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1.
The Apennine Chain provides the first example of stratigraphic (time) and synsedimentary tectonic (space) distribution of the calcari aLucina Miocene equivalents of modern cold-vent carbonates. Chemosynthetic faunal assemblages and related carbonate deposits are found at different stratigraphic levels, with peaks during Langhian-Serravallian and late Tortonian-early Messinian times. A general increase in frequency and volume occurs with time. A genetic link between venting and the Messinian Evaporite event is difficult to demonstrate. However,Lucina limestones are limited to preevaporitic times, and their maximum abundance is reached just before the onset of the Messinian Evaporite accumulation.Lucina limestones occur in almost all tectofacies of the orogen, from backland to foreland. 相似文献
2.
Elizabeth B. Kujawinski Rossana Del Vecchio Neil V. Blough Geoffrey C. Klein Alan G. Marshall 《Marine Chemistry》2004,92(1-4):23
Molecular-level characterization of natural organic matter (NOM) has been elusive due to the inherent complexity of natural organic mixtures and to the fact that individual components are often polar and macromolecular. Electrospray ionization (ESI) is a “soft” ionization technique that ionizes polar compounds from aqueous solution prior to injection into a mass spectrometer. The highest resolution and mass accuracy of compounds within NOM have been achieved when ESI is combined with an ultrahigh-resolution mass spectrometer such as the Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS). With this technique, individual molecules within a variety of natural organic mixtures can be detected and their elemental composition can be determined. At low mass-to-charge (m/z) ratio, the resolution is high enough to assign exact molecular formulas allowing specific components of these mixtures to be identified. In addition to molecular identification, we can now use ESI FT-ICR MS to examine molecular-level changes in different organic mixtures as a function of relevant geo-processes, such as microbial alterations and photochemistry. Here we present the results from the application of ESI FT-ICR MS to two geochemical questions: (1) the effect of photoirradiation on the molecular composition of fulvic acids and (2) the role of protozoan grazers in the modification of DOM in aquatic systems. 相似文献
3.
S. A. Gil-Zepeda J. C. Montalvo-Arrieta R. Vai F. J. Snchez-Sesma 《Soil Dynamics and Earthquake Engineering》2003,23(1):77-86
A hybrid indirect boundary element – discrete wavenumber method is presented and applied to model the ground motion on stratified alluvial valleys under incident plane SH waves from an elastic half-space. The method is based on the single-layer integral representation for diffracted waves. Refracted waves in the horizontally stratified region can be expressed as a linear superposition of solutions for a set of discrete wavenumbers. These solutions are obtained in terms of the Thomson–Haskell propagators formalism. Boundary conditions of continuity of displacements and tractions along the common boundary between the half-space and the stratified region lead to a system of equations for the sources strengths and the coefficients of the plane wave expansion. Although the regions share the boundary, the discretization schemes are different for both sides: for the exterior region, it is based on the numerical and analytical integration of exact Green's functions for displacements and tractions whereas for the layered part, a collocation approach is used. In order to validate this approach results are compared for well-known cases studied in the literature. A homogeneous trapezoidal valley and a parabolic stratified valley were studied and excellent agreement with previous computations was found. An example is given for a stratified inclusion model of an alluvial deposit with an irregular interface with the half-space. Results are displayed in both frequency and time domains. These results show the significant influence of lateral heterogeneity and the emergence of locally generated surface waves in the seismic response of alluvial valleys. 相似文献
4.
Maria Bianca Cita Luca Capraro Neri Ciaranfi Enrico Di Stefano Fabrizio Lirer Patrizia Maiorano Maria Marino Isabella Raffi Domenico Rio Rodolfo Sprovieri Simona Stefanelli Gian Battista Vai 《《幕》》2008,31(4):408-419
The name Calabrian was introduced in the geological literature by the French stratigrapher Maurice Gignoux in 1910, and later described in his important monograph （633 pages） ＂Les formations marines pliocknes et quaternaires de l＇ltalie du sud et de la Sicile ＂published in 1913. Detailed data were provided on several sections （Santa Maria di Catanzaro, Caraffa, Monasterace, Palermo） and on their fossil content. The Calabrian Stage has commonly been used for over fifty years as the oldest subdivision of the Qua- ternary, notably in the time scales of Berggren ＆ van Cou- vering （1974） and Haq ＆ Eysinga （1987）. However, after the GSSP for the Pliocene/Pleistocene boundary （P/P） was approved by INQUA in 1982 and ratified by lUGS in 1984 at the Vrica section of Calabria, there was a decline in the usage of the stage name, and an increasing tendency by many Quaternary workers to question the boundary stratotype. This was because there was increasing evidence that it did not correspond to the beginning of the ＂ice age＂. In doing so, they were not complying with the recommendations presented at the 18th International Geological Congress （IGC） in London, 1948 （Oakley, 1950）. 相似文献
5.
Photobleaching of chromophoric dissolved organic matter in natural waters: kinetics and modeling 总被引：9，自引：0，他引：9
The effects of monochromatic and polychromatic UV and visible (VIS) radiation on the optical properties (absorption and fluorescence) of chromophoric dissolved organic matter (CDOM) were examined for a Suwannee River fulvic acid (SRFA) standard and for water from the Delaware and Chesapeake Bays. The primary (direct) loss of absorption and fluorescence occurred at the irradiation wavelength(s), with smaller secondary (indirect) losses occurring outside the irradiation wavelength(s). The efficiency of both direct and indirect photobleaching decreased monotonically with increasing wavelength. Exposure to polychromatic light increased the CDOM absorption spectral slope (S), consistent with previous field measurements. An analysis of the monochromatic photobleaching kinetics argues that a model based on a simple superposition of multiple chromophores undergoing independent photobleaching cannot apply; this conclusion further implies that the absorption spectrum of CDOM cannot arise solely from a simple superposition of the spectra of numerous independent chromophores. The kinetics of CDOM absorption loss with the monochromatic irradiation were employed to create a simple, heuristic model of photobleaching. This model allowed us to examine the importance of the indirect photobleaching losses in determining the overall photobleaching rates as well as to model the photobleaching of natural waters under polychromatic light fields. Application of this model to natural waters closely predicted the change in the CDOM spectral shape caused by photodegradation. The time scale of this process was consistent with field observations acquired during the summertime for coastal waters in the Middle Atlantic Bight (MAB). The results indicate that the ratio of the photodegradation depth to the mixed layer depth is a key parameter controlling the rate of the photobleaching in surface waters. 相似文献
6.
Alexander Eleftheriou Carolina Filizzola Nicola Genzano Teodosio Lacava Mariano Lisi Rossana Paciello Nicola Pergola Filippos Vallianatos Valerio Tramutoli 《Pure and Applied Geophysics》2016,173(1):285-303
Real-time integration of multi-parametric observations is expected to accelerate the process toward improved, and operationally more effective, systems for time-Dependent Assessment of Seismic Hazard (t-DASH) and earthquake short-term (from days to weeks) forecast. However, a very preliminary step in this direction is the identification of those parameters (chemical, physical, biological, etc.) whose anomalous variations can be, to some extent, associated with the complex process of preparation for major earthquakes. In this paper one of these parameters (the Earth’s emitted radiation in the Thermal InfraRed spectral region) is considered for its possible correlation with M ≥ 4 earthquakes occurred in Greece in between 2004 and 2013. The Robust Satellite Technique (RST) data analysis approach and Robust Estimator of TIR Anomalies (RETIRA) index were used to preliminarily define, and then to identify, significant sequences of TIR anomalies (SSTAs) in 10 years (2004–2013) of daily TIR images acquired by the Spinning Enhanced Visible and Infrared Imager on board the Meteosat Second Generation satellite. Taking into account the physical models proposed for justifying the existence of a correlation among TIR anomalies and earthquake occurrences, specific validation rules (in line with the ones used by the Collaboratory for the Study of Earthquake Predictability—CSEP—Project) have been defined to drive a retrospective correlation analysis process. The analysis shows that more than 93 % of all identified SSTAs occur in the prefixed space–time window around (M ≥ 4) earthquake's time and location of occurrence with a false positive rate smaller than 7 %. Molchan error diagram analysis shows that such a correlation is far to be achievable by chance notwithstanding the huge amount of missed events due to frequent space/time data gaps produced by the presence of clouds over the scene. Achieved results, and particularly the very low rate of false positives registered on a so long testing period, seems already sufficient (at least) to qualify TIR anomalies (identified by RST approach and RETIRA index) among the parameters to be considered in the framework of a multi-parametric approach to t-DASH. 相似文献
7.
The Hercynian remnants present within the Alpidic structural zones of the Southern Alps are reviewed. The pattern of Hercynian metamorphism is zonal from granulites in the western area to anchimetamorphic facies in the eastern one. In the folded zone at the eastern margin a severe Hercynian folding phase took place during the Westphalian. Thrust sheets comprising sequences of different facies ranging in age from Caradocian to early Westphalian are sutured by late Westphalian molasse deposits. The assumption that the Southern Alps and the external Dinarides remained outside the Hercynian folding front is contradicted by field evidence. 相似文献
8.
Data supporting relevant Late Cretaceous–Early Eocene sinistral displacement along the Giudicarie fault zone and a minor Neogene dextral displacement along the Periadriatic lineament are discussed. The pre-Adamello structural belt is present only in the internal Lombardy zone, located W of the Adamello massif. This belt is unknown in the Dolomites and surrounding areas located to the E of the Giudicarie lineament. Upper Cretaceous–Early Eocene thick syntectonic Flysch deposits of Lombardy and Giudicarie are well preserved along the southern and eastern border of the pre-Adamello belt (S-vergent Alpine orogen). Towards the E, in the Dolomites and in the Carnic Alps and external Dinarides, only incomplete remnants of Flysch deposits, Aptian–Albian and Turonian–Maastrichtian in age, are present. They can be considered as equivalent to those of Lombardy and Giudicarie formerly in connection to each other along the N-Giudicarie corridor. To the S, the syntectonic Flysch deposits are laterally replaced by the calcareous red pelagites of the Scaglia Rossa and by the carbonate shelf deposits of the Friuli (to the E) and Bagnolo (to the S) carbonate platforms. The different location in the southern structural accretion of the eastern and western opposite blocks (the Dolomites versus the pre-Adamello belt) can be related to the Cretaceous–Eocene convergence. In this frame, the N-Giudicarie fault has been considered as part of a former transfer zone, which produced the sinistral lateral displacement of the Southern Alps front for an amount of some 50 km. During the Late Eocene to Early Oligocene the transfer zone was mostly sealed by the Paleogene Adamello batholith. Oligocene to Neogene compressional evolution inverted the N-Giudicarie fault into a backthrust of the Austroalpine units over the South-Alpine chain. 相似文献
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10.
An operational model to estimate hourly and daily crop evapotranspiration in hilly terrain: validation on wheat and oat crops 总被引：2，自引：1，他引：1
Gianfranco Rana Nader Katerji Rossana M. Ferrara Nicola Martinelli 《Theoretical and Applied Climatology》2011,103(3-4):413-426
In this paper, we present an operational model to estimate the actual evapotranspiration (ET) of crops cultivated on hilly terrains. This new model has the following three characteristics: (1) ET modelling is based on a Penman?CMonteith (PM) type equation (Monteith 1965) where canopy resistance is simulated by following an approach already illustrated by Katerji and Perrier (Agronomie 3(6):513?C521, 1983); (2) the estimation of ET, by means of the PM equation, is made by using meteorological variables simulated on sloped sites as input; (3) these variables are simulated by using simple relationships linking the variables measured at a reference site on plane to the topographic characteristics of the site (slope, orientation, altitude as difference between reference, and sloped sites). This approach presents two advantages if compared with previously proposed models: Not only computation steps are greatly simplified but also error sources due to the simulation of climatic variables in sloped sites and the ET estimation are well distinguished. This model was validated at hourly and daily scales at four sites cultivated with wheat and oats offering a wide range of slope and orientation values: a reference site on plane, site 1 (9° sloping, NW orientation, 7 m from the reference site in plane), site 2 (6°, SE, 12 m) and site 3 (1°, SE, 18 m). At hourly scale, the new model performed well at all sites studied. The observed slope of the linear relationships between estimated and measured ET values ranged between 0.93 and 1.03, with coefficients of determination, r 2, between 0.80 and 0.98. At daily scale, the slopes of the linear relationships between measured and estimated ET for the sites on plane and the sloped sites were practically the same (0.98?±?0.01); however, the coefficient of determination r 2 observed in the site on plane was clearly greater (0.98) than that observed in the sloped sites (0.83). The presented analysis does not show any significant systematic effect of topography (slope and orientation of the plots) on the good performance of the proposed model for the ET estimation. Furthermore, we observed that coefficients of determination tend to decrease with the increase in the slope of the site, which translates into increased inaccuracy of the climatic variables simulation, in particular the net radiation, as the slope of the site increases. The proposed model allows to verify the different steps for calculating the fluxes, to identify the eventual sources of error and to make the needed corrections. For this reasons, the proposed model seems to be particularly ??operational??, i.e. a useful tool for estimating fluxes on hilly terrains. 相似文献