2 and the original USGS RMs BCR-1, BHVO-1, AGV-1, DTS-1 and GSP-1 have been analysed by isotope dilution using thermal ionisation mass spectrometry (ID-TIMS) and by multi-ion counting spark source mass spectrometry (MIC-SSMS). The concentrations of K, Rb, Sr, Ba and the rare earth elements were determined with overall analytical uncertainties of better than 1% (ID-TIMS) and 3% (MIC-SSMS). The analyses of different aliquots and batches of BCR-2, BHVO-2, AGV-2 and GSP-2, respectively, agree within 1%, i.e. approximately the analytical uncertainties of the data. This indicates an homogeneous distribution of the trace elements in these RMs. Differences in element concentrations of up to 17% in different aliquots of the depleted RM DTS-2 are outside the analytical uncertainty of our data. They may be attributed to a slightly heterogeneous distribution of trace elements in this dunite sample. Our trace element data for BCR-2, BHVO-2, AGV-2 and GSP-2 agree within about 3% with preliminary reference values published by the USGS. They also agree within 1-6% with those of the original RMs BCR-1, BHVO-1, AGV-1 and GSP-1. Large compositional differences are found between DTS-2 and DTS-1, where the concentrations of K, Rb, Sr and the light REE differ by factors of 2 to 24.  相似文献   

On the ice age glaciation of the Tibetan highlands and its transformation into a 3-D model     

Prof. Matthias Kuhle Dr.  Klaus Herterich Dr.  R. Calov 《GeoJournal》1989,19(2):201-206

We present an interdisciplinary study on data and modeling intercomparison, concerning the possible existence of a Tibetan ice sheet and its climatological implications during the ice age. In the ice sheet model the fields of ice flow and temperature are calculated, and a highly parameterized formulation of the yearly snow balance is used, defining the forcing at the surface of the ice sheet. The data set used, supplies the height of the equilibrium line of the glaciers (=ELA) and documents the maximum extension of the glaciated areas. With prescribed snow accumulation above the ELA and melting below, the model is integrated for 10 000 model years and the model glaciation is then compared with the data.The main results are: Provided the height of the glacial equilibrium line has been reconstructed correctly, a Tibetan ice sheet can be bult up within 10 000 model years, using moderate rates of precipitation (maximum snow fall: 100 mm/year). Comparison of data and model glaciation suggests an increase of precipitation from the NW to the E of Tibet and from the S to the NE, which reflects the presently observed pattern of the monsoon circulation.  相似文献   

The spatial variability of Amazonian soils under natural forest and pasture     

José C. Correa  Prof. Dr. Klaus Reichardt 《GeoJournal》1989,19(4):423-427

Spatial variability of physical and chemical properties in Amazonian soils is evaluated on sites of natural rain forest and pastures of different age in the Amazon region. The sampling scheme was regionalized using transects of fifty points 3 m apart each. Variables analysed were: soil bulk density; resistance to penetration; soil water content; available water; pH and extractable ions such as Ca, K, Al, P and Zn. Geostatistical analyses show that most variables are space independent for the 3 m spacing used. Variances indicate a much lower variability of the measured properties in the forest as compared to pastures.  相似文献   

Gravity interpretation of a unified 2-D acoustic image of the central Alpine collision zone   总被引：1，自引：0，他引：1  

Klaus Holliger  Edi Kissling 《Geophysical Journal International》1992,111(2):213-225

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Announcements     

Stephan Schuhmann  Klaus Herrmann  Kurt Rothermel  Jan Blumenthal  Dirk Timmermann 《Stochastic Hydrology and Hydraulics》1993,7(1):83

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Neuere Veröffentlichungen     

Klaus Figge 《Ocean Dynamics》1993,45(1):55-56

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