Geochemical characterization of the volcanic gases at Deception Island (South Shetland Islands, Antarctica)

• Main Authors: Caselli, A.T., Dos Santos Afonso, M., Risso, C., García, A., Ortiz, R.
• Format: Journal/Newspaper
• Language: unknown
• Subjects: Antarctica; Deception Island; Fumarole; Geochemistry; Monitoring; hydrothermal activity; volcanic gas; Antarc*; South Shetland Islands
• Online Access: https://hdl.handle.net/20.500.12110/paper_00044822_v57_n1_p69_Caselli

Intense and periodical monitoring of fumaroles discharges of the Deception Island at Antarctica was made from 1993 until 1998, for every austral summer survey. The geochemical changes suggested that the fumaroles, at the anomaly area of Fumaroles Bay, have a strong hydrothermal character. Two different hydrological processes, with different magnitude, were used to explain the observed chemical variations. The gas fluid chemical compositions also have a correlation with the seismic activity. Some of the gas components, such as H2, CO2, CH4, C2H6, etc, increase their gas concentration while the seismic activity is increasing. The results obtained with a high number of seismic events show a good correlation between the H2S and CO2 composition of fluids. In opposition, the results obtained during a low seismic events season show a high dispersion on the data composition. The linear correlation should be assigned to a predominant magmatic effect while the dispersion should be related to a predominant hydrological effect. In a first approximation the linear relation of H2S with CO2 and H2O with H2S should be used as an indicator parameter of the increasing magmatic flux. These geochemical characteristics of the gas fluids should be used for monitoring and testing the eruptive activity.