Abstract

CASELLI, Alberto T.; DOS SANTOS AFONSO, María  and  AGUSTO, Mariano R.. The Fumarolic Gases at Deception Island (South Shetland Islands, Antarctica). Chemical Changes and Deposits Related to Seismic Crisis of 1999. Rev. Asoc. Geol. Argent. [online]. 2004, vol.59, n.2, pp.291-302. ISSN 0004-4822.

The compositional changes of fumarolic gases and chemical deposits that were generated in the vents of Deception Island fumaroles are studied. These chemical changes came out after the seismic crisis that happened during the summer of 1999. The most important characteristics of these changes are the homogenization of the chemical composition of the gas flow of F2 and F3 fumaroles and the increase of sulfur dioxide content (SO2 was not detected in previous years). Also, as a consequence of the SO2 increase, deposits of elemental sulfur and framboidal pyrite were formed in the fumarole F3 vent. Sodium and magnesium chlorides deposits were produced in the fumaroles F2 and submerged near to the coast due to the increase of HCl in the fumarolic gases. These superficial manifestations could show a new input of magmatic gases associated with possible shallow intrusions. The relative importance of these superficial manifestations is analyzed and the possibility that can be used as volcanic precursor is discussed.

Keywords : Antarctica; Deception Island; Fumarole; Geochemistry; Monitoring.

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