Abstract

CASELLI, A.T.  and  AGUSTO, M.R.. Recent hydrovolcanic deposits with evidence of magmatic immiscibility on Deception Island, Antarctica. Rev. Asoc. Geol. Argent. [online]. 2004, vol.59, n.3, pp.495-500. ISSN 0004-4822.

Outcrops of hydro-volcanic deposits on Deception Island are stratigraphically re-classified. The sequence was assigned to a pre-caldera phase, but it has very different compositional and consolidation characteristics, enabling it to be differentiated and redefined as a new unit. In this paper, it is stratigraphically relocated as a historical eruption, on the basis of its compositional similarity to ash-falls in Bransfield Basin. The studied deposits are bimodal (basaltic/rhyolitic) implying a relationship with magma immiscibility. The occurrence of more acidic periods would allow relatively more explosive vents with greater particle dispersion to take place.

Keywords : Historical eruptions; Hydrovolcanism; Deception Island; Antarctica.

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