Abstract

AGUSTO, Mariano R.; CASELLI, Alberto T.  and  DOS SANTOS AFONSO, María. Framboidal pyrite in fumaroles on Deception Island (Antarctica): Genetic implications. Rev. Asoc. Geol. Argent. [online]. 2004, vol.59, n.1, pp.152-157. ISSN 0004-4822.

Pyrite framboids have been recognized in fumaroles on Deception Island, Antarctica. The sulphide was deposited around reworked pyroclastic tephra (lapilli). The formation process starts as a reaction between glass and hydrogen sulphide, giving rise to nucleation and growth of iron monosulfide microcrystals. The microcrystals then convert to greigite, and form aggregates of uniformly sized microcrystals (development of framboids). Finally, greigite is replaced by pyrite. In this study pyrite was observed forming at 100ºCin less than one hour.

Keywords : Pyrite; Framboids; Fumarole; Deception Island; Antarctica.

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