Depositional processes on oceanic island shelves – Evidence from storm‐generated Neogene deposits from the mid‐North Atlantic     

Ricardo P. Meireles  Rui Quartau  Ricardo S. Ramalho  Ana C. Rebelo  José Madeira  Vittorio Zanon  Sérgio P. Ávila 《Sedimentology》2013,60(7):1769-1785

Oceanic islands – such as the Azores in the mid‐North Atlantic – are periodically exposed to large storms that often remobilize and transport marine sediments along coastlines, and into deeper environments. Such disruptive events create deposits – denominated tempestites – whose characteristics reflect the highly dynamic environment in which they were formed. Tempestites from oceanic islands, however, are seldom described in the literature and little is known about storm‐related sediment dynamics affecting oceanic island shelves. Therefore, the geological record of tempestite deposits at oceanic islands can provide invaluable information on the processes of sediment remobilization, transport and deposition taking place on insular shelves during and after major storms. In Santa Maria Island (Azores), a sequence of Neogene tempestite deposits was incorporated in the island edifice by the ongoing volcanic activity (thus preserved) and later exposed through uplift and erosion. Because it was overlain by a contemporary coastal lava delta, the water depth at the time of deposition could be inferred, constituting an excellent case‐study to gain insight on the still enigmatic processes of insular shelf deposition. Sedimentological, palaeontological, petrographic and palaeo‐water depth information allowed the reconstruction of the depositional environment of these sediments. The sequence typifies the characteristics of a tempestite (or successive tempestites) formed at ca 50 m depth, in a steep, energetic open insular shelf, and with evidence for massive sediment remobilization from the nearshore to the middle or outer shelf. The authors claim that cross‐shelf transport induced by storm events is the main process of sediment deposition acting on steep and narrow shelves subjected to high‐energetic environments, such as the insular shelves of open‐sea volcanic islands.  相似文献   

Sicilian serpentinite xenolihs conaining abioic organics wih nanodiamond clusers ans key model for prebioic processes     

Sergei K.Simakov  Vittorio Scribano  Nikolai N.Mel'Nik  Germana Barone 《地学前缘(英文版)》2021,12(1):255-263

Rock fragments from the deepest parts of a buried hydrothermal system belonging to the Mesozoic Tethys Oceanentered as xenoliths in a Miocenic diatreme. hence b...  相似文献   

Facies and Late Triassic fossils in the Roisan zone,Austroalpine Dent Blanche and Mt Mary-Cervino nappe system,NW Alps     

Gloria Ciarapica  Leonsevero Passeri  Franco Bonetto  Giorgio Vittorio Dal Piaz 《Swiss Journal of Geoscience》2016,109(1):69-81

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Sulla portata di un corso d'acqua dedotta dalla profondita' critica     

Prof. Dr. Ing. Vittorio Baggi 《Pure and Applied Geophysics》1942,4(1):106-110

Riassunto Con riferimenti pratici l'A. dimostra come i valori delle portate di fiumi e torrenti dedotti dalle formule relative alla pendenza critica e profondità critica risultano troppo discordi dal vero allorchè non sono soddisfatte tutte le ipotesi dalle quali derivano le formule.

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Zusammenfassung Der Verf. zeigt an Hand von sicheren Beobachtungsdaten, dass die Ergiebigkeitswerte von Flüssen und Bächen welche sich aus der Formeln der kritischen Gefälle und Tiefe ableiten lassen viel zu sehr von der Wirklichkeit abweichen können wenn die Annahmen welche für jene Formeln zugrundegelegt wurden nicht befriedigt sind.

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Sull'impiego dei gravimetri in terreni montagnosi     

Ing. Vittorio Scheffer 《Pure and Applied Geophysics》1941,3(1):194-199

Riassunto L'A. riferisce sugli accorgimenti da tener presente nell' impiego e specialmente nel trasporto dei gravimetri in terreni montagnosi: con riguardo ai metodi adottati nei rilievi da lui diretti nell'Appennino tosco-emiliano.

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Zusammenfassung Die Transportmöglichkeiten des Gravimeters und seiner Ausrüstung bei einer detaillierten Messung im Gebirge. Beschreibung einer Messmethode, welche von der geophysikalischen Abteilung der Società Petrolifera Italiana in den toscoemilianischen Appeninen mit gutem Erfolg angewendet wurde. Schweremesser und Ausrüstung wurden dabei auf Maultieren transportiert.

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Pliocene–Quaternary contourite depositional system along the south-western Adriatic margin: changes in sedimentary stacking pattern and associated bottom currents     

Claudio Pellegrini  Vittorio Maselli  Fabio Trincardi 《Geo-Marine Letters》2016,36(1):67-79

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Evaluating asbestos fibre concentration in metaophiolites: a case study from the Voltri Massif and Sestri–Voltaggio Zone (Liguria, NW Italy)     

Folco Giacomini  Vittorio Boerio  Simona Polattini  Massimo Tiepolo  Riccardo Tribuzio  Alberto Zanetti 《Environmental Earth Sciences》2010,61(8):1621-1639

This work is part of the project study for a road tunnel bypassing the town of Genova and was aimed at evaluating the amount of asbestos fibres in the metaophiolites belonging to the Voltri Group and the Sestri–Voltaggio Zone (Liguria, Northern Italy). The 85 studied rock samples (mainly mafic and ultramafic rocks) derive from exposed outcrops and prospecting boreholes. The study of field relations and petrographic/microtextural investigations under the optical microscope allowed for the identification and characterisation of asbestos-bearing settings and lithotypes. Mineralogy and concentration of asbestos fibres in powdered specimens were determined by means of a scanning electron microscope equipped with an energy-dispersive X-ray spectroscopy device. These investigations were combined with petrography on thin-section, X-ray diffraction analysis and phase contrast optical microscopy on rock powders. Mafic and ultramafic rocks commonly contain asbestos in concentrations below 1,000 mg/kg (considered as the contamination threshold under Italian law). However, the fibre concentration rises abruptly within localised zones, where the metaophiolite sequences were involved into late ductile to brittle tectono-metamorphic events. Two groups of asbestos-bearing settings have been so far identified in the area: (a) fracture networks within serpentinites (dominated by fibrous chrysotile), and (b) boudins of chlorite-tremolite schists, likely deriving from dynamic recrystallisation of mafic rocks under greenschist facies conditions (dominated by fibrous amphibole). Even considering the low volumetric incidence of these settings (metres to few tens of metres), their high asbestos content locally controls the total fibre amount in the excavation products, thus requiring special prevention measures during excavation, management and final storage of the contaminated debris.  相似文献   

La prospection gravimétrique dans la modélisation d'un substratum sous formation sédimentaire : apport à l'hydrogéologie d'une zone semi-aride du Sud de Madagascar     

Heritiana Rakoto  Pierre Andrieux  Jean-Bruno Ratsimbazafy  Vittorio Iliceto  Eddy Rasolomanana  Louis Pastor  Gian Maria Zuppi 《Comptes Rendus Geoscience》2003,335(4):355-363

A gravimetric survey has been carried out in a sedimentary basin, south of Madagascar, in order to define the bedrock morphology. The bedrock is made up of crystalline and volcanic rocks. The objective of the survey was to demonstrate whether a relationship could be established between bedrock morphology and groundwater mineralisation. Indeed, bedrock morphology has been successfully mapped and it is confirmed that most of the low mineralisation wells are located in areas where the slope of the bedrock is trending to the south-west, which ensures a higher hydraulic conductivity, i.e. a faster water flow, than in the other parts of the survey area. To cite this article: H. Rakoto et al., C. R. Geoscience 335 (2003).  相似文献   

The field of NGC 6397 as a test for Galactic models     

V. Castellani  S. Degl'Innocenti  S. Petroni  G. Piotto 《Monthly notices of the Royal Astronomical Society》2001,324(1):167-179

Taking advantage of recent Hubble Space Telescope ( HST ) data for field stars in the region of the Galactic globular cluster NGC 6397, we tested the predictions of several Galactic models with star counts reaching a largely unexplored range of magnitudes, down to V ∼26.5. After updating the input stellar ( V − I ) colours, we found that the two-component Bahcall–Soneira (B&S) model can be put into satisfactory agreement with observations for suitable choices of disc/spheroid luminosity functions (LFs). However, if one assumes the disc LF of Gould, Bahcall and Flynn together with the spheroid LF of Gould, Flynn and Bahcall, there is no way to reconcile the predicted and observed V -magnitude distribution. We also analysed the agreement between observed and predicted magnitude and colour distributions for two selected models with a thick disc component. Even in this case there are suitable combinations of model parameters and faint-magnitude LFs that can give a reasonable agreement with observational star counts in both magnitude and colour. However, the above-quoted combination of Gould et al. LFs again gives predictions in clear disagreement with observations.  相似文献   

A solar spectrum for PFS data analysis     

Carlo Fiorenza  Vittorio Formisano 《Planetary and Space Science》2005,53(10):1009-1016

A measured calibrated solar radiance in the range 1.2-, with the spectral sampling of does not exist. When studying the measured Planetary Fourier Spectrometer (PFS) spectra of the Earth's or Mars's atmosphere we discover that the most used solar spectrum contains several important errors. Here we present a “calibrated” solar radiance in the wavelength range 1.2-, with the spectral resolution of PFS , which we are going to use for studying Martian spectra. This spectrum has been assembled using measurements from Kitt Peak and from ATMOS Spacelab experiment (uncalibrated high resolution) and theoretical results, together with low resolution calibrated continuum. This is the best we can have in this moment to be used with PFS, while waiting to have good solar calibrated radiances. Examples of solar lines at Mars are given.  相似文献