Equivocal carbonatite markers in the mantle xenoliths of the Patagonia backarc: the Gobernador Gregores case (Santa Cruz Province,Argentina)     

Giorgio?RivalentiEmail author  Alberto?Zanetti  Maurizio?Mazzucchelli  Riccardo?Vannucci  Carlos?A.?Cingolani 《Contributions to Mineralogy and Petrology》2004,147(6):647-670

Amphibole ± phlogopite ± apatite-bearing mantle xenoliths at Gobernador Gregores display modal, bulk-rock and phase geochemical characteristics held as indicators of carbonatitic metasomatism. However, part of these xenoliths has high TiO₂/Al₂O₃ and those displaying the most pronounced carbonatitic geochemical markers modally trend towards harzburgite. Bulk-rock, clinopyroxene and amphibole show Zr, Hf and Ti negative anomalies, which increase at decreasing Na₂O and high field strength elements (HFSE) concentrations. Steady variation trends between xenoliths which have and do not have carbonatitic characteristics suggest a control by reactive porous flow of only one agent, inferred to be initially a ne-normative hydrous basalt (because of the presence of wehrlites) evolving towards silica saturation. Variation trends exhibit cusps when amphibole appears in the mode. Appearance of amphibole may explain the Ti anomaly variations, but not those of Zr and Hf. Numerical modelling [Plate Model (Vernières et al. in J Geophys Res 102:24771–24784, 1997)] gives results consistent with the observed geochemical features by assuming the presence of loveringite. Modest HFSE anomalies in the infiltrating melt may be acquired during percolation in the garnet-facies.In memory of Carlo Rivalenti  相似文献   

The Status of the Twaite Shad, Alosa agone, in Italy and the Western Balkans     

Pier Giorgio Bianco 《Marine Ecology》2002,23(S1):51-64

Abstract. The twaite shad, Alosa agone , is still quite common in Italy and the western Balkans, but locally is endangered or extinct. Two eco-phenotypes are recognized: the migratory'Cheppia'or'Laccia'and the landlocked'Agone'. The two forms have never been in contact, at least in Italy. The migratory form is more endangered since barriers and dams prevent it from reaching upstream spawning grounds. A few reproductive communities are documented, e. g. in the Po River in Italy and Neretva River in Croatia. Resident stocks have increased to substantial populations in the large lakes of Italy, especially in the last ten years, probably as a result of improved water quality. The landlocked form from northern Italy was successfully introduced into lakes of central Italy about 75 years ago. In Sardinia a population derived from the migratory form was established about 80 years ago in the artificial Lake Omodeo. In Croatia the'Cheppia'seems to live only in the lower course of the Neretva River. In Montenegro,'Cheppia'and'Agone'live in sympatry in Lake Skadar, but a dam built in 1960 caused a strong decline of both forms. The twaite shad is a very variable species, able to modify its morphology and biology according to its adaptation to freshwater or marine biotopes. In the Mediterranean area, only one taxon should be then recognized, Alosa agone (Scopoli, 1786). This will replace Alosa fallax (Lacépède, 1803), a taxon described from the Atlantic drainage area which seems to be distinct from Mediterranean populations. A survey of the distribution of reproductive communities of the migrating form in the Mediterranean area must be carried out.  相似文献   

Can Rock Composition Affect Sublittoral Epibenthic Communities?     

Riccardo Cattaneo-Vietti  Giancarlo Albertelli  Giorgio Bavestrello  Carlo Nike Bianchi  Carlo Cerrano  Mariachiara Chiantore  Laura Gaggero  Carla Morri  Stefano Schiaparelli 《Marine Ecology》2002,23(S1):65-77

Abstract. Biomineralogy, as the complex of interactions at different levels (cell, organism, species, and community) between organisms and minerals, may play a significant role in the spatial distribution and structure of marine communities. For instance, a negative influence of quartz has been underlined on the Mediterranean benthic communities, which show a species-poorer structure in quartz-rich environments. Excluding the role of quartz, the aim of this work is to verify whether the composition of various mineralogical substrata can affect a hard-bottom benthic community. In the Ligurian Sea, the Levanto area shows an astonishing complex of substrata with different petrographic characters: in a few kilometres, sandstones, serpentinites, gabbros, and basalts occur in geometric association. Consequently, this area represents a suitable frame for this type of study. Herein, algal photophilic assemblages growing on the four mineralogical substrata show significant differences in number of species and percentage cover or abundance. This suggests a significant influence of rock mineral composition on the hard bottom community. Therefore, rock composition must be taken into account for a better understanding of the processes at the basis of hard-bottom community development and diversity.  相似文献   

Field measurements of wave overtopping at the rubble mound breakwater of Rome–Ostia yacht harbour     

Riccardo Briganti  Giorgio Bellotti  Leopoldo Franco  Julien De Rouck  Jimmy Geeraerts 《Coastal Engineering》2005,52(12):351-1174

This paper describes a new station for full-scale measurement of wave overtopping at the Rome yacht harbour rubble mound breakwater in Ostia (Italy) and the results of the successful first measurement campaign carried out during the winter season 2003–2004. The equipment and the research activities were supported by the EU project CLASH, focusing on scale effects for wave overtopping at coastal structures. The site is characterized by a very small tidal range, a long shallow foreshore and depth-limited breaking waves which interact with a shallow sloping porous rock structure. Overtopping water is collected by a steel tank installed on the crown slab behind the parapet wall. The measurement of water level variation inside the tank by means of two pressure transducers allows the calculation of individual overtopping volumes. Incident waves, sea levels and wind are also measured. During seven independent storms, more than 400 individual overtopping events were recorded and about 86 h of valid data are available. This extensive dataset is presented, discussed and then used for comparison with two commonly used overtopping prediction formulae based on small-scale model tests showing their tendency to underestimate the prototype results. A strong correlation between the hourly mean overtopping discharge and corresponding maximum volume is also presented. The paper generally confirms the validity of the approach used in Troch et al. (2004) [Troch, P., Geeraets, J., Van de Walle, B., De Rouck, J., Van Damme, L., Allsop, W., Franco, L., 2004. Full-scale wave overtopping measurements on the Zeebrugge rubble mound breakwater. Coastal Engineering 51, 609–628] for field measurement of wave overtopping.  相似文献   

SCNAs recorded in florence by a riometer     

P. F. Checacci  M. T. de Giorgio 《Pure and Applied Geophysics》1963,54(1):103-104

Summary Some cases of Sudden Cosmic Noise Absorption, observed on 27.6 MHz, are reported. Most of these events appear to be stricly time correlated with solar flares.  相似文献   

Using carbon finance to support climate policy objectives in high mountain ecosystems     

Adrian Ward  Paul Dargusch  Giorgio Grussu  Rosalaura Romeo 《Climate Policy》2016,16(6):732-751

Carbon markets and climate finance payments are being used to incentivize the mitigation of CO₂ arising from anthropogenic land-use change in forests, marine ecosystems, and lowland grasslands. However, no such consideration has been given to how these ‘carbon finance incentives’ might be applied to mountain grasslands and shrublands, ecosystems that contain a substantial amount of carbon. These incentives amount to more than US$350 billion per annum and could potentially support underfunded natural resource management (NRM) activities, which are urgently needed to address numerous stressors impacting these important ecosystems. In the mountain context, NRM activities could include adaptive grazing management, sustainable cropping, ecosystem preservation, ecosystem restoration, and engineered soil conservation measures. This article investigates the stressors, challenges, and priorities related to the NRM of carbon stocks in mountain grasslands and shrublands; why carbon markets and climate finance have not yet been utilized in this context; and, what is required to position mountain-based NRM activities as eligible for carbon finance incentives. Using surveys and interviews triangulated with a systematic literature review, the study found that carbon finance incentives are not well understood, both amongst mountain-focused experts and in the literature. The study also found the required technical methodologies, policy frameworks, and data to be largely undeveloped. This article proposes a top-down conceptual policy framework that can be used to develop key ‘enabling factors’ with the view of extending the eligibility of carbon markets and climate finance to NRM activities undertaken in mountain grasslands and shrublands in the same way that has been afforded to other ecosystems.

Policy relevance

This is the first study to explicitly highlight the important role that the mountain grasslands and shrublands might play in international climate policy, and how carbon finance mechanisms might support better NRM in these areas. It is also the first to investigate why these incentives have not been adopted thus far. The article concludes by proposing a novel top-down ‘carbon incentive enabling’ framework that could be driven by governments and mountain development focused organizations so as to capture some of the opportunities offered by carbon-based incentives, and help meet international climate policy objectives.  相似文献   

The influence of hydrogeological properties,seawater intrusion and refreshening on the quality of groundwater used for irrigation in an agricultural coastal plain in North Sardinia,Italy     

Daniele Pittalis  Alberto Carletti  Giorgio Ghiglieri  Fulvio Celico 《Environmental Earth Sciences》2016,75(11):963

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Distribution and population structure of deep‐dwelling red coral in the Northwest Mediterranean          下载免费PDF全文

Michela Angiolillo  Andrea Gori  Simonepietro Canese  Marzia Bo  Cristina Priori  Giorgio Bavestrello  Eva Salvati  Fabrizio Erra  Michael Greenacre  Giovanni Santangelo 《Marine Ecology》2016,37(2):294-310

Commercially harvested since ancient times, the highly valuable red coral Corallium rubrum (Linnaeus, 1758) is an octocoral endemic to the Mediterranean Sea and adjacent Eastern Atlantic Ocean, where it occurs on rocky bottoms over a wide bathymetric range. Current knowledge is restricted to its shallow populations (15–50 m depth), with comparably little attention given to the deeper populations (50–200 m) that are nowadays the main target of exploitation. In this study, red coral distribution and population structure were assessed in three historically exploited areas (Amalfi, Ischia Island and Elba Island) in the Tyrrhenian Sea (Western Mediterranean Sea) between 50 and 130 m depth by means of ROV during a cruise carried out in the summer of 2010. Red coral populations showed a maximum patch frequency of 0.20 ± 0.04 SD patches·m^?1 and a density ranging between 28 and 204 colonies·m^?2, with a fairly continuous bathymetric distribution. The highest red coral densities in the investigated areas were found on cliffs and boulders mainly exposed to the east, at the greatest depth, and characterized by medium percentage sediment cover. The study populations contained a high percentage (46% on average) of harvestable colonies (>7 mm basal diameter). Moreover, some colonies with fifth‐order branches were also observed, highlighting the probable older age of some components of these populations. The Ischia population showed the highest colony occupancy, density and size, suggesting a better conservation status than the populations at the other study locations. These results indicate that deep dwelling red coral populations in non‐stressed or less‐harvested areas may diverge from the inverse size‐density relationship previously observed in red coral populations with increasing depth.  相似文献   

Early–Middle Pleistocene environmental changes and human evolution in the Italian peninsula     

Giorgio Manzi  Donatella Magri  Maria Rita Palombo 《Quaternary Science Reviews》2011,30(11-12):1420-1438

This paper is aimed to elucidate the ecological scenario in Italy in the Early to Middle Pleistocene, when species of the genus Homo are known to spread across Europe in two distinct waves: earlier than 1.2 Ma and at about 600 ka, respectively. This topic represents both (1) a fundamental aspect for a better understanding of the factors that allowed humans to colonize the middle latitudes of Eurasia, and (2) a reasonable frontier for current Quaternary palaeobiology, thanks to increasing knowledge of regional and local patterns. As for Italy, a combination of palaeobotanical and palaeontological data sets shows on the one hand a general complexity in both space and time, and on the other hand changes of considerable importance within and among the biological communities. These changes had a major importance during the worldwide change in the Earth climatic system known as “Middle Pleistocene Revolution”, which according to our data culminates with crucial effects of the extreme conditions of MIS 16. Subsequently, during great part of the Middle Pleistocene, the peculiar features of the Italian territory may have favoured isolation and a local persistence of plant populations and possibly mammal taxa, humans included, as for instance suggested by the corrected chronology of the Ceprano calvarium.  相似文献   

Mission-constrained design drivers and technical solutions for the MAGIA satellite     

Giorgio Perrotta  M. Stipa  D. Silvi  S. Coltellacci  G. Curti  G. Colonna  T. Formica  V. Casali  T. Fossati  F. Di Matteo  M. Zelli  M. Rinaldi  L. Ansalone  A. Di Salvo 《Experimental Astronomy》2011,32(1):63-82

The Mission MAGIA (Missione Altimetrica Geofisica GeochImica lunAre) was proposed in the framework of the ??Bando per Piccole Missioni?? of ASI (Italian Space Agency) in 2007. The mission was selected for a phase A study by ASI on February 7th 2008. The tight budget allocation, combined with quite ambitious scientific objectives, set challenging requirements for the satellite design. The paper gives a fast overview of the payloads complement and of the mission-constrained design drivers, including cost minimization, risk reduction, and AIT flexibility. The spacecraft architecture is then outlined, along with an overview of the key subsystems and trade-offs. Some details are given of a Moon gravitometric experiment based on a mother?Cdaughter satellite configuration with the daughter being a subsatellite released from the MAGIA satellite and intended to circle the Moon at a very low altitude. Budgets are appended at the end of the paper showing the key study results.  相似文献