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Mineralogical and chemical evolution of ochreous stream sediments from the Libiola Fe-Cu-sulphides mine (Eastern Liguria, Italy).
No full textMineralogical and chemical evolution of ochreous precipitates from the Libiola Fe-Cu-sulphides Mine (Eastern Liguria, Italy).
No full textGeogenic CO2 flux calculations from the Late Pleistocene Tivoli travertines (Acque Albule Basin, Tivoli, Central Italy)
No full textThe Lapis Tiburtinus travertine of the Acque Albule Basin (Tivoli, Central Italy) is a well-known travertine deposit composed by 10 units separated by unconformity surfaces. This travertine deposition is related to CO2 degassing of thermal waters circulating in deep carbonate-sulphate reservoirs. Since for each mole of calcite precipitated by groundwater, one mole of CO2 is degassing to the atmosphere, the volumes of travertine deposits can be used as an indirect proxy of the amount of CO2 degassed during travertine deposition. In the present work the volumes of the different travertine units and the cumulative amount of CO2 degassed per depositional unit (FCO2, which range between 1.56×108 mol a-1 to 5.93×108 mol a-1) have been computed. Furthermore, the fluxes of carbon dioxide per unit area (φCO2) were computed and compared to the δ18O curve and pollen data. The computed CO2 fluxes, range between 7.11×105 mol a-1 km-2 and 2.70×106 mol a-1 km-2. These values are minimum estimations of the deep CO2 degassing processes because of dissolution and erosion processes and possible CO2 loss from thermal water before their emergence at springs as well as because only the exposed travertine succession was used as proxy for the entire succession. The comparison of the CO2 flux data with the δ18O curve and pollen data shows that smaller variations in carbon dioxide flux are related to changes in climatic conditions, while greater variations are probably caused by the increase of the deep CO2 degassing process of the Acque Albule hydrothermal system, which is, in turn, relate to the activity of Colli Albani volcanic system
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The Achievements of the RockStar Group (Perugia) on Astrophysical Modelling and Pallasite Geochemistry
No full textIn the present work we summarize the first achievements of the RockStar Group of the Department of Physics and Geology (at the University of Perugia, Italy), which is made of a strict collaboration between Physicists and Geologists on astrophysical and planetological studies. The RockStar Group acts on two research lines: (i) astrophysical modeling and (ii) mineralogical and geochemical studies of meteorites. In the first part of the article we review the recent results concerning the development of theoretical modeling of nucleosynthesis and mixing process in asymptotic giant branch. In the second part we report (1) the catalog of the Meteorite collection of University of Perugia and (2) major and trace elements mapping, performed through EPMA and LA-ICP-MS, of the Mineo pallasite, a unique sample hosted by the collection. The new data constrain the Mineo meteorite among the Main Group Pallasites and support the hypothesis of the “early giant impact” formation
The relevance of biosignatures in siderite-nodules: an example from Quaternary continental deposits (Tiberino basin, Italy)
No full textFluxes of deep CO2 in the volcanic areas of central-southern Italy
No full textBoth the shallow (organic-derived) and deep (mantellic–magmatic–metamorphic) fluxes of CO2 [Flux CO2, mass time^(-1)] and specific fluxes of CO2 [Flux CO2 mass time^(-1) surface^(-1)] dissolving in the shallow groundwaters of the volcanic areas of Amiata, Vulsini-Vico-Sabatini, Albani, Roccamonfina, Vesuvio, Vulture, and Etna were evaluated by partitioning the composed population of total dissolved inorganic carbon in two individual populations and subsequent subtraction of local background population.
The flux of deep CO2 released from the geothermal fields of Piancastagnaio (Amiata), Torre Alfina, Latera, Marta, Bracciano south, Cesano, and Mofete and from the Overall Northern Latium Hydrothermal Reservoir were also evaluated by means of the total surface heat flux and the enthalpy and CO2 molality of the single liquid phase circulating in each geothermal reservoir.
These data suggest that the Flux CO2 released to the atmosphere varies from 9.5 x 10^6 to 3.0 x 10^6 mol x year^(-1) x km^(-2), over the geothermal fields of Bracciano south and Cesano, respectively, and that a total Flux CO2 of 3.8 x 10^8 mol x year^(-1) is cumulatively released from the geothermal fields of Torre Alfina, Latera and Cesano extending over an area of only 66 km^2. In addition, a flux of about 2.2 x 10^11 to 3.8 x 10^11 mol x year^(-1) of gaseous CO2 entering the atmosphere is obtained for the entire anomalous area of central Italy, extending from the Tyrrhenian coastline to the Apennine chain (45,000 km^2). Thus terrestrial CO2 emission in central-southern Italy appears to be a significant carbon sourc
The relevance of biosignatures in siderite-nodules: an example from quaternary continental deposits (Tiberino Basin, Italy)
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