The inner Galaxy resolved at IJK using DENIS data

We present the analysis of three-colour optical/near-infrared images, in IJK , taken for the DEep Near Infrared Southern Sky Survey (DENIS) project. The region considered covers 17.4 deg² and lies within <5°, b <1.°5. The adopted methods for deriving photometry and astrometry in these crowded images, together with an analysis of the deficiencies nevertheless remaining, are presented. The numbers of objects extracted in I , J and K are 748 000, 851 000 and 659 000 respectively, to magnitude limits of 17, 15 and 13. Eighty per cent completeness levels typically fall at magnitudes 16, 13 and 10 respectively, fainter by about 2 mag than the usual DENIS limits as a result of the crowded nature of these fields. A simple model to describe the disc contribution to the number counts is constructed, and parameters for the dust layer are derived. We find that a formal fit of parameters for the dust plane, from these data in limited directions, gives a scalelength and scaleheight of 3.4±1.0 kpc and 40±5 pc respectively, and a solar position 14.0±2.5 pc below the plane. This latter value is likely to be affected by localized dust asymmetries. We convolve a detailed model of the systematic and random errors in the photometry with a simple model of the Galactic disc and dust distribution to simulate expected colourmagnitude diagrams. These are in good agreement with the observed diagrams, allowing us to isolate those stars from the inner disc and bulge. After correcting for local dust-induced asymmetries, we find evidence for longitude-dependent asymmetries in the distant J and K sources, consistent with the general predictions of some Galactic bar models. We consider complementary L -band observations in the companion paper.     

Tableau de répartition stratigraphique des Grands Foraminifères caractéristiques du Crétacé moyen de la région Méditerranéenne

Le Groupe de Travail Européen des Grands Foraminifères présente un tableau de répartition stratigraphique de 42 espèces bien définies du Crétacé moyen de la région méditerranéenne. La répartition stratigraphique proposée pour chaque espèce est fondée soit sur des propres observations soit sur des données de la littérature supprimer et est contrôlée par la présence d'Ammonites ou de Foraminifères planctoniques.A summarizing account is presented of the deliberations of the research group for Large Foraminifers of the IGCP Project “Mid-Cretaceous Events”. Large Foraminifers are of incontestable value for dating carbonate platform sequences owing to the absence of many other diagnostic groups of organísms. A table of stratigraphical distributions for 42 species is presented.     

Palaeomagnetic evidence for large-scale dextral movement along the Trollfjord-Komagelv Fault,Finnmark, north Norway

Palaeomagnetic data from Late Precambrian dykes from the northern part of Varanger peninsula, north Norway, suggest a two-axis magnetization structure. The dominant component is considered to be syn- to late-tectonic and probably acquired at around 640 m.y. B.P. Superposed on this magnetization is a minor component which is compatible with the relative Lower-Middle Palaeozoic field; i.e. it was most likely imposed during the climax of the Caledonian orogenic movements in north Norway. The estimated relative Late Precambrian palaeopole cannot easily be reconciled with the European Late Precambrian polar path. This disagreement can be accounted for by assuming a post-magnetization dextral megashear, of the order of 500–1000 km, along the Trollfjord-Komagelv fracture zone. This type of displacement is in line with geological evidence and the palaeomagnetic reconstruction supports the long-held view of there having been continuity between the depositional environments of the Varanger Peninsula Barents Sea Group, the Eleonore Bay Group of east Greenland and the Hecla Hoek Formation of east Spitsbergen. The character and age of the horizontal displacement, post-640 to pre-500 m.y. B.P., is seen in conjunction with the opening up of the lapetus Ocean and reactivation of ancient deep-seated fractures during both the spreading and the contraction phases of ocean development.     

Kepone®: Toxicity and bioaccumulation in blue crabs

Two long-term studies were conducted to determine toxicity, uptake and depuration of Kepone in blue crabs (Callinectes sapidus). In the first, Kepone was administered to crabs in seawater (0.03 or 0.3 μg Kepone/I) or food (eastern oyster,Crassostrea virginica, containing 0.25 μg/g Kepone). Uptake of Kepone in 28 days was primarily through the contaminated oysters. When these crabs were held in Kepone-free seawater and fed Kepone-free oysters for 28 days, no loss of the insecticide was evident. There were adverse effects on molting and survival in crabs fed oysters that contained 0.25 μg/g Kepone. A second study was conducted to determine: (1) the depuration of Kepone over a 90-day period in blue crabs fed oysters from the James River, Virginia (containing 0.15 μg/g Kepone); and (2) the effects of Kepone on molting and survival of blue crabs fed James River oysters or laboratory-contaminated oysters that contained 0.15 or 1.9 μg/g Kepone. Crabs fed Kepone-contaminated oysters followed by a diet of Kepone-free oysters for 90 days had detectable concentrations of the insecticide in tissues. Also, blue crabs that ate oysters containing Kepone in concentrations similar to those found in oysters from the James River, died or molted less frequently than crabs fed Kepone-free oysters meats.     

Polymerization of silicate and aluminate tetrahedra in glasses,melts, and aqueous solutions—I. Electronic structure of H6Si2O7, H6AlSiO71−, and H6Al2O72−

As part of a study of the effect of geologically common network modifiers on polymerization in silicate melts, glasses, and silica-rich aqueous solutions, we have studied the energies, electronic structures, and inferred chemical properties of ^IVT-O-^IVT linkages in the tetrahedral dimers H₆,Si₂O₇, H₆AlSiO₇^1?, and H₆Al₂O₇^2? using semi-empirical molecular orbital theory (CNDO/2). Our results indicate that the electron donating character of the bridging oxygen, O(br), linking two tetrahedra increases with increasing T-O(br) bond length but decreases with decreasing T-O(br)-T angles and increasing O-T-O(br) angles. This increase or decrease of the donor character of O(br) coincides with an increase or decrease of the affinity of O(br) for hard acceptors. The calculated electronic structure for the H₆Si₂O₇ molecule is compared with the observed X-ray emission, absorption, and photoelectron spectra of quartz and vitreous silica; the reasonable match between calculated and observed oxygen Kα emission spectra of vitreous silica supports our assertion that non-bonded O(br) electron density energetically at the top of the valence band controls the chemical reactivity of ^IVT-O-^IVT linkages in polymerized tetrahedral environments.     

Pyrolysis-high resolution gas chromatography and pyrolysis gas chromatography-mass spectrometry of kerogens and kerogen precursors

A series of kerogens and kerogen precursors isolated from DSDP samples, oil shales and Recent algal mats have been examined by Curie point pyrolysis-high resolution gas chromatography and gas chromatography-mass spectrometry. This study has shown that the three main types of kerogens (marine, terrestrial and mixtures of both) can be characterized using these techniques. The marine (algal) kerogens yield principally aliphatic products and the terrestrial kerogens yield more aromatic and phenolic products with some n-alkanes and n-alkenes. The yields of n-alkanes and n-alkenes increase and phenols decrease with increasing geologic age, however, pyrolysis-GC cannot be used to characterize the influence of short term diagenesis on the kerogen structure.     

Sur l'existence de plusieurs facies geochimiques dans les schistes paleozoiques des pyrenees luchonnaises

Résumé Des formations paléozoïques d'origine essentiellement détritique, métamorphisées à des degrés divers (quartzophyllades, phyllades, micaschistes souvent feldspathiques à biotite, staurotide, andalousite, sillimamte) ont été échantillonnées méthodiquement dans les Pyrénées luchonnaises, à l'occasion de l'étude des relations structurales et géochimiques entre les formations granitiques du Massif du Lys-Caillaouas et leur environnement.La réalisation de 900 analyses (éléments majeurs) de ces « schistes » au sens large, prelevés le long de coupes systématiques à travers les principales unités régionales, pose avec acuité le problème d'une typologie chimique accordée aux connaissances sur la minéralogie des sédiments détritiques et sur leurs milieux de genèse.L'auteur tente en conséquence de présenter l'ensemble de ces analyses sous une forme qui mette en lumière quelques caractères importants de la sédimentation. Il propose à cet effet l'usage de deux diagrammes triangulaires dont l'un est destiné principalement à une présentation globale de la roche tandis que l'autre s'attache particulièrement aux silico-aluminates considérés comme la fraction la plus significative.Les différenciations que cette méthode de présentation fait apparaitre dans les séries échantillonnées, du Cambro-Ordovicien au Carbonifère inférieur, sont ensuite confrontées avec les connaissances classiques sur ce domaine pyrénéen. Au total, ce sont quelques uns des problèmes posés par l'utilisation de la géochimie dans des séries pélitiques fréquemment réputées monotones qui se trouvent évoqués sur un exemple assez large dont l'étude se poursuit.

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Paleozoic formations of mainly detrital origin, which are metamorphized to various extents (quartzophyllades, phyllades, micaschists frequently containing feldspar, biotite, staurotide, andalousite, sillimanite) have been systematically sampled in the Luchon Pyrenees. This opportunity was offered by a study devoted to the relationship between the granitic formations of the Lys-Caillaouas massive and its environment.Over 900 of these « schists » taken on systematic profiles cross-cutting the principal regional units have been analyzed for major elements. This leads to the difficult problem of a chemical characterization of the mineralogical knowledge of detrital sediments and their medium of genesis.An attempt is made to restitute the mass of these analyses in a way that might throw light on some particularly important aspects of sedimentation. With this aim, two triangular diagrams are proposed. The first gives a global representation of the rock, whereas the second is concerned with silico-aluminates considered as the most significant fraction.The differenciations which appear in this graphical method, in the studied series proceeding from Cambro-Ordovicien up to the Carboniferous, are then compared with the classical knowledge of this part of the Pyrenees.Briefly, these are some of the problems which arise from the application of geochemistry to pelitic series, often considered monotonous. And these problems are treated on a broad example, the study of which is still being pursued.

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Zusammenfassung Anläßlich umfassender, struktureller und geochemischer Untersuchungen in dem Granitmassiv des Lys-Caillaouas und seiner Umgebung wurden systematische Probenahmen in den Pyrenäen bei Luchon auch an diesen überwiegend detritischen Gesteinen durchgeführt. Sie liegen heute in verschiedenen Graden der Metamorphose vor. Quarzphyllite, Glimmerschiefer - oft mit Feldspat und Biotit, Andalusit und Sillimanit.900 Analysen des Makrochemismus dieser schiefrigen Gesteine erlauben systematische Profile durch die wichtigsten regionalen Einheiten zu geben. Es stellt sich das Problem, eine chemische Typologie zu finden, die sich in Übereinstimmung mit unseren Kenntnissen der Mineralogie detritischer Gesteine und ihrer Sedimentationsräume befindet.Verfasser versucht, die Gesamtheit dieser Analysen in Form eines Systems zu geben, das es gestattet, die wichtigsten Charakteristika der Sedimentation zu erfassen. Zu diesem Zweck werden zwei Dreiecks-Darstellungen vorgeschlagen, von denen die erste hauptsächlich dazu bestimmt ist, eine globale Darstellung des Gesteinschemismus zu geben. Das zweite Diagramm gibt vor allem eine Darstellung der Alumino-Silikate, die als charakteristische Fraktion dieser Gesteine anzusehen sind.Die Differenzierungen, die diese Methode in den Probenreihen vom Cambro-Ordoviz bis zum Karbon sichtbar werden läßt, verden anschließend verglichen mit den älteren, geologischen Kenntnissen dieses Abschnitts der Pyrenäen.Im Rahmen einer umfangreichen Arbeit, die noch fortgesetzt wird, sind dies einige Teilergebnisse, die den Wert geochemischer Untersuchungen gerade in pelitischen Serien zeigen, die gemeinhin als äußerst monoton gelten.

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On the transmissivity of the atmosphere in the water vapour absorption (6–6.5 μ) band

Summary The atmospheric transmissivity in the water vapour absorption band (6–6.5 ) is evaluated using the recent Tiros III data and based onGoody's statistical model.Work completed while on leave from the Department of Meteorology, University of California, Los Angeles.     

A cross section through the central-Pyrenees

Summary A structural analysis of the Pyrenees contains successively from young to old the Miocene morphogenic uplift, a Pyreneic and a Laramide folding phase each preceded by basin formation on the flanks of the central zone, and a rather complicated Hercynian folding period accompanied by magmatic hases. This Hercynian phase starts with a Devonian geosyncline and its folding movement is directed towards the centre, and proceeds later from the centre outwards. In the Hercynian structure one can discern a central anticlinorium and two or three anticlinoria in the flank.Summary of a lecture given in Köln on the 27^th Jan. 1956.     

Rainfall and the 6–9 day wave-like disturbance in West-Africa during summer 1989

Summary Using ECMWF analyses and daily rain amounts of 569 stations in Western Africa for summer 1989, the study documents the composite structure of the 6–9 day oscillation and its influence on rain. Rain is modulated by vorticity as displayed in the wave composite. There are rainfall maxima coincident with cyclonic vorticity and rainfall minima coincident with anticyclonic vorticity at the 700hPa level, at 17.5°N and 7.5°N.With 6 Figures