Provenance of the late Proterozoic to early Cambrian metaclastic sediments of the Sierra de San Luis (Eastern Sierras Pampeanas) and Cordillera Oriental, Argentina

Provenance studies have been performed utilising major and trace elements, Nd systematics, whole rock Pb–Pb isotopes and zircon U/Pb SHRIMP data on metasedimentary rocks of the Sierra de San Luis (Nogolí Metamorphic Complex, Pringles Metamorphic Complex, Conlara Metamorphic Complex and San Luis Formation) and the Puncoviscana Formation of the Cordillera Oriental. The goal was the characterisation of the different domains in the study area and to give insights to the location of the source rocks. An active continental margin setting with typical composition of the upper continental crust is depicted for all the complexes using major and trace elements. The Pringles Metamorphic Complex shows indications for crustal recycling, pointing to a bimodal provenance. Major volcanic input has to be rejected due to Th/Sc, Y/Ni and Cr/V ratios for all units. The εNd_{(540 Ma)} data is lower for the San Luis Formation and higher for the Conlara Metamorphic Complex, as compared to the other units, in which a good consistency is given. This is similar to the T_DM ages, where the metapsammitic samples of the San Luis Formation are slightly older. The spread of data is largest for the Pringles Metamorphic Complex, again implying two different sources. The whole rock ²⁰⁷Pb/²⁰⁶Pb isotopic data lies in between the South American and African sources, excluding Laurentian provenances. The whole rock Pb–Pb data is almost indistinguishable in the different investigated domains. Only the PMC shows slightly elevated ²⁰⁸Pb/²⁰⁴Pb values. Possible source rocks for the different domains could be the Quebrada Choja in the Central Arequipa–Antofalla domain, the Southern domain of the Arequipa–Antofalla basement, the Brazilian shield or southern Africa. Zircon SHRIMP data point to a connection between the Puncoviscana Formation and the Conlara Metamorphic Complex. Two maxima around 600 Ma and around 1000 Ma have been determined. The Nogolí Metamorphic Complex and the Pringles Metamorphic Complex show one peak of detrital zircons around 550 Ma, and only a few grains are older than 700 Ma. The detrital zircon ages for the San Luis Formation show age ranges between 590 and 550 Ma. A common basin can be assumed for the Conlara Metamorphic Complex and the Puncoviscana Formation, but the available data support different sources for the rest of the Complexes of the Sierra de San Luis. These share the diminished importance or the lack of the Grenvillian detrital peak, a common feature for the late Cambrian–early Ordovician basins of the Eastern Sierras Pampeanas, in contrast to the Sierras de Córdoba, the PVF and the Conlara Metamorphic Complex.     

Quantitative Integration of High-Resolution Hydrogeophysical Data: A Novel Approach to Monte-Carlo-Type Conditional Stochastic Simulations and Implications for Hydrological Predictions

Geophysical techniques can help to bridge the inherent gap that exists with regard to spatial resolution and coverage for classical hydrological methods. This has led to the emergence of a new and rapidly growing research domain generally referred to as hydrogeophysics. Given the differing sensitivities of various geophysical techniques to hydrologically relevant parameters, their inherent trade-off between resolution and range, as well as the notoriously site-specific nature of petrophysical parameter relations, the fundamental usefulness of multi-method surveys for reducing uncertainties in data analysis and interpretation is widely accepted. A major challenge arising from such endeavors is the quantitative Integration of the resulting vast and diverse database into a unified model of the probed subsurface region that is consistent with all available measurements. To this end, we present a novel approach toward hydrogeophysical data integration based on a Monte-Carlo-type conditional stochastic simulation method that we consider to be particularly suitable for high-resolution local-scale studies. Monte Carlo techniques are flexible and versatile, allowing for accounting for a wide variety of data and constraints of differing resolution and hardness, and thus have the potential of providing, in a geostatistical sense, realistic models of the pertinent target parameter distributions. Compared to more conventional approaches, such as co-kriging or cluster analysis, our approach provides significant advancements in the way that larger-scale structural information contained in the hydrogeophysical data can be accounted for. After outlining the methodological background of our algorithm, we present the results of its application to the integration of porosity log and tomographic crosshole georadar data to generate stochastic realizations of the detailed local-scale porosity structure. Our procedure is first tested on pertinent synthetic data and then applied to a field dataset collected at the Boise Hydrogeophysical Research Site. Finally, we compare the performance of our data integration approach to that of more conventional methods with regard to the prediction of flow and transport phenomena in highly heterogeneous media and discuss the Implications arising.     

A dynamical model with a new inversion technique applied to observations of Comet C/2000 WM1 (LINEAR)

Three continuum images of Comet C/2000 WM₁ (LINEAR) obtained on Nov 10, Nov 19, and Dec 03, 2001, are analyzed with the aid of a dynamical model, i.e. with a model that uses the size-dependent motion of dust grains under solar radiation pressure to determine the dust size distribution and its temporal change. The frames are photometrically calibrated in terms of the albedo filling factor product. On Nov 20.2 the Earth transited the orbital plane of the comet and an anti-tail was recognized in the image of Nov 19. For the determination of the particle fluxes describing the contribution of monodisperse particle shells to the cometary brightness the model uses a new regularization method employing Chebyshev polynomials of selected orders in emission time and particle size. It guarantees positiveness of the particle fluxes and imposes a varying degree of smoothness on their dependence on particle size and emission time. The particle emission velocities are still derived by trial and error. The dynamical model is described in detail. Results are presented for several low orders of the Chebyshev polynomials and are compared in order to understand the limitations imposed by the regularization process. The size distributions derived from the different observations do not always agree. This is particularly true for the earliest and most recent synchrones contributing to an image. In the observations of Nov 10 and Dec 03, i.e. excluding the anti-tail image, the integrated mass loss strongly decreases in the most recent time steps of the model although the comet is still approaching the Sun. This is interpreted as an artifact introduced by the overlap of the shells of large particle size emitted shortly before the observation. The model derives an increasing number of small particles released by the comet in the second half of November. This is at least in part considered as real and attributed to particle fragmentation occurring when the comet was at a heliocentric distance of about 1.4 AU.     

CLASSIFICATION OF A SECOND GROUP OF ORDINARY CHONDRITES FROM TEXAS

Based on optical microscopy and electron microprobe analyses of mafic minerals, six previously undescribed or poorly known ordinary chondrites from Texas were classified into compositional groups, petrologic types, and shock facies. These meteorites are Junction, L5d; Anton, H4b; Venus, H4d; Dalhart, H5a; Rosebud, H5c; and Cranfills Gap, H6c.     

Wert und Grenzen der Conodonten-Stratigraphie

Zusammenfassung Conodonten können mit Säuren aus Kalken und Dolomiten herausgeätzt werden. Die Vorzüge von Essigsäure, Ameisensäure und Monochloressigsäure für die verschiedenen Gesteinstypen werden diskutiert. Die systematische Stellung der Conodonten ist noch immer ungeklärt. Die Verbreitung ist vom Mittelkambrium bis in die obere Trias gesichert, das Vorkommen in der Oberkreide ist sehr wahrscheinlich. Hauptzeiten der Entwicklung sind Ordovicium, Mittelbis Oberdevon und Unterkarbon. Die wichtigsten Leitgattungen aus den verschiedenen Formationen werden zusammengestellt und in repräsentativen Arten abgebildet.Conodonten können sowohl in der praktisch-stratigraphischen Arbeit als auch zur Korrelation über weite Räume wertvoll sein. Dabei muß allerdings auf die Problematik offensichtlicher Differenzen des Ein- und Aussetzens bestimmter Arten des Devons und der Trias in den verschiedenen Gebieten hingewiesen werden. Diese beruhen vielleicht auf Unterschieden der Lebensweise der einzelnen Conodontengattungen, für das Vorhandensein solcher ökologisch-fazieller Unterschiede wird Material zusammengetragen.     

Erdstrombeobachtungen auf langen Meßstrecken nördlich von Berlin

Zusammenfassung Im Raum nördlich von Berlin werden Erdstrombeobachtungen auf zwei 50 km langen Meßstrecken durchgeführt. Aus dem Beobachtungsmaterial wurden 112 baiähnliche Erdstromvariationen ausgewählt. Zum Vergleich wurde die Niemegker Erdstromregistrierung (Länge der Meßstrecken 1000 m) herangezogen. Die Beobachtungsdaten der beiden Stationen wurden einer statistischen Bearbeitung unterworfen. Ähnlich wie in Niemegk haben auch auf diesen 50 km langen Meßstrecken die Erdstromvektoren der längerperiodischen Variationen eine Haupteinfallsrichtung, die für das Gebiet nördlich von Berlin bis nahe zur Küste vorherrschend sein dürfte. Der Vergleich der Vektorgrössen zeigt eine bessere Übereinstimmung.

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Summary Earth current observations were made in the north of Berlin along two measuring lines of about 50 km in length. 112 variations with bay character were chosen from the observation material and were compared with the telluric records of Niemegk (the measuring lines of Niemegk are 1000 m in length). The observation data of both stations were treated statistically. Analogous to Niemegk the earth current vectors of the longperiodical variations have a main direction of incidence on these 50 km measuring lines too which is expected to be predominant within a region from the north of Berlin up to near the coast. The comparison of the vector quantities gives a better agreement.

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Mitteilung aus dem Geomagnetischen Institut der DAW, Nr. 174

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Herrn Prof. Dr.Fanselau zur Vollendung des 60. Lebensjahres am 30. April 1964 gewidmet.     

Die Zirkulation an der Oberfläche der südostasiatischen Gewässer

Zusammenfassung Die Strömungen an der Oberfläche der südostasiatischen Gewässer zwischen 25 N und 20 S sowie 85 E und 143 E werden in sechs Karten für jeden zweiten Monat dargestellt. Die Veränderungen der Zirkulation im Laufe des Jahres werden im Zusammenhang mit denen der Monsune beschrieben. Die einzelnen Glieder der Zirkulation werden einer genauen Betrachtung unterzogen, und die Lage ihrer Stromgrenzen, des Hauptstromstriches und von Gegenströmungen wird diskutiert.

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The circulation at the surface of the southeast asian waters

Summary The currents at the surface of the southeast Asian waters between 25 N and 20 S and between 85 E and 143 E are represented in six charts for every second month. The variations of the circulation during the course of the year are correlated with those of the monsoons. The different branches of the circulation are taken under consideration and the position of their boundaries, of the current axis and of counter currents are discussed.

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La circulation superficielle dans les parages océaniques au sud-est de l'Asie orientale

Résumé Le travail actuel présente pour six mois alternatifs d'un an, commenÇant par le mois de février, des cartes représentant les courants superficiels rencontrés dans les parages au sud-est de l'Asie orientale compris entre les parallèles de 25 N à 20 S et entre les méridiens de 85 E et 143 E. Les variations annuelles de la circulation océanique et leurs relations avec celles des moussons sont exposées. On étudie d'une manière exacte les branches individuelles de la circulation et on discute la position de leurs limites et celle de l'axe du courant principal et des contre-courants.

     

Schwankungen im Wasserhaushalt der Ostsee

Zusammenfassung Durch die gleichzeitige Berücksichtigung aller Komponenten des Wasserhaushaltes der Ostsee wird das Zusammenwirken von Süßwasserzufuhr, Wasserstandsänderungen und Wasseraustausch mit der Nordsee einer Analyse unterzogen. Dabei wird der Einfluß der atmosphärischen Zirkulation und der Gang des Wasserstandes erklärt. Die Behandlung der vollständigen monatlichen Bilanz durch fünf Jahre zeigt, daß die Abweichungen von diesem Jahresgang erheblich sind. Der Wasseraustausch wird durch die Wasserbewegungen an der Oberfläche in den Belten und dem Sund repräsentativ wiedergegeben. Der Wasseraustausch ist intensiver als bisher angenommen. Die langjährigen Schwankungen der Haushaltsgrößen werden untersucht. Es wird gezeigt, daß die atmosphärische Zirkulation auf dem Wege über die Niederschläge und die Süßwasserzufuhr Schwankungen des Ausstroms bewirkt. Andererseits wirkt sie direkt auf den Wasserstand und durch Veränderungen der Intensität des Wasseraustausches auf den Salzgehalt ein. Eine Abschätzung des Salzhaushaltes der Ostsee wird gegeben.

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On fluctuations of the water volume of the Baltic

Summary The combined effects of fresh water influx, variations of sea level, and water exchange with the North Sea are analysed by simultaneously taking into account all components of the water volume of the Baltic Sea. The influence of the atmospheric circulation and of the variations of sea level are explained. The diseussion of the complete monthly water balance over a five years' period shows considerable departures from the annual variation of sea level. The surface currents in the Great and the Little Belt and in the Sound give a representative picture of the water exchange with the North Sea which is revealed to be more intensive than it was hitherto supposed to be. The secular fluctuations of the water volume are studied. Through the medium of precipitation and influx of fresh water the atmospheric circulation causes fluctuations in the outflow from the Baltic. On the other hand, the atmospheric circulation exercises a direct influence on the sea level and — owing to variations in the intensity of water exchange — an indirect one on the salinity. The salinity balance of the Baltic is evaluated.

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Sur les fluctuations du volume d'eau de la mer Baltique

Résumé En tenant compte de toutes les composantes du volume d'eau de la mer Baltique on fait l'analyse des effets réunis des affluences d'eau douce, des variations du niveau de la mer et le l'échange d'eau avec la mer du Nord. On explique l'influence de la circulation atmosphérique et de la variation du niveau de la mer. L'étude du bilan mensuel complet portant sur cinq années montre que les déviations de la marche annuelle sont considérables. Les courants de surface dans le Grand et le Petit Belt et le Sund donnent une image représentative de l'échange d'eau qui est plus intensif qu'on ne l'a supposé jusqu'ici. Les fluctuations séculaires des composantes du volume d'eau sont étudiées. On montre que par l'inter-médiaire des précipitations et de l'affluence d'eau douce la circulation atmosphérique donne lieu à des variations de l'écoulement de la mer Baltique. D'autre part, la circulation atmosphérique exerce une influence directe sur le niveau de la mer et, par suite des variations de l'intensité de l'échange d'eau, elle a une influence indirecte sur la salinité. Le bilan de la salinité est évalué.