Misplaced trace fossils in unlikely environments     

Javier Ortega Hernandez 《Geology Today》2009,25(2):71-74

Graphoglyptids are trace fossils that are generally acknowledged to have had a deep-sea origin, displaying complex, nutrient gathering strategies in response to stable environments with low productivity. However, two recently discovered graphoglyptids in the Permian of New Mexico seem to challenge previous assumptions. Rather than in deep-sea sediments, Spirorhaphe azteca and Augerinoichnus helicoidalis were discovered in tidal flat palaeoenvironments, showing that these behavioural patterns are also carried out by animals in tidal settings. Fine sediments of the region are recognized as the key factor in the preservation of these trace fossils. Presence of graphoglyptids in a transitional environment demonstrates that behaviour is not solely defined by depth, but many intricate factors are involved.  相似文献   

SLRS‐5 Elemental Concentrations of Thirty‐Three Uncertified Elements Deduced from SLRS‐5/SLRS‐4 Ratios     

Alexie Heimburger  Mickael Tharaud  Fabrice Monna  Rémi Losno  Karine Desboeufs  Elisabeth B. Nguyen 《Geostandards and Geoanalytical Research》2013,37(1):77-85

The fifth version of natural river water certified reference material, SLRS‐5 (National Research Council – Conseil National de Recherches Canada), is commonly used to control the quality of major and trace element measurements. Concentrations of silicon and thirty‐one uncertified trace elements have been reported for the certified reference material SLRS‐4, but they are not yet available for SLRS‐5. Here, SLRS‐5/SLRS‐4 ratios were deduced from SLRS‐5 and SLRS‐4 measurements by inductively coupled plasma‐atomic emission spectrometry and high‐resolution inductively coupled plasma‐mass spectrometry for certified elements and thirty‐five uncertified elements (rare earth elements, B, Bi, Br, Cs, Ga, Ge, Hf, Li, Nb, P, Pd, Rb, Rh, S, Sc, Si, Sn, Th, Ti, Tl, Y). Both reference materials were measured directly one after the other, so that calculated elemental ratios would not be notably influenced either by calibration uncertainties or by eventual long‐term instrumental drift. The computed ratios are in good agreement with those deduced from the certified values. We also report concentrations for thirty‐three uncertified elements in SLRS‐5 by combining the measured SLRS‐5/SLRS‐4 ratios and the published SLRS‐4 values. The resulting new data set provides target SLRS‐5 values, which will be useful in quality control procedures.  相似文献   

Using Java for distributed computing in the Gaia satellite data processing     

William O’Mullane  Xavier Luri  Paul Parsons  Uwe Lammers  John Hoar  Jose Hernandez 《Experimental Astronomy》2011,31(2-3):243-258

In recent years Java has matured to a stable easy-to-use language with the flexibility of an interpreter (for reflection etc.) but the performance and type checking of a compiled language. When we started using Java for astronomical applications around 1999 they were the first of their kind in astronomy. Now a great deal of astronomy software is written in Java as are many business applications. We discuss the current environment and trends concerning the language and present an actual example of scientific use of Java for high-performance distributed computing: ESA’s mission Gaia. The Gaia scanning satellite will perform a galactic census of about 1,000 million objects in our galaxy. The Gaia community has chosen to write its processing software in Java. We explore the manifold reasons for choosing Java for this large science collaboration. Gaia processing is numerically complex but highly distributable, some parts being embarrassingly parallel. We describe the Gaia processing architecture and its realisation in Java. We delve into the astrometric solution which is the most advanced and most complex part of the processing. The Gaia simulator is also written in Java and is the most mature code in the system. This has been successfully running since about 2005 on the supercomputer “Marenostrum” in Barcelona. We relate experiences of using Java on a large shared machine. Finally we discuss Java, including some of its problems, for scientific computing.  相似文献   

Implementing the Gaia Astrometric Global Iterative Solution (AGIS) in Java     

William O’Mullane  Uwe Lammers  Lennart Lindegren  Jose Hernandez  David Hobbs 《Experimental Astronomy》2011,31(2-3):215-241

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Reply to comments by G. Gambolati and G. Galeati     

Shlomo P. Neuman  Javier Samper  Mariano Hernandez 《Mathematical Geology》1987,19(3):259-266

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Stratigraphie et paléoenvironnement des dép?ts volcano-détritiques à dinosauriens du Jurassique inférieur de Toundoute (Province de Ouarzazate, Haut-Atlas – Maroc)     

Christian Montenat  Michel Monbaron  Ronan Allain  Najat Aquesbi  Jean Dejax  Jean Hernandez  Dale Russell et Philippe Taquet 《Eclogae Geologicae Helvetiae》2005,98(2):261-270

Resume. Le gisement de dinosauriens du Jurassique inférieur de Toundoute, à sauropode primitif (Tazoudasaurus naimi), est examiné sous ses aspects stratigraphiques, sédimentologiques et paléoenvironnementaux. Les couches continentales détritiques à dinosaures, succédant en continuité à des niveaux marins carbonatés trés peu épais du Lias inférieur (Hettangien-Sinémurien probables), sont rapportées au Lias moyen-supérieur. Les dép?ts continentaux contiennent une part importante de produits volcanoclastiques différents des basaltes triasiques. Les centres d’émission, non connus, étaient sans doute proches. La sédimentation continentale, de type chenaux fluviatiles – plaine d’inondation, refléte un climat chaud à périodes alternativement humides et séches, ces derniéres étant fortement marquées. Les deux niveaux à ossements correspondent à des coulées boueuses ayant charrié des ossements et portions de carcasses (os en connexion) sur de courtes distances. Ce mode de transport a préservé les ossements de l’érosion et favorisé un enfouissement rapide permettant leur conservation. Manuscrit re?u le 16 juillet 2004 Révision acceptée le 17 mars 2005  相似文献   

Interannual-decadal variability of wintertime mixed layer depths in the North Pacific detected by an ensemble of ocean syntheses     

Toyoda  Takahiro  Fujii  Yosuke  Kuragano  Tsurane  Kosugi  Naohiro  Sasano  Daisuke  Kamachi  Masafumi  Ishikawa  Yoichi  Masuda  Shuhei  Sato  Kanako  Awaji  Toshiyuki  Hernandez  Fabrice  Ferry  Nicolas  Guinehut  Stéphanie  Martin  Matthew  Andrew Peterson  K.  Good  Simon A.  Valdivieso  Maria  Haines  Keith  Storto  Andrea  Masina  Simona  Köhl  Armin  Yin  Yonghong  Shi  Li  Alves  Oscar  Smith  Gregory  Chang  You-Soon  Vernieres  Guillaume  Wang  Xiaochun  Forget  Gael  Heimbach  Patrick  Wang  Ou  Fukumori  Ichiro  Lee  Tong  Zuo  Hao  Balmaseda  Magdalena 《Climate Dynamics》2017,49(3):891-907

Climate Dynamics - The interannual-decadal variability of the wintertime mixed layer depths (MLDs) over the North Pacific is investigated from an empirical orthogonal function (EOF) analysis of an...  相似文献   

Tectonic deposition of mercury in the Almadén district,Las Cuevas deposit,Spain     

M. Jébrak  A. Hernandez 《Mineralium Deposita》1995,30(6):413-423

The Las Cuevas mercury deposit is located in the northern part of the Almadén district, Ciudad Real, Spain. It displays characteristic epigenetic features. A reinterpretation of the geological context of the deposit and a detailed structural analysis indicate that the host rocks at Las Cuevas belong to the same stratigraphic units that host the old Almadén mine, but that they experienced a different tectonic evolution. Two types of ore are distinguished at Las Cuevas: (1) hydraulic breccias in a black quartzite, identical to the San Francisco horizon of the Almadén mine. This ore has been interpreted as syngenetic and is associated with an alkaline explosive volcanic event; and (2) a stockwork composed of horizontal subcritical tension cracks which developed along the contact between black shales and volcanic rocks in the hinge of a drag fold, and which is associated with advanced argillic alteration. Mobilization of mercury from type 1 to type 2 ore was related to a local inversion of the stress field associated with an increase of permeability by self-sealing, which probably occurred during uplift. Las Cuevas is representative of a whole class of mercury deposits hosted within basement rocks.  相似文献   

El cretácico medio y superior de la parte meridional del Bloque Maya (Guatemala)     

F. Michaud  E. Fourcade  J. Azema  M.A. Carballo Hernandez  J.C.Franco Austin 《Journal of South American Earth Sciences》1992,5(3-4)

Study of the Cretaceous strata of the Altos Cuchumatanes (western Guatemala) and in Alta Verapáz (central Guatemala) has revealed a number of foraminifers never before reported from these areas. These data permit a similar nomenclature to be applied to both areas in regard to the division of the sequence into formations. Thus, we distinguish in both areas: a) the Cobán Formation, a shallow platform carbonate of early Aptian to early Senonian age; b) the Campur Formation, of Campanian age, composed of a lower carbonate member with rudists and large benthonic foraminifers, and an upper carbonate member with pelagic foraminifers; c) the Sepur Formation, of Maastrichtian age, with flysch-like sediments, including intercalated blocks of ophiolite complex obducted during the Maastrichtian. We conclude that in early Aptian time, a shallow carbonate platform developed along the southern margin of the Maya Block. The platform subsided and was drowned during the terminal Campanian. This subsidence led to the formation of a flysch-like basin that received turbiditic sedimentation from the carbonate platform to the north and fragments of serpentinite from the ophiolite complex to the south.  相似文献   

Treatment of groundwater contaminated with high levels of explosives using advanced oxidation processes     

M. E. Zappi  R. Hernandez  D. Gang  R. Bajpai  C. H. Kuo  D. O. Hill 《International Journal of Environmental Science and Technology》2016,13(12):2767-2778

Current and former military installations around the world have numerous sites with groundwater contaminated with explosive compounds polluted from military related activities. The test influent used in this study was a groundwater collected from an US Army facility that was contaminated with high levels of military derived explosives. The sample had a total explosive concentration in excess of 75 mg/l. Bench-scale evaluations were performed to determine the effectiveness of the candidate advanced oxidation processes for treatment of the groundwater in terms of removing the pollutants to method sub-detection limits with these results formulating the basis for comparison along with generating data that can be used toward increasing the understanding of treatment mechanisms associated with the various processes. Results indicate that the ozonated systems generally resulted in the removal of the explosives to the targeted levels with 1,3,5-trinitrobenzene removal lagging in terms of removal due to its simultaneous formation and degradation. The oxidation system that was irradiated using the medium-pressure UV lamp and dosed with hydrogen peroxide and ozone achieved the best performance with complete removal of all targeted pollutants within 10 min of treatment.  相似文献