Relationships between diffuse CO2 emissions and volcanic activity on the island of Vulcano (Aeolian Islands, Italy) during the period 1984–1994     

Iole Diliberto  Sergio Gurrieri  Mariano Valenza 《Bulletin of Volcanology》2002,64(3-4):219-228

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Larger foraminifera distribution and strontium isotope stratigraphy of the La Cova limestones (Coniacian–Santonian, “Serra del Montsec”, Pyrenees, NE Spain)     

Carme Boix  Gianluca Frijia  Vicent Vicedo  Josep M. Bernaus  Matteo Di Lucia  Mariano Parente  Esmeralda Caus 《Cretaceous Research》2011,32(6):806-822

The Upper Cretaceous La Cova limestones (southern Pyrenees, Spain) host a rich and diverse larger foraminiferal fauna, which represents the first diversification of K-strategists after the mass extinction at the Cenomanian–Turonian boundary.The stratigraphic distribution of the main taxa of larger foraminifera defines two assemblages. The first assemblage is characterised by the first appearance of lacazinids (Pseudolacazina loeblichi) and meandropsinids (Eofallotia simplex), by the large agglutinated Montsechiana montsechiensis, and by several species of complex rotalids (Rotorbinella campaniola, Iberorotalia reicheli, Orbitokhatina wondersmitti and Calcarinella schaubi). The second assemblage is defined by the appearance of Lacazina pyrenaica, Palandrosina taxyae and Martiguesia cyclamminiformis.A late Coniacian-early Santonian age was so far accepted for the La Cova limestones, based on indirect correlation with deep-water facies bearing planktic foraminifers of the Dicarinella concavata zone. Strontium isotope stratigraphy, based on many samples of pristine biotic calcite of rudists and ostreids, indicates that the La Cova limestones span from the early Coniacian to the early-middle Santonian boundary. The first assemblage of larger foraminifera appears very close to the early-middle Coniacian boundary and reaches its full diversity by the middle Coniacian. The originations defining the second assemblage are dated as earliest Santonian: they represent important bioevents to define the Coniacian-Santonian boundary in the shallow-water facies of the South Pyrenean province.By means of the calibration of strontium isotope stratigraphy to the Geological Time Scale, the larger foraminiferal assemblages of the La Cova limestones can be correlated to the standard biozonal scheme of ammonites, planktonic foraminifers and calcareous nannoplankton. This correlation is a first step toward a larger foraminifera standard biozonation for Upper Cretaceous carbonate platform facies.  相似文献   

Macrobenthos and multi-molecular markers as indicators of environmental contamination in a South American port (Mar del Plata,Southwest Atlantic)     

Mariano J. Albano  Paulo da Cunha Lana  Claudia Bremec  Rodolfo Elías  César C. Martins  Natalia Venturini  Pablo Muniz  Silvia Rivero  Eduardo A. Vallarino  Sandra Obenat 《Marine pollution bulletin》2013

We evaluated benthic habitat quality along a presumed contamination gradient in the Mar del Plata port (Southwestern Atlantic) by coupling biological and chemical proxies in a multidisciplinary approach. Organic matter and photosynthetic pigment contents were higher in silty-clay bottoms of the inner port sites. Levels of all fecal steroids decreased from the inner sites to the port inlet. High concentrations of coprostanol in the inner sites seemed to derive from a permanent population of sea lions rather than from sewage outfalls due to coprostanol/epicoprostanol ratio (IV) values <2.5. PAHs levels were also higher in the inner sector, related to both biomass combustion and petroleum combustion associated to local marine traffic. High disturbance and low ecological status were reflected in low benthic diversity and high AMBI values in the inner sites.  相似文献   

Bootstrap Pettitt test for detecting change points in hydroclimatological data: case study of Itaipu Hydroelectric Plant,Brazil     

Luiza Chiarelli Conte  Fábio Mariano Bayer 《水文科学杂志》2013,58(11):1312-1326

ABSTRACT

The Pettitt test is widely used in climate change and hydrological analyses. However, studies show difficulties of this test in detecting change points, especially in small samples. This study presents a bootstrap application of the Pettitt test, and compares it numerically with the classical Pettitt test by an extensive Monte Carlo simulation. The proposed test outperforms the classical test in all simulated scenarios. An application of the tests is conducted on the historical series of naturalized flows of the Itaipu Hydroelectric Plant in Brazil, for which several studies have shown a change point in the 1970s. When the series is split into shorter sub-series, to simulate actual situations of small samples, the proposed test is more powerful than the classical Pettitt test in detecting the change point. The proposed test can be an important tool for detecting abrupt changes in water availability, in support of hydroclimatological resources decision making.  相似文献   

Wind Forecasting Based on the HARMONIE Model and Adaptive Finite Elements     

Albert Oliver  Eduardo Rodríguez  José María Escobar  Gustavo Montero  Mariano Hortal  Javier Calvo  José Manuel Cascón  Rafael Montenegro 《Pure and Applied Geophysics》2015,172(1):109-120

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Discovery of a broad iron line in the black hole candidate Swift J1753.5−0127, and the disc emission in the low/hard state revisited     

Beike Hiemstra  Paolo Soleri  Mariano Méndez  Tomaso Belloni  Reham Mostafa  Rudy Wijnands 《Monthly notices of the Royal Astronomical Society》2009,394(4):2080-2088

We analysed simultaneous archival XMM–Newton and Rossi X-ray Timing Explorer observations of the X-ray binary and black hole candidate Swift J  1753.5−0127  . In a previous analysis of the same data, a soft thermal component was found in the X-ray spectrum, and the presence of an accretion disc extending close to the innermost stable circular orbit was proposed. This is in contrast with the standard picture in which the accretion disc is truncated at large radii in the low/hard state. We tested a number of spectral models and found that several of them fit the observed spectra without the need of a soft disc-like component. This result implies that the classical paradigm of a truncated accretion disc in the low/hard state cannot be ruled out by these data. We further discovered a broad iron emission line between 6 and 7 keV in these data. From fits to the line profile we found an inner disc radius that ranges between ∼6 and 16 gravitational radii, which can be in fact much larger, up to ∼250 gravitational radii, depending on the model used to fit the continuum and the line. We discuss the implications of these results in the context of a fully or partially truncated accretion disc.  相似文献   

The variability of European floods since AD 1500     

Rüdiger Glaser  Dirk Riemann  Johannes Schönbein  Mariano Barriendos  Rudolf Brázdil  Chiara Bertolin  Dario Camuffo  Mathias Deutsch  Petr Dobrovolný  Aryan van Engelen  Silvia Enzi  Monika Halíčková  Sebastian J. Koenig  Oldřich Kotyza  Danuta Limanówka  Jarmila Macková  Mirca Sghedoni  Brice Martin  Iso Himmelsbach 《Climatic change》2010,101(1-2):235-256

The paper presents a qualitative and quantitative analysis of flood variability and forcing of major European rivers since AD 1500. We compile and investigate flood reconstructions which are based on documentary evidence for twelve Central European rivers and for eight Mediterranean rivers. Flood variability and underlying climatological causes are reconstructed by using hermeneutic approaches including critical source analysis and by applying a semi-quantitative classification scheme. The paper describes the driving climatic causes, seasonality and variability of observed flood events within the different river catchments covering the European mainland. Historical flood data are presented and recent research in the field of historical flood reconstructions is highlighted. Additionally, the character of the different flood series is discussed. A comparison of the historical flood seasonality in relation to modern distribution is given and aspects of the spatial coherence are presented. The comparative analysis points to the fact that the number of flood events is predominately triggered by regional climatic forcing, with at most only minor influence on neighbouring catchments. The only exceptions are extreme, supra-regional climatic events and conditions such as anomalous cold winters, similar to that of 1784, which affected large parts of Europe and triggered flood events in several catchments as a result of ice-break at the beginning of the annual thaw. Four periods of increased occurrence of flooding, mostly affecting Central European Rivers, have been identified; 1540–1600, 1640–1700, 1730–1790, 1790–1840. The reconstruction, compilation and analysis of European-wide flood data over the last five centuries reveal the complexity of the underlying climatological causes and the high variability of flood events in temporal and spatial dimension.  相似文献   

Simplified seismic assessment of multi-span masonry arch bridges     

Paolo Zampieri  Mariano Angelo Zanini  Claudio Modena 《Bulletin of Earthquake Engineering》2015,13(9):2629-2646

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Fault‐controlled dolomite bodies as palaeotectonic indicators and geofluid reservoirs: New insights from Gargano Promontory outcrops          下载免费PDF全文

Andrea Rustichelli  Alessandro Iannace  Emanuele Tondi  Claudio Di Celma  Antonino Cilona  Maurizio Giorgioni  Mariano Parente  Monica Girundo  Chiara Invernizzi 《Sedimentology》2017,64(7):1871-1900

The Upper Jurassic to Lower Cretaceous platform‐slope to basinal carbonate strata cropping out in Gargano Promontory (southern Italy) are partly dolomitized. Fieldwork and laboratory analyses (petrographic, petrophysical and geochemical) allowed the characterization of the dolomite bodies with respect to their distribution within the carbonate succession, their dimensions, geometries, textural variability, chemical stability, age, porosity, genetic mechanisms and relation with tectonics. The dolomite bodies range from metres to kilometres in size, are fault‐related and fracture‐related, and probably formed during the Early Cretaceous at <500 m burial depths and temperatures <50°C. The proposed dolomitization model relies on mobilization of Early Cretaceous seawater that flowed, downward and then upward, along faults and fractures and was modified in its isotopic composition moving through Triassic and Jurassic strata that underlie the studied dolomitized succession. Despite the numerous cases reported in literature, this study demonstrates that hydrothermal and/or high‐temperature fluids are not necessarily required for fault‐controlled dolomitization. Distribution and geometries of dolomite bodies can be used for palaeotectonic reconstructions, as they partly record the characteristics (size, attitude and kinematics) of the palaeo‐faults, even if not preserved, that controlled dolomitization. In Gargano Promontory, dolomites record Early Cretaceous palaeo‐faults from metres to kilometres long, striking north‐west/south‐east to east/west and characterized by normal to strike‐slip kinematics. Dolomitization increases the matrix porosity by up to 7% and, therefore, can improve the geofluid storage capacity of tight, platform‐slope to basinal limestones. The results have a great significance for characterization of geofluid (for example, hydrocarbons) reservoirs hosted in similar dolomitized carbonate successions. Distribution, size and shapes of reservoir rocks (i.e. dolomite bodies) could be broadly predictable if the characteristics of the palaeo‐fault system present at the time of dolomitization are known.  相似文献   

Large-Scale Temperature Changes across the Southern Andes: 20th-Century Variations in the Context of the Past 400 Years   总被引：4，自引：0，他引：4  

Ricardo Villalba  Antonio Lara  José A. Boninsegna  Mariano Masiokas  Silvia Delgado  Juan C. Aravena  Fidel A. Roig  Andrea Schmelter  Alexia Wolodarsky  Alberto Ripalta 《Climatic change》2003,59(1-2):177-232

Long-term trends of temperature variations across the southern Andes (37–55° S) are examined using a combination of instrumental and tree-ring records. A critical appraisal of surface air temperature from station records is presented for southern South America during the 20th century. For the interval 1930–1990, three major patterns in temperature trends are identified. Stations along the Pacific coast between 37 and 43° S are characterized by negative trends in mean annual temperature with a marked cooling period from 1950 to the mid-1970s. A clear warming trend is observed in the southern stations (south of 46°S), which intensifies at higher latitudes. No temperature trends are detected for the stations on the Atlantic coast north of 45° S. In contrast to higher latitudes in the Northern Hemisphere where annual changes in temperature are dominated by winter trends, both positive and negative trends in southern South America are due to mostly changes in summer (December to February) temperatures. Changes in the Pacific Decadal Oscillation (PDO) around 1976 are felt in summer temperatures at most stations in the Pacific domain, starting a period with increased temperature across the southern Andes and at higher latitudes.Tree-ring records from upper-treeline were used to reconstruct past temperature fluctuations for the two dominant patterns over the southern Andes. These reconstructions extend back to 1640 and are based on composite tree-ring chronologies that were processed to retain as much low-frequency variance as possible. The resulting reconstructions for the northern and southern sectors of the southern Andes explain 55% and 45% ofthe temperature variance over the interval 1930–1989, respectively. Cross-spectral analysis of actual and reconstructed temperatures over the common interval 1930–1989, indicates that most of the explained varianceis at periods >10 years in length. At periods >15 years, the squaredcoherency between actual and reconstructed temperatures ranges between 0.6 and 0.95 for both reconstructions. Consequently, these reconstructions are especially useful for studying multi-decennial temperature variations in the South American sector of the Southern Hemisphere over the past 360 years. As a result, it is possible to show that the temperatures during the 20thcentury have been anomalously warm across the southern Andes. The mean annual temperatures for the northern and southern sectors during the interval 1900–1990 are 0.53 °C and 0.86 °C above the1640–1899 means, respectively. These findings placed the current warming in a longer historical perspective, and add new support for the existence of unprecedented 20th century warming over much of the globe. The rate of temperature increase from 1850 to 1920 was the highest over the past 360 years, a common feature observed in several proxy records from higher latitudes in the Northern Hemisphere.Local temperature regimes are affected by changes in planetary circulation, with in turn are linked to global sea surface temperature (SST) anomalies. Therefore, we explored how temperature variations in the southern Andes since 1856 are related to large-scale SSTs on the South Pacific and South Atlantic Oceans. Spatial correlation patterns between the reconstructions and SSTs show that temperature variations in the northern sector of the southern Andes are strongly connected with SST anomalies in the tropical and subtropical Pacific. This spatial correlation pattern resembles the spatial signature of the PDO mode of SST variability over the South Pacific and is connected with the Pacific-South American (PSA) atmospheric pattern in the Southern Hemisphere. In contrast, temperature variations in the southern sector of the southern Andes are significantly correlated with SST anomalies over most of the South Atlantic, and in less degree, over the subtropical Pacific. This spatial correlation field regressed against SST resembles the `Global Warming' mode of SST variability, which in turn, is linked to the leading mode of circulation in the Southern Hemisphere. Certainly, part of the temperature signal present in the reconstructions can be expressed as a linear combination of four orthogonal modes of SST variability. Rotated empirical orthogonal function analysis, performed on SST across the South Pacific and South Atlantic Oceans, indicate that four discrete modes of SST variability explain a third, approximately, of total variance in temperature fluctuations across the southern Andes.  相似文献