Search results for " geochimica"
showing 10 items of 446 documents
THE ARGONAUTICA ORPHICA VERSION FOR THE VOYAGE OF THE ARGONAUTS: A GEO-ANALYSIS
2017
This study traces and analyzes the itinerary followed by Argo and her crew, according to the unknown author of Argonautica Orphica: The voyage of the Argonauts from Iolcos to Colchis and their return following a different path, from Phasis River through central Europe to the Atlantic Ocean and then through the Mediterranean Sea. Conclusions are drawn about whether such a voyage could be possible in the remote antiquity and the “problematic” points of the description are pointed out.
Selenium mobilization during Rain-Soil Interaction at Etna volcano
2010
Humans are attracted by the fertile properties of volcanic soils. Currently around 10% of the world population lives within active volcanic areas. Volcanoes emit enormous amounts of potentially toxic elements, even in the absence of obvious volcanic activity. Selenium is particularly interesting due to it geochemical similarities with sulphur, a major compound in volcanic gasses. Although selenium (Se) is an essential element for humans, ingestion of an excess amount of Se can produce adverse effects. Mt. Etna, the biggest volcano in Europe, is persistently active for the last 200,000 years. It is one of the most intensely monitored volcanoes. In the area, volcanic gasses, rainwater and gro…
Continental degassing of helium in an active tectonic setting (northern Italy): the role of seismicity
2020
AbstractIn order to investigate the variability of helium degassing in continental regions, its release from rocks and emission into the atmosphere, here we studied the degassing of volatiles in a seismically active region of northern Italy (MwMAX = 6) at the Nirano-Regnano mud volcanic system. The emitted gases in the study area are CH4–dominated and it is the carrier for helium (He) transfer through the crust. Carbon and He isotopes unequivocally indicate that crustal-derived fluids dominate these systems. An high-resolution 3-dimensional reconstruction of the gas reservoirs feeding the observed gas emissions at the surface permits to estimate the amount of He stored in the natural reserv…
Steam and gas emission rate from La Soufriere volcano, Guadeloupe (Lesser Antilles): implications for the magmatic and hydrothermal fluid supply duri…
2014
Since its last magmatic eruption in 1530 AD, La Soufrière andesitic volcano in Guadeloupe has displayed intense hydrothermal activity and six phreatic eruptive crises. Here we report on the first direct quantification of gas plume emissions from its summit vents,which gradually intensified during the past 20 years. Gas fluxes were determined in March 2006 and March 2012 by measuring the horizontal and vertical distributions of volcanic gas concentrations in the air-diluted plume and scaling to the speed of plume transport. Fluxes in 2006 combine realtime measurements of volcanic H2S concentrations and plume parameters with the composition of the hot (108.5 °C) fumarolic fluid at exit. Fluxe…
Mercury Emissions Associated with Volcanoes and Geothermal Sources
2009
There is some debate at present regarding the quantity of mercury naturally released by volcanoes and its relative significance to the natural Hg budget. In order to better understand the role of volcanoes in the global mercury budget a number of field campaigns were carried out to evaluate the Hg/S ratios in volcanic gases around the world. Measurements have been made of emissions of Masaya (Nicaragua), Etna and Vulcano (Italy), Tatun (Taiwan), Taal and Makiling (Philippines) and Kilauea (Hawaii, USA). Emissions from open vents, fumaroles, hot springs, bubbling mud pools and altered ground were investigated at these sites and concentrations of mercury elevated above background levels were …
Changes in SO2 flux degassing regime prior to the 2014 Stromboli eruption
2015
Volcanic eruptions are often accompanied by release of huge amounts of magmatic SO2. Capturing sizeable precursory SO2 flux variations prior to eruption has revealed far more challenging, instead, in spite of the recent progresses in instrumental gas monitoring. Here, we report on the SO2 fluxes variations we detected at Stromboli volcano prior to the effusive eruption started on the 6th August 2014. The SO2 fluxes were regularly quantified at high-rate (0.5 Hz) using two fully autonomous permanent SO2 camera devices installed - within the framework the ERC-FP7 project "Bridge"- at two sites located at 0.5 km (Roccette) and 1.75 km (Sciara del Fuoco rim) distance from the crater terrace. Th…
High temporal and spatial resolution UV camera measurements at Stromboli: insights on passive SO2 gas emission, Strombolian eruptions, and puffing.
2011
Stromboli is one of the most active volcanoes on Earth, and one of the few where passive degassing persistently coexists with the (non-passive) release of over-pressurized gas pockets during both explosions and gas puffing activity. These transient gas bursting-puffing phenomena are difficult to study by conventional spectroscopic scanning techniques (e.g., DOAS), since these have far too low temporal resolution. Here, we take advantage of the high spatial and time resolution (0.6-1 Hz) of the recently developed UV camera technique to obtain a simultaneous characterisation of all the different forms of SO2 release at Stromboli (including passive degassing, Strombolian eruptions and puffing)…
Shallow submarine gas manifestations in the Aegean Sea: preliminary catalogue and geochemical characterization
2017
The Aegean area, like other regions of intense geodynamic activity, is characterised by extensive geogenic degassing. Gas manifestations widespread on land are also very frequent underwater. The present study aims at producing a first catalogue of these manifestations together with the geochemical characterization of the emitted gases. Sixty-one samples at 21 different sites have been collected by diving up to 15 m depth, mainly along the south Aegean active volcanic arc (SAAVA). The sites displayed very different gas fluxes. Most of them showed a very sluggish gas bubbling while a few had spatially large and strong bubbling. The most intense manifestation has been found at Kos Island along…
Source and Nature of Inhaled Atmospheric Dust from Trace Element Analyses of Human Bronchial Fluids
2011
International audience; Rapid volcanic eruptions quickly ejecting large amounts of dust provoke the accumulation of heavy metals in people living in surrounding areas. Analyses of bronchoalveolar lavage samples (BAL) collected from people exposed to the paroxysmal 2001 Etna eruption revealed a strong enrichment of many toxic heavy metals. Comparing the BAL to the dust composition of southeastern Sicily, we found that only V, Cr, Mn, Fe, Co, and U enrichment could be related to the volcanic event, whereas Ni, Cu, Cd, and Pb contents come from the dissolution of particles of anthropogenic origin. Furthermore, the nature of these inhaled anthropogenic particles was revealed by anomalous La and…
Duvalo “Volcano” (North Macedonia): A Purely Tectonic‐Related CO 2 Degassing System
2022
Duvalo “volcano” is a site of anomalous geogenic degassing close to Ohrid (North Macedonia) not related to volcanic activity, despite its name. CO2 flux measurements made with the accumulation chamber (321 sites over ∼50,000 m2) showed fluxes up to nearly 60,000 g m-2 d-1, sustaining a total output of ∼67 t d-1. Soil gas samples were taken at 50 cm depth from sites with high CO2 fluxes and analyzed for their chemical and isotope composition. The gas is mainly composed by CO2 (> 90%) with significant concentrations of H2S (up to 0.55 %) and CH4 (up to 0.32 %). The isotope compositions of He (R/RA 0.10) and of CO2 (δ13C ∼0‰) exclude significant mantle contribution, while δ13C-CH4 (∼ -35‰) …