Search results for "LCA"

A high-resolution record of the last deglaciation in the Sicily Channel based on foraminifera and calcareous nannofossil quantitative distribution

2003

Abstract Relative abundance fluctuations in planktic foraminiferal and calcareous nannofossil assemblages are reported on the basis of a high-resolution study of ODP Leg 160 Hole 963D, drilled in the Sicily Strait, near Capo Rossello (southern Sicily). With its 8 m of undisturbed sediments, the core covers the interval from 1.5 to 23 kyr, allowing a 50–100-yr sampling resolution. All the short warm and cold events and sub-events recorded in this time interval in the GRIP Greenland ice core and at several Mediterranean sites were recognized. On this basis, a total number of nine ecozones based on planktic foraminifera and seven ecozones based on calcareous nannofossils were identified. A sho…

Discrimination of Lithogenic and Anthropogenic Metals in Calcareous Agricultural Soils: A Case Study of the Lower Vinalopó Region (SE Spain)

2008

Analysis of heavy metal concentrations in soils and their sources is required to identify agricultural areas affected by contamination on a regional level, according to the European Thematic Strategy for Soil Protection. Pseudo-total and EDTA-extractable concentrations of nine elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in eighteen agricultural soils with vegetable crops in the Lower Vinalopo region (southeast Spain) were determined. The main aim was to assess the present state of the agricultural soils in relation to contamination processes by heavy metals for a representative area of the Mediterranean region under semiarid conditions. The pseudo-total concentrations for heavy metals …

Surface expression of eastern Mediterranean slab dynamics: Neogene topographic and structural evolution of the southwest margin of the Central Anatol…

2012

The southwest margin of the Central Anatolian Plateau has experienced multiple phases of topographic growth, including the formation of localized highs prior to the Late Miocene that were later affected by wholesale uplift of the plateau margin. Our new biostratigraphic data limit the age of uplifted marine sediments at the southwest plateau margin at 1.5 km elevation to <7.17 Ma, and regional lithostratigraphic correlations imply that the age is <6.7 Ma. Single-grain CA-TIMS U-Pb zircon analyses from a reworked ash within the marine sediments yield dates as young as 10.6 Ma, indicating a maximum age that is consistent with the biostratigraphy. Our structural measurements within the uplifte…

Degassing vs. eruptive styles at Mt. Etna volcano (Sicily, Italy). Part I: Volatile stocking, gas fluxing, and the shift from low-energy to highly ex…

2018

International audience; Basaltic magmas can transport and release large amounts of volatiles into the atmosphere, especially in subduction zones, where slab-derived fluids enrich the mantle wedge. Depending on magma volatile content, basaltic volcanoes thus display a wide spectrum of eruptive styles, from common Strombolian-type activity to Plinian events. Mt. Etna, in Sicily, is a typical basaltic volcano where the volatile control on such a variable activity can be investigated. Based on a melt inclusion study in products from Strombolian or lava-fountain activity to Plinian eruptions, here we show that for the same initial volatile content, different eruptive styles reflect variable dega…

Volatile contents of mafic-to-intermediate magmas at San Cristóbal volcano in Nicaragua

2017

San Cristóbal volcano in northwest Nicaragua is one of the most active basaltic–andesitic stratovolcanoes of the Central American Volcanic Arc (CAVA). Here we provide novel constraints on the volcano's magmatic plumbing system, by presenting the first direct measurements of major volatile contents in mafic-to-intermediate glass inclusions from Holocene and historic-present volcanic activity. Olivine-hosted (forsterite [Fo] &lt; 80; Fo&lt; 80) glass inclusions from Holocene tephra layers contain moderate amounts of H2O (0.1–3.3 wt%) and S and Cl up to 2500 μg/g, and define the mafic (basaltic) endmember component. Historic-present scoriae and tephra layers exhibit more-evolved olivines (Fo69…

Hyblean-like lithospheric components in the present-day Mount Etna volcanic activity: constraints from 2001-2006 melt inclusions

2009

Oil-degrading bacteria from a membrane bioreactor (MBR) system for treatment of saline oily waste: isolation, identification and characterization of …

2015

This study was focused on the microbial community characterization during operation of a Membrane Bioreactor System, used for the treatment of saline oily wastes, originated from marine transportation. A collection of forty-two (42) strains was obtained during microbiological screening and the bacterial diversity analyzed by amplification and 16S rRNA sequencing. Taxonomic analysis has shown a high level of identity with recognized sequences for a total of seven (7) distinct bacterial genera (Alcanivorax, Erythrobacter, Marinobacter, Microbacterium, Muricauda, Rhodococcus and Rheinheimera). The biotechnological potential of all isolates was identified by the estimate of two key factors, suc…

Il Mercurio nel suolo e in ambiente terrestre

2015

Le interazioni del Hg con l'ambiente costituiscono il ciclo geochimico di questo elemento che si esplica per mezzo di complessi processi fisico-chimici differenti per ciascun comparto geochimico. Si stima che circa i due terzi del mercurio presente in ambiente sia stato prodotto durante il ventesimo secolo, e che il carico di mercurio immesso attualmente sia aumentato di circa 3 volte rispetto agli inizi del 1900 (Mason et al.. 1994). Il comparto ambientale certamente più coinvolto dalle emissioni di mercurio è quello atmosferico, da cui poi l’elemento si diffonde anche negli altri comparti, suolo e sedimenti compresi (Filzgerald &amp; Clarkson, 1991). L’Atmosfera costituisce un importante …

Mercury fluxes from volcanic and geothermal sources: an update

2014

We review the state of knowledge on global volcanogenic Hg emissions to the atmosphere and present new data from seven active volcanoes (Poás, Rincón de la Vieja, Turrialba, Aso, Mutnovsky, Gorely and Etna) and two geothermal fields (Las Pailas and Las Hornillas). The variability of Hg contents (c. 4–125 ng m−3) measured in gaseous emissions reflects the dynamic nature of volcanic plumes, where the abundances of volatiles are determined by the physical nature of degassing and variable air dilution. Based on our dataset and previous work, we propose that an average Hg/SO2 plume mass ratio of c. 7.8×10−6 (±1.5×10−6; 1 SE, n=13) is best representative of open-conduit quiescent degassing. Takin…

Measurements of Hg0 (and H2S) at the Solfatara Crater (Southern Italy): Estimating the atmospheric distribution with a real-time approach

2015

Volcanic and geothermal areas are important emitters of natural gas compounds into the atmosphere, which can be of concern when discharging close to densely, populated sites. Mercury has a strong environmental impact, its organic and inorganic complexes being toxic. The dominant form of Hg in the atmosphere is gaseous elemental mercury (GEM), which has high volatility and residence time of 1-2 years. Volcanic degassing accounts for a significant part of the natural mercury emissions. No mercury limits or target values in ambient air are present in the EU legislations, whereas US-EPA and ATSDR impose 300 and 200 ng/m3, respectively, as a limit for chronic exposure. WHO has proposed the annua…