Please use this identifier to cite or link to this item:
http://hdl.handle.net/2122/5106
Authors: | Corrao, M.* Bartolotta, V.* Inguaggiato, S.* Nuccio, P.M.* |
Title: | Helium and Carbon isotopic characterization of the dissolved gases in Mt. Etna groundwater (Italy). | Issue Date: | 14-Sep-2009 | Keywords: | Helium Isotope Dissolved gases Etna |
Subject Classification: | 04. Solid Earth::04.08. Volcanology::04.08.01. Gases 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring 05. General::05.02. Data dissemination::05.02.01. Geochemical data |
Abstract: | We report the chemistry and He and C isotopic composition of dissolved gases in groundwaters of Mt. Etna for 17 sampling sites (wells, springs, artificial drainage) for the period February 2006-January 2007. A conceptual model on degassing and gas-water interaction processes, including the 2006 eruptive period of Mt. Etna is proposed. For all sites, CO2 is the most abundant dissolved gas phase, reaching concentrations up to 700 cc/l(w). Helium varies from 3,83x10-5 to 1.24x10-3 cc/l. The 13CCO2 (recalculated from 13CTDC) varies from -13.4 to -2.3 ‰ vs. V-PDB; the lower values result from mixing with organic carbon, while the higher values are identical to the C isotopic composition for Mediterranean volcanism. The 3He/4He ratios (R/RA with RA the 3He/4He ratio for air of 1.39x10-6) for dissolved gases in Etna groundwater ranges from 1.3 to 6.4 RA, depending on mixing proportions between air (1RA) and the Etnaean magmatic end-member (3He/4He = 7.1 RA). The groundwater at one site shows a clear trend towards mixing with a different magmatic end-member (3He/4He = 5.3 RA, western periphery), probably the result of the contribution of a more degassed magma. This is confirmed by the fact that this site does not show any temporal variations, as the others do during the 2006 eruption. The values for log(Ct/3He) are generally above 11, and can be as high as >13, clearly higher than log(Ct/3He) values for magmatic systems (~9.6). This is not surprising for dissolved gases, as CO2 is ~30 times more soluble in water than He wish is outgassed more easily. |
Appears in Collections: | Conference materials |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
corrao_abstract_icgg10.doc | Poster | 27 kB | Microsoft Word | View/Open |
Page view(s)
139
checked on Apr 20, 2024
Download(s) 50
86
checked on Apr 20, 2024