Search results for "Geogenic"
showing 9 items of 9 documents
Selenium mobilization in soils due to volcanic derived acid rain: An example from Mt Etna volcano, Sicily
2011
International audience; The significant amounts of selenium (Se) emitted by volcanoes may have important impact on human health due to the narrow range between nutrition requirement and toxic effects for living organisms upon Se exposure. Although soils play a key role in determining the level in food and water and thereby human health, little is known about the behaviour of Se in volcanic soils. In this work we evaluated the Se release during rainwater–soil interaction under controlled conditions using soils collected on the flanks of Etna volcano and synthetic rain. Selenium concentrations in soil leachate solutions displayed a spatial distribution, which cannot be explained by plume depo…
Geogenic carbon transport through karst hydrosystems of Greece
2022
The Earth C-cycle is complex, where endogenic and exogenic sources are interconnected, operating in a multiple spatial and temporal scale (Lee et al., 2019). Non-volcanic CO2 degassing from active tectonic structures is one of the less defined components of this cycle (Frondini et al, 2019). Carbon mass-balance (Chiodini et al., 2000) is a useful tool to quantify the geogenic carbon output from regional karst hydrosystems. This approach has been demonstrated for central Italy and may be valid also for Greece, due to the similar geodynamic settings. Deep degassing in Greece has been ascertained mainly at hydrothermal and volcanic areas, but the impact of geogenic CO2 released by active tecto…
Estimation of the geogenic carbon degassing of Greece
2019
Abstract Greece belongs to the most geodynamically active regions of the world and as such it has to be considered an area of intense geogenic degassing. Here we review all the papers already published in the scientific literature on both the geochemistry of gas manifestations and the CO2 and CH4 release, in an attempt to obtain the first nationwide inventory of the natural output of these carbon gases in Greece. The best studied and most exhaling area is the South Aegean Active Volcanic Arc (SAAVA), which releases more than 1.3 × 105 tons of CO2 per year. Continental Greece, on the contrary, is much less studied but may release CO2 in the same order of magnitude in its eastern-central and …
Geogenic element behaviour in soil-rainwater interaction at Mt Etna, Sicily: preliminary results
2008
Active volcanoes emit considerable amounts of contaminants such as As, Se and V. Previous studies have shown that the volcanic activity at Mt Etna (Sicily) has a strong influence on local rainwater compositions. However to date, the behaviour of trace elements in the soils around Mt Etna is poorly understood. 4-hr batch experiments have been performed with 1:5 soil solutions of air-dried soil (fraction <2 mm) and synthetic (acid) rainwater (using either deionized water with a pH of ~6 or a ~500 ppm of sulphuric acid solution with a pH of ~2). In general trace element concentrations are more enriched in soil solutions with low pH (e.g. enrichment factor (EF) acid compared to neutral soil sol…
Shallow Sea Gas Manifestations in the Aegean Sea (Greece) as Natural Analogs to Study Ocean Acidification: First Catalog and Geochemical Characteriza…
2022
The concepts of CO2 emission, global warming, climate change, and their environmental impacts are of utmost importance for the understanding and protection of the ecosystems. Among the natural sources of gases into the atmosphere, the contribution of geogenic sources plays a crucial role. However, while subaerial emissions are widely studied, submarine outgassing is not yet well understood. In this study, we review and catalog 122 literature and unpublished data of submarine emissions distributed in ten coastal areas of the Aegean Sea. This catalog includes descriptions of the degassing vents through in situ observations, their chemical and isotopic compositions, and flux estimations. Tempe…
Origin of the geogenic gases and preliminary estimation of the carbon release of Greece
2019
Volatiles are transported from the deep crust or mantle to the surface in geodynamically active areas where seismic, volcanic and geothermal activity is present; the circulation of hydrothermal fluids in the crust is enhanced. In such areas, faults may act as preferential pathways for advective gas-carrying fluid transport. Towards the surface, pressure decrease allows the gases to escape from the fluids into soil gas and eventually into the atmosphere (King, 1986). The migration of carbon-bearing crustal and mantle fluids contributes to Earth’s carbon cycle (Berner & Kothavala 2001). However, till now, the mechanisms, magnitudes and time variations of carbon transfer from depth to the …
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‰) …
Geogenic degassing from active tectonic areas of the Balkan Peninsula
2021
During the last decades, great interest of the scientific community has been addressed to the estimation of geogenic Carbon degassing from tectonically active areas (Tamburello et al., 2018). Due to its high solubility in water, CO2 can be dissolved, transported and released to the atmosphere by groundwater. The quantity released by such process is probably of the same order of magnitude as that directly emitted from active volcanoes. The quantification of this contribution has a substantial implication for the modelling of the global atmospheric carbon cycle. The Balkan peninsula, one of the geodynamically most active regions in Europe, is characterized by intense geogenic degassing. Until…
Gas geochemistry and CO2 output estimation at the island of Milos, Greece
2018
Abstract Twenty gas samples have been collected from the natural gas manifestations of Milos Island, the majority of which is found underwater along its coast. Furthermore, three anomalous degassing fumarolic areas (Kalamos, Paleochori and Adamas) have been recognized on-land. Almost all the gases are CO2-dominated with CO2 ranging from 88 to 99% vol for the samples taken underwater, while the on-land manifestations show a wider range (15–98%) due to air contamination. Methane reaches up to 1.0% vol, H2 up to 3.2% vol and H2S up to 3.5% vol indicating a hydrothermal origin of the gases. The isotope composition of He points out to mantle contributions up to 45%, while the C-isotope compositi…