首页 | 本学科首页   官方微博 | 高级检索  
     


Volcanic degassing at Somma–Vesuvio (Italy) inferred by chemical and isotopic signatures of groundwater
Affiliation:1. CVARG — Centre of Volcanology and Geological Risks Assessment;2. CIVISA — Centre for Information and Seismovolcanic Surveillance, Azores Department of Geosciences, University of the Azores Apartado, 1422 9501-801 Ponta Delgada, Portugal;1. U.S. Geological Survey, Alaska Volcano Observatory, 4230 University Dr., Anchorage, AK 99508, United States;2. U.S. Geological Survey, MS 910, 345 Middlefield Rd., Menlo Park, CA 94025, United States;3. Placer Hall, 6000 J Street, Sacramento, CA 95819-6129, United States;4. U.S. Geological Survey, Cascades Volcano Observatory, 1300 SE Cardinal Court, S100, Vancouver, WA 98683, United States;1. Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Palermo, Via Ugo La Malfa 153, 90146 Palermo, Italy;2. Istituto Nazionale di Geofisica e Vulcanologia - Osservatorio Etneo, Piazza Roma 2, 95123 Catania, Italy
Abstract:A geochemical model is proposed for water evolution at Somma–Vesuvio, based on the chemical and isotopic composition of groundwaters, submarine gas emission and chemical composition of the dissolved gases. The active degassing processes, present in the highest part of the volcano edifice, strongly influence the groundwater evolution. The geological–volcanological setting of the volcano forces the waters infiltrating at Somma–Vesuvio caldera, enriched in volcanic gases, to flow towards the southern sector to an area of high pCO2 groundwaters. Reaction path modelling applied to this conceptual model, involving gas–water–rock interaction, highlights an intense degassing process in the aquifer controlling the chemical and isotopic composition of dissolved gases, total dissolved inorganic C (TDIC) and submarine gas emission. Mapping of TDIC shows a unique area of high values situated SSE of Vesuvio volcano with an average TDIC value of 0.039 mol/L, i.e., one order of magnitude higher than groundwaters from other sectors of the volcano. On the basis of TDIC values, the amount of CO2 transported by Vesuvio groundwaters was estimated at about 150 t/d. This estimate does not take into account the fraction of gas loss by degassing, however, it represents a relevant part of the CO2 emitted in this quiescent period by the Vesuvio volcanic system, being of the same order of magnitude as the CO2 diffusely degassed from the crater area.
Keywords:
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号