0000000000495269
AUTHOR
D'alessandro W.
The CO2 output from the Sperchios Basin area (central Greece): the role of hidden degassing from streams
The Sperchios Basin is an actively spreading rift area with deeply rooted extensional faults and also a site of quaternary volcanic activity. Such geologic conditions favoured the formation of many hydrothermal systems, whose surface expressions are among the biggest thermal springs of the whole Greece. Degassing of deeply derived geogenic CO2 is highlighted by strong bubbling within the main pools of the springs. Flux measurements were made in the Thermopyles spring with the floating chamber method and results showed that bubbling gases in the spring release about 1 ton/day of CO2. The outgoing stream has a flow of more than 250 l/s of water rich in CO2 (about 16 mmol/l). Although no bubbl…
Potentially harmfull elements accumulation in fumarolic alteration products at three hydrothermal systems of Greece
Samples of efflorescences and encrustations of hydrothermal origin have been collected at three fumarolic areas in Greece. The three sites are Sousaki, Thiafi (Methana) and Kokkino Nero (Kos) and all belong to the South Aegean Active Volcanic Arc. Samples were analysed for their mineralogical (XRD and SEM-EDS) and chemical composition. Solutions obtained from both mineralization with HNO3 and leaching with distilled water, were analysed for major (ICP-OES), minor and trace metals (ICP-MS) and for sulfate contents (IC). Results show that their composition is mainly controlled by the petrological composition of the substrate (ultramafic rocks at Sousaki, felsic volcanic rocks at Methana and l…
Monitoraggio Geochimico del Fiume Oreto: primi risultati
Investigating diffuse CO2 degassing in tectonically active areas by groundwater
Origin of the geogenic gases and preliminary estimation of the carbon release of Greece
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 …
Geochemical characterization of groundwater quality in Hellenic karst systems
Karst aquifers are considered to be one of the most important aquifer types, as they constitute the main drinking water resource for the majority of the global population (Ford et al., 2007). They are generated from the dissolution of carbonate rocks (e.g. limestone, dolomite, marble etc.), a phenomenon commonly known as “karstification”. This process is mainly caused by the acidity of water enriched in dissolved CO2, with the concentration of the latter being dependent on both the temperature and the CO2 partial pressure of the atmosphere in contact with the water (Bakalowicz, 2005). Carbonate rocks cover about 35% of the land surface of Greece and are mainly located in the western, centra…
Gas hazard related to CO2 degassing at Loutra Ypatis, Greece
Earthquakes and volcanic eruptions represent a hazard. However, the impact of gases released in geodynamically active areas should not be underestimated. It is commonly known that geogenic sources release great amounts of gases, which, apart from having an important influence on the global climate, can also have a strong impact on human health causing both acute and chronic effects. In particular, CO2 and sulphur gases (mainly H2S and SO2) are the main compounds responsible for acute mortality due to their asphyxiating and/or toxic properties. One of the most known and also worst episodes occurred, took place on the 21th of August 1986 at Lake Nyos, Cameroon, when about 1700 people were kil…