Heavy metals accumulation in two syntopic sandhopper species: Talitrus saltator (Montagu) and Talorchestia ugolinii Bellan Santini and Ruffo     

Ugolini A  Borghini F  Focardi S  Chelazzi G 《Marine pollution bulletin》2005,50(11):1328-1334

We assessed the capacity for heavy metals accumulation in Talorchestia ugolinii by standard methods of heavy metals analysis. To compare the bioaccumulation in syntopic sandhopper species, we collected samples of T. ugolinii and Talitrus saltator living on the same and on different beaches in Corsica. There was a marked difference in the zonal distribution of the two species along the sea-land axis of the beach: T. ugolinii was distributed nearer the water line than T. saltator. The bioaccumulation capacity of T. ugolinii only partly matched that of the Mediterranean T. saltator: while Hg, Zn, Cu, and Cd were accumulated by both species, Al and Fe were accumulated by T. saltator but not by T. ugolinii. Pb was accumulated only by T. ugolinii, while Cr did not seem to be accumulated by either species. The bioaccumulation in sympatric T. saltator and T. ugolinii specimens collected on the same beach reflected the general trend of the two species on the Tyrrhenian and Corsican coasts, respectively. Moreover, six of the eight heavy metals considered (Hg, Pb, Zn, Fe, Al, Cu) were present in higher quantities in T. ugolinii than in T. saltator, independently of whether the trace elements were accumulated by the two species. Thus, there are some differences between T. ugolinii and T. saltator, even when the two species live in the same locality. These differences involve their zonation within the damp belt of sand, the bioaccumulation of some heavy metals (Al, Pb, Fe), and the quantity of each heavy metal in the body, independent of the bioaccumulation capacity.  相似文献   

Timescales and dynamics of the formation of a thermocline     

Giulio Boccaletti   《Dynamics of Atmospheres and Oceans》2005,39(1-2):21

In a state of equilibrium, the constraint of a balanced heat budget for the ocean strongly influences the depth of the tropical thermocline because that depth controls the rate at which the ocean absorbs heat from the atmosphere. Thus, an increase in the oceanic heat loss in high latitudes results in a shoaling of the equatorial thermocline so that the heat gain also increases. How does the ocean adjust to such a new equilibrium state after an abrupt change in the heat flux in high latitudes? The adjustment of the wind-driven circulation of the upper ocean is shown to involve two timescales. The first is the familiar adiabatic wave-adjustment time associated with the horizontal redistribution of warm water above the thermocline in shallow water models. (This is essentially the time it takes Rossby and Kelvin waves to propagate from the disturbed extra-equatorial region to the equator.) The second adjustment-time is associated with the diabatic processes that come into play once the waves from higher latitudes modify the thermal structure in low latitudes and hence the flux of heat into the ocean; it is the timescale on which the ocean recovers a balanced heat budget. The identification of this timescale is the main result of this paper.Through a series of simulations of an idealized ocean basin, we identify the diabatic timescale and argue that it is determined by the strength of the upwelling and the intensity of the air–sea heatfluxes. By simulating the formation of a thermocline from isothermal conditions, we are able to relate this timescale to other relevant timescales such as that associated with diffusive processes and the adiabatic timescale invoked by Gu and Philander [Gu, D., Philander, S.G.H., 1997. Interdecadal climate fluctuations that depend on exchanges between the tropics and extra-topics. Science 275, 805–807].  相似文献   

Climatic features of the Mediterranean Sea detected by the analysis of the longwave radiative bulk formulae     

M. E. Schiano  M. Borghini  S. Castellari  C. Luttazzi 《Annales Geophysicae》2000,18(11):1482-1487

Some important climatic features of the Mediterranean Sea stand out from an analysis of the systematic discrepancies between direct measurements of longwave radiation budget and predictions obtained by the most widely used bulk formulae. In particular, under clear-sky conditions the results show that the surface values of both air temperature and humidity over the Mediterranean Sea are larger than those expected over an open ocean with the same amount of net longwave radiation. Furthermore, the twofold climatic regime of the Mediterranean region strongly affects the downwelling clear-sky radiation. This study suggests that a single bulk formula with constant numerical coefficients is unable to reproduce the fluxes at the surface for all the seasons.  相似文献   

Inclined K–Ar illite age spectra in brittle fault gouges: effects of fault reactivation and wall‐rock contamination          下载免费PDF全文

Espen Torgersen  Giulio Viola  Horst Zwingmann  Iain H. C. Henderson 《地学学报》2015,27(2):106-113

K–Ar clay fraction ages of brittle faults often vary with grain size, decreasing in the finer size fractions, producing an inclined age–grain‐size spectrum. K–Ar ages and mineralogical characterization of gouges from two normal faults in the Kongsberg silver mines, southern Norway, suggest that inclined spectra derived from brittle fault rocks reflect the mixing of inherited components with authigenic mineral phases. The ages of the coarsest and finest fractions constrain faulting at c. 260–270 Ma and reactivation around 200–210 Ma, respectively. This study demonstrates how wall‐rock contamination influences the K–Ar age of the coarsest size fractions and that authigenic illite and K‐feldspar can crystallize synkinematically under equivalent conditions and thus yield the same K–Ar ages.  相似文献   

Direct 40Ar/39Ar dating of Late Ordovician and Silurian brittle faulting in the southwestern Norwegian Caledonides          下载免费PDF全文

Thomas Scheiber  Giulio Viola  Camilla Maya Wilkinson  Morgan Ganerød  Øyvind Skår  Deta Gasser 《地学学报》2016,28(5):374-382

Structural data as well as U–Pb zircon and ⁴⁰Ar/³⁹Ar biotite and muscovite ages were collected from the Rolvsnes granodiorite in western Norway. The granodiorite intruded at c. 466 Ma, cooled quickly and escaped later viscous deformation. Brittle top‐to‐the‐NNW thrust faults (Set I) and WNW–ESE striking dextral strike‐slip faults (Set II) formed in a NNW–SSE transpressional regime. ⁴⁰Ar/³⁹Ar dating of synkinematic mica from both sets reveals a c. 450 Ma (Late Ordovician) age of faulting, which constrains early‐Caledonian brittle deformation. Set I and II faults are overprinted by a set of lower‐grade, variably oriented chlorite‐ and epidote‐coated faults (Set III) constraining WNW–ESE shortening. A lamprophyric dyke oriented compatibly with this stress field intruded at c. 435 Ma (Silurian), indicating that Set III formed at the onset of the Scandian Baltica–Laurentia collision. The preservation of Caledonian brittle structures indicates that the Rolvsnes granodiorite occupied a high tectonic level throughout the Caledonian orogeny.  相似文献   

Evaluation of site effects in the Aterno river valley (Central Italy) from aftershocks of the 2009 L��Aquila earthquake     

F. Bergamaschi  G. Cultrera  L. Luzi  R. M. Azzara  G. Ameri  P. Augliera  P. Bordoni  F. Cara  R. Cogliano  E. D��Alema  D. Di Giacomo  G. Di Giulio  A. Fodarella  G. Franceschina  F. Galadini  M. R. Gallipoli  S. Gori  P. Harabaglia  C. Ladina  S. Lovati  S. Marzorati  M. Massa  G. Milana  M. Mucciarelli  F. Pacor  S. Parolai  M. Picozzi  M. Pilz  S. Pucillo  R. Puglia  G. Riccio  M. Sobiesiak 《Bulletin of Earthquake Engineering》2011,9(3):697-715

A temporary network of 33 seismic stations was deployed in the area struck by the 6th April 2009, Mw 6.1 (Scognamiglio et?al. in Seism Res Lett 6/81, 2010), L??Aquila earthquake (central Italy), with the aim to investigate the site amplification within the Aterno river Valley. The seismograms of 18 earthquakes recorded by 14 of the 33 stations were used to evaluate the average horizontal to vertical spectral ratio (HVSR) for each site and the standard horizontal spectral ratio (SSR) between a site and a reference station. The obtained results have been compared to the geological and geophysical information in order to explain the resonance frequencies and the amplification levels with respect to surface geology of the valley. The results indicate that there is no uniform pattern of amplification, because of the complex geologic setting, as the thickness and degree of cementation of the deposits is highly variable.  相似文献   

Diagenetic and thermal history of the Jurassic-Tertiary succession of the Zagros Mountains in the Dezful Embayment (SW Iran): constraints from fluid inclusions     

A. Ceriani  R. Calabrò  A. Di Giulio  R. Buonaguro 《International Journal of Earth Sciences》2011,100(6):1265-1281

To constraint the diagenetic and thermal history in the Mesozoic-Tertiary succession of the Zagros Fold-Belt, a study was performed on fluid inclusions trapped in intergranular, vug, and fracture-filling cements in Jurassic to Miocene outcrop samples collected along the Anneh and Fahliyan Valleys of Khuzestan Province, southwest Iran. Petrographic observations showed at least two systems of fractures that postdate intergranular cementation. Two different types of oil-filled fluid inclusions occur in the intergranular cements and in the first fracture network, but they are absent in the second fracture network. Microthermometry of fluid inclusions was used to determine the temperature and salinity of fluids responsible for mineral precipitation. Within intergranular cements and calcite fillings the oldest fractures, precipitation occurred from high saline fluids in a temperature range of 60–120°C, depending on the stratigraphic depth. The strong correlation between fluid inclusions temperature and stratigraphic depth suggests that the intergranular cementation and the first fracture-filling event occurred prior to structural deformation. Furthermore, this correlation indicates a relatively constant paleogeothermal gradient at the time of cement precipitation of about 28°C/Km. On the contrary, fluid inclusions trapped in cements within the second fracture network lack oil and contain freshwater trapped at low temperatures that do not correlate to the stratigraphic position. This suggests second fracturing event occurred after oil migration and during or after deformation of the Zagros Fold-Belt, when the samples were in a near-surface position.  相似文献   

Flexural response of the Venetian foreland to the Southalpine tectonics along the TRANSALP profile     

C. Barbieri  G. Bertotti  A. Di Giulio  R. Fantoni  R. Zoetemeijer 《地学学报》2004,16(5):273-280

The Venetian Basin was affected by flexure related to the Southalpine shortening phase during the Middle Miocene – Early Pliocene. This downbending is quantified here using a two‐dimensional flexural model. A recently improved data set on basin geometry based on the bottom of the Serravallian–Tortonian clastic wedge, on palaeobathymetry and gravity anomalies is used to constrain the components of flexure and to test the importance of the initial bathymetry in evaluating the contribution of surface loads to deflection. A good fit is obtained assuming a northward broken plate configuration of the downbent Adriatic plate with an effective elastic thickness of 20 km. Results highlight that, in the studied region, flexure related to the Eastern Southern Alps is totally due to surface loads (topographic load partly replacing initial bathymetry) and that no hidden loads are required. Furthermore, the palaeobathymetry contributes up to 50% to the total flexure in the studied region.  相似文献   

Correlations between diffuse interstellar bands and atomic lines     

G. A. Galazutdinov  Giulio Manicò  Valerio Pirronello  Jacek Kre&#;owski 《Monthly notices of the Royal Astronomical Society》2004,355(1):169-177

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Xenotime-(Y) formation from zircon dissolution–precipitation and HREE fractionation: an example from a metamorphosed phosphatic sandstone,Espinhaço fold belt (Brazil)     

Gerhard Franz  Giulio Morteani  Dieter Rhede 《Contributions to Mineralogy and Petrology》2015,169(4):1-22

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