New thermoelastic parameters of natural <Emphasis Type="Italic">C</Emphasis>2/<Emphasis Type="Italic">c</Emphasis> omphacite     

Francesco?PandolfoEmail author  Fabrizio?Nestola  Fernando?Cámara  M.?Chiara?Domeneghetti 《Physics and Chemistry of Minerals》2012,39(4):295-304

The compressibility at room temperature and the thermal expansion at room pressure of two disordered crystals (space group C2/c) obtained by annealing a natural omphacite sample (space group P2/n) of composition close to Jd₅₆Di₄₄ and Jd₅₅Di₄₅, respectively, have been studied by single-crystal X-ray diffraction. Using a Birch–Murnaghan equation of state truncated at the third order [BM3-EoS], we have obtained the following coefficients: V ₀ = 421.04(7) Å³, K _T0 = 119(2) GPa, K′ = 5.7(6). A parameterized form of the BM3 EoS was used to determine the axial moduli of a, b and c. The anisotropy scheme is β _c  ≤ β _a  ≤ β _b , with an anisotropy ratio 1.05:1.00:1.07. A fitting of the lattice variation as a function of temperature, allowing for linear dependency of the thermal expansion coefficient on the temperature, yielded α_V(1bar,303K) = 2.64(2) × 10⁻⁵ K⁻¹ and an axial thermal expansion anisotropy of α _b  ≫ α _a  > α _c . Comparison of our results with available data on compressibility and thermal expansion shows that while a reasonable ideal behaviour can be proposed for the compressibility of clinopyroxenes in the jadeite–diopside binary join [K _T0 as a function of Jd molar %: K _T0 = 106(1) GPa + 0.28(2) × Jd_(mol%)], the available data have not sufficient quality to extract the behaviour of thermal expansion for the same binary join in terms of composition.  相似文献   

Geochemical traces of CO₂-rich fluid flow along normal faults in central Italy     

Fabrizio Agosta  reas Mulch †  Page Chamberlain  Atilla Aydin 《Geophysical Journal International》2008,174(2):758-770

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A comparison of seismic risk maps for Italy   总被引：5，自引：3，他引：2  

Helen Crowley  Miriam Colombi  Barbara Borzi  Marta Faravelli  Mauro Onida  Manuel Lopez  Diego Polli  Fabrizio Meroni  Rui Pinho 《Bulletin of Earthquake Engineering》2009,7(1):149-180

National seismic risk maps are an important risk mitigation tool as they can be used for the prioritization of regions within a country where retrofitting of the building stock or other risk mitigation measures should take place. The production of a seismic risk map involves the convolution of seismic hazard data, vulnerability predictions for the building stock and exposure data. The seismic risk maps produced in Italy over the past 10 years are compared in this paper with recent proposals for seismic risk maps based on state-of-the-art seismic hazard data and mechanics-based vulnerability assessment procedures. The aim of the paper is to open the discussion for the way in which future seismic risk maps could be produced, making use of the most up-to-date information in the fields of seismic hazard evaluation and vulnerability assessment.  相似文献   

Benthic foraminifera as bio-indicators of trace element pollution in the heavily contaminated Santa Gilla lagoon (Cagliari, Italy)     

Fabrizio Frontalini  Carla Buosi  Rodolfo Coccioni  Carla Bucci 《Marine pollution bulletin》2009,58(6):858-877

In order to assess the response of benthic foraminifera to trace element pollution, a study of benthic foraminiferal assemblages was carried out into sediment samples collected from the Santa Gilla lagoon (Sardinia, Italy). The lagoon has been contaminated by industrial waste, mainly trace elements, as well as by agricultural and domestic effluent. The analysis of surficial sediment shows enrichment in trace elements, including Cr, Cu, Hg, Ni, Pb and Zn. Biotic and abiotic data, analyzed with multivariate techniques of statistical analysis, reveal a distinct separation of both the highly polluted and less polluted sampling sites. The innermost part of the lagoon, comprising the industrial complex at Macchiareddu, is exposed to a high load of trace elements which are probably enhanced by their accumulation in the finer sediment fraction. This area reveals lower diversity and higher percentages of abnormalities when compared to the outermost part of the lagoon.  相似文献   

Love wave tomography in Italy from seismic ambient noise     

Hongyi Li  Fabrizio Bernardi  Alberto Michelini 《地震学报(英文版)》2010,(5):487-495

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Drying and dying of a subducted slab: Coupled Li and B isotope variations in Western Anatolia Cenozoic Volcanism   总被引：1，自引：0，他引：1  

Samuele Agostini  Jeffrey G. Ryan  Sonia Tonarini  Fabrizio Innocenti   《Earth and Planetary Science Letters》2008,272(1-2):139-147

In lavas spanning ~ 10Ma of subduction-related volcanism in Western Anatolia, we observe remarkably similar patterns of δ⁷Li and δ¹¹B variation. In this setting, magmatism records a transition from calc–alkaline to ultrapotassic character, consistent with overall lower mean extents of melting, and a changing mantle source that reflects a fractionating, higher temperature slab input consistent with the gradual cessation of subduction. Subsequent rift-related intraplate magmatism record δ⁷Li signatures within the range observed for MORBs and OIBs, indicating an abrupt transition to a mantle source unmodified by subduction.  相似文献   

Origin of mud in turbidites and hybrid event beds: Insight from ponded mudstone caps of the Castagnola turbidite system (north-west Italy)     

Marco Patacci  Mattia Marini  Fabrizio Felletti  Andrea Di Giulio  Massimo Setti  William McCaffrey 《Sedimentology》2020,67(5):2625-2644

The partitioning of different grain-size classes in gravity flow deposits is one of the key characteristics used to infer depositional processes. Turbidites have relatively clean sandstones with most of their clay deposited as part of a mudstone cap or as a distal mudstone layer, whereas sand-bearing debrites commonly comprise mixtures of sand grains and interstitial clay; hybrid event beds develop alternations of clean and dirty (clay-rich) sandstones in varying proportions. Analysis of co-genetic mudstone caps in terms of thickness and composition is a novel approach that can provide new insight into gravity flow depositional processes. Bed thickness data from the ponded Castagnola system show that turbidites contain more clay overall than do hybrid event beds. The Castagnola system is characterized by deposits of two very different petrographic types. Thanks to this duality, analyses of sandstone and mudstone composition allow inference of which proportion of the clay in each of the deposit types was acquired en route. In combination with standard sedimentological observations the new data allow insight into the likely characteristics of their parent flows. Clean turbidites were deposited by lower concentration, long duration, erosive, muddy turbidity currents which were more efficient at fractionating clay particles away from their basal layer. Hybrid event beds were deposited by shorter duration, higher-concentration, less-erosive sandier flows which were less efficient at clay fractionation. The results are consistent with data from other turbidite systems (for example, Marnoso-arenacea). The approach represents a new method to infer the controls on the degree of clay partitioning in gravity flow deposits.  相似文献   

Magnetic history of a dyke on Mount Etna (Sicily)   总被引：1，自引：0，他引：1  

Ciro Del Negro  & Fabrizio Ferrucci 《Geophysical Journal International》1998,133(2):451-458

During the 1989 eruption of Mount Etna, two fracture systems, trending c. N45°E and N150°E, opened at the foot of its 3000 m high SE Crater and propagated quickly downslope to distances of ≈3 and 7 km, respectively. The northeastern fracture fed a flank eruption, whereas the southeastern fracture remained dry and offered contrasting volcanological and geophysical evidence of the presence of magma at a shallow depth. During the opening of this non-eruptive fracture system, a differential magnetic network was set up on a short profile across its distant extremity. Initially, the magnetic field did not display any change along the profile between frequent surveys. However, repeated measurements at intervals of about 3 months for two years revealed the slow build-up of a 130 nT anomaly. The anomaly vanishes laterally within 0.2 km of the surface expression of the fracture system. This exceptional set of observations constrains the location and time of cooling of a shallow dyke. The increase in magnetization of the dyke inferred by the rate of growth of the anomaly leads to the interpretation that the dyke was emplaced near the end of the eruption.  相似文献   

Behind every robust result is a robust method: Perspectives from a case study and publication process in hydrological modelling     

Fabrizio Fenicia  Dmitri Kavetski 《水文研究》2021,35(8):e14266

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Hydrological and biogeochemical features of the Northern Adriatic Sea in the period 2003–2006     

Giorgio Socal  Francesco Acri  Mauro Bastianini  Fabrizio Bernardi Aubry  Franco Bianchi  Daniele Cassin  Joan Coppola  Amelia De Lazzari  Vinko Bandelj  Gianpiero Cossarini  Cosimo Solidoro 《Marine Ecology》2008,29(4):449-468

This paper reports on the main biogeochemical properties of the Northern Adriatic Sea in the period May 2003–November 2006 within the framework of the European program INTERREG III Italy‐Slovenia. Spatial and temporal distributions of water density, dissolved oxygen, nutrients (nitrogen, phosphorous and silicon) and chlorophyll a are presented. Multivariate methods such as fuzzy k‐means, self‐organising maps and cluster analysis were used to identify the different water masses and to characterise the temporal and spatial variability of the main biogeochemical features present in the area. The results confirm that the Po River outflows and the meteorological forcing factors are the main components triggering the alternation of stratification and mixing of the water column and that strongly affect the trophic state of the basin. In general, oligotrophic conditions dominate, and were more pronounced offshore, but mesotrophy occurred episodically in May 2004 and July 2005, when phytoplankton blooms were observed concomitant with vertical stability of the water column. A marked interannual variability was also observed, supporting the importance of maintaining long‐term observations of the basin.  相似文献