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|Authors: ||Liotta, M.*|
|Title: ||Isotope geochemistry in volcanic gases, new perspectives from Infrared Spectrometry.|
|Issue Date: ||7-Sep-2007|
|Abstract: ||Volcanic gases, being the most mobile phase of magmas, are worldwide monitored for geochemical surveillance. Together with chemical analyses, stable isotopic studies may be useful in understanding the origin of the fluids emerging in a volcanic system, providing new insights on their subsurface history and geochemical reactions. Isotopic composition of volcanic gases depends on various processes (physical and chemical fractionation, mixing of different end-members, etc.) many of which are strongly influenced by the approaching of paroxysmal activity.
The most used isotopic ratios to detect the variable contribution of the magmatic component in volcanic gases are 13C of carbon dioxide and D and 18O of water vapor. Nevertheless, others isotope ratios have been related to volcanic activity (34S, 15N). Until now sampling frequency has been at most limited to monthly collection, but ideally continuous monitoring, impossible with routine methods, would be preferable.
Isotopic ratios of many compounds have been also used to estimate the temperatures of magmatic/hydrothermal systems in their gaseous or vapor phase, assuming that exchange reactions reached isotopic equilibrium. Examples of such applications are 13C in carbon dioxide and methane and D in H2 and H2O.
In recent times remote techniques have been applied for the study of chemical composition of volcanic gases because in situ sampling is often impractical or hazardous. New remote sensing technique, allowing isotopic analysis of volcanic gases, would be especially useful at volcanoes with open conduit activity, where almost all volcanic gases escape to the atmosphere through the summit craters and direct sampling is very difficult.
Infrared Spectrometry could allow both continuous monitoring and remote sensing of isotopic composition of volcanic gases.|
|Appears in Collections:||Conference materials|
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