Zur Ökologie des bayerischen Flysches auf Grund der Mikrofossilführung

Zusammenfassung Die Foraminiferen im bayerischen Flysch (Kreide) lassen sich in zwei ökologische Gruppen untergliedern: Die mehr oder minder reichen Faunen der Psammite deuten auf ein Klarwasserbiotop, sind aber umgelagert. Die primitiven, artenarmen Sandschaler-Populationen in den Peliten sind dagegen autochthon. Ökologisch aussagekräftig sind nur die benthonischen Foraminiferen, unter denen innerhalb der Flyschfolge Faziesanzeiger und Durchläuferfossilien erkannt wurden. Die statistische Erfassung ergab für die Flyschzone eine zunehmende Primitivierung des Benthos und eine Abnahme des Planktongehaltes in der stratigraphischen Abfolge. Im flyschartigen Südultrahelvetikum vollzieht sich das gleiche dagegen in horizontaler Richtung nach Süden. Erklärungen hierfür durch große Meerestiefen oder niedrige Wassertemperaturen sind unbefriedigend. Reine, primitive Sandschaler-Gememschaften sind auf Wassertrübung und auf paläogeographische Isolierung zurückzuführen.

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Foraminifera of Bavarian Flysch deposits (Cretaceous) can be divided into two ecological groups: More or less rich faunas of psammitic layers indicate clearwater-conditions, but they are redeposited. Primitive, poor populations of arenaceous Foraminifera in the pelitic intercalations are autochthoneous fossils. Benthonics are the only indicators of Flysch-ecology, among which there are indicators of special facies and common fossils in Flysch sequence. By statistical research it has been stated, that there are an increase in ratio of primitive benthonics and a decrease in number of planktonics during stratigraphical succession in the Flysch-zone, while in Flysch-like Südultrahelvetikum there are the same changes in horizontal direction southward. It is not sufficient, to explain these facts by deep-sea- nor by coldwater-conditions. Turbid state of water and paleogeographical isolation are the main factors controlling extreme, primitive associations of arenaceous Foraminifera of Flysch-beds.

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Résumé Les foraminifères du Flysch crétacé de la Bavière peuvent être divisés en deux groupes écologiques. D'une part, les faunes rencontrées dans les psammites: elles sont plus ou moins riches, indiquent un biotope d'eau claire mais sont remaniées. D'autre part, les populations des pélites: constituées de foraminifères agglutinants typiques, elles sont pauvres en espèces, mais autochtones. Les foraminifères benthoniques ne sont que des indicateurs écologiques. On peut distinguer parmi eux des formes communes au Flysch en général et des formes caractéristiques de faciès particuliers. Les recherches statistiques montrent que dans la série stratigraphique du Flysch bavarois, le benthos devient prépondérant tandis que le plancton diminue. La même chose se produit dans la zone sud du «Ultrahelvetikum» mais cette fois en direction horizontale vers le Sud. Une température basse ou une grande épaisseur d'eau sont des explications insuffisantes de ces faits, car c'est la présence d'eaux troubles et l'isolement paléogéographique qui sont à l'origine des associations importantes de foraminifères agglutinants typiques.

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Vortrag, gehalten auf der 56. Jahrestagung der Geologischen Vereinigung in Wien, am 25.2.1966.     

Stress-induced natural transformation of ortho- to clinohypersthene in metagabbros of the Ivrea Zone,Northern Italy

Summary Orthopyroxenes of a high temperature protomylonite of the Ivrea Zone, Northern Italy show twin like polysynthetic lamellae parallel to {210} of the hypersthene host. The transformation is caused by plastic deformation under high metamorphic conditions which has resulted in dynamic recrystallization of pyroxene and plagioclase. The lamellae consist of clinohypersthene. The twin plane and the lamellar clino-ortho-inversion of hypersthene due to natural deformation have not been described hitherto.

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Stressinduzierte natürliche Transformation von ortho- zu Klinohypersthen in Metagabbros der Ivrea-Zone, Norditalien

Zusammenfassung Orthopyroxene aus hoch temperierten Protomyloniten der Ivrea-Zone, Nord Italien zeigen polysynthetische Lamellen parallel {210} des Wirtes. Ihr Erscheinungsbild entspricht Deformationszwillingen. Die Lamellen sind invertiert zu Klinohypersthen. Die Ortho-Klino-Transformation ist auf eine Hochtemperaturdeformation zurückzuführen, wie dies anhand der dynamischen Rekristallisation der Pyroxene und Plagioklase bewiesen werden kann. Weder die speziellen Verwachsungsflächen noch die Ortho-Klino-Inversion durch natürliche Deformation wurden bisher beschrieben.

     

Internal secular variability in an ocean general circulation model

We describe results of an experiment in which the Hamburg Large-Scale Geostrophic Ocean General Circulation Model was driven by a spatially correlated white-noise freshwater flux superimposed on the climatological fluxes. In addition to the red-noise character of the oceanic response, the model exhibits pronounced variability in a frequency band around 320 years. The centers of action of this oscillation are the Southern Ocean and the Atlantic.This paper was presented at the International Conference on Modelling of Global Climate Change and Variability, held in Hamburg 11–15 September 1989 under the auspices of the Meteorological Institute of the University of Hamburg and the Max Planck Institute for Meteorology. Guest Editor for these papers is Dr. L. Dümenil.     

Image tube spectra of pluto and triton from 6800 to 9000 Å

To search for a possible atmosphere on Pluto and Triton, spectra of these objects as well as comparison stars were obtained with a three-stage Varo image tube for the spectral region from 6800 to 9000 Å. Ratio spectra indicate an absorption feature near 8900 Å, although the steeply diminishing response of the image tube at that wavelength casts some doubt on the reality of this feature. The feature appears more definitive in the spectrum of Pluto and less certain in the spectrum of Triton. The absorption was analyzed using our recently determined band-model parameters for methane. Under the assumption of a pressure higher than 0.01 atm an abundance of 3 m-amagat was determined. For pressures limited by the methane abundance itself, an abundance of 50 m-amagat and a pressure of 10^?3 atm was derived (using g = 0.20 g⊕ for both Pluto and Triton). This pressure is close to the pressure that can be expected from the equilibrium vapor pressure of a methane frost. If the absorption at 8900 Å is spurious, our analysis will be applicable as an upper limit for the presence of methane gas on Pluto or Triton.     

Temperature and pressure determinations in the Venus atmosphere by means of high-resolution spectra from 1 to 2.5 μm

Twenty-one bands of CO₂ and the 2-0 band of CO were analyzed for best temperature and pressure fits from Venus spectra obtained with the “Connes” interferometer at the Steward Observatory 2.25-m telescope during the spring of 1971. An average temperature of 241 ± 7°K, an effective pressure of 0.12 ± 0.06 atm, and an average two-way transmission abundance of 3 km-amagat were determined. No difference in temperature or pressure between hot bands, a double hot band, and regular bands was found. Our results were compared to model calculations for a reflecting layer and scattering atmosphere. The results indicate that, most likely, spectroscopic line formation occurs in a relatively clear space above a scattering cloud layer with a reasonably well-defined upper boundary.     

A parameter database for large scientific projects: application to the Gaia space astrometry mission

The parallel development of many aspects of a complex space science mission like Gaia, which includes numerous participants in ESA, industrial companies, and a large and active scientific collaboration throughout Europe, makes keeping track of the many design changes, instrument and operational parameters, and numerical values for the data analysis and simulations, a challenging but crucially important problem. A comprehensive, easily-accessible, up-to-date, and definitive compilation of a large range of numerical quantities is required, and the Gaia parameter database has been established to satisfy these needs. The database is a centralised repository containing, besides mathematical, physical, and astronomical constants, many satellite and subsystem design parameters. Version control provides both a ‘live’ version with the most recent parameters, as well as previous ‘reference’ versions of the full database contents. Query results are formatted by default in HTML, while an important feature is that data can also be retrieved as Java, ANSI-C, C++, Ruby, or XML structures for direct inclusion into software codes, such that all collaborating scientists can use the retrieved database parameters and values directly linked to computational routines.     

The first large meteorite impact structure discovered in the Middle East: Jebel Waqf as Suwwan,Jordan

Abstract— Triggered by re‐evaluation of a 1960s report on the regional geology of the northeastern border region of Jordan and following Landsat satellite image investigation, a 5.5 km diameter, complex, circular structure was discovered in the central eastern region of the Kingdom of Jordan. Initial ground truthing revealed complex geological structures involving Upper Cretaceous and Paleogene strata, and including a prominent outer rim rising up to 60 m above the surrounding plain, an intermediate ring of up to 20 m elevation within a ring syncline, and a central zone of stratigraphically uplifted sedimentary strata characterized by intense macroscopic (folding and faulting, widespread cataclasis) and locally mesoscopic (cataclasis) deformation. Ten sites with shatter cone development in fine‐grained sandstone or limestone have been mapped to date, mostly in the outer parts of the central uplifted area. This finding confirms that the Jebel Waqf as Suwwan structure was formed as the result of the impact of an extraterrestrial projectile. Search for impact‐diagnostic micro‐deformation has been rather unsuccessful: only 1 quartz grain with both planar deformation features and planar fractures has been detected in a sandstone sample to date. The overall majority of the approximately 70 samples investigated by micropetrographic analysis consist of extremely fine‐grained chert, siltstone, or marly limestone. Cataclasis is widespread in chert and limestone, also on the micro‐scale. Considering the severely limited amount of characteristic impact microdeformation, and the stratigraphic situation within the central uplift, it is likely that a relatively deep level of the central uplift is currently exposed. The extensive drainage demonstrated for this region supports the conclusion that this impact structure could be quite deeply eroded‐especially as its geology involves some relatively soft lithologies (marls, limestones). The age of this impact event is at present poorly constrained at post‐Middle to Lower Eocene.     

Suevite at the Roter Kamm impact crater,Namibia

Abstract— A small area littered with loose decimeter-sized fragments of glass and melt fragment-bearing suevite has been discovered on the western rim of the Roter Kamm impact crater in southern Namibia. The clast population and results of major and trace element chemical analyses are consistent with this breccia having been formed from granitoid basement lithologies only, without contribution from the metasedimentary Gariep and Cenozoic cover sequences. It is assumed that the limited amount of impact melt observed in the Roter Kamm structure could be the result of melt dissipation due to explosive shock-induced devolatilization of the significant marble component of the Gariep supracrustal cover. Preservation of very limited remnants of impact breccia on the rim of the Roter Kamm crater suggests a relatively deep level of erosion of the crater rim.